Burden of Pulmonary Arterial Hypertension (PAH) on Patients Admitted for Asthma: A Nationwide Analysis, 2016-2020

Background Pulmonary arterial hypertension (PAH) is known to impact other pulmonary disease outcomes, but there is a lack of data showing the degree of its impact. This study aims to elucidate the burden that PAH brings to patients admitted due to asthma. Methods The National Inpatient Sample (NIS) Database 2016-2020 was used to identify patients admitted due to asthma exacerbation. Patients admitted with a primary diagnosis of asthma, with or without a secondary diagnosis of PAH, were identified using International Classification of Diseases, 10th Edition (ICD-10) codes. PAH was classified using ICD-10 codes, specifically Group 3 PAH. The primary outcome was all-cause in-hospital mortality. Secondary outcomes were length of stay, resource utilization, and the necessity for endotracheal intubation. STATA v.13 (StataCorp LLC, College Station, TX, USA) was used for univariate and multivariate analysis. Data were considered statistically significant at p < 0.05. Results From 2016 to 2020, 491,990 patients were admitted due to asthma, and 7,860 had PAH. Patients with asthma and PAH had a 226% higher chance of dying during the index admission (OR 2.26; 95% CI 1.27-4.03; p = 0.006), an additional 0.75 days of hospital stay (regression coefficient 0.75; 95% CI 0.54-0.95; p < 0.001), and an average of $11,558.41 more spent per hospital stay (regression coefficient 11,558.41; 95% CI 8,657.33-14,459.49; p < 0.001). These patients had no statistically significant difference in endotracheal intubation rates (OR 1.69; 95% CI 0.80-1.94; p = 0.42). Discussion Asthma patients with PAH experience higher all-cause in-hospital mortality compared to those with asthma alone. These results highlight the increased risk associated with the coexistence of PAH and asthma, potentially due to the added hemodynamic burden imposed by PAH, which exacerbates respiratory and cardiovascular compromise. Activation of the transcription factor nuclear factor of activated T cells (NFAT) is an important marker known to link PAH and asthma. Due to its activation in both diseases, it may serve as a critical pathway for developing more effective therapeutic strategies targeting both conditions. There is also some research suggesting that increased neutrophils in asthma are correlated with PAH. Some limitations of using the NIS database are that it is subject to coding errors, misclassification, and variability across institutions, potentially affecting diagnostic and procedural accuracy. Conclusion PAH significantly impacts in-hospital outcomes in patients admitted due to asthma; thus, physicians should be aware of this difference. Future studies are needed to differentiate PAH patients by severity and to verify whether PAH treatment reverses this impact.