Appendicular Lean Mass Loss Does Not Impact Physical Performance Change During Caloric Restriction in Older Adults

Data from 11 six-month randomized controlled trials were pooled, with 902 participants randomized to caloric restriction (CR; n=762) or Non-CR (n=140) to determine if CR-induced appendicular lean mass (ALM) loss was associated with change in physical performance among older adults. After adjusting for age, sex, race, body mass index, exercise assignment and baseline value of the outcome, CR had significant ALM loss [-0.77 kg (95% CI: -0.89, -0.65)], while Non-CR had ALM gain [+0.28 kg (0.08, 0.49)]; p<0.001. Both groups experienced similar improvements in the Short Physical Performance Battery (SPPB) score [CR: +0.45 (0.35, 0.55) vs Non-CR: +0.50 (0.30, 0.69); p=0.63] and sit-to-stand time [CR: -1.42 s (-1.81, -1.03) vs Non-CR: -1.85 s (-2.49, -1.21); p=0.19]. Change in SPPB score and sit-to-stand time was not associated with change in ALM (both p>0.15). In spite of significant ALM loss, CR resulted in overall improvements in physical performance in older adults.

Appendicular Lean Mass, Grip Strength, and the Development of Hospital-Associated Activities of Daily Living Disability among Older Adults in the Health ABC Study

Background Half of all physical disability, including activity of daily living (ADL) disability, among older adults occurs in the setting of hospitalization. This study examines whether appendicular lean mass (ALM) and grip strength, which are commonly included in various definitions of sarcopenia, are associated with development of hospital-associated ADL disability in older adults in the Health ABC Study. Methods Individuals hospitalized during the first 5 years of follow-up (n=1,724) were analyzed. ALM to body mass index (BMI) ratio (ALMBMI), by dual energy x-ray absorptiometry (DXA), and grip strength, by hand-held dynamometery, were assessed annually. Development of new ADL disability was assessed at the time of the next annual assessment after hospitalization. Separate regression analyses modeled the association of pre-hospitalization ALMBMI or grip strength with death before the next scheduled annual assessment. Next, among those who survived to the next annual assessment, separate regression analyses modeled the association of ALMBMI or grip strength with development of ADL disability. Results Each standard deviation decrement in pre-hospitalization grip strength was associated with an adjusted 1.80 odds of new ADL disability at follow-up (95% CI: 1.18, 2.74). Low, compared to not low, grip strength (per FNIH definition) was associated with an adjusted 2.36 odds of ADL disability at follow-up (95% CI: 1.12, 4.97). ALM measures were not associated with development of hospital-associated ADL disability. ALM and grip strength measures were not associated with death. Conclusions Pre-hospitalization lower grip strength may be an important risk factor for ADL disability among older adult survivors of hospitalization.

Lean mass as a risk factor for intensive care unit admission: an observational study

Purpose Intensive care unit (ICU) survivors have reduced physical function likely due to skeletal muscle wasting and weakness acquired during critical illness. However, the contribution of pre-morbid muscle mass has not been elucidated. We aimed to examine the association between pre-ICU muscle mass and ICU admission risk. Secondary outcomes include the relationship between muscle mass and ICU outcomes. Methods ICU admissions between June 1, 1998, and February 1, 2019, were identified among participants of Geelong Osteoporosis Study (GOS), a population-based cohort study. Cox proportional hazard regression models estimated hazard ratios (HR) for ICU admission across T-score strata and continuous values of DXA-derived lean mass measures of skeletal mass index (SMI, lean mass/body mass %) and appendicular lean mass corrected for height (ALM/h2, kg/m2). Multivariable regression was used to determine the relationship between lean mass and ICU outcomes. Results One hundred and eighty-six of 3126 participants enrolled in GOS were admitted to the ICU during the follow-up period. In adjusted models, lean mass was not predictive of ICU admission (SMI: HR 0.99 95%CI 0.97–1.01, p = 0.32; ALM/h2: HR 1.11 95%CI 0.94–1.31, p = 0.23), while greater appendicular lean mass was related to reduced 28-day mortality (ALM/h2 adjOR: 0.25, 95%CI 0.10–0.63, p = 0.003, SMI adjOR: 0.91, 95%CI 0.82–1.02, p = 0.09). Conclusion Lean mass was not associated with ICU admission in this population-based cohort study; however, greater appendicular lean mass was associated with reduced mortality. This suggests pre-ICU muscle status may not predict development of critical illness but is associated with better survival after critical illness occurs.