Long term evolution of renal function in essential hypertensive patients with no baseline proteinuria.

Data on the long term evolution of renal function in essential hypertensive patients are scarce, showing a low incidence of end stage renal diseases but without information on how the renal function evolves. Our aim is to describe the long term evolution of renal function and possible trajectories in hypertensive patients. We included patients from an ongoing cohort with essential hypertension, no proteinuria at baseline and no diabetes during follow-up and with at least two creatinine dosages 4 years apart. A long term (average 16 years) follow-up was available in 609 patients (baseline age 51.8 ± 11.1 years, 52 % male, mean office BP 156//95 mmHg). The trajectories of creatinine were modeled through a flexible latent class mixed model. The analysis identified three classes of significantly different trajectories. In the first (n = 560), there was no significant variation of creatinine over time. In the second (n = 40), there was a significant rise of creatinine (117 ± 20 vs 85 ± 17 µmol/l, p < 0.0001). The third class (n = 9) was very heterogeneous, mainly composed of outliers. Further analysis showed the nonlinearity of the evolution of creatinine in classes 2 and 3. So the model of progressive renal deterioration in essential hypertension does not fit with our results. A large majority (92%) of patients show no significant change in creatinine level with time. In the others 8%, the increase in creatinine is not progressive but conversely show one or more sudden bouts of elevation.