Clinical prognostic factors in biopsy-proven benign nephrosclerosis

Hypertensive renal damage has become one of the most important causes of end-stage renal failure (ESRF) in Western countries. Affected patients rarely have a kidney biopsy and their diagnoses therefore remain uncertain. The objective of the present study was to examine patients suspected of renal glomerular disease, which at biopsy proved to have isolated benign nephrosclerosis. We wanted to study the effect of different clinical and laboratory variables at the time of biopsy on the short-term and long-term progression to ESRF and death.

We retrospectively examined 102 patients who were diagnosed by kidney biopsy in Norway between April 1988 and December 1990. All patients were followed by means of registries for approximately 13 years to describe renal and patient survival.

The age of the patients at the time of biopsy was 55+/-15 years (range 15-88 years). Three years after the time of biopsy, 18% had developed ESRF and 24% had died; the corresponding numbers 13 years after biopsy were 32% and 47%. By Kaplan-Meier analyses, the following variables indicated short-term progression to ESRF: serum creatinine > or = 200 micro mol/l, systolic blood pressure > or = 160 mmHg and proteinuria > or = 1 g/24 h. In addition, patients with increased diastolic blood pressure, increased age and decreased serum albumin tended to develop ESRF more often. Long-term predictors of ESRF in Kaplan-Meier analyses were increased serum creatinine and urinary protein. Independent risk factors for progression to ESRF were increased serum creatinine and increased urinary protein. Independent risk factors for death were increased age and increased serum creatinine.

Benign nephrosclerosis is a common condition that is associated with a high morbidity and mortality. Short-term predictors of ESRF differ from long-term predictors and this may reflect a pathophysiologically meaningful difference.