Extended prognostic value of urinary albumin excretion for cardiovascular events

Abstract

Because urinary albumin excretion (UAE) is a marker of cardiovascular (CV) risk, some have proposed screening the general population; however, it is unknown how the predictive power of a single screening value changes over time. In this study, data of 8496 individuals in a community-based, prospective cohort were used to evaluate this question. For each doubling of baseline UAE, the hazard ratio (HR) for a CV event was 1.36 (95% confidence interval [CI] 1.31 to 1.42). Baseline UAE similarly predicted events occurring >5 yr after baseline, suggesting that it remains a good predictor during at least the first 5 yr after measurement. Approximately 4 yr after baseline, UAE was measured again in 6800 individuals. Once again, high UAE (>75th percentile) predicted subsequent CV events, whether defined using the baseline UAE or follow-up UAE (HR 3.39 [95% CI 2.58 to 4.45] and HR 2.50 [95% CI] 1.90 to 3.29, respectively; P = 0.3 for difference). Finally, compared with individuals with consistently low UAE, individuals who progressed from low to high UAE during follow-up had a significantly higher risk for CV events (HR 3.68; 95% CI 2.45 to 5.53). In conclusion, UAE remains a good predictor of CV events during the first 5 yr after measurement, but repeating the measurement several years later also detects progression of UAE, which is also associated with increased CV risk. Future studies are required to determine the optimal interval of repeat testing and its cost-effectiveness.

Figure 1.

Event-free survival for CV morbidity and mortality after follow-up screening. Individuals are stratified according to the presence of a high or low UAE. High and low UAE are defined either using the UAE measurement from the baseline screening (gray lines) of approximately 4.2 yr before follow-up screening or the repeated UAE measurement at time of the follow-up screening (black lines). To allow comparison, the survival curves for the 6800 individuals using either the baseline or follow-up measurement of UAE are plotted in the same graph. (A) A high UAE (dashed lines) is defined as a UAE ≥16.2 mg/24 h, being the 75th percentile of UAE using the UAE measurement of the baseline screening. (B) A high UAE (dashed lines) is defined as a UAE ≥9.1 mg/24 h, being the median UAE using the UAE measurement of the baseline screening. These cutoff points were defined using the 6800 individuals participating at both baseline and follow-up screening.

Figure 2.

Flowchart of the PREVEND Study.