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A systematic review of workplace interventions to prevent low back pain |
Maher C G |
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Authors' objectives To evaluate the effectiveness of workplace interventions for the prevention of lower-back pain (LBP).
Searching MEDLINE, EMBASE, CINAHL, PEDro, PsycLIT, and occupational safety and health databases (via OSHROM) were searched from database inception to January 1999. A search strategy developed by the Cochrane Back Review Group was used, coupled with search terms representing 'LBP' and 'prevention', and with common LBP prevention interventions. References in the papers were also checked for additional trials. Only full papers, published in English in peer-reviewed journals, were included.
Study selection Study designs of evaluations included in the reviewRandomised controlled trials (RCTs). The trials were of the following duration: 6.25 to 18 months for exercise; 3 to 8 months for braces; 3 to 12 months for education; and 12 and 65 months for education and workplace modification. Trials could be included if the method of allocation was not truly random but was intended to be, e.g. allocation by employee number.
Specific interventions included in the reviewFor inclusion, the intervention had to be a treatment to prevent LBP in the workplace. The interventions included exercise, the use of braces, education, and education combined with workplace modification.
Participants included in the reviewFor inclusion, the participants had to be adult workers in an industrial setting. The ages and gender of the participants was not stated. The occupations of the participants included hospital workers, nurses, home care workers, factory workers, baggage handlers, postal workers, and warehouse and mailing company workers. Studies that included participants with LBP at trial commencement were eligible for inclusion.
Outcomes assessed in the reviewStudies had to report outcomes for LBP in order to be included in the review. Studies were only included if the reported outcomes provided direct evidence of the prevention of cases or the sequelae of LBP. The outcomes reported were: the number of episodes of LBP, the duration of LBP, the severity of LBP, lost work time due to LBP, and the direct and indirect costs of LBP. Trials where the outcomes were restricted to risk factors for LBP were not considered for inclusion.
How were decisions on the relevance of primary studies made?One author determined whether the studies were relevant for inclusion.
Assessment of study quality All included trials were rated for quality using the 11-criteria PEDro scale (see Other Publications of Related Interest). A study was considered to be of high quality if it scored at least 6 out of the 11 points. The level of evidence for each intervention was classified as either strong, moderate, limited, or no evidence, based on the amount, consistency and quality of the evidence from the studies. All the trials were rated by two raters, with any discrepancies arbitrated by a third rater. The raters rated clean copies of the original papers, and so were not blinded to the authors of the studies or the journals in which they were published.
Data extraction The author does not state how the data were extracted for the review, or how many of the reviewers performed the data extraction.
Data were extracted for the following categories: study identification; characteristics of the participants; the interventions and numbers of participants in each group; follow-up period; and main results.
Methods of synthesis How were the studies combined?A narrative synthesis was undertaken, in which the studies were grouped and presented according to the level of evidence for the findings.
How were differences between studies investigated?Heterogeneity was not formally assessed. However, the authors decided that statistical pooling was not possible, because the trials did not present sufficient data and there was not a common set of outcomes across trials.
A sensitivity analysis was also performed to determine the effect on the results of using a quality score cut-off of 4 or 5 points out of 11, rather than the predetermined 6 points.
Results of the review Thirteen RCTs with 7,184 participants were included in the review . Five trials (474 participants) investigated the effectiveness of exercise. Four trials (1,095 participants) investigated the effectiveness of braces. Six trials (1,410 participants) investigated the effectiveness of education. Two trials (4,205 participants) investigated the effectiveness of education and workplace modification.
Quality: the quality scores ranged from 1 to 8 with a mean score of 4.8 points.
Effectiveness of braces (4 trials, n=1,095): there was strong evidence that belts were ineffective in reducing the prevalence of LBP, severity of LBP, and leave due to LBP.
Effectiveness of exercise (5 trials, n=474): there was moderate evidence that exercise reduced LBP severity and leave due to LBP. There was limited evidence that exercise reduced the prevalence of LBP. Effectiveness of education (6 trials, n=1,410): there was moderate evidence that education was ineffective in reducing the prevalence of LBP, severity of LBP, and leave due to LBP.
Effectiveness of education and workplace modification (2 trials, n=4,205): there was no evidence that education and workplace modification was ineffective in reducing prevalence of LBP, and leave due to LBP.
Sensitivity analysis.
Changing the quality score cut-off from 6 to 4 or 5 points out of 11 did not generally change the conclusion with regards to the efficacy of exercise, braces and education, except to increase the level of evidence. For workplace modification and education, the adoption of the less strict criteria changed the conclusion from no evidence to limited evidence that this intervention was ineffective.
Cost information There was no evidence that exercise reduced the cost of LBP. All of the trials, with the exception of one low-quality trial, found no evidence to suggest that braces had no effects on the costs of LBP. There was limited evidence that education was ineffective in reducing the costs of work-related LBP. There were no results stated for the cost outcome for workplace modification and education for the prevention of LBP.
Authors' conclusions At present, the only workplace intervention with demonstrated efficacy in the prevention of LBP is exercise. Other common interventions have either been shown to be ineffective or have not been properly evaluated.
CRD commentary This was a good review of the area. The research question and inclusion and exclusion criteria were clearly stated. The literature search appears to have been thorough, although the searches were limited to English language publications and did not include unpublished data or data published as an abstract. It is possible that additional studies were missed. The author reported who, and how many of the assessors, performed the selection of studies and the validity assessment. The author did not report who extracted the data. The validity of the included studies was assessed, and this information was used to assess the impact of the results in a level of evidence table.
The review was a narrative discussion with no statistical pooling, which was appropriate given the nature of the evidence. Differences between the studies were discussed and investigated using sensitivity analyses.
The author's conclusions appeared to follow from the results.
Implications of the review for practice and research Practice: The author did not state any implications for practice.
Research: The author states that more research is required to evaluate the effects of interventions used to prevent LBP in workers.
Bibliographic details Maher C G. A systematic review of workplace interventions to prevent low back pain. Australian Journal of Physiotherapy 2000; 46(4): 259-269 Other publications of related interest Verhagen A, de Vet H, de Bie R, Kessels A, Boers M, Bouter L, et al. The Delphi List: a criteria list for quality assessment of randomized clinical trials for conducting systematic reviews developed by Delphi consensus. J Clin Epidemiol 1998;51:1235-41.
Indexing Status Subject indexing assigned by NLM AccessionNumber 12001005108 Date bibliographic record published 31/05/2002 Date abstract record published 31/05/2002 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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