Prediction of Sarcopenia Onset in Type 2 Diabetes Using Urinary Titin Levels: A Japanese Prospective Cohort Study

OBJECTIVE The predictive power of urinary titin for incident sarcopenia was studied in Japanese individuals with type 2 diabetes. RESEARCH DESIGN AND METHODS Baseline urinary titin levels were measured, and sarcopenia was evaluated annually using the Asian Working Group for Sarcopenia (AWGS) 2019 criteria. Kaplan-Meier curves, Cox models, and time-dependent receiver operating characteristic analyses were used to assess incident sarcopenia. RESULTS Among 444 participants (median follow-up, 1,078 days), 41 developed sarcopenia. The high titin tertile was associated with an elevated sarcopenia risk (log-rank P = 0.04). Cox models associated titin with sarcopenia (adjusted hazard ratio per SD 1.37, 95% CI 1.05–1.77, P = 0.019) and low muscle strength. Risk estimates were consistent across subgroups, including those aged ≥70 years, men, individuals with BMI <25 kg/m2, HbA1c ≥7%, and estimated glomerular filtration rate ≥60 mL/min/1.73 m2 (P for interaction > 0.05). CONCLUSIONS Elevated urinary titin levels predict sarcopenia and low muscle strength in individuals with type 2 diabetes, supporting its use as a noninvasive biomarker.