Association of microalbuminuria with diabetes is stronger in people with prehypertension compared to those with ideal blood pressure.

Aim Microalbuminuria (MA) has been demonstrated as a biomarker for microvascular dysfunction. This study is aimed to evaluate the association of glycemic status with MA in prehypertensive and ideal BP subjects and to evaluate the interaction between glycemic and blood pressure status as risk factors for MA prevalence. Methods 1059 subjects aged 40-70 with non-hypertension who were recruited from 6 districts of Tianjin were divided into prehypertensive group (622 cases) and ideal blood BP (437 cases). Subjects of prehypertensive group and ideal BP group were divided respectively into 3 subgroups: normoglycemia subgroup, prediabetes subgroup and diabetes subgroup. The prevalence of MA in the above 3 subgroups of subjects with prehypertension and ideal BP were assessed. We performed a statistical analysis for interaction test between glycemia and BP status on microalbuminuria in the overall study sample by a multivariate logistic regression model.The association of glycemic status (defined as normoglycaemia, prediabetes, and diabetes) with MA was evaluated separately in prehypertensive and ideal BP subjects. Results Results showed that the prevalence of MA in both prehypertensive and ideal BP groups rose with the increasing of classification of glycemic level of subgroups (32.6%, 18.3%, 14.8% vs. 23.1%, 16.2%, 13.4%), the differences in prehypertensive group were statistically significant(Pearson χ2=15.24, P﹤0.001). The ORs (95% CI) of MA were 1.25 (0.86~1.83) for prediabetes and 2.56 (1.62~4.03) for diabetes in the fully adjusted model. There was no interaction between prediabetes and BP status regarding MA (P=0.237) but we found a significant interaction between diabetes and BP status (P<0.001). In prehypertensive group, multivariate logistic regression models showed that the diabetes subgroup had an significant association with MA, and the adjusted odd ratio of the diabetes subgroup to the normoglycemia subgroup was 2.68 (95%CI 1.54~4.67) (P﹤0.001). However, there was no significant association of glycemic status with MA in ideal BP group. Stratified analysis by a multivariate logistic regression model in the whole study population showed that people with both perhypertension and diabetes had the highested risk of MA (adjusted OR=2.50 , 95%CI 1.16~5.36; P=0.019), compared with those with ideal BP and normoglycemia(reference group). Conclusions Our findings suggest that there was a statistically significant association between diabetes and microalbuminuria only in prehypertensive subjects. In addition, our study highlights the interaction between perhypertension and diabetes as a risk factor for MA.