OP0221 HAVE 5-YEAR SURVIVAL RATE AND MORTALITY CHANGED IN PATIENTS WITH EARLY RHEUMATOID ARTHRITIS IN THE PAST TWENTY YEARS?-RESULTS FROM THE IORRA COHORT

Abstract

Background:The mortality of patients with rheumatoid arthritis (RA) had been reported as being worse than that of the general population [1, 2], but is expected to have improved over time because the progress in treatment of RA during the past twenty years has been actively adopted to RA management [3, 4]. However, the change in the mortality still remains controversial in patients with early RA [5, 6].Objectives:To investigate whether the vital prognosis of patients with early RA has changed in the past twenty years.Methods:The IORRA cohort is a large observational cohort established in 2000 at the Institute of Rheumatology, Tokyo Women’s Medical University. Essentially, all Japanese patients diagnosed with RA at our institute were registered and clinical parameters were assessed biannually. As there is no National Death Registry in Japan, we obtained death report from residual families who responded to our mail query to patients who failed to conduct the subsequent IORRA survey, from physicians of affiliated hospitals and from police in case they found dead patient outside of a hospital. In this study, the patients with early RA (less than 2 years of disease duration) who participated in the survey for the first time from 2001 to 2012 were included and observed for five years from the date of the initial survey. We classified patients into group A (enrolled in 2001-2006) and B (enrolled in 2007-2012). Five-year survival rate and standardized mortality ratio (SMR) were calculated for each group. SMR was calculated using the life tables in Japanese general population reported by the Ministry of Health, Labour and Welfare, Japan. The effects of loss to follow-up cases were evaluated by multiple imputation method as a sensitivity analysis of SMR.Results:A total of 3,217 patients with early RA were analyzed. The number of patients was 1,609 (79.4% female) in the group A and 1,608 (81.8% female) in B. The median age at baseline was 55 in both groups. Among a total of 3,217 patients, 486 (15.1%) patients were lost during 5-year follow-up; 213 (13.2%) in the group A and 273 (17.0%) in B, respectively. During the observational period, deaths were confirmed in 47 cases (2.9%) in the group A and 45 (2.8%) in B. Major causes of death included malignancies (28% in the group A, 38% in B), respiratory involvement (23% in the group A, 40% in B), cerebrovascular disorders (11% in the group A, 2% in B), and cardiovascular disorders (11% in the group A, 0% in B). The five-year survival rate was 88.8% for the group A and 87.8% for B, and the SMR was 0.81 (95%CI: 0.59-1.08) for the group A and 0.78 (0.57-1.04) for B when assuming all the lost to follow-up patients were alive for 5 years. In the sensitivity analysis assuming that the mortality rate of patients who were lost to follow-up was twice as that of the general population, the SMR was 0.90 (0.68-1.19) for the group A and 0.92 (0.68-1.23) for B.Conclusion:The mortality of patients with early RA in the past twenty years has been comparable to that of the Japanese general population. In addition, the SMR and the five-year survival rate did not change overtime.