Morning hypertension and night non-dipping in patients with diabetes and chronic kidney disease

Morning hypertension (HTN) and nocturnal non-dipping (ND) are closely associated with target organ damage and cardiovascular events. However, their importance in diabetics with advanced renal disease is unclear. We evaluated the relationships of morning HTN and ND with estimated glomerular filtration rate (eGFR) and proteinuria, and determined the risk of morning HTN and ND according to presence of diabetes mellitus (DM) and chronic kidney disease (CKD) stage. A total of 1312 patients, including 439 with diabetes, were prospectively recruited at 21 centers in Korea. All patients had HTN and an eGFR of 15-89 ml min(-1) per 1.73 m(2). Ambulatory 24-h blood pressure was assessed. The rates of morning HTN (25.2% vs. 13.6%, P<0.001) and ND (58.2% vs. 48.2%, P=0.002) were higher in diabetics than in non-diabetics. eGFR was correlated with ND in all patients (P<0.05) and with morning HTN only in non-diabetics (P=0.005). Proteinuria was related to ND in all patients (P<0.05) and to morning HTN only in diabetics (P=0.001). In a regression analysis, the risk of morning HTN was 2.093 (95% confidence interval (95% CI): 1.070-4.094) for the DMCKD2 group, 1.634 (95% CI: 1.044-2.557) for the CKD3-4-only group and 2.236 (95% CI: 1.401-3.570) for the DMCKD3-4 group compared with the CKD2-only group. The risk of ND was high for stage 3-4 CKD: 1.581 (95% CI: 1.180-2.120) for non-diabetics and 1.842 (95% CI: 1.348-2.601) for diabetics. Diabetics showed higher rates of morning HTN, ND and uncontrolled sustained HTN compared with non-diabetics with CKD of the same stages.