Serial changes in proteinuria a useful way to predict cerebral infarction risk

All patterns of changes in proteinuria appear to be associated with an increased risk of cerebral infarction relative to the absence of proteinuria, according to a Korean cohort study.

The study used data from the national health insurance service in Korea and included 276,861 Koreans who were assessed for urine dipstick proteinuria both in 2003–2004 and 2007–2008. They were grouped into four, according to changes in proteinuria over 4 years: negative (negative → negative), resolved (proteinuria ≥1+ → negative), incident (negative → proteinuria ≥1+), and persistent (proteinuria ≥1+ → proteinuria ≥1+).

The mean age of the population was 56.5 years, and 56.67 percent were men. Compared with the negative proteinuria group, other groups were characterized by worse clinical conditions such as older age; higher levels of body mass index, blood pressure, total cholesterol, fasting blood glucose; and greater proportion of participants who currently smoked.

During the study period, a total of 10,966 cases of incident cerebral infarction occurred. Of these cases, 5,886 were in men (3.75 percent) and 5,080 were in women (4.23 percent). Multivariate adjusted Cox-proportional hazard models showed that all types of proteinuria changes were associated with the increased risk of cerebral infarction as compared with negative proteinuria.

The hazard ratios for cerebral infarction were 1.443 (95 percent confidence interval [CI], 1.089–1.912) in the persistent group, 1.345 (95 percent CI, 1.188–1.522) in the incident group, and 1.166 (95 percent CI, 1.009–1.347) in the resolved group.

In a subgroup analysis, the association between changes in proteinuria and the risk of cerebral infarction was more pronounced in men (resolved: HR, 1.284, 95 percent CI, 1.057–1.560; incident: HR, 1.351, 95 percent CI, 1.149–1.589; persistent: HR, 1.428, 95 percent CI, 1.014–2.012).

The present data suggest that the persistent presence of proteinuria and new onset of proteinuria are potential risk factors for incident cerebral infarction. As such, assessment of the serial changes in proteinuria may prove useful to predict the risk of cerebral infarction.