Urine Protein Levels Predict Future Development of Cerebral Infarction in Koreans

PURPOSE: Proteinuria is a clinical sign of adverse cardiovascular outcomes, including stroke. We aimed to assess the relationship between proteinuria and the occurrence of cerebral infarction. MATERIALS AND METHODS: In total, 208854 Koreans who participated in the 2009 medical examination were followed up until 2013 using the database of the National Health Insurance Service. The results of urine dipstick tests were utilized to assess proteinuria as absent, 1+, 2+, or ≥3+. The International Classification of Diseases code 163 was used to document cerebral infarction. RESULTS: Between 2009 and 2013, 2383 cases (1.14%) of cerebral infarction occurred during 912772.9 person-years of follow-up. Hazard ratios for incident cerebral infarction increased with inceasing amounts of urine protein from 1.53 (1.23–1.90) in group 2 (1+), 1.67 (1.22–2.28) in group 3 (2+), and 2.66 (1.79–3.96) in group 4 (≥3+), compared to the reference group with little to no detectable urine protein (p<0.001, respectively). CONCLUSION: An increase in urine protein levels was significantly related to the risk of developing cerebral infarction. Our results suggest that proteinuria might be a potential risk factor for cerebral infarction and that urine dipstick test analysis may be clinically useful for predicting stroke.