Enabling meta-analysis in systematic reviews on carpal tunnel syndrome

Abstract

Possible solutions to the problems of clinical heterogeneity of outcome measures and inadequate reporting of results for randomized controlled trials (RCTs) on carpal tunnel syndrome (CTS) are presented. Meta-analysis was impeded by these problems in 2 systematic reviews concerning conservative and surgical treatment options for CTS. A solution to the problem of inadequate data presentation is to add explicit information on minimal requirements with regard to data presentation to guidelines for the reporting of studies. To resolve the problem of clinical heterogeneity of the outcomes there should be consensus on the (validated) outcomes that should be used in RCTs. For CTS there is little evidence available on the reliability, validity, and responsiveness to change of the commonly used outcomes in RCTs.Resolving both problems will increase the comparability of RCTs, enabling the calculation of a pooled estimate of effect in a meta-analysis. Systematic reviews of high-quality, randomized controlled trials (RCTs) are considered to be the highest level of evidence in research concerning medical interventions. 1 To quantify the effect of the various treatment options, preferably a meta-analysis is performed. By combining individual study results a precise estimate of the magnitude of the treatment effect can be obtained. Meta-analysis is, therefore, an important part of a systematic review. Meta-analysis is only feasible if RCTs are clinically homogeneous, that is, if the patients, interventions, comparisons, outcomes, and timing of follow-up measurements are sufficiently similar. 2 Randomized controlled trials, however, may use a range of different outcome measures. 3,4 Another prerequisite for combining study results is adequate and uniform data presentation. Reporting of results in biomedical journals is often inadequate. 5,6 This article presents possible solutions to the problems of clinical heterogeneity of the outcome measures and inadequate reporting of results for RCTs on carpal tunnel syndrome (CTS). First we show, however, that meta-analysis was impeded by these problems in 2 systematic reviews concerning conservative and surgical treatment options for CTS. 7,8

The Outcome of Carpal Tunnel Decompression in Elderly Patients

“…A problem in comparing the results of surgery is the number of different outcome measures used to report results. 18 Both Amadio et al 19 and Katz et al 4 have found that subjective outcome scores were more sensitive to change than traditional physical measures and that physical examination had little usefulness for predicting postsurgical functional limitations, symptoms, or satisfaction. Improvements have been reported in general outcomes scores such as the Arthritis Impact Measurement Scale and the ShortForm 36; however, these changes were not as great as those seen with the condition-specific Symptom Severity Score.…”

A systematic review of outcomes assessed in randomized controlled trials of surgical interventions for carpal tunnel syndrome using the International Classification of Functioning, Disability and Health (ICF) as a reference tool

“…Conservative treatment of CTS also accounts for a large proportion of resources and includes splinting, nerve gliding, ultrasound and carpal bone mobilisation[2]. Whilst the reported success rates of carpal tunnel release range from 70 to 90 percent there is little agreement on how results should be evaluated[4]. …”

“…Outcomes from carpal tunnel release have been assessed in many different ways including objective nerve conduction studies, clinical measures of sensibility, muscle function and dexterity, patient-reported symptoms and perceived function and the impact on daily activity, work and leisure. It has also been noted, that there is a lack of consensus among clinicians over what constitutes the most reliable, valid and responsive instruments to evaluate outcomes in carpal tunnel syndrome[4,6]. …”

A Practical Guide to Meta-Analysis

“…The number of meta-analyses conducted in hand surgery has been modest to date. This may be the result of a lack of common outcomes or incompatible data, as found by Gerritsen et al 37 In the hand surgery field, meta-analysis is still in the infancy stage because high-quality clinical trials that provide robust data that can be pooled are still lacking. When performed appropriately, however, a meta-analysis can lend evidence to many of the difficult decisions we make in our daily practice.…”