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The H-Wave device is an effective and safe non-pharmacological analgesic for chronic pain: a meta-analysis |
Blum K, Chen A L, Chen T J, Prihoda T J, Schoolfield J, DiNubile N, Waite R L, Arcuri V, Kerner M, Braverman E R, Rhoades P, Tung H |
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CRD summary The review authors concluded that the H-Wave device had a moderate to strong beneficial effect on relieving pain, reducing pain medication use and increasing functionality, in patients with chronic soft tissue inflammation or neuropathic pain. Given limitations of the review methodology and reporting, it is not possible to determine whether the results are reliable. Authors' objectives To determine the safety and efficacy of the H-Wave device in chronic soft tissue inflammation and neuropathic pain. Searching A search for studies published in English of the following databases was made: MEDLINE (1966 to Sept 2006), PubMed (1950 to Sept 2006), CINAHL (1982 to August 2006), Cochrane Central Register of Controlled trials (to July 2006), Science Citation Index (1945 to Sept 2006), Biological Abstracts (1969 to August 2006) and TOXLINE (1965 to Sept 2006). Search terms were reported. Bibliographies of relevant studies were searched by hand. Study selection Published studies of people with chronic soft tissue inflammation or neuropathic pain, who were treated with the H-Wave device, using appropriate waveform, frequency, amperage and voltage, were eligible for inclusion. Outcome inclusion criteria were a measure of pain relief or overall improvement (use of pain medication or functionality). In addition, studies had to have used an appropriate statistical analysis.
No participant or intervention details were given for the included studies. It was not stated how the outcomes for each of the included studies were measured. The included studies appeared to be either before-after studies or randomised controlled trials (RCTs).
Two reviewers independently selected the studies for inclusion, and discrepancies were resolved by consensus. Assessment of study quality Study validity was assessed using the Jadad scale.
The authors did not state how the validity assessment was performed. Data extraction Effect sizes were derived from reported test statistics (z-statistic, p-value or proportion).
One author extracted the data onto a standardised form, and another reviewer checked the data extraction for accuracy and completeness. Methods of synthesis Random-effects meta-analysis was used to determine weighted mean effect sizes and variance. Multiple regression was used to determine variability in outcome measures and study design. This regression, and tests of heterogeneity, were performed using Hedges and Olkin methods. Results of the review Five studies (n=at least 6,535 participants) were included in the review.
For all outcomes combined, the weighted mean effect size across eight comparisons was 0.66 (95% confidence interval (CI): 0.65 to 0.67), indicating a moderate to large beneficial effect of the H-Wave device. There was significant heterogeneity (p<0.05).
For pain relief, the weighted mean effect size was 0.59 (95% CI: 0.58 to 0.60; p<0.001, four studies), indicating a moderate to large beneficial effect of the H-Wave device.
For pain medication use, the weighted mean effect size was 0.56 (95% CI: 0.55 to 0.57; p<0.001, two studies), indicating a moderate to large beneficial effect of the H-Wave device.
For patient functionality, the weighted mean effect size was 0.70 (95% CI: 0.69 to 0.71; p<0.001, two studies), indicating a moderate to large beneficial effect of the H-Wave device.
Weighted mean effect size for RCTs was smaller than for other study designs. Actual weighted mean effect size was not reported, but the 95% CI for RCTs was 0.29 to 0.33 and for non-RCTs was 0.62 to 0.62. The weighted mean effect size for patient function was greater than for pain reduction, and the weighted mean effect size for pain relief was greater than for pain medication use.
No adverse effects of H-Wave device use were reported in any study. Authors' conclusions The H-Wave device has moderate to strong effects in relieving pain, reducing pain medication use and increasing functionality in patients with chronic soft tissue inflammation or neuropathic pain. CRD commentary The authors addressed a clear research question. The search of published databases was comprehensive. However, in addition to no systematic attempt being made to identify unpublished studies, the search was restricted to English language publications, raising the possibility of both language and publication bias. Patient, intervention and outcome inclusion criteria were well-defined. Very limited details of the included studies are given in the review. It was unclear which studies were randomised, no control interventions were detailed, and there were insufficient details on the outcome measures used. Although a validity assessment was performed, the results were not presented. Given these omissions, it is difficult to assess either the internal or external validity of the results.
The authors used meta-analysis to combine the results, but different measures of effect appeared to be combined in a single effect size. Insufficient details on the outcome measures used in the included studies meant that it was not possible to determine if this was appropriate or not. The authors investigated heterogeneity, and made an attempt to investigate possible reasons for this.
It should be noted that, in addition to four authors being independent consultants for Electronic Waveform Lab (the makers of the H-Wave device), two authors were members of the research groups responsible for conducting the primary studies.
Given these limitations of the review methodology and reporting, it is not possible to determine whether the results are reliable. Implications of the review for practice and research Practice: The authors did not state any implications for practice.
Research: The authors stated that more rigorous, controlled studies are required. Funding Partly funded by Electronic Waveform Lab, Inc. Bibliographic details Blum K, Chen A L, Chen T J, Prihoda T J, Schoolfield J, DiNubile N, Waite R L, Arcuri V, Kerner M, Braverman E R, Rhoades P, Tung H. The H-Wave device is an effective and safe non-pharmacological analgesic for chronic pain: a meta-analysis. Advances in Therapy 2008; 25(7): 644-657 Indexing Status Subject indexing assigned by NLM MeSH Chronic Disease; Drug Utilization; Electric Stimulation Therapy /instrumentation /methods; Humans; Inflammation /therapy; Pain Management; Peripheral Nervous System Diseases /therapy; Soft Tissue Injuries /therapy AccessionNumber 12009103007 Date bibliographic record published 06/05/2009 Date abstract record published 26/08/2009 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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