Association between Sarcopenia and Dipstick Proteinuria in the Elderly Population: The Korea National Health and Nutrition Examination Surveys 2009–2011

BACKGROUND: Sarcopenia and proteinuria are significant health difficulties in the elderly; however, few studies have investigated their relationship. In this study, we investigated the association between sarcopenia and proteinuria in Korean subjects over 60 years old. METHODS: We included data from the Korean National Health and Nutrition Examination Survey, a cross-sectional, nationally representative survey conducted from 2009 to 2011 (n=4,008). Sarcopenia was defined using appendicular skeletal muscle mass as a percentage of body weight. Proteinuria was defined by a urine dipstick test result above trace levels. RESULTS: The overall proteinuria prevalence was 7.2%. The incidence of sarcopenia was significantly higher in subjects with proteinuria. The prevalence of proteinuria was significantly higher in the sarcopenic group (5.5% vs. 14.5% in the non-chronic kidney disease (CKD) group; 17.2% vs. 23.2% in the CKD group) than in the non-sarcopenic group. Furthermore, sarcopenic participants had worse metabolic parameters, such as higher body mass indexes, waist circumferences, and fasting glucose levels, and lower high-density lipoprotein cholesterol levels than those in the non-CKD group. After adjustment for confounders, the odds ratios (95% confidence interval) for proteinuria were 2.84 (1.92–4.18) in the sarcopenic non-CKD group, 3.70 (2.59–5.30) in the non-sarcopenic CKD group, and 5.19 (2.64–10.18) in the sarcopenic CKD group, compared to the non-sarcopenic, non-CKD group. Sarcopenia increased the proteinuria risk in elderly participants without CKD, even after adjustment for obesity, hypertension, diabetes, and metabolic syndrome. CONCLUSION: These findings showed that sarcopenia was associated with dipstick proteinuria, especially in elderly participants without CKD, regardless of comorbidities.