Prevalence of Pulmonary Hypertension in Patients Hospitalized with Sickle Cell Crisis

Introduction: Sickle cell syndromes are a group of hereditary blood disorders that include hemoglobinopathies resulting from either homozygous inheritance, such as sickle cell anemia (HbSS), or compound heterozygous inheritance with another mutant globin gene, which could be either alpha-globin gene or beta-globin gene, or gamma-globin gene, examples of such syndromes include sickle-HbC disease (HbSC), sickle β0 thalassemia (HbSβ0), and sickle β+ thalassemia (HbSβ+). The term sickle cell disease (SCD) includes genotypes commonly associated with chronic hemolytic anemia and vaso-occlusive pain crises. These most commonly include homozygous sickle cell anemia (HbSS), sickle-HbC disease (HbSC), sickle β0 thalassemia (HbSβ0), and sickle β+ + thalassemia (HbSβ+). Pulmonary hypertension (PH) is a significant complication that commonly affects individuals with sickle cell disease (SCD) and can contribute to increased morbidity and mortality. Investigating the prevalence of PH in patients hospitalized with sickle cell crisis (SCC) using Nationwide Inpatient Sample (NIS) data can provide valuable insights into the burden of this condition and further improve the management and outcomes of these patients. Methods: The National Inpatient Sample database from 2018 to 2020 was analyzed to identify adult hospitalizations (age > 18) with a diagnosis of sickle cell crisis (SCC) using appropriate ICD 10 codes. This population was stratified based on concomitant Class V Pulmonary Hypertension (PH). We compared the all-cause in-hospital mortality, length of hospital stays (LOS), and total costs in patients admitted with SCC with PH compared to those without PH. Categorical variables were compared using the chi-square test, and the t-test compared continuous variables. Multivariable regression analyses were performed adjusting for demographics, hospital-level characteristics, and relevant co-morbidities. Results: We identified a total of 249,300 adult hospitalizations with a primary diagnosis of SCC, of which 70.6% (N=176,005) had concomitant PH. 57 % of SCC admissions were females, and the mean age was 39 years. Hospitalizations with SCC with concomitant PH had significantly higher in-hospital mortality (OR 3.64, 95% CI 2.67- 4.98, p<0.001). Multivariate regression analysis revealed that the presence of PH increased the chance of mortality in SCC hospitalizations (adjusted OR 2.14, 95% CI 1.53 - 3.00, P<0.001). SCC hospitalizations with PH had higher odds of complications like Right Heart Failure (adjusted OR 21.45, 95% CI 14.41 - 31.94, p<0.001), compared to those without PH. Lastly, SCC hospitalizations with PH had a longer length of stay (mean 7 vs 5 days, p<0.001) and higher total hospital costs (mean $65,349 vs $41,995, p<0.01) compared to those without PH. Conclusion: Pulmonary hypertension in patients with sickle cell crises has worse outcomes characterized by a decrease in quality of life, an increase in the hospital mortality rate, longer hospitalization stays, and higher total charges. Overall, the study highlights the critical relationship between pulmonary hypertension and SCC in hospitalized patients and the need for careful management and monitoring of these patients to improve their clinical outcomes. Given the high prevalence and significant impact of PH in SCC patients, early diagnosis and management of this patient population can lead to improved health outcomes. Further research may be warranted to investigate targeted interventions for managing PH in this population. Additionally, prospective studies could explore the potential benefits of early screening for PH in patients with SCC.