Reliability of Quadruplicated Serological Parameters in the Korean Genome and Epidemiology Study / 한국역학회지

OBJECTIVES: The aim of this study was to evaluate whether clinical test values from different laboratories in the Korean Genome and Epidemiology Study (KoGES) can be integrated through a statistical adjustment algorithm with appropriate intra- and inter-laboratory reliability. METHODS: External quality control data were obtained from the Korean Society for Laboratory Medicine and quadruplicated standardized serological samples (N=3,200) were manufactured in order to check the intra- and inter-laboratory reliability for aspartic acid transaminase (AST), alanine transaminase (ALT), gamma-glutamyl transpeptidase (gamma-GTP), blood urea nitrogen (BUN), creatinine, uric acid (UA), fasting blood sugar (FBS), cholesterol, and triglyceride (TG). As an index of inter- and intra-rater reliability, Pearson's correlation coefficient, intraclass correlation coefficients and kappa statistics were estimated. In addition, to detect the potential for data integration, we constructed statistical compensation models using linear regression analysis with residual analysis, and presented the R-square values. RESULTS: All correlation coefficient values indicated good intra- and inter-laboratory reliability, which ranged from 0.842 to 1.000. Kappa coefficients were greater than 0.75 (0.75-1.00). All of the regression models based on the trial results had strong R-square values and zero sums of residuals. These results were consistent in the regression models using external quality control data. CONCLUSION: The two laboratories in the KoGES have good intra- and inter-laboratory reliability for ten chemical test values, and data can be integrated through algorithmic statistical adjustment using regression equations.

Estimation of Nationwide Vaccination Coverage and Comparison of Interview and Telephone Survey Methodology for Estimating Vaccination Status

This study compared interview and telephone surveys to select the better method for regularly estimating nationwide vaccination coverage rates in Korea. Interview surveys using multi-stage cluster sampling and telephone surveys using stratified random sampling were conducted. Nationwide coverage rates were estimated in subjects with vaccination cards in the interview survey. The interview survey relative to the telephone survey showed a higher response rate, lower missing rate, higher validity and a less difference in vaccination coverage rates between card owners and non-owners. Primary vaccination coverage rate was greater than 90% except for the fourth dose of DTaP (diphtheria/tetanus/pertussis), the third dose of polio, and the third dose of Japanese B encephalitis (JBE). The DTaP4: Polio3: MMR1 fully vaccination rate was 62.0% and BCG1:HepB3:DTaP4:Polio3:MMR1 was 59.5%. For age-appropriate vaccination, the coverage rate was 50%-80%. We concluded that the interview survey was better than the telephone survey. These results can be applied to countries with incomplete registry and decreasing rates of landline telephone coverage due to increased cell phone usage and countries. Among mandatory vaccines, efforts to increase vaccination rate for the fourth dose of DTaP, the third dose of polio, JBE and regular vaccinations at recommended periods should be conducted in Korea.

Reliability and Data Integration of Duplicated Test Results Using Two Bioelectrical Impedence Analysis Machines in the Korean Genome and Epidemiology Study / 예방의학회지

OBJECTIVES: The Korean Genome and Epidemiology Study (KoGES), a multicenter-based multi-cohort study, has collected information on body composition using two different bioelectrical impedence analysis (BIA) machines. The aim of the study was to evaluate the possibility of whether the test values measured from different BIA machines can be integrated through statistical adjustment algorithm under excellent inter-rater reliability. METHODS: We selected two centers to measure inter-rater reliability of the two BIA machines. We set up the two machines side by side and measured subjects' body compositions between October 2007 and December 2007. Duplicated test values of 848 subjects were collected. Pearson and intra-class correlation coefficients for inter-rater reliability were estimated using results from the two machines. To detect the feasibility for data integration, we constructed statistical compensation models using linear regression models with residual analysis and R-square values. RESULTS: All correlation coefficients indicated excellent reliability except mineral mass. However, models using only duplicated body composition values for data integration were not feasible due to relatively low R2 values of 0.8 for mineral mass and target weight. To integrate body composition data, models adjusted for four empirical variables that were age, sex, weight and height were most ideal (all R2>0.9). CONCLUSIONS: The test values measured with the two BIA machines in the KoGES have excellent reliability for the nine body composition values. Based on reliability, values can be integrated through algorithmic statistical adjustment using regression equations that includes age, sex, weight, and height.