Factors affecting renal function in 119 985 adults over three years.

Blood pressure, proteinuria and serum creatinine (SCr) were examined in 119 985 adults, aged 40 years and older, who attended annual health examinations both in 1993 and 3 years later. Renal function was assessed from SCr; changes in individuals' renal function were estimated using the slope of the regression line for the reciprocal of the SCr level vs. time (slope of rSCr) over the 3-year period. Age-dependent SCr concentration increments were observed; however, there was no significant age-dependent change in the slope of rSCr. SCr in hypertensives on anti-hypertensive medication was significantly higher than that in untreated hypertensives, borderline hypertensives and normotensives. The slopes of rSCr in hypertensives (treated, untreated and borderline) were steeper than normotensives in males, and that in untreated hypertensives was steeper than other groups in females. In hypertensives with proteinuria, SCr was higher and renal function deteriorated more rapidly, compared with hypertensives without proteinuria. Hypertension with proteinuria appears to be an important indicator for progressive decline in renal function, this trend being more obvious in males. Renal function decreases with age; however, the rate of decline is constant. The influences of proteinuria and blood pressure on renal function are different in males and females.