Background Urine albumin excretion in the high normal range [urine albumin to creatinine ratio (UACR) 10-29 mg/g)] predicts hypertension in European-origin populations. However, the prognostic significance of UACR in the high normal range for incident hypertension is unclear in Indo-Asians. The objective of this study was to examine the relationship of normal to high normal levels of UACR and incident hypertension.MethodsWe conducted a nested cohort study within a cluster randomized controlled trial in Pakistan on 1272 normotensive non-diabetic adults aged <40 years with UACR <30 mg/g. Incident hypertension was defined as new onset of systolic blood pressure (SBP) <140 mmHg or diastolic < 90 mmHg or initiation of antihypertensive therapy.ResultsA total of 920 (72.3) participants completed the 2-year final follow-up. During this time, 105 (11.4) developed incident hypertension. In the multivariable model, the odds [95 confidence interval (CI)] for incident hypertension were 2.45(1.21-4.98) for those in the fourth (top) quartile (<6.1 mg/g) and 2.12 (1.04-4.35) in the third quartile (3.8-6.1 mg/g) compared to those in the lowest quartile (<2.8 mg/g). In addition, a significant interaction between UACR and baseline SBP was observed suggesting that the odds (95 CI) of incident hypertension with UACR were greater at lower baseline SBP (interaction P 0.044).ConclusionsHigh normal levels of albuminuria as measured by UACR predict hypertension in non-diabetic Indo-Asians, and this relationship may be enhanced in individuals with low baseline SBP. Further research is needed to assess the clinical applicability of these findings.