Microproteinuria and long-term prognosis with respect to renal function and survival in normotensive and hypertensive women--a 24-year follow-up of a representative population sample of women in Gothenburg, Sweden.

OBJECTIVE

This study aimed to assess albuminuria and subclinical proteinuria, their association with hypertension and their role as predictors of hypertension, impaired renal function and mortality.

MATERIAL AND METHODS

A baseline population study comprising 1462 women in five different age groups in Gothenburg, Sweden, was carried out in 1968-69. Comprehensive clinical examinations and laboratory tests were performed, including blood pressure measurement and an Albustix test. A systematic subsample of women additionally collected a 24 h urine sample for quantitative protein analysis. Values of urinary protein (u-protein) excretion between 80 and 300 mg/24 h were defined as microproteinuria. The results described in this paper are based on a 24-year follow-up.

RESULTS

The baseline Albustix test was positive in 6.8% of 1458 women, from whom a urine sample was obtained. Of 741 baseline urine collections for u-protein excretion, 16.9% were in the microproteinuric range (80-300 mg/24 h), 1.1% in the macroproteinuric range (> 300 mg/24 h) and 82.1% in the normoproteinuric range (< 80 mg/24 h). Hypertension was more common in Albustix-positive women than in those with negative Albustix, and hypertension was also more prevalent in women with microproteinuria than in women with normoproteinuria. Neither positive Albustix nor microproteinuria was related to later renal impairment. Hypertension was associated with increased mortality in both Albustix-positive and Albustix-negative women, and in women with both normoproteinuria and microproteinuria at baseline. The mortality ratio during the follow-up period was, however, not significantly influenced by positive Albustix or by microproteinuria at baseline, in either hypertensive or non-hypertensive women.

CONCLUSIONS

This study demonstrated that both a positive Albustix test and microproteinuria were associated with hypertension. Hypertension at baseline increased the risk for death during the follow-up period, while neither albuminuria, defined as a positive Albustix test, nor microproteinuria was associated with an impaired long-term prognosis with respect to renal function or survival in this cohort of Swedish middle-aged women during 24 years of follow-up. Microproteinuria in otherwise healthy normotensive or hypertensive women does not appear to impair the long-term prognosis.