LAUSR

Background: Identifying clinical variables that predict outcome of Systemic lupus erythematosus (SLE)-pulmonary arterial hypertension (PAH) is important.[1] Data focusing on SLE-PAH is lacking as previous studies were based on connective tissue disease (CTD)-PAH patients. Objectives: To examine clinical, serological and echocardiographic features that are 1) associated with SLE-PAH at baseline and 2) predictors of mortality in SLE-PAH. Methods: Data on SLE-PAH patients (SLE-PAH group, n=67) attending the Prince of Wales Hospital, from 2008 to 2018 was retrieved. Diagnosis of PAH was based on echocardiogram showing pulmonary artery systolic pressure (PASP) > 30mmHg. Age-, sex- and disease duration-matched SLE patients with PASP < 30mm Hg were selected from the same database as control (SLE-non PAH group, n=154). Clinical, serological, echocardiographic features and medication at baseline (PAH diagnosis) were collected. Censor date was death or last visit on or before 31st December 2018. PAH targeted therapy and immunosuppressant used for PAH were recorded after diagnosis of PAH. Hazard ratio were analysed by cox regression model, and adjusted by age-, sex-, disease-duration, comorbidities and baseline medication. Results: The cohort (n=221) mean age was 42.7 +/- 12.6 with 96.3% female, and a disease duration of 8.26 +/- 7.61 years. At baseline, the SLE-PAH group had higher anti-ds DNA titre; lower haemoglobin level; higher prevalence of renal impairment; but a lower prevalence of arthritis and thrombocytopenia/neutropenia and anti-phospholipid antibodies compared to the control (Table 1). SLE-PAH group’s echocardiogram had a higher prevalence of reduced left ventricular ejection fractions, moderate-severe tricuspid regurgitation and pericardial effusion compared to the control (Table 1). Amongst the SLE-PAH group, 11/67 had a right heart catherization done and all were confirmed to have PAH. 8/11 patients received PAH specific treatment and 23/67 received escalated immunosuppressive therapy for presumed PAH, within 1 years of PAH diagnosis. The mortality rate of the SLE-PAH group was 3.82 (95% confident interval 1.50-9.83; p=0.005) compared to the control after adjusting for baseline parameters and medication used after the diagnosis of PAH. Poor prognostic factors at baseline are summarized in table 2.Table 1. Comparison between SLE-PAH and control at baseline SLE non-PAH (N=154) SLE-PAH (N=67) p-value Female 149 (96.8%) 64 (95.5%) 0.701 Age, Mean (SD) 41.84 (11.76) 44.78 (14.18) 0.111 Follow up time (year) [Median (IQR)] 9.78 (4.39-12.42) 8.24 (4.54-12.07) 0.835 Disease duration (year), Median (IQR) 6.85 (1.29-11.77) 7.33 (0.94-15.06) 0.681 Death at end of follow up (%) 8/154 (0.05%) 14/67 (20.1%) 0.001 Renal impairment 25/154 [16.3%] 19/67 [29.7%] 0.026 Arthritis 91/154 [59.9%] 29/67 [43.3%] 0.023 Thrombocytopenia/neutropenia 78/154 [51.3%] 24/67 [35.8%] 0.047 Anti-ds DNA titre(median [IQR]) 52 IU/ml [IQR 0-292.5] 160 IU/ml [IQR 0-789.5] 0.036 Haemoglobin(median [IQR]) 11.7 g/dL [IQR 10.5-12.9] 10.8 g/dL [IQR 10-10.2] 0.009 Anti-phospholipid antibodies 38/154 [25.5%] 8/67 [12.1%] 0.027 Reduced left ventricular ejection fractions 1/154 [0.6%] 6/67 [9%] 0.003 Moderate-severe tricuspid regurgitation 2/154 [1.3%] 20/67[29.9%] <0.001 Pericardial effusion 22/154 [14.3%] 17/67 [25.4%] 0.047Table 2 Predictors of mortality in SLE-PAH at baseline Alive (N=53) Death (N=14) p-value Hyponatremia 7/49 [14%] 4/12 [30.8%] p=0.011* Renal impairment 11/51 [21.6%] 8/13 [61.5%] p=0.007* Severe tricuspid regurgitation 2/53 [3.8%] 2/14 [14.3%] p=0.071 Conclusion: SLE-PAH had 3.8-fold increase in mortality despite treatment with PAH specific therapy and immunosuppressants. Hyponatremia and renal disease were associated with poor survival outcome in SLE-PAH patients. Reference: [1] Raina, A, et al. European Respiratory Review, 2016 Disclosure of Interests: None declared