Hospitalizations and mortality in systemic sclerosis: results from the Nationwide Inpatient Sample

Abstract

Objective: To study the causes of hospitalizations and predictors of subsequent adverse outcomes for contemporary cohorts of patients with systemic sclerosis (SSc) in the USA.

Methods: The data source was the 2002 and 2003 Healthcare Cost and Utilization Project-Nationwide Inpatient Sample (HCUP-NIS) databases. We identified all discharges with an International Classification of Diseases-Clinical Modification (ICD9-CM) code of 710.1 (limited and diffuse SSc), then excluded those with concomitant diagnoses for lupus or rheumatoid arthritis. We calculated hospitalization rates, in-hospital mortality rates and mean length of stay (LOS). Multivariate logistic and linear regression models for in-hospital death and LOS were performed adjusting for sociodemographic and comorbidity covariates.

Results: The overall in-hospital mortality rate was 6.3% and the mean LOS was 6.6 days. Hospitalization rates were 4.5 times higher in women than in men, but in-hospital mortality was approximately 25% lower (P = 0.005). SSc was the most common principal diagnosis for all SSc hospitalizations, with the most common secondary diagnosis (24%) being pulmonary fibrosis. After SSc, respiratory failure was the second most common principal diagnosis in patients who died. Pulmonary fibrosis increased the odds of in-hospital death by 2.63 [95% confidence interval (CI) 1.98-3.49] fold and increased LOS by 7.25% (95% CI 0.90-13.60).

Conclusions: Women with SSc had higher rates of hospitalization but lower in-hospital mortality than men. Pulmonary fibrosis was the major predictor of poor hospitalization outcomes in SSc patients in recent years, emphasizing the importance of continuing to develop more effective therapies for this fatal complication of the disease.