OBJECTIVES: Annual national health statistics are valuable reference for healthcare-related cost researches. However, there is a gap between cost of 1-calendar-year and that for 1-complete-year, depending on the patient’s date of first hospital visit. This research aims to quantitatively identify the difference between healthcare cost in the annual national health statistics and that for 1-complete-year according to chronic or acute diseases.

METHODS: Annual cost per patient was calculated by two methods: the 1-calendar-year method in which the study period spanned from January 1 to December 31, 2012 regardless of patient’s date of first visit, and the 1-complete-year method which estimated the cost for one year from patient’s date of first visit. The target diseases were the 20 most prevalent diseases in South Korea, divided into acute (acute tonsillitis, common cold, etc.) and chronic diseases (hypertension, diabetes mellitus, etc.). National Sample Cohort data provided by the South Korea National Health Insurance Service was used, and patients coded with applicable diseases were selected in 2012. To provide basis for the results, we additionally investigated the distribution of the date of first visit and consequent annual cost of each patient.

RESULTS: The average ratios of 1-calendar-year cost to 1-complete-year cost for acute and chronic diseases were 0.87 (± 0.03) and 0.85 (± 0.02), respectively. When the dates of first visit were analyzed according to quarters, significantly more patients with chronic diseases were identified in the 1^st quarter than acute diseases. The annual cost increased as the first visit occurred earlier, which was more apparent in chronic than acute diseases.

CONCLUSIONS: Healthcare cost reported by annual national health statistics was 85~87% level of 1-complete-year cost, which was similar for both acute and chronic diseases. These ratios could compensate the structural limitations of annual national health statistics and enable researchers to make elaborate estimations in socioeconomic burdens from diseases.