Completeness Estimation of the Korean Medical Insurance Data in Childhood Asthma

Ha, M N; Kwon, H J; Kang, D H; Cho, S H; Yoo, K Y; Joo, Y S; Sung, J H; Kang, J W; Kim, D S; Lee, S I

Abstract

OBJECTIVES
: The purpose of this paper is to estimate the completeness of the Korean Medical Insurance Data in childhood asthma.
METHODS
: Capture-recapture method was used to estimate the prevalence of childhood asthma and case ascertainment rate(completeness) of Korean Medical Insurance Data using two source model, 'Korean Medical Insurance Committee Data (KMICD)' and 'Nationwide Study of Asthma and Allergies in Korean Children'. The asthma cases were restricted to those who were born from 1981 to 1989 and were identified by their Resident Register Number. Asthma cases in Korean Medical Insurance Data were defined as cases coded by ICD-9 493 and ICD-10 J45. In 'Nationwide Study of Asthma and Allergies in Korean Children', asthma cases were defined as the children who had been diagnosed asthma and had experienced symptoms of asthma during the past 12 months. The defined cases in two data sources were matched by 13 digits Resident Register Number. The numbers of matched patients in two data sources were 245 of 32,825 eligible total subjects. Chapman and Wittes' nearly unbiased estimation was used for capture-recapture analysis of two data sources.
RESULTS
: Observed prevalence rate of childhood asthma was 5.3% and estimated prevalence rate by capture-recapture analysis was 11.6%. The highest prevalence rate was observed in 6-7 age group and the older the rate decreased. The completeness (the proportion of cases ascertained by KMICD to the total observed cases by two data sources) was 20.6%, and ranged from 10.8% to 28.8% by area.
CONCLUSIONS
: Invalid diagnosis of cases might overestimate the prevalence of childhood asthma and might underestimate the completeness of Korean Medical Insurance Committee Data in this study