Pregabalin for chronic prostatitis (Review) Aboumarzouk OM, Nelson RL The Cochrane Library
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Pregabalin for chronic prostatitis (Review) Aboumarzouk OM, Nelson RL The Cochrane Library
Pregabalin for chronic prostatitis (Review) Aboumarzouk OM, Nelson RL This is a reprint of a Cochrane review, prepared and maintained by The Cochrane Collaboration and published in The Cochrane Library 2012, Issue 8 http://www.thecochranelibrary.com Pregabalin for chronic prostatitis (Review) Copyright © 2012 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd. TABLE OF CONTENTS HEADER . . . . . . . . . . ABSTRACT . . . . . . . . . PLAIN LANGUAGE SUMMARY . BACKGROUND . . . . . . . OBJECTIVES . . . . . . . . METHODS . . . . . . . . . RESULTS . . . . . . . . . . Figure 1. . . . . . . . . Figure 2. . . . . . . . . Figure 3. . . . . . . . . DISCUSSION . . . . . . . . AUTHORS’ CONCLUSIONS . . ACKNOWLEDGEMENTS . . . REFERENCES . . . . . . . . CHARACTERISTICS OF STUDIES DATA AND ANALYSES . . . . . HISTORY . . . . . . . . . . CONTRIBUTIONS OF AUTHORS DECLARATIONS OF INTEREST . SOURCES OF SUPPORT . . . . INDEX TERMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pregabalin for chronic prostatitis (Review) Copyright © 2012 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1 2 2 3 3 5 6 7 7 8 9 9 10 11 14 14 14 14 14 14 i [Intervention Review] Pregabalin for chronic prostatitis Omar M Aboumarzouk1 , Richard L Nelson2 1 Dept. of Urology, Wales Deanery, Cardiff, UK. 2 Department of General Surgery, Northern General Hospital, Sheffield, UK Contact address: Omar M Aboumarzouk, Dept. of Urology, Wales Deanery, 40 Hollybush Road, Cyncoed, Cardiff, Wales, CF23 6TA, UK. [email protected]. [email protected]. Editorial group: Cochrane Prostatic Diseases and Urologic Cancers Group. Publication status and date: New, published in Issue 8, 2012. Review content assessed as up-to-date: 29 May 2012. Citation: Aboumarzouk OM, Nelson RL. Pregabalin for chronic prostatitis. Cochrane Database of Systematic Reviews 2012, Issue 8. Art. No.: CD009063. DOI: 10.1002/14651858.CD009063.pub2. Copyright © 2012 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd. ABSTRACT Background Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) is a condition that is detrimental to the quality of life of men. Evidence suggests that it may have a neuropathic origin and therefore medications such as pregabalin might have a role in the controlling of symptoms. Objectives The primary objective was to compare pregabalin to other modalities of pain relief to alleviate men’s symptoms of CP/CPPS. The secondary objective was to assess the safety and effectiveness of pregabalin to improve various individual symptoms consistent with CP/CPPS. Search methods We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (1966 to May 2012), EMBASE (1980 to May 2012), CINAHL, clinicaltrials.gov, Google Scholar, and reference lists of articles and abstracts from conference proceedings, without language restriction for pregabalin treatment of Class III prostatitis and CP/CPPS. Selection criteria Randomized controlled trials (RCTs) comparing pregabalin to placebo or other types of analgesics for the management of patients with CP/CPPS were included. Patients with known causes of pain/discomfort were excluded. Data collection and analysis Only one RCT was included. The trial compared pregabalin to placebo for patients who had CP/CPPS. Main results For men who responded clinically (≥ 6-point improvement), there was no difference between the pregabalin (103/218; 47.2%) and placebo (38/106; 35.8%) arms (risk ratio (RR) 1.32; 95% CI 0.99 to 1.76). There was less pain with a higher point improvement in the pregabalin group compared to the placebo group (4.2 points versus 1.7 points, respectively; mean difference (MD) -2.3 points; 95% CI -4.0 to -0.7 points). Though 59% (191/324) of the patients developed side effects, no serious effects were experienced. There were significantly more neurologic side effects in the pregabalin group compared to the placebo group (38.5% (84/218) versus 22.6% (24/106), respectively; Pregabalin for chronic prostatitis (Review) Copyright © 2012 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd. 1 RR 1.7; 95% CI 1.15 to 2.51), and less pain in the pregabalin group than in the placebo group (17.4% (38/218) versus 33.3% (35/106), respectively; RR 0.53; 95% CI 0.36 to 0.78). However, no significant differences were seen between the pregabalin and placebo groups with regards to gastrointestinal disturbances (18.3% (40/218) versus 18.9% (20/106), respectively; RR 0.97; 95% CI 0.60 to 1.58), ocular/visual symptoms (6.9% (15/218) versus 2.8% (3/106), respectively; RR 2.43; 95% CI 0.72 to 8.22), and renal/genitourinary symptoms (5.5% (12/218) versus 1.9% (2/106), respectively; RR 3.03; 95% CI 0.67 to 13.79). Authors’ conclusions There is evidence from one RCT that pregabalin does not improve CP/CPPS symptoms and causes adverse effects in a large percentage of men. However, research is required to assess further whether pregabalin has a role in patients with CP/CPPS for symptom control. PLAIN LANGUAGE SUMMARY The use of pregabalin analgesia for patients with chronic prostatitis/chronic pelvic pain syndrome It has been suggested that chronic prostatitis/chronic pelvic pain syndrome is due to pain caused by the nerves in or around the prostate. Pregabalin is a pain killer that is specific for nerve pain. Therefore we conducted a search of the literature to evaluate the use of pregabalin for this ailment and whether or not it was better than placebo. We concluded that pregabalin was no more effective than placebo and is associated with adverse effects. Though there was no conclusive evidence for the use of pregabalin, further research is recommended. BACKGROUND Description of the condition Prostatitis has been generally defined as inflammation of the prostate; however, this is a misnomer as not all patients with this condition have prostatic inflammation (Weiss 2001). Fifty per cent of men will experience one form of prostatitis during their life (Bartoletti 2007; Weiss 2001), while 3% will have pelvic pain, and 10% painful ejaculation (Bartoletti 2007). Through the National Institutes of Health (NIH) the International Prostatitis Collaborative Network (NIH-IPCN) has classified this clinical entity and redefined it (Bartoletti 2007; Krieger 1999). 1. Class I: acute bacterial prostatitis; 2. Class II: chronic bacterial prostatitis; 3. Class III: chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS): i) Class IIIA: inflammatory; ii) Class IIIB: non inflammatory; 4. Class IV: asymptomatic inflammatory prostatitis. Class I, as its description implies, is caused by an acute bacterial infection, while chronic bacterial prostatitis (Class II) is due to recurrent episodes of bacterial urinary tract infections (UTIs) (Krieger 1999; Reynard 2006; Weiss 2001). Class IV patients are those who have no symptoms, but during prostate biopsy investi- gation prostatic inflammation was found (Krieger 1999). Ten per cent of patients fit into these three classifications (Classes I, II, IV), with the remaining 90% being Classes IIIA or IIIB (Collins 1998; Krieger 1999; Weiss 2001). The incidence of CP/CPPS is about 3.3/1000 persons per year, with a prevalence of 9% to 16% in the general male population, and with an annual cost in 2001 of USD4397 per person (Collins 1998; CPCRN 2004; Nickel 2001; Pontari 2007; Roberts 1998). CP/CPPS is detrimental to the quality of life of patients and accounts for 8% of visits to a urologist and 1% of visits to a general practitioner in the US (Bartoletti 2007; Johansen 2002; Strauss 2010). To be diagnosed with CP/CPPS, patients must have one or more of the following symptoms over a three-month period (Litwin 1999; Magri 2010; McNaughton Collins 2008; Reynard 2006): • localized pain to the perineum, supra pubis, penis, or groin; • pain during ejaculation; • lower urinary tract symptoms (LUTS), such as dysuria (painful urination), frequency, nocturia (night-time urination), urgency, and poor stream flow; • sexual and psychosocial disturbances. These symptoms lead to the formation of a symptom index by which the severity can be scored, where 0 to 9 is mild, 10 to 18 is moderate, and 19 to 31 is severe (’Online Symptom Index’). Pregabalin for chronic prostatitis (Review) Copyright © 2012 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd. 2 Though CP/CPPS is a common condition, little is known about the pathophysiology and etiology. However, numerous hypotheses do exist for both Class III sub classifications (IIIA and IIIB). For example, with Class IIIA the theory is that inflammation is caused by micro-organisms (Weiss 2001) whereas for Class IIIB, it is theorized that urine refluxes (flows backward) into the prostatic ducts leading to inflammation, either due to bladder neck spasms, pelvic floor muscle spasms, or increased tone (Weiss 2001). Moreover, there are other suggestions that perineal microtrauma might be a cause, owing to higher prostate-specific antigen (PSA) in sportsmen, and especially cyclists (Bartoletti 2007). However, the etiology of both classifications remains to be confirmed (CPCRN 2004; Strauss 2010). Though there have not been any recent breakthroughs in understanding the pathophysiology or etiology of CP/CPPS, one study has shown that some lifestyle and dietary factors were significantly higher in patients with CP/CPPS than in healthy individuals (Bartoletti 2007). CP/CPPS was found to be more prevalent in patients who smoke, practice coitus interruptus, have sexual relationships with more than one partner, and consume a high caloric diet - specifically milk, cheese, pasta, rice and cake, with low fruit and vegetable consumption. Description of the intervention Pregabalin, approved by the European Agency for the Evaluation of Medicinal Products (EAEMP) and the US Food and Drug Administration (FDA), is an antiepileptic drug that is also effective for neuropathic pain control (Arnold 2010; Cappuzzo 2009; Dworkin 2010; Jain 2005). Pregabalin is a derivative of the inhibitory neurotransmitter gamma aminobutyric acid (GABA) but does not bind to GABA (Arnold 2010; Cappuzzo 2009; Jain 2005). It selectively binds to alpha2-delta protein subunits of voltage-gated calcium channels in the brain and the superficial dorsal horn of the spinal cord, thus reducing the influx of calcium into synaptic endings. This in turn inhibits the release of excitatory neurotransmitters that stimulate neurons (Dworkin 2005; Jain 2005). Pregabalin is well absorbed, has an oral bioavailability of > 90%, and is excreted by the kidneys with minimal metabolism (Cappuzzo 2009). Its main side effects include dizziness, somnolence, and peripheral edema, although there are also reports of dry mouth, blurred vision, weight gain, ataxia (lack of co-ordinated muscle movement), headache, and nausea (Arnold 2010; Cappuzzo 2009). However, in spite of these, pregabalin has been shown to be effective and well tolerated for the management of neuropathic pain (Arnold 2010). Owing to the highly detrimental impact of CP/CPPS on the quality of life of men, there have been numerous studies, including RCTs and cohort studies, conducted to find a satisfactory method of alleviating symptoms (Gottsch 2010; Johansen 2002; McNaughton Collins 2008; Reynard 2006; Sikiru 2008; Strauss 2010; Weiss 2001). Some studies have found evidence to suggest that CP/CPPS is neuropathic (i.e. pathology of the peripheral nerves) in nature. Pontari found that men with CP/CPPS were five times more likely to have neurologic diseases, such as migraine headaches, vertebral disk disease, or numbness or tingling in their limbs, than men who did not have CP/CPPS (Pontari 2005). In addition, studies have found abnormalities in the autonomic nervous system in patients with CP/CPPS, causing pain sensitization (becoming highly sensitive) (Yang 2003; Yilmaz 2007). Furthermore, nerve-growth factor, a neurotrophin that acts as a mediator in neurogenic inflammation, has been found to have a role in CP/CPPS (Miller 2002). Therefore, a neuropathic analgesic, such as pregabalin, might have a role in alleviating symptoms in patients with CP/CPPS. Why it is important to do this review A thorough review of the literature and a meta-analysis or review of the data is required to evaluate whether or not pregabalin is an effective modality to control the symptoms of CP/CPPS. Furthermore, a review of the safety of pregabalin is also necessary to weigh against its benefits. OBJECTIVES The primary objective was to assess the overall effectiveness of pregabalin compared to other types of pain relief and to improve overall symptoms of CP/CPPS. The secondary objective was to assess the effectiveness of pregabalin to improve LUTS, pain/discomfort, and overall quality of life, in addition to assessing side effects from the drug. METHODS Criteria for considering studies for this review Types of studies How the intervention might work Randomized controlled trials (RCTs) comparing pregabalin to placebo or any other analgesic for CP/CPPS were considered for inclusion. Pregabalin for chronic prostatitis (Review) Copyright © 2012 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd. 3 Types of participants Participants were patients who had CP/CPPS Classes IIIA or IIIB. Patients who had chronic pain due to a known cause were excluded (e.g. infection, catheter in situ, previous surgery or radiation therapy, cancer). Types of interventions Patients receiving pregabalin were compared to those receiving a placebo, an analgesia, or any other method of symptom relief. 11. World Health Organization (WHO) International Clinical Trials Registry Platform (www.who.int/ictrp/en/); 12. www.clinicalstudyresults.org/. The following search strategy was used to identify relevant RCTs: 1. Prostatitis OR Chronic Prostatitis OR Chronic Pelvic Pain Syndrome, 2. Pregabalin, 3. Randomized Control Trials, 4. Men, 5. #1 AND #2, 6. #1 AND #2 AND #3, 7. #1 AND #2 AND #3 AND #4. Types of outcome measures Searching other resources Primary outcomes • Improvement in men’s overall symptoms: judged clinically (an improvement of 6 or more points), measured by the NIHChronic Prostatitis Symptom Index (NIH-CPSI) score, where the range of pain or discomfort = 0 to 21, urinary symptoms = 0 to 10, and quality of life impact = 0 to 12, with a total range of 0 to 43 (Online Symptom Index). A higher score indicates worse discomfort, symptoms, and quality of life. The levels used, based on the final score, are grouped into mild (0 to 9), moderate (10 to 18), and severe (19 to 31). Secondary outcomes • Improvement of LUTS measured by: ◦ sexual health, ◦ work status, ◦ mental health. • Assessing side effects from pregabalin Search methods for identification of studies The references of all identified studies were inspected for more trials. We had also handsearched systematic reviews and clinical practice guidelines. Data collection and analysis Selection of studies Two review authors (OMA and RLN) independently assessed relevant titles and abstracts identified by the literature search against the predefined inclusion criteria. Full-text papers of the titles and abstracts selected were further assessed for inclusion or exclusion. Any problems were resolved by discussion and consensus. Papers of in any language were considered for inclusion. Data extraction and management Two review authors (OMA and RLN) independently extracted data from the included study using a predetermined data extraction form. Any disagreement was resolved by consensus. The authors of the included study were not contacted for clarification of data or additional information as this was not needed. Electronic searches The following electronic databases were searched: 1. the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library); 2. MEDLINE (1966 to 2012); 3. EMBASE (1980 to 2012); 4. ClinicalTrials.gov; 5. Google Scholar; 6. Web of Science; 7. Biosys Previews; 8. LILACS; 9. Health Technology Assessments (HTA); 10. Current Controlled Trials (www.controlled-trials.com/); Assessment of risk of bias in included studies The review authors (OMA and RLN) assessed the risk of bias as described in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011). Factors that were assessed included: 1. sequence generation (i.e. was the allocation sequence adequately generated?); 2. allocation sequence concealment (i.e. was allocation adequately concealed?); 3. blinding (i.e. was knowledge of the allocated intervention adequately prevented during the study?); Pregabalin for chronic prostatitis (Review) Copyright © 2012 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd. 4 4. incomplete outcome data (i.e. were incomplete outcome data adequately addressed?); 5. selective outcome reporting (i.e. are reports of the study free of suggestion of selective outcome reporting?); 6. other potential sources of bias (i.e. was the study apparently free of other problems that could put it at a high risk of bias?). A judgment of ’yes’ indicated low risk of bias; ’no’ indicated high risk of bias, and ’unclear’ indicated unclear or unknown risk of bias. Assessment of heterogeneity Heterogeneity was not assessed as a meta-analysis was not conducted owing to only one included trial. Assessment of reporting biases Reporting biases were not assessed as a meta-analysis was not conducted owing to only one included trial. Data synthesis Measures of treatment effect Review Manager 5 (RevMan 2011) was used to analyze data. Analyses were performed using an intention-to-treat (ITT) principle. If we had performed a meta-analysis, data from individual trials would have been combined when the interventions and controls were similar. Dichotomous data would have been calculated as risk ratios (RR) with 95% confidence intervals (95% CI). A fixedeffect model would have been used. The weighted mean difference (WMD) with 95% CI would have been calculated for continuous outcomes. Unit of analysis issues In addition to simple parallel group designs, variations such as cluster-randomization and cross-over trials were to be analyzed; however, no such trials were included. Dealing with missing data The authors of papers with missing data (studies, outcomes, summary data, individuals, measures of variance, or study level characteristics) were not contacted as no missing data were identified. Patients who withdrew or dropped out of the study were considered as non responders and included into the failure group on an ITT basis. Data synthesis was not performed as a meta-analysis was not conducted owing to only one included trial. Subgroup analysis and investigation of heterogeneity A subgroup analysis was not conducted. Sensitivity analysis A sensitivity analysis was not performed as a meta-analysis was not conducted owing to only one included trial. RESULTS Description of studies See: Characteristics of included studies; Characteristics of excluded studies. See ’Characteristics of included studies’ and ’Characteristics of excluded studies’. Results of the search A flow chart of the article selection process is displayed in Figure 1. The literature search yielded 153 articles, of which 139 articles were excluded. Thirteen articles were excluded after reviewing the full-text paper and only one article was included in this review. Pregabalin for chronic prostatitis (Review) Copyright © 2012 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd. 5 Figure 1. Flow chart of article selection process. Included studies Only one study was found that compared pregabalin to a placebo to improve patients’ symptoms of CP/CPPS (Pontari 2010). Pontari 2010 conducted an RCT over 10 North American tertiary care centres and included 324 patients between the ages of 19 to 78 years. The pregabalin and placebo groups were comparable regarding age of the patients; the pregabalin group had a mean age of 48 years (range 21 to 78 years) while the mean age in the placebo group was 45.2 years (19 to 76 years) (P = 0.09). Also, no difference was found when comparing race, educational level, employment, and annual income (P = 0.17, P = 0.97, P = 0.25, and P = 0.7, respectively). There was also no difference between the two groups regarding ’years since first diagnosis’ (8.7 years versus 9.2 years) and ’years since first symptoms’ (10.3 years versus 9.9 years, respectively; P = 0.63). The study was conducted with patients who had a minimum score of 15 out of 43 on the NIH-CPSI. During the six-week trial, the initial dose of pregabalin was 50 mg three times daily for two weeks. It was then escalated to 100 mg three times daily for a further two weeks, and again to 200 mg three times daily for the final two weeks. Patients who developed side effects were maintained on the pre-escalation dose. See ’Characteristics of included studies’. Excluded studies Eight of the 13 articles were duplicates and so were removed. Three of the studies were not RCTs (Johansen 2002; Pontari 2007; Strauss 2010). One study was on nerve growth factor levels in CP/ CPPS (Watanabe 2011) and the last study was an RCT but on transcutaneous electrical nerve stimulation (TENS) for CP/CPPS rather than pregabalin (Sikiru 2008). See ’Characteristics of excluded studies’. Risk of bias in included studies See ’Figure 2’ and ’Figure 3’. Pregabalin for chronic prostatitis (Review) Copyright © 2012 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd. 6 Figure 2. ’Risk of bias’ graph: review authors’ judgments about each ’Risk of bias’ item presented as percentages across all included studies. Figure 3. ’Risk of bias’ summary: review authors’ judgments about each ’Risk of bias’ item for each included study. Pregabalin for chronic prostatitis (Review) Copyright © 2012 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd. 7 Allocation The sequence generation was adequate in the included study; however, it was not clear how the allocation was concealed (Pontari 2010). Blinding The study was double blind. (improvement: 5.0 points with pregabalin versus 1.6 points with placebo; MD 1.3; 95% CI -0.5 to 3.2). However, both the Global Response Assessment (GRA) and the McGill Pain Questionnaire scores showed that there was more improvement (less pain) in the pregabalin group compared to the placebo group (GRA: 31.2% of patients improved versus 18.9% of patients improved, respectively; RR 1.95; 95% CI 1.11 to 3.43); McGill: 4.2-point improvement versus 1.7-point improvement, respectively; MD -2.3; 95% CI -4.0 to -0.7). Incomplete outcome data There was a total of 11 patients who withdrew from the trial, eight in the pregabalin group and three in the placebo group (P > 0.05). Selective reporting There were no indications of selective reporting in the included study. Other potential sources of bias No other sources of bias were identified. Effects of interventions For the NIH-CPSI, there was no difference in clinical improvement (≥ 6 points) between the pregabalin and placebo groups (47.2% versus 35.8%, respectively; RR 1.32; 95% CI 0.99 to 1.76). However, there were significant differences in the final scores of individual NIH-CP/CPPS domains between the pregabalin and placebo groups compared to baseline scores. With regards to pain there was a 3.2/21 point improvement in the pregabalin group compared to 2.3/21 point improvement in the placebo group (MD -1.0 points; 95% CI -2.00 to -0.04 points), urinary symptoms improved by 1.2/10 points versus 0.7/10 points in the respective groups (MD -0.70 points; 95% CI -1.0 to -0.02 points), and quality of life improvement was 2.0/12 points versus 1.5/12 points (MD -0.70 points; 95% CI -1.20 to -0.10 points). Furthermore, there were varying results with the other assessment tools used. There was no difference between the pregabalin and placebo groups with regard to anxiety and depression assessment (improvement: 2.4 points with pregabalin versus 1.9 points with placebo; MD -0.70; 95% CI -2.00 to 0.07), sexual health assessment (improvement: 0.5 points with pregabalin versus 0.2 points with placebo; MD -0.6; 95% CI -2.1 to 0.9), mental assessment component of the Medical Outcomes Study 12-Item Short Form Health Survey (MOS SF-12) (improvement: 3.2 points with pregabalin versus 1.8 points with placebo; MD 1.4; 95% CI -0.9 to 3.8), and the physical assessment component of the MOS SF-12 Side effects A large number of patients (191/324; 59%) developed at least one side effect related to pregabalin, although they were designated as mild (24.6%) and moderate (24.4%). No-one reported serious side effects. There was no significant difference in the incidence of side effects between the two groups (P = 0.4). In the pregabalin group, 18.3% (40/218) of patients developed gastrointestinal disturbances compared to 18.9% (20/106) in the placebo group (P = 0.91; RR 0.97; 95% CI 0.60 to 1.58), while 6.9% (15/218) of patients developed ocular/visual symptoms compared to 2.8% (3/106) (P = 0.08; RR 2.43; 95% CI 0.72 to 8.22), and 5.5% (12/218) of patients developed renal/genitourinary symptoms compared to 1.9% (2/106) (P = 0.16; RR 3.03; 95% CI 0.67 to 13.79). However there were more neurologic symptoms in the pregabalin group compared to the placebo group (38.5% (84/218) versus 22.6% (24/106), respectively; P = 0.01; RR 1.7; 95% CI 1.15 to 2.51) and there was less pain in the pregabalin group compared to the placebo group (17.4% (38/218) versus 33% (35/106), respectively; P = 0.003; RR 0.53; 95% CI 0.36 to 0.78). There was no mention of specific neurologic symptoms; however, the authors do mention that headaches were the predominant side effect in each group but more significant in the placebo group with 4.6% (10/218) of patients in the pregabalin group and 17% (18/106) of patients in the placebo group (RR 0.27; 95% CI 0.13 to 0.56). No explanation could be found as to why the placebo group had more headaches. DISCUSSION Summary of main results There was no significant evidence that pregabalin was better than placebo in the overall NIH-CP/CPPS score. However, there was significant improvement in the individual NIH-CPSI subscores, Pregabalin for chronic prostatitis (Review) Copyright © 2012 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd. 8 favouring the pregabalin group. No difference was found between the two groups with regard to anxiety and depression scores, sexual health, and mental and physical assessment scores. There was no difference between the pregabalin and placebo groups with regards to adverse events. Although there was significantly less pain in patients who took pregabalin compared to placebo, the presence of increased neurologic adverse events in just six weeks in the pregabalin group questions the extended use of pregabalin over longer periods of time. Similarly to the authors of the RCT, we conclude that pregabalin therapy is not superior to a placebo, though there were some biases detected in the trial methodology. However, our interpretation of the results agreed with their conclusion. Agreements and disagreements with other studies or reviews Though this review could not show that pregabalin, a neuropathic analgesic, was more effective than placebo for overall symptom relief, pregabalin did improve overall pain symptoms, which supports the theory that CP/CPPS is neuropathic in nature as suggested in numerous publications (Miller 2002; Pontari 2005; Yang 2003; Yilmaz 2007). No other systematic review was identified in the literature search. AUTHORS’ CONCLUSIONS Implications for practice Overall completeness and applicability of evidence The included trial addressed the primary and secondary objectives of this review, with relevant participants and interventions. However, a conclusive decision cannot be drawn from one trial. The one included trial did calculate for power, had a less that 10% dropout rate, and was considered a well-conducted, double-blinded, randomized placebo-controlled trial, and therefore their evidence can be taken into consideration. Quality of the evidence The included study was a randomized, double-blind, placebo-controlled trial that included a representative portion of the population of the US. The quality of the study had low risk of bias. Although a conclusive decision cannot be made from only one included paper, there was evidence to suggest that pregabalin does not improve overall CP/CPPS symptoms; however, pregabalin might be of benefit for individual symptoms such as pain, urinary symptoms, and overall quality of life. Pregabalin did cause adverse effects in a large percentage of men. Implications for research Further trials are required to confirm whether or not pregabalin has a role in the management of CP/CPPS. However, trials should measure the benefits against the risk of side effects with taking these medications over long periods of time to avoid the replacement of one group of symptoms with another. Therefore, further double-blind, placebo-controlled, randomized trials are required specifically focused on symptom relief based on etiology, in addition to a prolonged follow-up period. Trials comparing different analgesics to pregabalin, in addition to comparisons with other neuropathic analgesics such as gabapentin and amitriptyline, will add more information and clarify whether neuropathic analgesics have a role in CP/CPPS. Potential biases in the review process The potential risk of this review is that it only included one single trial. This does not reflect the methodology of the review as the literature was meticulously searched for studies by two independent review authors. ACKNOWLEDGEMENTS The Prostatic Diseases and Urologic Cancers Review Group. Pregabalin for chronic prostatitis (Review) Copyright © 2012 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd. 9 REFERENCES References to studies included in this review Pontari 2010 {published data only} Pontari M, Krieger J, Litwin M, White P, Anderson R, McNaughton-Collins M, et al.Pregabalin for the treatment of men with chronic prostatitis/chronic pelvic pain syndrome. Archives of Internal Medicine 2010;170(17): 1586–93. References to studies excluded from this review Johansen 2002 {published data only} Johansen T, Weidner W. Understanding chronic pelvic pain syndrome. Current Opinion in Urology 2002;12:63–7. Pontari 2007 {published data only} Pontari M, Joyce G, Wise M, McNaughton-Collins M, and the Urologic Diseases in America Project. Prostatitis. The Journal of Urology 2006;177:2050–7. Sikiru 2008 {published data only} Sikiru L, Shmaila H, Muhammed S. Transcutaneous electrical nerve stimulation (TENS) in the symptomatic management of chronic prostatitis/chronic pelvic pain syndrome: a placebo-control randomized trial. International Brazilian Journal of Urology 2008;34:708–14. CPCRN 2004 The Chronic Prostatitis Collaborative Research Network. The economic impact of chronic prostatitis. Archives of Internal Medicine 2004;164:1231–6. Dworkin 2005 Dworkin R, Kirkpatrick P. Pregabalin. Nature Review Drug Discovery 2005;4:455–6. Dworkin 2010 Dworkin R, O’Connor AB, Audette J, Baron R, Gourlay GK, Haanpää ML, et al.Recommendations for the pharmacological management of neuropathic pain: an overview and literature update. Mayo Clinical Proceedings 2010;85(3):S3–14. Gottsch 2010 Gottsch HP, Yang CC, Berger RE. A pilot study of botulinum toxin A for male chronic pelvic pain syndrome. Scandinavian Journal of Urology and Nephrology 2010; Vol. 45, issue 1:72–6. [PUBMED: 21062115] Higgins 2011 Higgins JPT, Green S (editors). Chapter 8: Assessing risk of bias in included studies. Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 [updated March 2011]. The Cochrane Collaboration, 2011. Available from www.cochrane-handbook.org. Strauss 2010 {published data only} Strauss A, Dimitrakov J. New treatments for chronic prostatitis/chronic pelvic pain syndrome. Nature Review Urology 2010;7:127–35. Jain 2005 Jain KK. Clinical summary: pregabalin, 2011. www.medlink.com/medlinkcontent.asp (accessed 15 June 2012). Watanabe 2011 {published data only} Watanabe T, Inoue M, Sasaki K, Araki M, Uehara S, Monden K, et al.Nerve growth factor level in the prostatic fluid of patients with chronic prostatitis/chronic pelvic pain syndrome is correlated with symptom severity and response to treatment. BJU International 2011;108(2):248–51. Krieger 1999 Krieger J, Nyber L, Nickel JC. NIH consensus definition and classification of prostatitis. Journal of the American Medical Association 1999;282(3):236–7. Additional references Arnold 2010 Arnold L, Mease P, Silverman S. Pregabalin: an alpha2delta ligand for the management of fibromyalgia. American Journal of Management and Care 2010;16:S138–43. Bartoletti 2007 Bartoletti R, Mondaini N, Pavone C, Dinelli N, Prezioso D. Introduction to chronic prostatitis and chronic pelvic pain syndrome (CP/CPPS). Archivio Italiano di Urologia e Andrologia 2007;79(2):55–7. Cappuzzo 2009 Cappuzzo K. Treatment of postherpetic neuralgia: focus on pregabalin. Clinical Interventions in Aging 2009;4:17–23. Collins 1998 Collins M, Stafford R, O’Leary M, Barry M. How common is prostatitis? A national survey of physician visits. The Journal of Urology 1998;159:1224–8. Litwin 1999 Litwin M, McNaughton-Collins M, Fowler FJ Jr, Nickel JC, Calhoun EA, Pontari MA, et al.The National Institutes of Health Chronic Prostatitis Symptom Index: development and validation of a new outcome measure. The Journal of Urology 1999;162:369–75. Magri 2010 Magri V, Wagenlehner F, Perletti G, Schneider S, Marras E, Naber KG, et al.Use of the UPOINT chronic prostatitis/ chronic pelvic pain syndrome classification in European patient cohorts: sexual function domain improves correlations. The Journal of Urology 2010;184:2339–45. McNaughton Collins 2008 McNaughton Collins M, Wilt T. Allopurinol for chronic prostatitis. Cochrane Database of Systematic Reviews 2008, Issue 4. [DOI: 10.1002/14651858.CD001041] Miller 2002 Miller LJ, Fischer KA, Goralnick SJ, Litt M, Burleson JA, Albertsen P, et al.Nerve growth factor and chronic prostatitis/chronic pelvic pain syndrome. Urology 2002;59 (4):603–8. Pregabalin for chronic prostatitis (Review) Copyright © 2012 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd. 10 Nickel 2001 Nickel JC, Downey J, Hunter D, Clark J. Prevalence of prostatitis-like symptoms in a population based study using the National Institutes of Health Chronic Prostatitis Symptom Index. Journal of Urology 2001;165:842–5. Online Symptom Index Chronic Prostatitis Collaborative Research Network. NIH Chronic Prostatitis Symptom Index. www.prostatitis.org/ symptomindex.html (accessed 15 June 2012). Pontari 2005 Pontari M, McNaughton-Collins M, O’Leary MP, Calhoun EA, Jang T, Kusek JW, et al.A case-control study of risk factors in men with chronic pelvic pain syndrome. BJU International 2005;96(4):559–65. RevMan 2011 The Nordic Cochrane Centre, The Cochrane Collaboration. Review Manager (RevMan). 5.1. Copenhagen: The Nordic Cochrane Centre, The Cochrane Collaboration, 2011. Reynard 2006 Reynard J, Brewster S, Biers S. Oxford Handbook of Urology. 1st Edition. New York: Oxford University Press, 2006. Roberts 1998 Roberts RO, Lieber MM, Rhodes T, Girman CJ, Bostwick DG, Jacobsen SJ. Prevalence of a physician-assigned diagnosis of prostatitis: the Olmsted County study of urinary symptoms and health status among men. Urology 1998;51(4):578–84. Weiss 2001 Weiss R, George N, O’Reilly P. Comprehensive Urology. Vol. 1, London: Mosby, 2001. [: ISBN: 0723429499] Yang 2003 Yang CC, Lee JC, Kromm BG, Ciol MA, Berger RE. Pain sensitization in male chronic pelvic pain syndrome: why are symptoms so difficult to treat?. Journal of Urology 2003;170 (3):823–7. Yilmaz 2007 Yilmaz U, Liu YW, Berger RE, Yang CC. Autonomic nervous system changes in men with chronic pelvic pain syndrome. Journal of Urology 2007;177:2170–4. ∗ Indicates the major publication for the study Pregabalin for chronic prostatitis (Review) Copyright © 2012 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd. 11 CHARACTERISTICS OF STUDIES Characteristics of included studies [ordered by study ID] Pontari 2010 Methods Randomized, placebo-controlled, double-blind, multi centered Participants 324 patients ages 19 to 78 years with CP/CPPS Diagnosis based on a minimum score of 15 out of 43 on the NIH-CPSI Inclusion criteria: at least 18 years of age, pain/discomfort in the pelvic region during at least 3 of the last 6 months, and with a minimum score of 15 on the NIH-CPSI Exclusion criteria: calculated creatinine clearance < 60 mL/minute/1.73 m2 , platelet count < 100,000 x 103 /µL, allergy to any anti-seizure medication, known sensitivity to pregabalin, treatment with thiazolidine or antidiabetic agents, New York Heart Association class III or IV congestive heart failure, history of thrombocytopenia or bleeding diathesis, and history of alcohol abuse Interventions Patients were divided into 2 groups to receive either pregabalin or a placebo for 6 weeks. Initial dose of pregabalin was 50 mg 3 times daily for 2 weeks, followed by 100 mg 3 times daily for 2 weeks, followed by 200 mg 3 times daily for 2 weeks. Patients who developed side effects were maintained on the pre-escalation dose Outcomes Primary outcome: improvement in the NIH-CPSI score of at least 6 points from baseline Secondary outcomes: sub scores of the NIH-CPSI (pain 0 to 21, urinary symptoms 0 to 10, and quality of life 0 to 12), GRA (7-question patient self-reported assessment that measures change in symptoms, i.e. improvement, no change, or deterioration where 0 is no change), the McGill Pain Questionnaire (0 to 45; 0 = least pain), the MOS SF12 which was also divided into physical (0 to 100) and mental (0 to 50) component summary scores (0 = worse quality of life), HADS (0 to 42; the higher the number the more anxiety and depression), and SHIM (1 to 25 higher scores indicating better sexual function) Adherence to treatment was calculated by capsule count at 2-, 4-, and 6-week follow-up Notes 11 patients withdrew from the trial, 8 from the pregabalin group and 3 from the placebo group The participants were included in the intent-to-treat analysis Risk of bias Bias Authors’ judgement Random sequence generation (selection Low risk bias) Pregabalin for chronic prostatitis (Review) Copyright © 2012 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd. Support for judgement The authors explained that participants were randomly assigned 2:1 randomizations via a centrally controlled Web-based data management system to group patients using a permuted block randomizations procedure with randomly assigned block sized of 3, 6, and 9 12 Pontari 2010 (Continued) Allocation concealment (selection bias) High risk No report of concealment Blinding (performance bias and detection Low risk bias) All outcomes The authors report that the Investigators and participants were unaware of treatment assignment Incomplete outcome data (attrition bias) All outcomes High risk The authors report that there were patients who withdrew and that they conducted an intention-to-treat analysis. However in the final analysis table the author states that fewer patients were analyzed than were included, with no mention as to why there were fewer patients Selective reporting (reporting bias) Low risk There were no indications of selective reporting Other bias Low risk No other sources of bias could be identified CP/CPPS: chronic prostatitis/chronic pelvic pain syndrome; GRA: Global Response Assessment; HADS: Hospital Anxiety and Depression Scale; MOS SF-12: Medical Outcomes Study 12-Item Short Form Health Survey; NIH-CPSI: National Institutes of Health Chronic Prostatitis Symptom Index; SHIM: Sexual Health Inventory for Men. Characteristics of excluded studies [ordered by study ID] Study Reason for exclusion Johansen 2002 Not an RCT or a study for pregabalin treatment Pontari 2007 Not an RCT or a study on pregabalin treatment Sikiru 2008 An RCT but on TENS for CP/CPPS rather than pregabalin Strauss 2010 Not an RCT or a study for pregabalin treatment Watanabe 2011 Study on nerve growth factor levels in prostatic fluid, not on pain control CP/CPPS: chronic prostatitis/chronic pelvic pain syndrome; TENS: transcutaneous electrical nerve stimulation. Pregabalin for chronic prostatitis (Review) Copyright © 2012 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd. 13 DATA AND ANALYSES This review has no analyses. HISTORY Protocol first published: Issue 4, 2011 Review first published: Issue 8, 2012 CONTRIBUTIONS OF AUTHORS Both OMA and RLN assessed relevant papers and abstracts, extracted data, assessed the risk of bias, and contributed to writing the review. DECLARATIONS OF INTEREST None known. SOURCES OF SUPPORT Internal sources • Prostatic Diseases and Urologic Cancers Group, USA. External sources • No sources of support supplied INDEX TERMS Medical Subject Headings (MeSH) Analgesics [∗ therapeutic use]; Chronic Disease; Pelvic Pain [∗ drug therapy]; Prostatitis [∗ drug therapy]; Randomized Controlled Trials as Topic; gamma-Aminobutyric Acid [∗ analogs & derivatives; therapeutic use] MeSH check words Humans; Male Pregabalin for chronic prostatitis (Review) Copyright © 2012 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd. 14