Maternal outcomes in sickle cell trait patients hospitalized with preeclampsia and eclampsia

Abstract Introduction Preeclampsia and Eclampsia are progressive hypertensive disorders of pregnancy that begin after 20 weeks of gestation and can rapidly lead to seizures and other life-threatening complications. These conditions are major contributors to maternal and perinatal morbidity and mortality worldwide. Sickle cell trait (SCT), the heterozygous carrier state of the sickle β-globin gene, is present in more than two million people in the United States. Although SCT is often considered clinically benign, evidence suggests it is associated with negative health outcomes in some situations. Methods We retrospectively assessed hospitalizations from 2016- 2021 using the National Inpatient Sample (NIS) databases of the Healthcare Cost and Utilization Project (HCUP). We identified admissions with a primary diagnosis of preeclampsia and eclampsia using International Classification of Diseases (ICD) codes as the primary diagnosis. ICD-10 codes were also used to identify admissions with a secondary diagnosis of SCT. We applied the discharge weight (DISCWT) provided in the database to generate the national estimates. Pearson's Chi-square test for categorical variables and Student's t-tests/one-way ANOVA for continuous variables were applied to compare the baseline demographics and hospital characteristics between admissions with and without SCT. We investigated clinical outcomes including mortality, first time seizure, acute lower extremity deep vein thrombosis, acute pulmonary embolism, postpartum hemorrhage, acute kidney injury and acute pulmonary edema, as well as healthcare utilization outcomes such as length of stay and total hospital cost. Results We identified 1,129,400 hospitalizations for preeclampsia or eclampsia; 9,050 (0.8 %) involved patients with sickle cell trait (SCT). Compared with those without SCT, patients with SCT were younger (median age 28.7 vs 29.3 years, P < 0.001) and more commonly of Black race. They had higher comorbidity burden (mean Charlson score 0.20 vs 0.13; P < 0.001) and were more likely to be admitted in Southern hospitals and from lower-income ZIP-codes. Medicaid was the primary payer for most SCT patients (60.2 % vs 42.6 %; P < 0.001). In terms of clinical outcomes, there were no deaths or cases of pulmonary embolism in either group. SCT patients experienced significantly more postpartum hemorrhage (8.6 % vs 7.2 %; adjusted odds ratio [aOR] 1.20, 95 % CI 1.02–1.45, P = 0.030) and acute kidney injury (201.8 vs 9,186 per 1.12 million hospitalizations; aOR 2.47, 95 % CI 1.71–3.57; P < 0.001). Rates of first-time seizure, acute lower extremity deep vein thrombosis, and acute pulmonary edema were not significantly different. In terms of healthcare utilization and hospital outcomes, hospital costs were significantly higher ($9,610 vs $8,075; aOR 1.16, 95 % CI 1.12–1.21; P < 0.001) and mean length of stay significantly longer (4.2 vs 3.8 days; aOR 1.09, 95 % CI 1.05–1.12; P < 0.001) for patients with SCT. Conclusion There is a paucity of data on the outcomes of patients with SCT who experience hypertensive disorders of pregnancy. We found that postpartum hemorrhage and acute kidney injury were more likely to occur in pre-eclamptic women with SCT compared to those without, and that those with SCT were hospitalized for longer and at higher cost. We advocate for more robust retrospective studies as well as prospective studies to further outline both short and long-term risks associated with SCT in pregnancy to help inform peripartum management and ideally improve both fetal and maternal outcomes.