How does self-reported and newly-identified hypertension differently predict the risk of developing type 2 diabetes among urban adults in Mainland China? A pooled analysis of community-based prospective cohort studies

To simultaneously examine the impact of self-reported and newly-identified hypertension upon subsequent risk of developing type 2 diabetes. Data were pooled from two community-based urban adult cohort studies, which were separately conducted during 2004–2007 and 2007–2010 in Nanjing, China. Type 2 diabetes was identified using the 1999 World Health Organization diagnosis criteria and hypertension was diagnosed using the 2004 Chinese guidelines for the management of hypertension. Based on blood pressure status, participants were categorized as: (1) people with normal blood pressure at baseline and during the follow-up period (normotension), (2) subjects with self-reported or newly-diagnosed hypertension at baseline (self-reported hypertension) and (3) those with normal blood pressure at baseline but diagnosed having hypertension during the follow-up period (newly-identified hypertension). All covariates were assessed at baseline and study end. Among 4,550 participants, the 3-year cumulative incidence of type 2 diabetes was 14.1 %, 6.5 % and 3.2 % for participants with newly-identified hypertension, self-reported hypertension and normtension, respectively. After adjustment for potential confounders, compared to people with normotension, participants with newly-identified (OR = 4.25; 95%CI = 3.04, 5.93) or self-reported (OR = 1.76; 95 %CI = 1.25, 2.48) hypertension were more likely to develop type 2 diabetes. Furthermore, subjects with newly-identified hypertension (OR = 2.53; 95 %CI = 1.71, 3.73) were at elevated risk of developing type 2 diabetes relative to their counterparts with self-reported hypertension. The similar associations of hypertension with type 2 diabetes were also found in men and women, separately. Newly-identified hypertensive people were at the particularly high risk of developing type 2 diabetes compared to those with self-reported hypertension.