Related Experiment Video
Updated: May 15, 2026
Identifying Frailty Using Point-of-Care Ultrasonography: Image Acquisition and Assessment
Published on: July 26, 2024
Urinary N-terminal titin fragment as a supplementary marker for frailty in chronic obstructive pulmonary disease
Fumiya Kotajima1, Yasuhiko Koga2, Masakiyo Yatomi2
1Department of Rehabilitation Sciences, Gunma University Graduate School of Health Sciences, 3-39-22 Showa-machi, Maebashi, Gunma, 371-8514, Japan; Department of Rehabilitation Medicine, Gunma University Hospital, 3-39-15 Showa-machi, Maebashi, Gunma, 371-8511, Japan.
Background:
Frailty is common in patients with chronic obstructive pulmonary disease (COPD); however, its objective assessment in routine clinical management remains challenging. This exploratory study aimed to investigate the association between the urinary N-terminal titin fragment-to-creatinine ratio (N-titin/Cr), a noninvasive biomarker of muscle injury, and physical frailty in COPD.
Methods:
In this cross-sectional study, stable outpatients with COPD (n = 27) were enrolled. Physical frailty was assessed using the Japanese version of the Cardiovascular Health Study (J-CHS) criteria, and patients were classified as frail (J-CHS ≥3) or non-frail (J-CHS ≤2). Urinary N-titin/Cr was measured using enzyme-linked immunosorbent assay. Associations between N-titin/Cr and clinical variables were examined using correlation and multivariable regression analyses, and receiver operating characteristic (ROC) analysis was performed to evaluate frailty discrimination.
Results:
Urinary N-titin/Cr levels were significantly higher in the frailty group (median: 15.9 pmol/mg Cr vs. 6.1 pmol/mg Cr, P < 0.01). Multiple regression analysis revealed a significant association between N- titin/Cr and J-CHS scores (β = 4.38, P = 0.004), independent of age, pulmonary function, serum creatine kinase, and walking speed. ROC analysis showed moderate discrimination for frailty (area under the curve = 0.75).
Conclusion:
These findings suggest that urinary N-titin/Cr reflects chronic muscle damage associated with frailty in COPD and may serve as a noninvasive and quantitative supplementary biomarker for frailty assessment.
