Medication adherence has an impact on disease activity in rheumatoid arthritis: a systematic review and meta-analysis

Disease activity of rheumatoid arthritis (RA) patients was often measured by the 28-joint count disease activity score (DAS-28), which consists of 28 swollen and tender joint counts, patient's assessment of disease activity (visual analog scale [VAS]) and erythrocyte sedimentation rate. C-reactive protein was also used to measure disease activity in RA patients. The aim was to explore the impact of medication adherence on disease activity in patients with RA.

A systematic search was performed in major electronic databases (PubMed, Web of Science, the Cochrane Library, CNKI, VIP and Wan fang) to identify studies reporting medication adherence and disease activity in RA patients. Results were expressed as mean difference (MD) and 95% CI.

A total of seven identified studies matched the inclusion criteria, reporting on a total of 1,963 adult RA patients in the analysis. The total score of DAS-28 was significantly lower in adherent patients than in nonadherent subjects (MD =-0.42, 95% CI [-0.80, -0.03], P=0.03). Similarly, a significant difference was observed between medication adherent and nonadherent groups in erythrocyte sedimentation rate (MD =-7.39, 95% CI [-11.69, -3.08], P<0.01) and tender joint count (MD =-1.29, 95% CI [-2.51, -0.06], P=0.04). Interestingly, the results of the meta-analysis showed no significant difference between medication adherent and nonadherent patients in swollen joint count (MD =-0.16, 95% CI [-2.13, 1.80], P=0.87), visual analog scale (MD =1.41, 95% CI [-3.68, 6.50], P=0.59) and C-reactive protein (MD =0.35, 95% CI [-0.64, 1.34], P=0.49).

The study suggests that RA patients with higher medication adherence tended to have lower disease activity.