TY - JOUR
T1 - A Novel Creatinine Muscle Index Based on Creatinine Filtration
T2 - Associations with Frailty and Mortality
AU - Ballew, Shoshana H.
AU - Zhou, Linda
AU - Surapaneni, Aditya
AU - Grams, Morgan E.
AU - Windham, B. Gwen
AU - Selvin, Elizabeth
AU - Coresh, Josef
AU - Miao, Shiyuan
AU - Inker, Lesley A.
AU - Levey, Andrew S.
N1 - Publisher Copyright:
© 2023 American Society of Nephrology. All rights reserved.
PY - 2023/3/1
Y1 - 2023/3/1
N2 - Significance StatementLow muscle mass is related to frailty and increased mortality in older adults. However, muscle mass is not easily assessed in routine clinical practice. This paper describes a novel creatinine muscle index (CMI) on the basis of serum creatinine and cystatin C. CMI was moderately associated with frailty among older adults. A significantly higher proportion of individuals with weak grip strength were in the lowest tertile of CMI. The index was also associated with mortality. These results are consistent with the hypothesis that creatinine filtration may be an index of muscle mass, which may have utility in clinical practice.BackgroundLow muscle mass is related to frailty and increased mortality in older adults. However, muscle mass is not easily assessed in routine clinical practice.MethodsThis study describes a novel creatinine muscle index (CMI) on the basis of serum creatinine and cystatin C in a community-based sample of older adults from the Atherosclerosis Risk in Communities Study. Analyses included 4639 participants who attended visit 5 (2011-2013) and 12,786 participants who attended visit 2 (1990-1992). CMI was defined as creatinine filtration (the product of serum creatinine times eGFR on the basis of cystatin C) and was analyzed in sex-specific tertiles. Cross-sectional associations of CMI with a frailty trichotomy, defined by the number (robust [0]/prefrail [1-2]/frail [3-5]) of five frailty components (weight loss, slowness, exhaustion, weakness, and low physical activity), were studied using polychotomous logistic regression and binary logistic regression with each frailty component. Cox regression was used to estimate associations of CMI at visit 5 and visit 2 with mortality. Models were adjusted for demographics, clinical variables, and comorbid conditions.ResultsCMI (tertile 1 versus 3) was moderately associated with frailty (visit 5: adjusted odds ratio 4.23 [95% confidence interval (CI), 2.02 to 8.87] in men and 2.34 [95% CI, 1.41 to 3.89] in women) and with mortality (visit 5: adjusted hazard ratio 1.45 [95% CI, 1.08 to 1.94] in men and 1.55 [95% CI, 1.13 to 2.12] in women; similar results were seen at visit 2).ConclusionLower CMI was associated with frailty and increased mortality, two clinical outcomes known to be associated with decreased muscle mass. Creatinine filtration may be an index of muscle mass and have utility in clinical practice, particularly at low levels.
AB - Significance StatementLow muscle mass is related to frailty and increased mortality in older adults. However, muscle mass is not easily assessed in routine clinical practice. This paper describes a novel creatinine muscle index (CMI) on the basis of serum creatinine and cystatin C. CMI was moderately associated with frailty among older adults. A significantly higher proportion of individuals with weak grip strength were in the lowest tertile of CMI. The index was also associated with mortality. These results are consistent with the hypothesis that creatinine filtration may be an index of muscle mass, which may have utility in clinical practice.BackgroundLow muscle mass is related to frailty and increased mortality in older adults. However, muscle mass is not easily assessed in routine clinical practice.MethodsThis study describes a novel creatinine muscle index (CMI) on the basis of serum creatinine and cystatin C in a community-based sample of older adults from the Atherosclerosis Risk in Communities Study. Analyses included 4639 participants who attended visit 5 (2011-2013) and 12,786 participants who attended visit 2 (1990-1992). CMI was defined as creatinine filtration (the product of serum creatinine times eGFR on the basis of cystatin C) and was analyzed in sex-specific tertiles. Cross-sectional associations of CMI with a frailty trichotomy, defined by the number (robust [0]/prefrail [1-2]/frail [3-5]) of five frailty components (weight loss, slowness, exhaustion, weakness, and low physical activity), were studied using polychotomous logistic regression and binary logistic regression with each frailty component. Cox regression was used to estimate associations of CMI at visit 5 and visit 2 with mortality. Models were adjusted for demographics, clinical variables, and comorbid conditions.ResultsCMI (tertile 1 versus 3) was moderately associated with frailty (visit 5: adjusted odds ratio 4.23 [95% confidence interval (CI), 2.02 to 8.87] in men and 2.34 [95% CI, 1.41 to 3.89] in women) and with mortality (visit 5: adjusted hazard ratio 1.45 [95% CI, 1.08 to 1.94] in men and 1.55 [95% CI, 1.13 to 2.12] in women; similar results were seen at visit 2).ConclusionLower CMI was associated with frailty and increased mortality, two clinical outcomes known to be associated with decreased muscle mass. Creatinine filtration may be an index of muscle mass and have utility in clinical practice, particularly at low levels.
KW - creatinine
KW - cystatin c
KW - frailty
KW - glomerular filtration rate
KW - mortality
KW - muscle mass
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U2 - 10.1681/ASN.0000000000000037
DO - 10.1681/ASN.0000000000000037
M3 - Article
C2 - 36735317
AN - SCOPUS:85149172417
SN - 1046-6673
VL - 34
SP - 495
EP - 504
JO - Journal of the American Society of Nephrology
JF - Journal of the American Society of Nephrology
IS - 3
ER -