Evaluation of comorbid diseases of rheumatoid arthritis patients followed up in Hacettepe University Hospital rheumatology outpatient clinic and receiving biological treatment

The aim of this study is to determine the prevalence of comorbidities accompanying Rheumatoid Arthritis (RA) patients receiving biological DMARD (bDMARD) treatment, to examine the course of these diseases under biological treatment, and to determine the effect of comorbidities on disease activity. The study included 581 RA patients who were followed up in the Department of Rheumatology at Hacettepe University between 2013 and 2020 and received bDMARD treatment. All patient records from the date of the first bDMARD were reviewed retrospectively. Accordingly, 143 (24.6%) of the patients were male. The mean age at last visit was 50.3 (13.8). The mean follow-up period was 26.0 (20.9) months. Charlson comorbidity index was calculated in all patients, with a mean of 2.43 (1.72) and a median of 2.0 (1-13). 228/581 (39.2%) patients had at least one comorbidity. 41.1% of patients were obese at the start of BDMARD. Women were heavier than men (27.5 versus 29.8 p:0.002). At the last visit, 42.1% of 516 patients with known BMI were obese. Diabetes mellitus was present in 13.8% of patients with known diabetes history at the start of BDMARD. At follow-up, 21 patients developed diabetes, and the incidence of diabetes was calculated as 2.47 (95% CI: 1.62-3.77) in 100 patient-years. At the beginning of BDMARD, 28.6% of the patients had hypertension. LDL-C was found to be high in 51.4%, TG in 25.5%, and total cholesterol in 17.4% of patients with known lipid parameters. Coronary artery disease (CAD) was present in 42 (7.2%) patients, 29 of them were found to have premature CAD. At follow-up, 17 patients developed CAD, and the incidence of CAD was 1.84 (95% CI 1.15-2.94) in 100 patient-years, and the incidence of premature CAD was 1.08 (95% CI 0.58-2.0) in 100 patient-years. Obesity was more common in patients with a high DAS-28 score before BDMARD. It was observed that those with high HAQ-DI scores were mostly women, were older, had a higher BMI, had a higher number of comorbidities and had higher cardiovascular risks. In the multivariate analysis, it was observed that the presence of obesity at the beginning of bDMARD negatively affected the DAS-28 treatment response (OR 1.04, 95% CI 1.0-1.08). In conclusion, comorbidities appear to be important in the treatment response of RA patients receiving bDMARDs. Keywords: Rheumatoid arthritis, biologic disease-modifying anti-rheumatic drugs (bDMARDs), comorbidity, disease activity