Effect of season on clinical outcomes of Thai systemic sclerosis: Analysis of the Thai national healthcare database.

Objectives

We aimed to determine rate of admission, mortality rate, and causes of death in systemic sclerosis (SSc) patients after stratifying by season.Method: A cross-sectional analysis was performed of patients over 15 in the national database with a primary diagnosis of SSc (ICD-10:M34) covered by the National Health Security Office hospitalized between 2014 and 2018. The seasons were stratified into hot, rainy, and Cool dry seasons.

Results

Included were 2480 SSc patients with 3684 admissions: most (64.3%) were female. The respective mean age and median length of stay was 56.9 ± 12.3 years and 3 days (IQR 2-6). The admission rate was highest during the rainy season (1574 visits, 42.7%), followed by the cool dry season (1183 visits, 32.1%) then the hot season (927 visits, 25.2%). During the 13,180 person-days, 1660 SSc patients died resulting in a mortality rate of 12.1 per 100 person-days. The proportion of SSc patients who died in the Cool dry season was significantly higher than in the hot or rainy season (p = .04). Pulmonary involvement in SSc was the most common cause of death in the hot season, which is greater than in the other seasons (p = .004). By comparison, death due to cardiac involvement in SSc was common during the rainy season and cool dry seasons (p = .04).

Conclusion

The admission rate among Thai SSc patients was greatest during the rainy season, while mortality was highest during the cool dry season. The most common causes of death were SSc-related irrespective of season, particularly cardiopulmonary involvement.