Aims: While the American Diabetes Association (ADA) 1997 diagnostic criteria advocate the use of fasting plasma glucose only, the World Health Organization (WHO) criteria retain the use of the standard oral glucose tolerance test (OGTT). The present study evaluated the relative merit of the respective diagnostic criteria in Chinese.
Methods: Data collected for the Hong Kong Cardiovascular Risk Factor Prevalence Study was analysed. This was a representative population-based study, conducted from 1995 to 1996 among 2,900 Chinese subjects aged 25-74 years using a 75-g OGTT.
Results: The prevalence of diabetes (known plus unknown) was 6.2% (95% confidence interval 5.3-7.1%), 9.2% (8.1-10.3%), and 9.8% (8.7-10.9%) based on ADA 1997, WHO 1985 and WHO 1998 criteria, respectively, with a very high prevalence in older subjects. The 2,451 subjects classified as normal under ADA 1997 criteria were heterogenous: 15.3% had impaired glucose tolerance; 2.1% had diabetes under WHO 1998 criteria. These latter two smaller groups had cardiovascular risk profiles comparable to that found among the impaired fasting glucose subjects (under ADA), but worse than that among the concordant normal glucose tolerance subjects.
Conclusions: The ADA criteria underestimate both diabetes prevalence and cardiovascular risk in this population. Hence fasting glucose alone is an inadequate approach and OGTT should be retained to identify at-risk individuals in both clinical diagnosis and epidemiological studies.