Background/Purpose: Pulmonary arterial hypertension (PAH) is a rare manifestation of Systemic Lupus Erythematosus (SLE) with increased morbidity and mortality. It has historically been underdiagnosed in SLE patients due to nonspecific symptoms and overlap with other conditions but has recently come into light as an important SLE associated complication due to increased awareness. This study aims to analyze yearly trends in PAH and its types in SLE population in the U.S. as well as in-hospital mortality.

Methods: We performed a retrospective review of annual trends in PAH among SLE patients using the National Inpatient Sample (NIS) from 2016 – 2020. Hospitalizations with SLE were identified using ICD-10 codes and cases with a concurrent PAH diagnosis were included. We examined the baseline demographic characteristics and inpatient mortality rate. Yearly trend in PAH among SLE patients was analyzed. Trends across various WHO groups of PAH in SLE patients were also compared. Statistical analysis was performed on STATA 7, with P-value less than 0.05 was considered statistically significant.

Results: A total of 41,445 hospitalizations with concurrent SLE and PAH were identified between 2016 and 2020. Most patients were females (89.4% in 2020) and by 2020, white race comprised 39.9%, African Americans 37.9%, Hispanic 13.2% and Asian 8.9%. Mean age increased from 54.5 years in 2016 to 57.4 years in 2020. Overall, yearly hospitalizations of SLE with PAH increased substantially from 200 in 2016 to over 12,000 by 2018 (p < 0.001). (Figure 1) This was also seen according to WHO groups of PAH, especially for Group 5 (Figure 2). There was a significant increase in comorbidity burden, with the proportion of patients with a CCI ≥4 increasing from 6.8% in 2016 to 77.2% in 2019. Comorbidities with notable uptrend included congestive heart failure (CHF) (47.5% to 63.1%, p = 0.001), hyperlipidemia (20.0% to 35.9%, p = 0.005), and protein-energy malnutrition (PEM) (7.5% to 11.8%, p = 0.005). Despite rising complexity, in-hospital mortality was 5.0% in 2016 and continued like this to 2020 with 4.9% (p = 0.249). (Figure 3) Mean length of stay (7.3 days in 2016 vs 7.2 in 2020) and Total Hospital Charges ($86,676 in 2016 and $96,961 by 2020) remained stable. However, rates of adverse in-hospital events increased, including mechanical ventilation (MV) (2.5% to 8.1%, p =0.004), acute myocardial infarction (AMI) (5.0% to 7.5%, p = 0.001), acute respiratory failure (ARF) (12.5% to 16.6%, p = 0.001), and pulmonary embolism (PE) (0% to 2.1%, p =0.019). There was no change in the trend for sepsis, acute kidney injury (AKI), need for pressors, or cerebrovascular accident (CVA).

Conclusion: Hospitalizations of SLE patients with PAH increased significantly from 2016 to 2020, with an uptrend in comorbidities including CHF, hyperlipidemia and PEM. There was an increase in-hospital events including MV, AMI, ARF and PE. Despite this rise in complexity and events, mortality and healthcare utilization remained similar from 2016 to 2020. These findings highlight the evolving clinical profile of SLE patients with more frequent PAH diagnosis over time, and underscores the need for targeted interventions to improve outcomes in patients with SLE-related PAH.

Figure 1: Yearly trends of PAH with and without SLE

Figure 2: Yearly trends of SLE with PAH by WHO GROUP

Figure 3: Yearly in-hospital mortality trend in SLE with PAH

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/evolving-trends-in-pulmonary-arterial-hypertension-among-systemic-lupus-erythematosus-patients-a-nationwide-analysis/