Annual deterioration of renal function in hypertensive patients with and without diabetes

Chronic kidney disease (CKD) complicates hypertension and diabetes. Knowledge of the deterioration rate of CKD may anticipate adjustment of therapies with renal elimination. This study evaluates the rate of annual deterioration of renal function in hypertensive patients either with type 2 diabetes (DM2) or without it (non-DM) followed for 5 years and relates it with blood pressure (BP) and glycemic control.

Out of a total of 1924 patients, 1023 patients (594 non-DM and 429 DM2, 53% female, aged 62.1±10.2 years) were evaluated over 5 years for the annual evolution of renal function (estimated glomerular filtration rate [eGFR], Modification of Diet in Renal Disease) ambulatory 24-hour blood pressure and metabolic parameters, corresponding to the analysis of 2378 patient-years.

DM2 and non-DM did not differ for age, mean 24-hour BP levels, nighttime BP, albuminuria, and body mass index. DM2 versus non-DM showed a higher (p<0.02) prevalence of stage 3 CKD (24.0% vs 18.0%, eGFR 30-59), stage 4 (5.4% vs 2.7%, eGFR 15-29), and stage 5 (0.8% vs 0.5%, eGFR <15). Average annual decline of eGFR was 3.3±8.2 in DM2 versus 2.4±7.7 in non-DM (p=0.12, nonsignificant). Annual changes of eGFR and of albuminuria correlated (r=0.578, p<0.001). In multivariate analysis, age, nighttime BP, double inhibition of renin angiotensin system, albuminuria, and HbA1c >8.0% in DM2 predicted the decline in eGFR. On average, 16.2% of DM2 and 13.1% of non-DM moved each year toward a more severe stage of CKD. For initial eGFR <90 mL/min/1.73 m², 26.4% of DM2 and 18.1% of non-DM patients showed a reduction per year >10% from the previous eGFR value (p=0.042).

Progressive deterioration of renal function each year is frequent in hypertensive diabetic and non-diabetic patients. Beyond aging, this is particularly dependent on BP control particularly at nighttime, on drug therapy, and on highly abnormal glucose control.