FRI0062 THE USE OF A COMORBIDITY INDEX FOR PREDICTING CLINICAL RESPONSE IN RHEUMATOID ARTHRITIS PATIENTS RECEIVING THEIR FIRST BIOLOGICAL AGENT
Authors: S. Garcia, B. M. Fernandes, G. Terroso, M. Bernardes, L. Costa
Journal: Annals of the Rheumatic Diseases (2020)

Background: Several studies in Rheumatoid arthritis (RA) have suggested that a greater number of comorbidities is associated with worse functional status and disease activity measures. However, it is useful to use a composite comorbidity index, such as Rheumatic Disease Comorbidity Index (RDCI) that is validated for the use in patients with rheumatic diseases, to better understand the overall role of comorbidities in treatment outcomes. Objectives: To evaluate the impact of comorbidities on 12-month clinical response in a cohort of patients with RA treated with a first-line biologic disease-modifying antirheumatic drug (bDMARD), by using the RDCI. Methods: Observational retrospective study was performed including consecutive patients with the diagnosis of RA followed at our Rheumatology Department. The prevalence of comorbidities was computed, and patients were stratified according to RDCI for evaluating its role in clinical response disease activity at baseline and follow up (6 and 12 months). Correlations between variables were studied using Spearman correlation analysis, comparison between groups was performed using Kruskal-Wallis and Chi-square. A multivariate logistic regression model was developed to examine the role of RDCI along with other baseline factors as potential predictor of achieving remission, low disease activity (LDA), and EULAR good/moderate response. Statistical analyses were performed using SPSS statistical software, version 23.0. Results: A total of 251 patients were included: 83.7% (n=210) females, mean age of 58 (± 11.10) years old, with a median disease duration of 16.11 years [10.79 - 23.04]. The majority exhibited a very high or high disease activity at baseline (median DAS28 3V 5.48 [4.70 – 6.19]) and 90% (n=226) of them were concomitantly using corticosteroids and/or other disease-modifying anti-rheumatic drugs (129 with methotrexate (MTX), 96 with leflunomide and 35 with sulfasalazine). The most frequently reported comorbidities were cardiovascular disorders (37.5%), osteoporosis (7.6%) and depression (6.8%). The median RDCI score was 1.0 [0.0 – 2.0] and the majority of patients (63.6%) carried at least one comorbidity. When comparing baseline demographic and clinical characteristics of the 4 subgroups, stratified according to RDCI score (RDCI=0, 1, 2, or ≥3), we found statistically significant differences in age, age at diagnosis, sex and the prescribed anti-TNF agent (p&lt;0.05). There was a progressive increase in the mean age as the RDCI score increased between the subgroups. RDCI strongly correlates with the number of comorbidities (NC) (r=0.764, p&lt;0.01). NC was weakly correlated with patient and physician global assessment of disease activity (pVAS and phVAS) (r=0.183, p&lt;0.01 and r=0.196, p=0.019, respectively), DAS28 3V (r=0.192, p=0.046) and HAQ-DI (r=0.301, p&lt;0.01) at 6 months. Moreover, RDCI poorly correlated with CRP (r=0.192, p=0.01), pVAS (r=0.183, p=0.02) and HAQ-DI (r=0.202, p&lt;0.01). Weaker correlations were also found at 12 months: NC with pVAS (r= 0.196, p=0.02), DAS28 3V (r=0.216, p=0.01) and HAQ-DI (r=0.187, p=0.04); RDCI with phVAS (r= 0.196, p=0.04). The 12-month DAS28 remission rate was 37.8% (n=95); 6.7% (n=17) achieved EULAR good response and 54.4% (n=137) a moderate EULAR response. RDCI was not an independent predictor of DAS remission (OR 0.794, 95% CI 0.561- 1.125, p = 0.194) nor it was of EULAR good/moderate response (OR 0,720, 95% CI 0.430- 1.206, p= 0.212). Conclusion: Although our data point to a weak association between morbidities, assessed by the RDCI, and response to a first bDMARD, it is important to consider this simple and useful tool in future prospective and broader studies, since information bias regarding comorbidities may have been responsible for our results. Disclosure of Interests: Salomé Garcia: None declared, Bruno Miguel Fernandes: None declared, Georgina Terroso: None declared, Miguel Bernardes Speakers bureau: Abbvie, Amgen, Biogen, Eli-Lilly, Glaxo-Smith-Kline, Pfizer, Janssen, Novartis, Lúcia Costa: None declared