Background Biologics (BIO) therapy has become general treatment in rheumatoid arthritis (RA) patients. One goal of BIO therapy is to stop BIO therapy after reaching targets to treat (Bio-free), another goal is to continue BIO therapy and sustain targets to treat. Some patients drop out from the BIO therapy for several reasons. In previous study, we found patient with diabetes mellitus (DM) might have low drug survival on BIO therapy.
Objectives The purpose of this retrospective study was to investigate the influence of DM on drug survival and treatment efficacy of BIO therapy in RA patients.
Methods A retrospective single-center study was conducted in patients with RA who started any of BIO (infliximab, etanercept, adalimumab, tocilizumab, abatacept, golimumab) between 2003 and 2013 in our institute. Patients were divided into two groups: diabetics (group D) and non-diabetics (group N). Baseline characteristics, BIO therapy continuation rate, and reasons for discontinuation were analyzed and compared with two groups using Chi squared test, Mann–Whitney U test, Wilcoxon signed-rank test and log-rank test. Switching one BIO to another was defined as continuation of BIO therapy. Treatment efficacy and quality of life (QOL) were assessed and compared in both groups at baseline and the last observation day, using the DAS28-CRP, SDAI, and the modified health assessment questionnaire (mHAQ).
Results A total of 245 patients were studied (30 patients for group D/215 patients for group N). RA duration, methotrexate (MTX) dose, prednisolone (PSL) dose, DAS28-CRP, SDAI, and mHAQ were similar between two groups at baseline (13.5±14.0 years vs. 10.8±10.3 years, 9.4±2.6 mg/week vs. 8.5±2.6 mg/week, 5.1±1.4mg/day vs. 5.0±1.5 mg/day, 5.0±0.97 vs. 4.7±1.2, 27.9±11.1 vs. 25.4±13.0, 1.0±0.7 vs. 0.8±0.7, for group D and group N, respectively; p>0.05 for all). We found significant difference between group D and group N at baseline in mean age (65.4±6.8 vs. 56.7±13.1 p<0.01), %female (63.3% vs. 85.5% p=0.03), RF positive rate (93.3% vs. 77.2% p=0.04), estimated glomerular filtration rate (77.6 ml/min/1.73 m2 vs. 92.9 ml/min/1.73 m2 p<0.01), PSL-concomitant rate (83.3% vs. 52.5% p<0.01), and MTX-concomitant rate (60.0% vs. 85.6% p<0.01). Drug survival of BIO therapy was significantly shorter in group D than in group N (Fig. 1). Continuation rate after 1, 3, 5 years was 76.4%, 68.9%, 41.3% for group D, and 90.5%, 83.6%, 75.2% for group N (p<0.01). The most common reason for quitting BIO therapy was infection in both groups. The rate of infection leading to discontinuation of BIO therapy was significantly higher in group D than in group N (16.7% vs. 5.6% p=0.03). Treatment efficacy and QOL at the last observation were significantly worse in group D than in group N (DAS28-CRP 3.07±1.49 vs. 2.05±0.97, SDAI 12.7±12.7 vs. 5.64±6.23 and mHAQ 0.69±0.52 vs. 0.46±0.59, for group D and group N, respectively; p<0.01 for all).
Conclusions Our data suggest that diabetic RA patients have high risk of infection leading to discontinuation of BIO therapy. The short drug survival of BIO therapy may be the reason for the poor treatment efficacy at the last observation in diabetic RA patients compared with that of non-diabetic RA patients. We conclude that DM is one of the considerable factors when starting the BIO therapy in RA patients.
Disclosure of Interest None declared