Sustained maintenance of exercise induced muscle strength gains and normal bone mineral density in patients with early rheumatoid arthritis: a 5 year follow up

Abstract

Objective: To investigate at 5 years whether an initial 2 year home based strength training period imposes sustained effects on muscle strength, bone mineral density (BMD), structural joint damage, and on disease activity in patients with early rheumatoid arthritis (RA).

Methods: Seventy patients were randomised either to perform home based strength training with loads of 50-70% of repetition maximum (EG) or range of motion exercises (CG). Both groups were encouraged to take part in aerobic activities 2-3 times a week. Maximal muscle strength of different muscle groups was measured by dynamometers, and BMD at the femoral neck and lumbar spine by dual x ray densitometry. Disease activity was assessed by the 28 joint disease activity score, and joint damage by x ray findings.

Results: 62 patients completed 2 years' training and 59 patients attended check up at 5 years. Mean (SD) maximum muscle strength indices increased from baseline to 2 years-in EG from 212 (78) kg by a mean (95% CI) of 68 (55 to 80) and in CG from 195 (72) kg by 35 (13 to 60) kg-and remained at that level for the next 3 years. Development of BMD in EG tended to be more favourable than that in CG. Muscle strength training was not detrimental to joint structures or disease activity.

Conclusion: The patients' exercise induced muscle strength gains during a 2 year training period were maintained throughout a subsequent self monitored training period of 3 years. Despite substantial training effects in muscle strength, BMD values remained relatively constant. Radiographic damage remained low even at 5 years.

Figure 1

Trial profile.

Figure 2

Disease modifying antirheumatic drugs taken by the experimental (A) and 31 control (B) patients with early RA. The percentage of patients taking each drug or combination over 5 years is shown. INFL, infliximab; COMBO+MTX, combination of DMARDs including methotrexate; DMARD, disease modifying antirheumatic drug; MTX, methotrexate; COMBO–MTX, combination of DMARDs without methotrexate; SSZ, sulfasalazine; MYO, intramuscular gold; HCQ, hydroxychloroquine.

Figure 3

Bone mineral density of the lumbar spine (A) and femoral neck (B) in the experimental (EG) and control groups (CG) at baseline and after 5 years' follow up.

Figure 4

Individual values of the Larsen scores in experimental (EG) and control (CG) groups at baseline and after 5 years' follow up.