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Drugs for relief of pain in patients with sciatica: systematic review and meta-analysis |
Pinto RZ, Maher CG, Ferreira ML, Ferreira PH, Hancock M, Oliveira VC, McLachlan AJ, Koes B |
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CRD summary The review concluded that the efficacy and tolerability of drugs commonly prescribed for the management of sciatica in primary care was unclear. Despite some limitations to the review searching and selection processes, the authors' conclusions were suitably cautious in reflecting the limited evidence available and appear likely to be reliable. Authors' objectives To investigate the efficacy and tolerability of analgesic and adjuvant pain drugs typically administered in primary care for the management of patients with sciatica. Searching The following databases were searched to 15 March 2010: International Pharmaceutical Abstracts, PsycINFO, MEDLINE, EMBASE, Cochrane Central Register of Clinical Trials (CENTRAL), CINAHL and LILACS. Search strategies were presented in a supplementary online appendix. Searches were restricted to studies published in English, German, Dutch, Portuguese or Spanish. Reference lists were also examined. Study selection Randomised controlled trials (RCTs) that assessed the efficacy and tolerability of single or combination analgesic or adjuvant drugs for patients with sciatica were eligible for inclusion. Eligible trials could use a synonym to describe sciatica. Drugs had to be able to be administered in a primary care setting (by an oral, topical, or parental route). Eligible comparators included placebo, no treatment, or other treatment options. Trials had to report one of the outcomes of overall pain intensity (when not specified as leg or back pain), leg or back pain intensity, disability status, work status, and adverse events. Six classes of drugs were used in the included trials: non-steroidal anti-inflammatory drugs (NSAIDs), antidepressants, corticosteroids, opioid analgesics, muscle relaxants, and anticonvulsants. Most trials used oral administrations. Around half the trials were placebo-controlled; other comparators included another NSAID, corticosteroids combination, acupuncture and an antidepressant. Patients had varying periods of symptom duration (acute or chronic pain); their mean ages also varied across trials. One reviewer screened titles and abstracts. Two reviewers independently evaluated full reports for eligibility. Disagreements were resolved by discussion. Assessment of study quality Two independent reviewers assessed trial quality using the PEDro scale (resulting in a score out of 10). Disagreements were resolved by a third reviewer. The overall quality of evidence was summarised using the GRADE (Grades of Recommendation Assessment, Development and Evaluation) system. Data extraction Two independent reviewers extracted means (final scores or change score) with standard deviations. Data were extracted for follow-up at immediate term (two weeks or less after randomisation), short term (more than two weeks but less than three months), intermediate term (more than three months but less than 12 months), and long term (12 months or more). Participants were classified as having acute (less than six weeks), subacute (six to 12 weeks), or chronic (12 weeks or more) symptoms. Scores for pain intensity and disability were converted to a scale from zero to 100. Authors were contacted for missing data; otherwise various methods were used to estimate missing data where possible. Methods of synthesis Where trials were considered to be clinically homogeneous, meta-analyses were performed to calculate pooled mean differences (MDs) with 95% confidence intervals (CIs), using a random-effects model. A sensitivity analysis investigating the effect of the definition of sciatica (for diagnostic methods) was planned, but was not possible due to the lack of trials. Heterogeneity was assessed using I2. Leg pain and overall pain were pooled as outcomes. The authors did not assess for possible publication bias as there were too few trials. Results of the review Twenty four RCTs were included (n=2,607, range 15 to 532 participants). PEDro scores ranged from 3 to 9 out of 10. Six trials did not blind participants to treatment. Fifteen trials did not perform an intention-to-treat analysis. Seven trials reported using methods to conceal treatment allocation. There were no significant differences between either NSAIDs or corticosteroids and placebo for immediate pain, although corticosteroids did significantly reduce short-term pain (MD -12.2, 95% CI -20.9 to -3.4; two RCTs). There was no evidence of heterogeneity in any analysis. The NSAID evidence was low quality and the corticosteroids evidence was moderate quality. Trials that compared different types of NSAID found no significant differences between treatments. One low quality trial reported that the anticonvulsant gabapentin was significantly better than placebo for relieving pain in the short-term (MD -26.6, 95% CI -38.3 to -14.9). The median number of adverse events (interquartile range) was 17% (10 to 30%) for the active drugs and 11% (3 to 23%) for placebo. Adverse event types varied between drugs and between trials of the same drug. Further results (of individual trials) were reported. Authors' conclusions As the existing evidence from clinical trials was of low quality, the efficacy and tolerability of drugs commonly prescribed for the management of sciatica in primary care was unclear. CRD commentary The review addressed a clear question supported by appropriate inclusion criteria. Attempts to identify relevant studies were undertaken by searching relevant databases and checking references, although not all languages were eligible and there was no search to identify unpublished studies; it was possible that some relevant studies may have been missed. Suitable methods were employed to reduce the risks of reviewer error and bias for the processes of data extraction and trial quality assessment. However, only one reviewer selected titles/abstracts for inclusion, which meant that the risk of reviewer error and bias was not minimised for this process. Trial quality was assessed and was used in interpreting the results of the review. Sufficient trial details were provided. Appropriate methods were used to pool data. Despite some limitations in the review searching and selection processes, the authors' conclusions were suitably cautious in reflecting the limited evidence available and appear likely to be reliable. Implications of the review for practice and research Practice: The authors advised that clinicians treating sciatica patients who exhibit clinical features of neuropathic pain should consider evidence based guidelines; for other patients with sciatica they should consider therapeutic recommendations from current guidelines for the management of non-specific low back pain. Research: The authors stated that priorities for the design of future trials should include consideration of duration of symptoms, recruitment of large samples, and collection of outcomes relevant to patients. Bibliographic details Pinto RZ, Maher CG, Ferreira ML, Ferreira PH, Hancock M, Oliveira VC, McLachlan AJ, Koes B. Drugs for relief of pain in patients with sciatica: systematic review and meta-analysis. BMJ 2012; 344:e497 Indexing Status Subject indexing assigned by NLM MeSH Adrenal Cortex Hormones /adverse effects /therapeutic use; Analgesics, Opioid /adverse effects /therapeutic use; Anti-Inflammatory Agents, Non-Steroidal /adverse effects /therapeutic use; Anticonvulsants /adverse effects /therapeutic use; Antidepressive Agents /adverse effects /therapeutic use; Confounding Factors (Epidemiology); Evidence-Based Medicine; Humans; Neuromuscular Agents /adverse effects /therapeutic use; Randomized Controlled Trials as Topic; Sciatica /drug therapy; Treatment Outcome AccessionNumber 12012007150 Date bibliographic record published 16/02/2012 Date abstract record published 21/02/2012 Record Status This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn. |
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