Aim: The clinical importance of the anti-Ro antibody has not been completely understood. This study investigated identification of the association between mortality and clinical features in patients with autoimmune rheumatic diseases and detectable anti-Ro antibody titers.
Methods: We retrospectively analyzed a total of 336 patients with autoimmune rheumatic diseases and positive anti-Ro antibody titers from January 2012 to January 2015. Clinical manifestations and other autoantibodies detected during the follow-up period were identified. Cumulative survival rates were assessed by Kaplan-Meier analysis. Differences between survival curves for each risk factor were analyzed by log-rank test. The relative risk of mortality was assessed using standardized mortality ratios (SMRs).
Results: There was no difference in the mortality rates of patients with autoimmune rheumatic diseases with or without detectable anti-Ro antibody (SMR: 1.373, 95% CI: 0.539-2.791). Six patients (4 with systemic lupus erythematosus [SLE] and two with Sjögren's syndrome [SS]) died during the follow-up period. In the whole study population, the mortality rate of patients with lymphopenia was higher than those without lymphopenia (P = 0.023). In a sub-group of patients with both SLE and SS, Kaplan-Meier analysis showed that lymphopenia and interstitial lung disease were associated with increased mortality (P = 0.024 and P = 0.023, respectively).
Conclusion: This study demonstrated that presence of the anti-Ro antibody was not associated with increased mortality in patients with autoimmune rheumatic disease. Conversely, we found that lymphopenia was independently associated with mortality in patients with autoimmune rheumatic disease.
Keywords: Sjögren’s syndrome; anti-Ro antibody; mortality; systemic lupus erythematosus.
© 2018 Asia Pacific League of Associations for Rheumatology and John Wiley & Sons Australia, Ltd.