Print Email Facebook Twitter What works best for whom? An exploratory, subgroup analysis in a randomized, controlled trial on the effectiveness of a workplace intervention in low back pain patients on return to work Title What works best for whom? An exploratory, subgroup analysis in a randomized, controlled trial on the effectiveness of a workplace intervention in low back pain patients on return to work Author Steenstra, I.A. Knol, D.L. Bongers, P.M. Anema, J.R. van Mechelen, W. de Vet, H.C.W. TNO Kwaliteit van Leven Publication year 2009 Abstract STUDY DESIGN. Exploratory subgroup analysis in a randomized controlled trial (RCT). OBJECTIVE. To detect possible moderators in the effectiveness of a workplace intervention in a population of workers with sick leave due to sub acute nonspecific low back pain. SUMMARY OF BACKGROUND DATA. In a recently published RCT, a workplace intervention was effective on return to work, compared to usual care. Examining the heterogeneity of effect sizes within the population in this RCT (n = 196) can lead to information on the effectiveness of the intervention in subgroups of patients. METHODS. A subgroup analysis was performed by adding interaction terms to the statistical model. Before analysis the following possible moderators for treatment were identified: age, gender, pain, functional status, heavy work, and sick leave in the previous 12 months. Cox regression analyses were performed and survival curves were plotted. RESULTS. The interaction (P = 0.02) between age (dichotomized at the median value) and the workplace intervention indicates a modifying effect. The workplaceintervention is more effective for workers <44 years (HR, 95% CI = 2.5, [1.6, 4.1] vs. 1.2 [0.8, 1.8] for workers <44 years old). The interaction between sick leave in the previous 12 months and the workplace intervention is significant (P = 0.02). The intervention is more effective for workers with previous sick leave (HR, 95% CI = 2.8 [1.7, 4.9] vs. 1.3 [0.8, 2.0]). A modifying effect of gender, heavy work, and pain score and functional status on the effectiveness of this intervention was not found. CONCLUSION. The findings from these exploratory analyses should be tested in future RCTs. This workplace intervention seems very suitable for return to work of older workers and workers with previous sick leave. Gender, perceived heavy work, and baseline scores in pain and functional status should not be a basis for assignment to this intervention. © 2009 Lippincott Williams & Wilkins, Inc. Subject WorkplaceVeilig en Gezond WerkenLow back painModeratorsReturn to workSubgroupsWorkersWorkplace interventionActivities of Daily LivingAdultAge DistributionAge FactorsCohort StudiesDisability EvaluationFemaleHealth PromotionHuman EngineeringHumansIntervention StudiesLow Back PainMaleMiddle AgedOccupational DiseasesOccupational ExposureOccupational HealthOutcome Assessment (Health Care)Pain MeasurementProgram DevelopmentSex FactorsSick LeaveSingle-Blind MethodWork Capacity EvaluationWork Schedule ToleranceWorkplaceYoung Adult To reference this document use: http://resolver.tudelft.nl/uuid:64be1532-0418-43f7-9a83-54ce1ac02eea DOI https://doi.org/10.1097/brs.0b013e3181a09631 TNO identifier 241542 ISSN 0362-2436 Source Spine, 34 (12), 1243-1249 Document type article Files To receive the publication files, please send an e-mail request to TNO Library.