Prevalence of diabetes and pre-diabetes in rural Tehri Garhwal, India: influence of diagnostic method

BackgroundThere are few available data regarding the prevalence of diabetes in the sub-Himalayan region of India. The aim of this study was to determine the prevalence of pre-diabetes and diabetes in rural Garhwal based on glycosylated hemoglobin.MethodsIn a cross-sectional survey of 500 adults from five randomly selected villages in Chamba, a mountainous Tehri Garhwal district in Uttarakhand in north-west India, we determined the prevalence of diabetes (hemoglobin (Hb) A(1c)6.5%) and pre-diabetes (5.7%HbA(1c)6.4%). In a sub-sample of those diagnosed with diabetes or pre-diabetes (n=140), fasting blood glucose (FBG, n=117) or postprandial blood glucose (PBG, n=23), and blood hemoglobin concentration, was measured at follow-up.ResultsBased on HbA(1c), 10.0% had diabetes and 56.4% pre-diabetes. Of those diagnosed as diabetic by HbA(1c), 10 of 16 (62.5%) were diagnosed as diabetic by FBG (>125mg/dL) or PBG (200mg/dL). In those diagnosed as pre-diabetic by HbA(1c), only 55 of 124 (44.4%) were diagnosed as pre-diabetic by FBG (100-125mg/dL) or PBG (140-199mg/dL). A large proportion of these 140 individuals (67.1%) were moderately to severely anemic (Hb <11.4mg/dL). The diagnostic gap for pre-diabetes between HbA(1c) and FBG/PBG was similar for the groups with and without moderate to severe anemia.ConclusionsHbA(1c) and FBG/PBG have similar diagnostic performance for diabetes in this population. However, many individuals were diagnosed with pre-diabetes by HbA(1c) but not FBG/PBG. The relative excess diagnosis of pre-diabetes with HbA(1c) does not appear to be explained by anemia, an endemic condition in India. The prognostic significance of diagnosis of pre-diabetes by HbA(1c) but not FBG/PBG remains unknown, but merits investigation.