Dose or content? Effectiveness of pain rehabilitation programs for patients with chronic low back pain: A systematic review Franka P.C. Waterschoot a,⇑ , Pieter U. Dijkstra a,b , Niek Hollak c , Haitze J. de Vries a , Jan H.B. Geertzen a , Michiel F. Reneman a a Department of Rehabilitation Medicine, Center for Rehabilitation, University Medical Center Groningen, University of Groningen, The Netherlands b Department of Oral and Maxillofacial Surgery, University Medical Centre Groningen, University of Groningen, The Netherlands c Center for Human Movement Sciences, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands Sponsorships or competing interests that may be relevant to content are disclosed at the end of this article. article info Article history: Received 9 February 2013 Received in revised form 2 October 2013 Accepted 4 October 2013 Keywords: Chronic low back pain Dose Effectiveness Pain rehabilitation programs abstract We sought to systematically analyze the influence of dose of pain rehabilitation programs (PRPs) for patients with chronic low back pain (CLBP) on disability, work participation, and quality of life (QoL). Literature searches were performed in PubMed, Cochrane Library, Cinahl, and Embase up to October 2012, using MeSH terms, other relevant terms and free-text words. Randomized controlled trials in English, Dutch, and German, analyzing the effect of PRPs, were included. One of the analyzed interventions had to be a PRP. Outcomes should be reported regarding disability, work participation, or QoL. To analyze dose, the number of contact hours should be reported. Two reviewers independently selected titles, abstracts, and full-text articles on the basis of inclusion and exclusion criteria. Data were extracted and risk of bias was assessed. Effect sizes (ES) were calculated for each intervention, and influence of dose variables was analyzed by a mixed model analysis. Eighteen studies were identified, reporting a wide variety of dose variables and contents of PRPs. Analyses showed that evaluation moment, number of dis- ciplines, type of intervention, duration of intervention in weeks, percentage of women, and age influ- enced the outcomes of PRPs. The independent effect of dose variables could not be distinguished from content because these variables were strongly associated. Because dose variables were never studied separately or reported independently, we were not able to disentangle the relationship between dose, content, and effects of PRPs on disability, work participation, and QoL. Ó 2013 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved. 1. Introduction Multidisciplinary pain rehabilitation programs (PRPs) are effec- tive in improving daily functioning of patients with chronic low back pain (CLBP) [12,14,30]. Most studies investigating the effects of PRPs focused on the relationship between therapy content and effect. Guidelines for managing CLBP are based on evidence ob- tained from these studies [1,27]. However, this evidence might be biased. In a literature search, we could not identify any study analyzing the relationship between dose and effect as a primary objective. Two systematic reviews [14,30] were identified that analyzed dose and effect as a secondary objective. These reviews presented con- flicting conclusions on dose effects. In a review by Guzman et al. [14], 10 randomized controlled trials (RCTs) were included reporting on 12 PRPs. PRPs were di- vided into 2 categories: daily intensive programs with more than 100 h of therapy, and once- or twice-weekly programs with less than 30 h of therapy. On the basis of that distinction, it appeared that multidisciplinary PRPs of more than 100 h were superior to monodisciplinary treatment, and PRPs of less than 30 h were not. The authors concluded that intensive multidisciplinary PRPs are superior to less intensive multidisciplinary PRPs [14]. These results have been used in guidelines and clinical practice [1,31]. However, it may be debated whether the conclusion regarding dose is valid to support its clinical implications. First, there is an absence of knowledge about PRPs with doses between 30 to 100 h. Second, no distinction was made within intensive and less intensive PRPs, although there was a wide variety within the groups. Less intensive PRPs ranged from 17.5 to 30 h, while intensive PRP ranged from 100 to 280 h. Third, the review [14] was designed to assess the effect of different PRPs on clinically relevant outcomes. All PRPs differed not only in dose but also in content, setting, and number 0304-3959/$36.00 Ó 2013 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.pain.2013.10.006 ⇑ Corresponding author. Address: Department of Rehabilitation Medicine, Center for Rehabilitation, University Medical Center Groningen, University of Groningen, PO Box 30.002, 9750 RA Haren, The Netherlands. Fax: +31 505338258. E-mail address: f.p.c.waterschoot@cvr.umcg.nl (F.P.C. Waterschoot). PAIN Ò 155 (2014) 179–189 www.elsevier.com/locate/pain