Exercise for lower limb osteoarthritis: systematic review incorporating trial sequential analysis and network meta-analysis
BMJ 2013; 347 doi: https://doi.org/10.1136/bmj.f5555 (Published 20 September 2013) Cite this as: BMJ 2013;347:f5555
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We would like to thank Ida Svege and colleagues for their appreciation of our systematic review, and their important comments regarding the imbalance of evidence for the effectiveness of exercise for lower limb osteoarthritis, which - as we emphasised in our review - is dominated by trials in knee osteoarthritis. This imbalance was indeed compounded in our meta-analysis by the fact that we had to exclude two of the small number of available trials in patients with hip OA (Fernandes et al. (1) and Juhakoski et al. (2)). Exclusion of these two trials was not due to diagnostic criteria used for selecting study participants, as all trials using accepted, standardised clinical or radiological criteria for osteoarthritis were eligible for inclusion. We understand the confusion as we indeed referred to the ACR guidelines in our paper, but this was meant to be an example which we should have clarified.
The reason for exclusion of these two trials was related to the fact that both these trials investigated exercise in addition to another intervention (GP care or patient education) versus the GP care or patient education alone. These designs are highly useful in direct comparisons, as they provide an estimate of the effectiveness of exercise as an add-on to another commonly used intervention for osteoarthritis. In a network meta-analysis, however, where direct as well as indirect comparisons are included in the analysis, it is difficult to disentangle the effect of exercise from such combined treatments. Therefore, we decided to exclude trials which explicitly stated that exercise was used in combination with another intervention package, and also excluded such arms from the analysis for trials with more than two treatment arms. We realise this distinction can be difficult to make in circumstances where investigators have combined exercise with other co-interventions, but designed and presented this as a single package of care (e.g. Hurley et al. (3)). However, the decision to exclude trials/arms that explicitly offered combinations of treatments was made a priori and applied to all potentially eligible trials, regardless of the location of osteoarthritis.
We fully agree with the authors of this letter that there is a strong need for high quality trials in patients with hip osteoarthritis. A network meta-analysis focusing on exercise interventions was not yet feasible for hip osteoarthritis, but the two highlighted trials do provide an important contribution to the growing body of evidence. Future systematic reviews and meta-analysis should provide more conclusive evidence on the effectiveness of exercise interventions for hip osteoarthritis. With the impending publication of several new trials there will also be an opportunity for earlier application of sequential analysis which may help investigators and funders recognise when sufficient evidence on the basic question of effectiveness vs no exercise control has been accrued for hip osteoarthritis.
1. Fernandes L, Storheim K, Sandvik L, Nordsletten L, Risberg MA. Efficacy of patient education and supervised exercise vs patient education alone in patients with hip osteoarthritis: a single blind randomized clinical trial. Osteoarthritis Cartilage 2010;18(10):1237-1243.
2. Juhakoski R, Tenhonen S, Malmivaara A, Kiviniemi V, Anttonen T, Arokoski JP. A pragmatic randomized controlled study of the effectiveness and cost consequences of exercise therapy in hip osteoarthritis. Clin Rehabil 2011;25(4):370-83.
3. Hurley MV, Walsh NE, Mitchell HL, Pimm TJ, Patel A, Williamson E, Jones RH, Dieppe PA, Reeves BC. Clinical effectiveness of a rehabilitation program integrating exercise, self-management, and active coping strategies for chronic knee pain: a cluster randomized trial. Arthritis Rheum 2007;57(7):1211-9.
Competing interests: No competing interests
We highly acknowledge the comprehensive work conducted by Uthman and his co-authors(1), and their effort towards comparing different exercise approaches for lower extremity osteoarthritis (OA).
Nevertheless, our concern targets the handling of evidence for exercise in hip OA. Overall, few randomized trials have investigated the effect of exercise modalities in hip OA. Therefore, evidence is sparse, and largely based on RCTs including both knee and hip OA patients or RCTs in knee OA only. To our understanding, this present review fits into this tradition. Of the 60 trials included in this systematic review and meta-analysis, 44 included patients with knee osteoarthritis exclusively, 14 included patients with knee and/or hip OA, while only two of the studies included hip OA patients exclusively.
To our knowledge, no general consensus exists regarding diagnostic criteria for hip OA. The American College of Rheumatology criteria for classification of osteoarthritis are widely used, but also other classification criteria exists. By including only the criteria proposed by Altman(2) as selection criteria, the authors have consequently excluded several trials using other classification systems. In the field of the efficacy of exercise therapy in hip OA this seems to be particularly selective, as so few trials exist. The studies by Tak et al(3) and Stener-Victorin et al(4) are the only two studies included in this systematic review, that exclusively have included patients with hip OA. We consider that inclusion of the studies by Juhakoski et al(5) and Fernandes et al(6) would have provided further knowledge that may have altered the evidence of exercise treatment in this patient group.
We question the appropriateness in evaluating the aggregated effect of exercise in knee and hip osteoarthritis. The trials forming the basis of this meta-analysis are imbalanced with regard to site of affected limb, particularly as some of the very few available trials are excluded by the use of other classification criteria for osteoarthritis. As the authors themselves emphasized, the findings in this systematic review was mainly based on patients with knee OA, and an increased focus on research evaluating the role and effect of exercise in hip OA is needed. We impatiently await the results of ongoing studies evaluating the effect of different exercise modalities in patients with hip OA(7-11).
Reference List
(1) Uthman OA, van der Windt DA, Jordan JL et al. Exercise for lower limb osteoarthritis: systematic review incorporating trial sequential analysis and network meta-analysis. BMJ 2013;347:f5555.
(2) Altman RD. The classification of osteoarthritis. J Rheumatol Suppl 1995 February;43:42-43.
(3) Tak E, Staats P, Van HA, Hopman-Rock M. The effects of an exercise program for older adults with osteoarthritis of the hip. J Rheumatol 2005 June;32(6):1106-1113.
(4) Stener-Victorin E, Kruse-Smidje C, Jung K. Comparison between electro-acupuncture and hydrotherapy, both in combination with patient education and patient education alone, on the symptomatic treatment of osteoarthritis of the hip. Clin J Pain 2004 May;20(3):179-185.
(5)Juhakoski R, Tenhonen S, Malmivaara A, Kiviniemi V, Anttonen T, Arokoski JP. A pragmatic randomized controlled study of the effectiveness and cost consequences of exercise therapy in hip osteoarthritis. Clin Rehabil 2010 November 15.
(6) Fernandes L, Storheim K, Sandvik L, Nordsletten L, Risberg MA. Efficacy of patient education and supervised exercise vs patient education alone in patients with hip osteoarthritis: a single blind randomized clinical trial. Osteoarthritis Cartilage 2010 October;18(10):1237-1243.
(7) Jensen C, Roos EM, Kjaersgaard-Andersen P, Overgaard S. The effect of education and supervised exercise vs. education alone on the time to total hip replacement in patients with severe hip osteoarthritis. A randomized clinical trial protocol. BMC Musculoskelet Disord 2013;14:21.
(8) van Es PP, Luijsterburg PA, Dekker J et al. Cost-effectiveness of exercise therapy versus general practitioner care for osteoarthritis of the hip: design of a randomised clinical trial. BMC Musculoskelet Disord 2011;12:232.
(9) Krauss I, Steinhilber B, Haupt G, Miller R, Grau S, Janssen P. Efficacy of conservative treatment regimes for hip osteoarthritis--evaluation of the therapeutic exercise regime "Hip School": a protocol for a randomised, controlled trial. BMC Musculoskelet Disord 2011;12:270.
(10) Poulsen E, Christensen HW, Roos EM, Vach W, Overgaard S, Hartvigsen J. Non-surgical treatment of hip osteoarthritis. Hip school, with or without the addition of manual therapy, in comparison to a minimal control intervention: protocol for a three-armed randomized clinical trial. BMC Musculoskelet Disord 2011;12:88.
(11) Bennell KL, Egerton T, Pua YH et al. Efficacy of a multimodal physiotherapy treatment program for hip osteoarthritis: a randomised placebo-controlled trial protocol. BMC Musculoskelet Disord 2010;11:238.
Competing interests: No competing interests
After going through this article one is tempted to infer that exercises will prevent so many problems in old age1. As such it is a well established fact that exercises guard against osteoporosis and hence fractures in old age2. However, the intensity, duration, frequency and type of exercises are to be worked out2 as per individual as indiscriminate exercising may cause various musculoskeletal injuries.
References:
1. BMJ 2013;347:f5555
2. S J Birge and G Dalsky. The role of exercise in preventing osteoporosis.Public Health Rep. 1989 Sep-Oct; 104(Suppl): 54–58.
Competing interests: No competing interests
Re: Exercise for lower limb osteoarthritis: systematic review incorporating trial sequential analysis and network meta-analysis
We would like to congratulate Uthman et al. [1] on their thorough and extensive review on an important topic. We would however also like to point out that the statement: “The totality of evidence, although largely based on trials in knee OA shows that further trials of exercise versus no exercise are unlikely to overturn this positive result.”, together with the similar statement in the Abstract, has potential to mislead the reader in believing future research investigating effectiveness of exercise for hip osteoarthritis (OA) is no longer needed. In fact, only 139 patients were enrolled in the two trials that included patients with hip OA only and for which no concurrent knee OA could potentially confound results. Svege and her colleagues in their letter rightfully point out that the practice of aggregating results from trials investigating the effectiveness of exercise interventions in hip and knee OA is unfortunate because it could potentially mask differences in response to exercise therapies between patients with hip and knee OA.
Finally, in response to the letter by Svege and her colleagues, we would like to point out that the trial by Poulsen et al. [2] does not fit the objective nor the inclusion criteria of the Uthman review. This is because the primary aim was to determine, in a proof-of- principle study, the effectiveness of a patient education program with or without the addition of manual therapy when compared to a simple program of home stretching exercises in patients with early OA of the hip. The results of our trial were recently published in Osteoarthritis & Cartilage [3].
1. Uthman OA, van der Windt DA, Jordan JL, et al. Exercise for lower limb osteoarthritis: systematic review incorporating trial sequential analysis and network meta-analysis. BMJ 2013;347:f5555 doi: 10.1136/bmj.f5555[published Online First: Epub Date]|.
2. Poulsen E, Christensen HW, Roos EM, et al. Non-surgical treatment of hip osteoarthritis. Hip school, with or without the addition of manual therapy, in comparison to a minimal control intervention: Protocol for a three-armed randomized clinical trial. BMC.Musculoskelet.Disord. 2011;12:88
3. Poulsen E, Hartvigsen J, Christensen HW, et al. Patient education with or without manual therapy compared to a control group in patients with osteoarthritis of the hip. A proof-of-principle three-arm parallel group randomized clinical trial. Osteoarthritis and cartilage / OARS, Osteoarthritis Research Society 2013;21(10):1494-503 doi: 10.1016/j.joca.2013.06.009[published Online First: Epub Date]|.
Competing interests: No competing interests