Application of cut-points for low muscle strength and lean mass in mobility-limited older adults

Authors: GROSICKI, GREGORY - Georgia Southern University; TRAVISON, THOMAS - Harvard University; ZHU, HAO - Hebrew Senior Life; MAGAZINER, JAY - University Of Maryland; BINDER, ELLEN - Washington University; PAHOR, MARCO - University Of Florida; CORREA-DE-ARAUJO, ROSALY - National Institute On Aging (NIA, NIH); CAWTHON, PEGGY - California Pacific Medical Center Research Institute; BHASIN, SHALENDER - Brigham & Women'S Hospital; ORWIG, DENISE - University Of Maryland; GREENSPAN, SUSAN - University Of Pittsburgh; MANINI, TODD - University Of Florida; MASSARO, JOE - Harvard Clinical Research Institute; SANTANASTO, ADAM - University Of Pittsburgh; PATEL, SHEENA - California Pacific Medical Center Research Institute; FIELDING, ROGER - Jean Mayer Human Nutrition Research Center On Aging At Tufts University

Submitted to: Journal of the American Geriatrics Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/7/2020
Publication Date: 7/7/2020
Citation: Grosicki, G., Travison, T.G., Zhu, H., Magaziner, J., Binder, E.F., Pahor, M., Correa-De-Araujo, R., Cawthon, P.M., Bhasin, S., Orwig, D., Greenspan, S., Manini, T., Massaro, J., Santanasto, A., Patel, S., Fielding, R.A. 2020. Application of cut-points for low muscle strength and lean mass in mobility-limited older adults. Journal of the American Geriatrics Society. 68:1445-1453. https://doi.org/10.1111/jgs.16525.
DOI: https://doi.org/10.1111/jgs.16525

Interpretive Summary: The Sarcopenia Definitions and Outcomes Consortium (SDOC) is a collaborative initiative seeking to develop and evaluate criteria for sarcopenia (low muscle strength and low muscle mass) that predict an increased risk for slow walking speed among older adults. The goal of this study was to provide clinicians and researchers with an understanding of the diagnostic implications of employing these criteria in mobility-limited older adults. Using data from older individuals with specific medical conditions that render them at increased risk for mobility limitation, we evaluated the performance characteristics of five newly developed sarcopenia -or age-associated muscle mass and strength loss- criteria and then compared these values to previously recommended diagnostic criteria for sarcopenia. We found that maximal handgrip strength was the best discriminator of slowness. When applying previously recommended sarcopenia definitions in our population, we found that fewer individuals met those criteria. In conclusion, we found that a greater number of individuals fell below SDOC Grip strength criteria compared to previous recommendations. This finding has implications for measures of muscle strength in older adults and the diagnosis of sarcopenia.

Technical Abstract: BACKGROUND: The Sarcopenia Definitions and Outcomes Consortium (SDOC) is a collaborative initiative seeking to develop and evaluate cut-points for low muscle strength and lean mass that predict an increased risk for slowness (usual walking speed <.8m/s) among older adults. OBJECTIVES: The goal of the present study was to provide clinicians and researchers with an understanding of the diagnostic implications of using SDOC variables and cut-points in mobility-limited older adults. Using data from older individuals with specific conditions that render them at increased risk for mobility limitation, we evaluated the performance characteristics (ie, sensitivity and specificity) of five putative sarcopenia parameters and then compared these values with previously recommended diagnostic criteria for sarcopenia. DESIGN: Retrospective analysis of six randomized controlled trials enriched in persons at risk for mobility limitation. SETTING: National and international geriatric clinical research centers. PARTICIPANTS: A total of 925 mobility-limited older adults (>=55 years of age; 58% women) were included in the analysis. MEASUREMENTS: The prevalence of low muscle strength and lean mass were assessed using five candidate metrics discriminative of slowness. Analyses of sensitivity and specificity were used to compare muscle weakness criteria with published diagnostics for sarcopenia. RESULTS: Odds ratios (ORs) supported maximal grip strength (Grip max <35.5 and 20.0 in men and women, respectively) as the most discriminative of slowness in both men and women (OR = 3.66 and 3.53, respectively). More men (58%) than women (30%) fell below sex-specific maximal grip cut-points. When applying previously recommended sarcopenia component definitions in our population, we found that fewer individuals met those criteria (range = 6%-32%). CONCLUSION: A greater number of individuals fall below SDOC Grip max cut-points compared with previous recommendations. Clinicians and researchers working with older adults may consider these thresholds as an inclusive means to identify candidates for low-risk lifestyle promyogenic and function-promoting therapies.