PREDICTORS FOR HYPERTENSIVE NEPHROPATHY - RESULTS OF A 6-YEAR FOLLOW-UP-STUDY IN ESSENTIAL-HYPERTENSION

Objective and design: To identify predictors for the development of ea rly hypertensive nephropathy, 88 previously untreated patients with mi ld-to-moderate essential hypertension (World Health Organization stage I or II) were re-examined after 6 years of follow-up. According to pr evious results, protein excretion, urinary excretion of N-acetyl-beta- glucosaminidase (NAG), serum NAG concentration and glomerular filtrati on rate (creatinine clearance) may predict the change in renal functio n. Results: Serum creatinine level increased significantly, but none o f the patients developed serum creatinine of >1.3 mg/dl. An elevated p rotein excretion between 200 and 500 mg/day at baseline (microproteinu ria), urinary NAC excretion, serum NAG concentration and blood pressur e control during treatment were not related to serum creatinine level at follow-up or change in serum creatinine level throughout the 6 year s of follow-up. In contrast, a high creatinine clearance at baseline w as related to a marked rise in serum creatinine level after 6 years. T he patients with a clear-cut increase in serum creatinine level of >0. 2 mg/dl (n=23) were characterized by a significantly higher pretreatme nt blood pressure at the worksite and a significantly greater initial creatinine clearance than the patients with no significant change in s erum creatinine level. In the two groups age, blood pressure level dur ing therapy, and the intensity and duration of blood pressure control were not different. Conclusion: In patients with uncomplicated essenti al hypertension, microproteinuria, NAG parameters and treatment blood pressure fever did not predict the change in serum creatinine level in the first 6 years of follow-up. A high creatinine clearance (suggesti ng glomerular hyperfiltration) emerged as a clinical diagnostic marker of early hypertensive nephropathy.