Proteinuria Is Associated With an Increased Risk of Sudden Cardiac Arrest in the Young Population

Background Proteinuria is a risk factor for cardiovascular events, but its prognostic value for sudden cardiac arrest (SCA) in young individuals remains unproven. We aimed to evaluate whether proteinuria in young people is associated with an increased risk of SCA. Methods and Results Individuals aged between 20 and 39 years who underwent health screening between 2009 and 2012 in South Korea were included (n=6 891 400). Urine protein was measured using the spot urine dipstick method. Main outcome was SCA identified by International Classification of Diseases, Tenth Revision (ICD-10). Participants included in the analysis were followed-up till December 2020, and Cox proportional hazards model was used to demonstrate the risk of SCA. The mean age was 30.9 +/- 5.0 years, and 3 775 535 (59.5%) were men. The mean follow-up duration was 9.4 +/- 1.2 years. During follow-up, SCA occurred in 5352 individuals (0.08%). Participants with proteinuria had a higher incidence of SCA (n=182, incidence rate 0.19, during 962 956 person-year follow-up) than those without proteinuria (n=5170, incidence rate 0.09, during 58 465 181 person-year follow-up). Adjustment of confounders resulted higher risk of SCA in participants with proteinuria (adjusted hazard ratio 1.71 [95% CI=1.47-1.99], P<0.001). Participants with proteinuria +3-4 showed a significant increase in the risk of SCA (2.94 [1.96-4.40], P<0.001). The influence of proteinuria on SCA was stronger in advanced chronic kidney disease (stage 3 and stage 4-5). Conclusions Proteinuria was significantly associated with an increased risk of SCA in young people. Individuals with pre-existing chronic kidney disease showed a stronger association between proteinuria and the risk of SCA.