Incidence and Risk Factors Associated With Hospitalization for Variant Angina in Korea

Abstract

This study aimed to determine the incidence and the risk factors of hospitalization for variant angina (VA) in Korean patients. Using the National Inpatient Sample (NIS) database, manufactured and released by the Health Insurance Review and Assessment Service (HIRA) in Korea, the incidence of hospitalization and rehospitalization for VA were calculated. The numbers of patients hospitalized for VA were estimated to be 14,362 in 2009, 17,492 in 2010, and 20,592 in 2011. The standardized incidence rates of hospitalization for VA were 31.4% in 2009, 36.5% in 2010, and 41.7% in 2011 (relative increase rate from 2009 to 2011, 33.0%, P for trend < 0.0001). VA patients predominantly belonged to the middle-age group between 40 and 69 years (75.5%), and there were 54.3% male. Based on the hospitalization episodes, the number of rehospitalization was calculated to be 879, 1141, and 1446 patients out of 1867, 2274, and 2677 patients from 2009, 2010, and 2011, respectively. The rates of rehospitalization for VA were 47.1% in 2009, 50.2% in 2010, and 54.0% in 2011 (P for trend < 0.0001). Age was an independent factor associated with rehospitalization for VA. Hospitalization for VA occurred most frequently in fall from 2009 to 2011. In conclusion, hospitalization rates for VA steadily increased from 2009 to 2011 in Korea, and about a half of VA patients was hospitalized more than once a year in 2009 to 2011. Proper health policy and patient education are warranted to control the high rate of hospitalization for VA.

FIGURE 1

Time series distribution of hospitalization for variant angina from 2009 to 2011 (based on the episodes of hospitalization).

FIGURE 2

Seasonal variation in hospitalization for variant angina from 2009 to 2011.