Physical activity and exercise for chronic pain in adults: an overview of Cochrane Reviews

Abstract

Background: Chronic pain is defined as pain lasting beyond normal tissue healing time, generally taken to be 12 weeks. It contributes to disability, anxiety, depression, sleep disturbances, poor quality of life, and healthcare costs. Chronic pain has a weighted mean prevalence in adults of 20%.For many years, the treatment choice for chronic pain included recommendations for rest and inactivity. However, exercise may have specific benefits in reducing the severity of chronic pain, as well as more general benefits associated with improved overall physical and mental health, and physical functioning.Physical activity and exercise programmes are increasingly being promoted and offered in various healthcare systems, and for a variety of chronic pain conditions. It is therefore important at this stage to establish the efficacy and safety of these programmes, and furthermore to address the critical factors that determine their success or failure.

Objectives: To provide an overview of Cochrane Reviews of adults with chronic pain to determine (1) the effectiveness of different physical activity and exercise interventions in reducing pain severity and its impact on function, quality of life, and healthcare use; and (2) the evidence for any adverse effects or harm associated with physical activity and exercise interventions.

Methods: We searched theCochrane Database of Systematic Reviews (CDSR) on the Cochrane Library (CDSR 2016, Issue 1) for systematic reviews of randomised controlled trials (RCTs), after which we tracked any included reviews for updates, and tracked protocols in case of full review publication until an arbitrary cut-off date of 21 March 2016 (CDSR 2016, Issue 3). We assessed the methodological quality of the reviews using the AMSTAR tool, and also planned to analyse data for each painful condition based on quality of the evidence.We extracted data for (1) self-reported pain severity, (2) physical function (objectively or subjectively measured), (3) psychological function, (4) quality of life, (5) adherence to the prescribed intervention, (6) healthcare use/attendance, (7) adverse events, and (8) death.Due to the limited data available, we were unable to directly compare and analyse interventions, and have instead reported the evidence qualitatively.

Main results: We included 21 reviews with 381 included studies and 37,143 participants. Of these, 264 studies (19,642 participants) examined exercise versus no exercise/minimal intervention in adults with chronic pain and were used in the qualitative analysis.Pain conditions included rheumatoid arthritis, osteoarthritis, fibromyalgia, low back pain, intermittent claudication, dysmenorrhoea, mechanical neck disorder, spinal cord injury, postpolio syndrome, and patellofemoral pain. None of the reviews assessed 'chronic pain' or 'chronic widespread pain' as a general term or specific condition. Interventions included aerobic, strength, flexibility, range of motion, and core or balance training programmes, as well as yoga, Pilates, and tai chi.Reviews were well performed and reported (based on AMSTAR), and included studies had acceptable risk of bias (with inadequate reporting of attrition and reporting biases). However the quality of evidence was low due to participant numbers (most included studies had fewer than 50 participants in total), length of intervention and follow-up (rarely assessed beyond three to six months). We pooled the results from relevant reviews where appropriate, though results should be interpreted with caution due to the low quality evidence. Pain severity: several reviews noted favourable results from exercise: only three reviews that reported pain severity found no statistically significant changes in usual or mean pain from any intervention. However, results were inconsistent across interventions and follow-up, as exercise did not consistently bring about a change (positive or negative) in self-reported pain scores at any single point. Physical function: was the most commonly reported outcome measure. Physical function was significantly improved as a result of the intervention in 14 reviews, though even these statistically significant results had only small-to-moderate effect sizes (only one review reported large effect sizes). Psychological function and quality of life: had variable results: results were either favourable to exercise (generally small and moderate effect size, with two reviews reporting significant, large effect sizes for quality of life), or showed no difference between groups. There were no negative effects. Adherence to the prescribed intervention: could not be assessed in any review. However, risk of withdrawal/dropout was slightly higher in the exercising group (82.8/1000 participants versus 81/1000 participants), though the group difference was non-significant. Healthcare use/attendance: was not reported in any review. Adverse events, potential harm, and death: only 25% of included studies (across 18 reviews) actively reported adverse events. Based on the available evidence, most adverse events were increased soreness or muscle pain, which reportedly subsided after a few weeks of the intervention. Only one review reported death separately to other adverse events: the intervention was protective against death (based on the available evidence), though did not reach statistical significance.

Authors' conclusions: The quality of the evidence examining physical activity and exercise for chronic pain is low. This is largely due to small sample sizes and potentially underpowered studies. A number of studies had adequately long interventions, but planned follow-up was limited to less than one year in all but six reviews.There were some favourable effects in reduction in pain severity and improved physical function, though these were mostly of small-to-moderate effect, and were not consistent across the reviews. There were variable effects for psychological function and quality of life.The available evidence suggests physical activity and exercise is an intervention with few adverse events that may improve pain severity and physical function, and consequent quality of life. However, further research is required and should focus on increasing participant numbers, including participants with a broader spectrum of pain severity, and lengthening both the intervention itself, and the follow-up period.

Conflict of interest statement

LG: none known.

RAM has received grant support from Grünenthal relating to individual patient level analyses of trial data regarding tapentadol in osteoarthritis and back pain (2015). He has received honoraria for attending boards with Menarini concerning methods of analgesic trial design (2014), with Novartis (2014) about the design of network meta‐analyses, and RB on understanding pharmacokinetics of drug uptake (2015). He has received honoraria from Omega Pharma (2016) and Futura Pharma (2016) for providing advice on trial and data analysis methods.

CC: none known.

DM: none known.

LC: none known. For transparency, LC has received honoraria for speaking at educational meetings to healthcare professionals on a range of chronic pain topics (Pfizer (October 2015), Astellas (June 2014, March 2015)); editor on the British Journal of Anaesthesia (receives an honorarium plus a contribution toward related departmental expenses (October 2010 ‐ to date)). LC is a medical clinician attending patients in the NHS Lothian Pain Service.

BHS: none known. BHS is a medical clinician attending patients in the NHS Tayside Pain Service.

This review was identified in a 2019 audit as not meeting the current definition of the Cochrane Commercial Sponsorship policy. At the time of its publication it was compliant with the interpretation of the existing policy. As with all reviews, new and updated, at update this review will be revised according to 2020 policy update.

Figures

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Study flow diagram.

References

References to included reviews Bartels 2007

Bidonde 2014 Boldt 2014 Brown 2010 Busch 2007 Busch 2013 Cramp 2013 Fransen 2008 Fransen 2014 Fransen 2015 Gross 2015a Han 2004 Hayden 2005 Hurkmans 2009 Kay 2012 Koopman 2015 Lane 2014 Lauret 2014 Regnaux 2015 Saragiotto 2016 Silva 2010 van der Heijden 2015 Yamato 2015 References to excluded reviews Aggarwal 2011 Bierma‐Zeinstra 2011 Brønfort 2014 Brønfort 2015 Choi 2010 Craane 2006 Dagfinrud 2008 Dahm 2010 Dal Bello‐Haas 2013 de Souza 2012 Fokkenrood 2013 Franke 2015 Green 2003 Gross 1998 Gross 2012 Gross 2015b Hayden 2012 Heintjes 2003 Henschke 2010 Heymans 2004 Hilde 2006 Hoving 2014 Hurley 2013 IJzelenberg 2011 Jones 2000 Jordan 2010 Kamper 2014 Karjalainen 1999 Karjalainen 2003 Larun 2016 Liddle 2015 Liu 2013 Miller 2014 Moi 2013 O'Brien 2004 O'Connell 2013 Page 2012 Page 2014 Peters 2013 Preston 2004 Proctor 2007 Radner 2012 Regnaux 2012 Regnaux 2014 Richards 2012 Riemsma 2003 Schaafsma 2013 Steultjens 2004 Stones 2005 Takken 2008 van der Heijden 2013 van Dessel 2014 White 2004 Zammit 2010 Østerås 2013 Additional references Abdulla 2013 American College of Sports Medicine 2007 Benton 2011 Bigal 2012 Bouchard 2012 Bousema 2007 Breivik 2006 Cohen 1988 Collins 1997 Daenen 2015 Deschartes 2013 Dworkin 2005 Dworkin 2008 Eccleston 2014 Elliott 1999 Elzahaf 2012 Engers 2008 Enoka 1997 Exercise is Medicine Finan 2013 Gross 2009 Harvard 2013 Hoffman 2014 IDF 2012 IntHout 2015 Leadley 2014 Mayer 2008 Merskey 2011 Messier 2013 Mooney 2006 Moore 1998 Moore 2008 Moore 2010 Moore 2013 Moore 2014a Moore 2014b National Library of Medicine NICE 2014 Nnoaham 2008 Nüesch 2010 Nüesch 2011 Park 2012 Perruchoud 2014 RevMan 2014 [Computer program] Sakuma 2012 Schofield 2011 Shea 2007 SIGN 2013 Smith 2007 Stagg 2011 Straube 2015 Thornton 2000 Timmons 2014 To 2012 Torrance 2010 Turk 2003 Turner 2013 Ursini 2011 van Hecke 2013a van Hecke 2013b Vigorito 2014 Vos 2015 Waddell 1987 WHO 2015 Wieland 2013 Williams 2012 References to other published versions of this review Geneen 2014