Red blood cell distribution width as a potential predictor of survival of pulmonary arterial hypertension associated with primary Sjogren's syndrome: a retrospective cohort study

Pulmonary arterial hypertension (PAH) is a severe complication and leading cause of mortality in patients with primary Sjogren's syndrome (pSS). This study was to investigate the overall survival rates and the utility of red blood cell distribution width (RDW) as a potential prognostic factor of pSS-PAH. This cohort study retrospectively enrolled 55 patients with pSS-PAH who were followed up at the Department of Rheumatology of Peking Union Medical College Hospital (PUMCH) between August 2007 and May 2017. The patients were stratified according to the level of RDW (<= 15.0 and >15.0%). Baseline demographics, laboratory results, pulmonary function conditions, hemodynamic assessments, and treatment regimens were analyzed. Cox proportional hazards regression analysis was used to identify whether RDW level is a factor related to adverse outcome. A total of 55 patients were recruited, with an average age of 38.9 +/- 9.3 years. Fifty-four were female (98.2%), and the average duration at the time of PAH diagnosis was 25.5 +/- 33.2 months. Higher RDW levels were found in patients who deceased in follow-up (13.8 +/- 2.6 vs 16.5 +/- 1.6%, p = 0.003) and with higher NYHA classes (13.8 +/- 1.8 vs 16.5 +/- 2.9%, p < 0.001). Patients with RDW >15% had a significantly worse overall survival than patients with RDW <= 15% (3-year survival rate 59.5 vs. 88.7% log-rank p = 0.015). Cox regression analysis identified RDW >15% as a prognostic factor for adverse outcome (HR 1.786, 95% CI 1.137-2.803, p = 0.012). RDW can serve as a potential negative prognostic factor of pSS-PAH.