Epidemiology, outcomes, and expenditures of hospitalized patients with systemic sclerosis: Insights from the U.S. National Inpatient Sample.

OBJECTIVES

The inpatient epidemiology, morbidity, mortality, and healthcare expenditures associated with systemic sclerosis (SSc) remain poorly characterized. This study utilizes a national inpatient database to provide a comprehensive assessment of these parameters.

METHODS

We identified adult patients with SSc from the 2021 National Inpatient Sample (NIS) using ICD-10-CM codes. The NIS, the largest publicly available all-payer inpatient healthcare database in the U.S., represents data from over 4000 non-federal acute care hospitals. A matched comparator group without SSc was created to serve as comparators. Extracted data included demographics, primary admission diagnoses, length of stay (LOS), in-hospital mortality and morbidity, comorbidities, and healthcare expenditures. Multivariable analyses were adjusted for age, sex, race/ethnicity, Charlson Comorbidity Index, payer type, median income, and hospital characteristics.

RESULTS

The inpatient prevalence of SSc was 86.7 per 100,000 admissions. The most common primary diagnoses among SSc hospitalizations were sepsis (22.7%), heart failure with hypertension (14.4%), and COVID-19 (11.5%). The cohort was predominantly female (84.2%) with a mean age of 63.5 years. Compared to non-SSc admissions, SSc hospitalizations were associated with significantly longer LOS (mean difference 0.7 days; 95% CI: 0.5-0.9) and greater healthcare costs, including an adjusted mean increase of $3277 in hospital costs (95% CI: $2051-$4504) and $11,801 in total charges (95% CI: $6485-$17,116). SSc was also associated with increased odds of in-hospital mortality (adjusted OR 1.42; 95% CI: 1.26-1.61), shock (aOR 1.30; 95% CI: 1.17-1.44), systemic inflammatory response syndrome (aOR 1.32; 95% CI: 1.01-1.74), and acute respiratory distress syndrome (aOR 1.45; 95% CI: 1.12-1.87). Multivariate analysis also revealed that patients with SSc had significantly higher odds of several comorbid conditions, including pulmonary hypertension, interstitial lung disease, osteoporosis, Sjögren's syndrome, and hypertension.

CONCLUSIONS

The inpatient prevalence of SSc exceeds its general population prevalence, indicating a high need for hospital-level care. Hospitalizations among patients with SSc are associated with worse clinical outcomes and significantly greater healthcare expenditures.