Pulmonary arterial hypertension (PAH) is a relatively rare complication of systemic lupus erythematosus (SLE), but systemic hypertension may be a predictive factor of PAH in this population, according to a study published in Arthritis Research & Therapy.
Investigators conducted a retrospective cohort study with data abstracted from Taiwan’s National Health Insurance Research Database (NHIRD). With 99% of the Taiwanese population enrolled, the NHIRD contains detailed healthcare information for more than 23 million individuals. Investigators used the International Classification of Diseases, ninth revision, clinical modification (ICD-9-CM) code for SLE to identify patients with the condition. Patients with SLE index dates between January 1, 2000, and December 31, 2013, were selected for analysis. Baseline comorbidities including diabetes, hyperlipidemia, hypertension, and chronic kidney disease were identified based on 1 inpatient claim or 3 ambulatory claims prior to SLE diagnosis. PAH diagnosis was defined as having at least 3 outpatient visits or at least 1 inpatient visit with the associated ICD-9-CM code. Investigators used the Kaplan-Meier method to estimate PAH prevalence and survival of patients with both SLE and PAH. Cox proportional hazards regression models were used to identify predictors of PAH development.
Among 15,783 patients with SLE, PAH developed in 336 (2.13%) during the study course. Women comprised approximately 90% of each diagnostic group. The mean interval from SLE diagnosis to PAH diagnosis was 3.66 years, with an interquartile range of 0.69 to 5.79. The 3- and 5-year cumulative incidence of PAH were 1.2% and 1.8%, respectively, and PAH occurred in the majority (70.0%) of patients within 5 years of SLE onset.
Comorbidity rates were relatively low among patients, although hypertension was significantly higher among those with both SLE and PAH (P =.006). Additionally, patients with hypertension had a significantly higher risk for PAH than those without hypertension (P <.001).
After adjusting for age, sex, and other comorbidities, systemic hypertension remained an independent predictor of PAH (adjusted hazard ratio [aHR], 2.17; 95% CI, 1.59-2.97). The 1-, 3-, and 5-year survival rates of patients with SLE following PAH diagnosis were 87.7%, 76.8%, and 70.1%, respectively. Mortality risk among patients with PAH increased 120% compared with patients without PAH (aHR, 2.20; 95% CI, 1.78-1.71).
Per these data, PAH was a rare complication of SLE and typically occurred within the first 5 years following SLE diagnosis. Further research into potential PAH risk factors is necessary to improve treatment options for patients with comorbid SLE and PAH.
Chen H-A, Hsu T-C, Yang S-C, et al. Incidence and survival impact of pulmonary arterial hypertension among patients with systemic lupus erythematosus: a nationwide cohort study. Arthritis Res Ther. 2019;21(1):82.