Neighborhood Socioeconomic Deprivation and Health Care Costs in Older Community-Dwelling Adults: Importance of Functional Impairment and Frailty.

BACKGROUND: Low neighborhood socioeconomic status is associated with adverse health outcomes, but its association with health care costs in older adults is uncertain. OBJECTIVES: To estimate the association of neighborhood Area Deprivation Index (ADI) with total, inpatient, outpatient, skilled nursing facility (SNF), and home health care (HHC) costs among older community-dwelling Medicare beneficiaries, and determine whether these associations are explained by multimorbidity, phenotypic frailty, or functional impairments. DESIGN: Four prospective cohort studies linked with each other and with Medicare claims. PARTICIPANTS: In total, 8165 community-dwelling fee-for-service beneficiaries (mean age 79.2 years, 52.9% female). MAIN MEASURES: ADI of participant residence census tract, Hierarchical Conditions Category multimorbidity score, self-reported functional impairments (difficulty performing four activities of daily living), and frailty phenotype. Total, inpatient, outpatient, post-acute SNF, and HHC costs (US 2020 dollars) for 36 months after the index examination. KEY RESULTS: Mean incremental annualized total health care costs adjusted for age, race/ethnicity, and sex increased with ADI ($3317 [95% CI 1274 to 5360] for the most deprived vs least deprived ADI quintile, and overall p-value for ADI variable 0.009). The incremental cost for the most deprived vs least deprived ADI quintile was increasingly attenuated after separate adjustment for multimorbidity ($2407 [95% CI 416 to 4398], overall ADI p-value 0.066), frailty phenotype ($1962 [95% CI 11 to 3913], overall ADI p-value 0.22), or functional impairments ($1246 [95% CI -706 to 3198], overall ADI p-value 0.29). CONCLUSIONS: Total health care costs are higher for older community-dwelling Medicare beneficiaries residing in the most socioeconomically deprived areas compared to the least deprived areas. This association was not significant after accounting for the higher prevalence of phenotypic frailty and functional impairments among residents of socioeconomically deprived neighborhoods.

Hip Fracture Risk Assessment Tools for Adults Aged 80 Years and Older.

Importance: While adults aged 80 years and older account for 70% of hip fractures in the US, performance of fracture risk assessment tools in this population is uncertain. Objective: To compare performance of the Fracture Risk Assessment Tool (FRAX), Garvan Fracture Risk Calculator, and femoral neck bone mineral density (FNBMD) alone in 5-year hip fracture prediction. Design, Setting and Participants: Prognostic analysis of 3 prospective cohort studies including participants attending an index examination (1997 to 2016) at age 80 years or older. Data were analyzed from March 2023 to April 2024. Main Outcomes and Measures: Participants contacted every 4 or 6 months after index examination to ascertain incident hip fractures and vital status. Predicted 5-year hip fracture probabilities calculated using FRAX and Garvan models incorporating FNBMD and FNBMD alone. Model discrimination assessed by area under receiver operating characteristic curve (AUC). Model calibration assessed by comparing observed vs predicted hip fracture probabilities within predicted risk quintiles. Results: A total of 8890 participants were included, with a mean (SD) age at index examination of 82.6 (2.7) years; 4906 participants (55.2%) were women, 866 (9.7%) were Black, 7836 (88.1%) were White, and 188 (2.1%) were other races and ethnicities. During 5-year follow-up, 321 women (6.5%) and 123 men (3.1%) experienced a hip fracture; 818 women (16.7%) and 921 men (23.1%) died before hip fracture. Among women, AUC was 0.69 (95% CI, 0.67-0.72) for FRAX, 0.69 (95% CI, 0.66-0.72) for Garvan, and 0.72 (95% CI, 0.69-0.75) for FNBMD alone (FNBMD superior to FRAX, P = .01; and Garvan, P = .01). Among men, AUC was 0.71 (95% CI, 0.66-0.75) for FRAX, 0.76 (95% CI, 0.72-0.81) for Garvan, and 0.77 (95% CI, 0.72-0.81) for FNBMD alone (P < .001 Garvan and FNBMD alone superior to FRAX). Among both sexes, Garvan greatly overestimated hip fracture risk among individuals in upper quintiles of predicted risk, while FRAX modestly underestimated risk among those in intermediate quintiles of predicted risk. Conclusions and Relevance: In this prognostic study of adults aged 80 years and older, FRAX and Garvan tools incorporating FNBMD compared with FNBMD alone did not improve 5-year hip fracture discrimination. FRAX modestly underpredicted observed hip fracture probability in intermediate-risk individuals. Garvan markedly overpredicted observed hip fracture probability in high-risk individuals. Until better prediction tools are available, clinicians should prioritize consideration of hip BMD, life expectancy, and patient preferences in decision-making regarding drug treatment initiation for hip fracture prevention in late-life adults.

Difference between kidney function by cystatin C versus creatinine and association with muscle mass and frailty.

BACKGROUND: A higher difference in estimated glomerular filtration rate by cystatin C versus creatinine (eGFRDiff = eGFRCys - eGFRCreat) is associated with decreased frailty risk. Since eGFRCreat is influenced by muscle more than eGFRCys, muscle mass may explain this association. Previous work could not account for this when considering regional muscle measures by imaging. Deuterated creatine (D3Cr) dilution measures whole body muscle mass (kilograms). We aimed to determine whether eGFRDiff is associated with D3Cr muscle mass and whether muscle mass explains the association between eGFRDiff and frailty. METHODS: Cross-sectional analysis within the multicenter MrOS Study at Year 14 (visit 4). 490 men of the original cohort of 5994 MrOS participants (aged ≥65 at enrollment) were included. Exposure was eGFRDiff (= eGFRCys - eGFRCreat), calculated using CKD-EPI equations 2012/2021. Primary outcome was D3Cr muscle mass. Secondary outcome was phenotypic pre-frailty (one or two criteria) and frailty (≥three criteria) including the following: weight loss, weakness, slow gait, physical activity, poor energy. The association of eGFRDiff with D3Cr muscle mass was examined by linear regression, that with prefrailty / frailty by multinomial logistic regression. RESULTS: Mean ± SD age was 84 ± 4 years, eGFRCreat 68 ± 16, eGFRCys 52 ± 16, eGFRDiff -15 ± 12 mL/min/1.73 m2 and D3Cr muscle mass 24 ± 4 kg. For each SD increment in eGFRDiff, D3Cr muscle mass was 1.4 kg higher on average, p < 0.0001 (fully adjusted). Higher eGFRDiff was associated with lower odds of frailty (OR = 0.63 95% CI [0.45;0.89]), but this was partially attenuated and insignificant after additionally adjusting for D3Cr muscle mass (OR = 0.85 95% CI [0.58; 1.24]). CONCLUSIONS: Higher eGFRDiff is associated with lower odds of frailty among late-life men. D3Cr muscle mass accounts for some of this association. This suggests that non-GFR determinants of creatinine and cystatin C, such as muscle mass, play a role in explaining the association of eGFRDiff with frailty. Future studies are needed to confirm.

Balancing fracture risk versus risk of mortality before fracture among women aged 80 years or older.

BACKGROUND: Most fractures occur in women aged ≥80 years but competing mortality unrelated to fracture may limit the benefit of osteoporosis drug therapy for some women in late life. Our primary aim was to develop separate prediction models for non-spine fracture (NSF) and mortality before fracture to identify subsets of women with varying fracture versus mortality risks. METHODS: Separate prediction models were developed for NSF and mortality before NSF for 4895 women aged ≥80 years enrolled in the Study of Osteoporotic Fractures (SOF) or the Health Aging and Body Composition (HABC) study. Proportional hazards models modified to account for competing mortality were used to identify candidate risk factors for each outcome. Predictors associated with NSF or mortality (p < 0.2) were included in separate competing risk models to estimate the cumulative incidence of NSF and mortality before NSF during 5 years of follow-up. This process was repeated to develop separate prediction models for hip fracture and mortality before hip fracture. RESULTS: Significant predictors of NSF (race, total hip BMD, grip strength, prior fracture, falls, and use of selective serotonin reuptake inhibitors, benzodiazepines, or oral/transdermal estrogen) differed from predictors of mortality before NSF (age, walking speed, multimorbidity, weight change, shrinking, smoking, self-rated health, dementia, and use of warfarin). Within nine subsets of women defined by tertiles of risk, 5-year outcomes varied from 28% NSF and 8% mortality in the high-risk NSF/low-risk mortality subset, to 9% NSF and 22% mortality in the low-risk NSF/high-risk mortality subset. Similar results were seen for predictors of hip fracture and mortality before hip fracture. CONCLUSION: Considerable variation in 5-year competing mortality risk is present among women in late life with similar 5-year NSF risk. Both fracture risk and life expectancy should inform shared clinical decision-making regarding initiation or continuation of osteoporosis drug therapy for women aged ≥80 years.

Optimizing exoskeleton assistance to improve walking speed and energy economy for older adults.

BACKGROUND: Walking speed and energy economy tend to decline with age. Lower-limb exoskeletons have demonstrated potential to improve either measure, but primarily in studies conducted on healthy younger adults. Promising techniques like optimization of exoskeleton assistance have yet to be tested with older populations, while speed and energy consumption have yet to be simultaneously optimized for any population. METHODS: We investigated the effectiveness of human-in-the-loop optimization of ankle exoskeletons with older adults. Ten healthy adults > 65 years of age (5 females; mean age: 72 ± 3 yrs) participated in approximately 240 min of training and optimization with tethered ankle exoskeletons on a self-paced treadmill. Multi-objective human-in-the-loop optimization was used to identify assistive ankle plantarflexion torque patterns that simultaneously improved self-selected walking speed and metabolic rate. The effects of optimized exoskeleton assistance were evaluated in separate trials. RESULTS: Optimized exoskeleton assistance improved walking performance for older adults. Both objectives were simultaneously improved; self-selected walking speed increased by 8% (0.10 m/s; p = 0.001) and metabolic rate decreased by 19% (p = 0.007), resulting in a 25% decrease in energetic cost of transport (p = 8e-4) compared to walking with exoskeletons applying zero torque. Compared to younger participants in studies optimizing a single objective, our participants required lower exoskeleton torques, experienced smaller improvements in energy use, and required more time for motor adaptation. CONCLUSIONS: Our results confirm that exoskeleton assistance can improve walking performance for older adults and show that multiple objectives can be simultaneously addressed through human-in-the-loop optimization.

Associations Between Walking Speed and Gut Microbiome Composition in Older Men From the MrOS Study.

BACKGROUND: Gut dysbiosis has been linked to frailty, but its association with early mobility decline is unclear. METHODS: First, we determined the cross-sectional associations between walking speed and the gut microbiome in 740 older men (84 ±â€…4 years) from the MrOS cohort with available stool samples and 400 m walking speed measured in 2014-2016. Then, we analyzed the retrospective longitudinal associations between changes in 6 m walking speed (from 2005-2006 to 2014-2016, calculated by simple linear equation) and gut microbiome composition among participants with available data (702/740). We determined gut microbiome composition by 16S sequencing and examined diversity, taxa abundance, and performed network analysis to identify differences in the gut microbiome network of fast versus slow walkers. RESULTS: Faster 400 m walking speed (m/s) was associated with greater microbiome α-diversity (R = 0.11; p = .004). The association between a slower decline in 6 m walking speed and higher α-diversity (R = 0.07; p = .054) approached borderline significance. Faster walking speed and less decline in walking speed were associated with a higher abundance of genus-level bacteria that produce short-chain fatty acids, and possess anti-inflammatory properties, including Paraprevotella, Fusicatenibacter, and Alistipes, after adjusting for potential covariates (p < .05). The gut microbiome networks of participants in the first versus last quartile of walking speed (≤0.9 vs ≥1.2 m/s) exhibited distinct characteristics, including different centrality measures (p < .05). CONCLUSIONS: Our findings suggest a possible relationship between gut microbiome diversity and mobility function, as indicated by the associations between faster walking speed and less decline in walking speed over 10 years with higher gut microbiome diversity in older men.

Breaking Up Sedentary Time Reduces Recurrent Fall Risk, but Not Incident Fracture Risk in Older Men.

Apart from physical activity volume, frequent breaks from sedentary bouts and active bouts may differentially reduce fall and fracture risk. We assessed the longitudinal relationship between frequency of breaks from time spent sedentary and frequency of active bouts with recurrent falls and fractures. The sample included 2918 men aged 79.0 ± 5.1 years with free-living activity (SenseWear Armband) at the Osteoporotic Fractures in Men Study (MrOS) year 7 (2007-2009) visit. Men were divided into quartiles by the number of breaks from sedentary bouts (sedentary bout: 5+ minutes sedentary; <1.5 metabolic equivalents of task [METS]) and separately by active bout frequency (active bout: 5+ minutes of activity; ≥1.5 METS). Recurrent falls (2+ falls/year) and fractures were ascertained by self-report; fractures were radiographically confirmed. Generalized estimating equations estimated the recurrent fall odds, with restricted cubic splines applied to assess nonlinear relationships. Cox proportional hazards models estimated fracture risk. Over 4 years of follow-up after year 7, 1025 (35.1%) men were fallers. Over 8.40 ± 4.10 years of follow-up, 640 (21.9%) men experienced a fracture. There was a significant nonlinear U-shaped relationship between number of breaks from sedentary bouts and recurrent falls (p < 0.001); compared with men with few breaks from sedentary bouts (1.4-<13.6), the odds of recurrent falls were lower with a moderate number (13.6-<17.0, odds ratio [OR] = 0.82, 95% confidence interval [CI] 0.66, 1.01; 17.0-<20.4, OR = 0.79, 95% CI 0.64, 0.99), but not with the highest number of breaks from sedentary bouts (20.4-34.6, OR = 1.01, 95% CI 0.81, 1.27). Results remained borderline significant after adjusting for total sedentary time. Men with the highest compared with the lowest number of breaks from sedentary bouts had a lower fracture risk, but the association was attenuated after adjustment for total sedentary time. No associations were observed for active bout frequency. In conclusion, breaking up extended periods of sedentary time reduces fall risk regardless of total sedentary time. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC. on behalf of American Society for Bone and Mineral Research.