Slight increase of urinary albumin excretion predicts incident hypertension in the Japanese general population

Abstract

Background: Previous studies suggested that urine albumin excretion in the high normal range predicts hypertension. However, this still remains unclear in the Japanese general population. Aim: To clarify the relationship between the levels of urinary albumin-creatinine ratio (UACR) and incident hypertension among subjects without diabetes and renal insufficiency. Methods: We conducted a cohort study of 459 normotensives without diabetes and renal insufficiency (eGFR ≤60 ml/min/1.73m2) in a community-based study in Japan and followed for 7 years (median 6.7 years). We examined the incidence of hypertension depending on the UACR levels at baseline. The incident hypertension was defined as new onset of systolic blood pressure ≥140 mmHg or diastolic blood pressure ≥90 mmHg or taking any anti-hypertensive drugs. Results: During follow-up period, 256 subjects (55.8%) developed hypertension. The incidence of hypertension was increased along with the increase in UACR at baseline (41.5% in UACR <5mg/g, 59.1% in 5-14 mg/g and 66.0% in 15-29 mg/g, P<0.05). Multivariate logistic regression analysis after adjustment with age, sex, obesity, smoking status, alcohol consumption, and estimated 24-hour urinary excretion of sodium showed that UACR 5-14 mg/g and 15-29 mg/g were independent risk for incident hypertension, compared with UACR <5 mg/g (odds ratio [OR] 1.99, 95% confidence interval [CI] 1.20-3.30 and OR 2.12, 95% CI 1.01-4.54, respectively). Subgroup analysis showed that UACR 5-29 mg/g was a significant risk for incident hypertension compared with UACR <5 mg/g, especially in the subjects conventionally regarded as low risk, such as women, young (<60 years), non-obese, non-smoker, no habitual drinker, and subjects on low sodium diet (NaCl <10 g/day). Conclusions: This study showed that a slight increase of urinary albumin excretion might predict incident hypertension in the Japanese general population, especially in the subjects conventionally regarded as low risk group.