Iranian Journal of

In April 2005, the International Diabetes Federation (IDF) has formulated a new worldwide definition of the metabolic syndrome in a global consensus statement built on earlier WHO, the ATPIII definitions. The aim of this study was to estimate the prevalence of this syndrome using the IDF definition among Iranian adults and to compare it with the prevalence estimated using the two other definitions. 

Methods: The prevalence of the MES was determined according to the three different definitions in 10368 men and women aged≥20 years participated in the cross-sectional phase of the Tehran Lipid and Glucose Study (TLGS). To assess the degree of agreement between different MES definitions, the k test was used. 

Results: The prevalence of MES (95% confidence interval) was 32.1% (31.2-33.0) by the IDF definition, 33.2% (32.3-34.1) by the ATPIII and 18.4% (17.6-19.2) according to the WHO definition. The sensitivity, specificity and concordance of the IDF definition for detecting MES were 91%, 89% for the ATPIII definitions and 73%, 77% for the WHO definition, respectively. The k statistics for the agreement of the IDF definition was 66.3±0.01 with the ATPIII and 39.5±0 with the WHO definition.

Conclusion: In the Iranian population, the IDF definition for MES has a good concordance with the ATP III definition and a low concordance with the WHO definition.

In medical studies, measures are required to reveal the effect of exposures and interventions and also the precision of measurements. This paper aimed to introduce the measures of effect and agreement and inferences about them in these studies. Principles and method of calculating measures of effect and agreement and inference about them were presented for all types of medical studies taking into account the relevant considerations. To assess the effect of risk factors on outcomes in case-control and cohort studies, and to determine the relevant effect, the attributable risk and fraction in the exposed group and population were used along with their confidence intervals. Also the relative risk reduction, absolute risk reduction and number needed to treat were applied as the measures of effect of intervention in the interventional studies especially in trails. The sensitivity, specificity and related measures along with their confidence intervals were computed for diagnostic accuracy and screening studies. In addition it is needed to evaluate the precision of measurements using standard error of measurements, ICC, Altman and Bland’s limits of agreement and Lin’s concordance correlation coefficient for quantitative variables and using kappa and weighted kappa for nominal and ordinal variables. In each of these situations the results of research based examples were presented along with the methods of their calculations.To assess the measures of effect and agreement, the mentioned analyses are recommended considering the situation and purpose of the study.