Indications for hospitalization and in-hospital mortality in Thai systemic sclerosis

Abstract

This study aimed to identify the indications for hospitalization, hospital mortality rate, predictors of hospital mortality, and clinical parameters affecting length of stay (LOS) among Thai systemic sclerosis (SSc). A retrospective study was performed in SSc patients admitted in Khon Kaen University, Thailand, between January 2008 and December 2010. The respective clinical factors affecting LOS and predictors of mortality were analyzed using the Spearman's rank correlation and the Cox regression model. There were 202 hospital admissions among 131 SSc patients. The female-to-male ratio was 1.6:1. The median age at admission was 54.7 years (interquartile range (IQR) 49.2-62.9), the duration of disease at admission was 2.9 years (IQR 1.1-7.8), and the LOS was 5 days (IQR 2-10). The indications for hospitalization were divided equally between SSc-related and non-SSc-related events (53.5 vs. 46.5 %, respectively). The most common indication for hospitalization was infection (23.3 %) and pneumonia is the most common cause of infection (58.0 %). Prolonged LOS was related to fatigability status (p < 0.01), intestinal involvement (p < 0.01), electrolyte disorders (p < 0.01), multiple comorbidities (p < 0.01), modified Rodnan skin score ≥20 points (p = 0.01), disease duration under 5 years (p = 0.02), cardiac arrhythmia (p = 0.04), and deficiency anemia (p = 0.04). Hospital mortality was 16.8 per 100 person-years (95 % confidence interval (95 % CI) 10.8-24.3). Infection (59.1 %) was the most common cause of death, particularly from bacterial pneumonia. Clinical predictors of mortality were: disseminated intravascular coagulation related to infection (hazard ratio (HR) 52.73; 95 % CI 1.26-403.74), cardiac arrhythmia (HR 32.89; 95 % CI 3.00-359.95), electrolyte disorders (HR 15.66; 95 % CI 2.04-119.98), renal crisis (HR 13.38; 95 % CI 1.80-99.36), intestinal involvement (HR 10.42; 95 % CI 2.58-42.01), admission due to a non-SSc-related condition (HR 8.93; 95 % CI 2.21-36.13), and disease duration under 5 years (HR 6.67; 95 % CI 1.21-36.52). Infection was the most common cause of hospitalization. Prolonged LOS and hospital mortality should be warning signs in patients with shorter disease duration, presence of intestinal involvement, cardiac arrhythmia, and multiple comorbidities.