Lung involvement in systemic sclerosis is associated with adverse hospital outcomes: insights from the National Inpatient Sample

Abstract

This study aimed to compare outcomes of systemic sclerosis (SSc) hospitalizations with and without lung involvement. The primary outcome was inpatient mortality while secondary outcomes were hospital length of stay (LOS) and total hospital charge. Data were abstracted from the National Inpatient Sample (NIS) 2016 and 2017 database. This database is the largest collection of inpatient hospitalization data in the USA. The NIS was searched for SSc hospitalizations with and without lung involvement as principal or secondary diagnosis using International Classification of Diseases 10th Revision (ICD-10) codes. SSc hospitalizations for patients aged ≥18 years from the above groups were identified. Multivariate logistic and linear regression analysis was used to adjust for possible confounders for the primary and secondary outcomes, respectively. There were over 71 million discharges included in the combined 2016 and 2017 NIS database. 62,930 hospitalizations were for adult patients who had either a principal or secondary ICD-10 code for SSc. 5095 (8.10%) of these hospitalizations had lung involvement. Lung involvement group had greater inpatient mortality (9.04% vs 4.36%, adjusted OR 2.09, 95% CI 1.61 to 2.73, p<0.0001), increase in mean adjusted LOS of 1.81 days (95% CI 0.98 to 2.64, p<0.0001), and increase in mean adjusted total hospital charge of $31,807 (95% CI 14,779 to 48,834, p<0.0001), compared with those without lung involvement. Hospitalizations for SSc with lung involvement have increased inpatient mortality, LOS and total hospital charge compared with those without lung involvement. Collaboration between the pulmonologist and the rheumatologist is important in optimizing outcomes of SSc hospitalizations with lung involvement.