Impact of biologic therapy on functional status in patients with rheumatoid arthritis--a meta-analysis

Objective: Using meta-analysis methods, this study aimed to estimate the impact of biologic agents on physical function in patients with RA.

Methods: A systematic literature search was conducted independently by two investigators. Double-blind randomized controlled trials (RCTs) investigating the efficacy of abatacept, adalimumab, certolizumab, etanercept, golimumab, infliximab or rituximab in approved dosages in comparison with treatment with non-biologic disease-modifying anti-rheumatic drugs (nbDMARDs) and placebo were included. The outcome parameter was improvement in function measured by the standardized mean difference (SMD) of HAQ scores. The SMD is the difference of the change in HAQ between biologic and DMARD comparator groups divided by the pooled standard deviation. Mixed effect models were applied separately for RCTs with DMARD-naive patients and those with DMARD inadequate responders (IRs).

Results: Thirty-five RCTs were included in the analysis, 10 with DMARD-naive patients and 25 with DMARD IRs. Overall, biologics led to a greater improvement of physical function than nbDMARDs, with an SMD of the HAQ of 0.44 (95% CI 0.38, 0.50). The improvement was greater for DMARD IRs (SMD 0.48, 95% CI 0.41, 0.56) than for DMARD-naïve patients (SMD 0.32, 95% CI 0.23, 0.41). There were no significant differences between individual biologics in both groups.

Conclusion: Treatment with biologics led to a clinically relevant greater improvement in physical function than treatment with nbDMARDs. Our results suggest that the improvement found on the group level was caused by a clinically relevant improvement on the patient level in more than 50% of the patients.