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A critical analysis of randomised clinical trials on neck pain and treatment efficacy: a review of the literature |
Kjellman G V, Skargren E I, Oberg B E |
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Authors' objectives To critically review randomised studies of neck pain in regard to methodological quality and treatment effect size, as well as types of assessment, inclusion criteria and interventions.
Searching MEDLINE and CINAHL were searched for relevant articles from 1966 to 1995 (keywords provided) and reference lists were checked. Abstracts, unpublished studies and studies published in a language other than English or Scandinavian were excluded.
Study selection Study designs of evaluations included in the reviewRandomised controlled trials (RCTs).
Specific interventions included in the reviewPhysiotherapy or chiropractic treatment. Specific interventions included acupuncture, manipulation, mobilisation, traction, active physiotherapy, electrostimulation/local heat. Control interventions included placebo, neck collars, manual treatment, advice, rest and analgesia, medication, rehabilitation exercises, cold packs, acupuncture, group exercise. Follow-up period ranged from two weeks to two years.
Participants included in the reviewOngoing neck pain. Participants in the studies had chronic headache, acute/chronic whiplash, acute/chronic neck pain, or mixed indications. Studies that involved people with both neck and lower back pain were excluded.
Outcomes assessed in the reviewOutcomes were classified according to the Disablement Process (see Other Publications of Related Interest no.1). The components of this process include the pathology, the impairment, the functional limitations, disability, extra-individual factors, intra-individual factors, and risk factors.
Outcomes assessed in the included studies included pain (SF-36 pain relief and neck pain disability index), range of motions, activities of daily living, analgesic and other medication consumption, headache frequency, associated symptoms such as dizziness, sleep disturbance, social dysfunction, subjective assessment of progress.
How were decisions on the relevance of primary studies made?One reviewer determined whether a published trial fulfilled the inclusion criteria.
Assessment of study quality Methodological quality was examined using a procedure described by Ter Riet et al and modified by Koes et al (see Other Publications of Related Interest no.2 and no.3). The validity criteria covered four main areas: study population, intervention, measurement of effect and data presentation and analysis. Specific criteria assessed were homogeneity, comparability of relevant baseline characteristics, randomisation procedure, drop-outs described for each study group separately, percentage of loss to follow-up, sample size, interventions included and described, pragmatic study, co-intervention avoided, placebo controlled, patients blinded, relevant outcome measures, blinded assessments, adequate follow-up period, intention to treat analysis, frequencies of most important outcomes presented for each treatment group. One reviewer determined whether a published trial fulfilled the inclusion criteria. This reviewer was blinded to the author(s), to the journal of publication and to treatment outcome. The same paper was then independently assessed by the other two reviewers. If divergent results were obtained, a consensus was reached through discussion. The maximum score was 100 points. A study scoring 50-100 points was considered to be good quality. Details of scores for individual studies given in the report.
Data extraction The authors do not state how the data were extracted for the review, or how many of the authors performed the data extraction. Inclusion criteria, interventions and outcomes were classified according to the Disablement Process. Tables reported in the review included information on methodological criteria, bibliographic inclusion criteria, individual intervention and reference treatment details and outcome details.
Methods of synthesis How were the studies combined?Effect sizes were calculated for the studies using Cohen's D as described by Rosenthal (see Other Publications of Related Interest no.4).
How were differences between studies investigated?The authors do not state how differences between the studies were investigated.
Results of the review Twenty-seven RCTs with a total of 2075 participants. Four of the studies used acupuncture, four manipulation, three mobilisation, three traction, eight active physiotherapy, and five electrostimulation/local heat.
Methodological quality.
Only nine of the 27 studies had a score of 50 or more (out of a possible 100). The total scores varied from 24 to 62. Methodological quality was high in studies using electromagnetic therapy, manipulation, traction, acupuncture or active physiotherapy.
Effect sizes.
Of the 27 studies, based on the conclusions of the publishing authors, 18 had a positive outcome, and nine showed an equivalent/negative outcome between the treatment used. Pooling data and calculation of effect size showed that treatments used in the studies were effective for pain (median effect size 0.4, interquartile range 0.59, n=16), range of motion (median effect size 0.1, interquartile range 0.37, n=8), and activities of daily living median effect size 0.3, interquartile range 0.37, n=4).
Authors' conclusions Few randomised clinical trials on neck problems are of high methodological quality and comprise a sufficiently long follow-up time. In the studies that did show high quality, three different interventions led to a slight tendency towards positive results but the number of publications considered was inadequate to allow general conclusions to be drawn. The effect size calculations and the disablement process analysis indicated that the intervention in the trials had a positive influence on two impairment components, pain and range of motion. Effect size was also positive for one disability component, activities of daily living, but this finding was based on a very limited number of studies. Further analyses are needed to determine whether physiotherapy and chiropractic treatments have positive effects on functional limitation and various aspects of disability.
CRD commentary The review question and inclusion/exclusion of studies were clearly described. However, the literature search was limited to only English and Scandinavian language trials and unpublished studies were excluded. Thus publication bias cannot be ruled out. Authors described the methods used to select studies but not to extract data from studies. The validity of the included studies was assessed thoroughly and details of primary studies were presented in detail. The methods used to combine the data were unclear and details on effectiveness were sparse. The conclusions of the authors relate primarily to methodological quality of the studies and these conclusions are appropriate. Conclusions on the effectiveness of the interventions should be viewed with caution.
Implications of the review for practice and research Further analyses are needed to determine whether physiotherapy and chiropractic treatments have positive effects on functional limitation and various aspects of disability.
Funding Swedish Council for Work Life Research.
Bibliographic details Kjellman G V, Skargren E I, Oberg B E. A critical analysis of randomised clinical trials on neck pain and treatment efficacy: a review of the literature. Scandinavian Journal of Rehabilitation Medicine 1999; 31(3): 139-152 Other publications of related interest 1. Verbrugge LM, Jette AM. The disablement process. Soc Sci Med 1994;38:1-14. 2. Ter Riet G, Kleijnen J, Knipschild P. Acupuncture and chronic pain: a criteria-based meta-analysis. J Clin Epidemiol 1990;4:1191-9. 3. Koes BW, Assendelft WJ, Heijden GJ, et al. Spinal manipulation and mobilization for back and neck pain. A blinded review. BMJ 1991;303:1298-303. 4. Rosenthal R. Meta-analytic procedures for social research. Beverly Hills (CA): Sage Publications; 1984. Applied Social Research Methods Series, Vol 6.
Indexing Status Subject indexing assigned by NLM MeSH Activities of Daily Living; Bias (Epidemiology); Chiropractic /standards; Disabled Persons /rehabilitation; Effect Modifier, Epidemiologic; Humans; Neck Pain /physiopathology /therapy; Physical Therapy Modalities /standards; Randomized Controlled Trials as Topic; Range of Motion, Articular; Research Design; Treatment Outcome AccessionNumber 11999001539 Date bibliographic record published 31/03/2001 Date abstract record published 31/03/2001 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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