Maintenance of independent living is the top health priority among patients with advanced chronic kidney disease (CKD). Mobility limitation is often the first sign of functional limitation leading to loss of independence. Regular assessments of physical capacity can help provide kidney health providers identify patients at risk of frailty and other adverse health-related outcomes that contribute to the loss of functional independence. These physical capacities can be measured with commonly used self-reported measures of physical function or by objective physical performance testing. The current review describes commonly used assessments of self-reported physical function and physical performance. First, we describe the disablement process and how these assessments can be performed with commonly used quality of life instruments measuring self-reported physical function or objective physical performance tests. Second, we identify the determinants and correlates of self-reported physical function and physical performance and their contribution to the frailty phenotype. Third, we describe the association of physical capacities with clinical outcomes. We conclude with on possible approach to identifying and intervening on persons with CKD at high risk of functional decline.

Objectives

To examine the prevalence of mobility device use in community-dwelling older adults in the United States and to investigate the incidence of falls and worry about falling according to type and number of mobility devices used.

Design

Analysis of cross-sectional and longitudinal data from the 2011-12 National Health and Aging Trends Study.

Setting

In-person interviews in the homes of study participants.

Participants

Nationally representative sample of Medicare beneficiaries (n=7,609).

Measurements

Participants were asked about mobility device use (e.g., canes, walkers, wheelchairs and scooters) in the last month, 1-year fall history and worry about falling.

Results

Twenty-four percent of adults aged 65 and older reported mobility device use in 2011, and 9.3% reported using multiple devices within the last month. Mobility device use increased with advancing age and was associated with nonwhite race and ethnicity, female sex, lower education level, greater multimorbidity, and obesity (all P<.001). Adjusting for demographic and health characteristics and physical function, the incidence of falls and recurrent falls was not associated with the use of multiple devices or any particular type of mobility device. Activity-limiting worry about falling was significantly higher in cane-only users than in nonusers.

Conclusion

The percentage of older adults reporting mobility device use is higher than results from previous national surveys, and multiple device use is common in those who use any device. Mobility device use is not associated with greater incidence of falls. Cane-only users may compensate for worry about falling by limiting activity.

Purpose of the study

The purpose of this study was to describe prevalence of technology use among adults ages 65 and older, particularly for those with disability and activity-limiting symptoms and impairments.

Design and methods

Data from the 2011 National Health and Aging Trends Study, a nationally representative sample of community-dwelling Medicare beneficiaries (N = 7,609), were analyzed. Analysis consisted of technology use (use of e-mail/text messages and the internet) by sociodemographic and health characteristics and prevalence ratios for technology usage by disability status.

Results

Forty percent of older adults used e-mail or text messaging and 42.7% used the internet. Higher prevalence of technology use was associated with younger age, male sex, white race, higher education level, and being married (all p values <.001). After adjustment for sociodemographic and health characteristics, technology use decreased significantly with greater limitations in physical capacity and greater disability. Vision impairment and memory limitations were also associated with lower likelihood of technology use.

Implications

Technology usage in U.S. older adults varied significantly by sociodemographic and health status. Prevalence of technology use differed by the type of disability and activity-limiting impairments. The internet, e-mail, and text messaging might be viable mediums for health promotion and communication, particularly for younger cohorts of older adults and those with certain types of impairment and less severe disability.

Objective

The risk of falls among adults with knee osteoarthritis (OA) has been documented, yet, to our knowledge no studies have examined knee OA and the risk of medically treated injurious falls (overall and by sex), which is an outcome of substantial clinical and public health relevance.

Methods

Using data from the Health Aging and Body Composition Knee Osteoarthritis Substudy, a community-based study of white and African American older adults, we tested associations between knee OA status and the risk of injurious falls among 734 participants with a mean ± SD age of 74.7 ± 2.9 years. Knee radiographic OA (ROA) was defined as having a Kellgren-Lawrence grade of ≥2 in at least 1 knee. Knee symptomatic ROA (sROA) was defined as having both ROA and pain symptoms in the same knee. Injurious falls were defined using a validated diagnosis code algorithm from linked Medicare fee-for-service claims. Cox regression modeling was used to estimate hazard ratios (HRs) and 95% confidence intervals (95% CIs).

Results

The mean ± SD follow-up time was 6.59 ± 3.12 years. Of the 734 participants, 255 (34.7%) had an incident injurious fall over the entire study period. In the multivariate model, compared with those without ROA or pain, individuals with sROA (HR 1.09 [95% CI 0.73-1.65]) did not have a significantly increased risk of injurious falls. Compared with men without ROA or pain, men with sROA (HR 2.57 [95% CI 1.12-5.91]) had a significantly higher risk of injurious falls. No associations were found for women or by injurious fall type.

Conclusion

Knee sROA was independently associated with an increased risk of injurious falls in older men, but not in older women.

Objective

To evaluate whether HIV infection was associated with reduced physical performance, and to examine if reduced physical performance predicted mortality in our aging cohort of HIV-infected and HIV-uninfected persons.

Design

Prospective, observational cohort of current and former injection drug users in the AIDS Linked to the IntraVenous Experience study in Baltimore, Maryland, USA.

Methods

The Short Physical Performance Battery (SPPB) was used as an objective measure of physical performance and measured semiannually along with behavioral and demographic data. Correlates of reduced physical performance (SPPB score ≤10) were identified and the relationship between reduced physical performance, HIV infection and mortality was analyzed by Cox regression.

Results

Among 12 270 person-visits contributed by 1627 participants, the median age was 51, 30.3% were HIV-infected and 32.6% had an SPPB score 10 or less. In multivariable models, HIV infection was independently associated with 30% increased odds of reduced physical performance [odds ratio 1.30; 95% confidence interval (CI):1.12-1.52]. Reduced physical performance predicted mortality in a dose-response manner and within all HIV disease strata. Whereas reduced physical performance alone (hazard ratio 2.52, 95% CI: 1.59-4.00) and HIV infection alone (hazard ratio 2.78, 95% CI: 1.70-4.54) increased mortality, HIV-infected participants with reduced physical performance had a six-fold increased mortality risk (hazard ratio 6.03, 95% CI: 3.80-10.0) compared with HIV-uninfected participants with higher physical performance.

Conclusion

HIV infection was independently associated with reduced physical performance. HIV and reduced physical performance have independent and joint effects on mortality. Physical performance measurement may be an important research and clinical tool to predict adverse outcomes among aging HIV-infected persons.

Objective

To determine whether anemia is associated with incident dementia in older adults.

Methods

We studied 2,552 older adults (mean age 76.1 years; 38.9% black; 51.8% female) participating in the Health, Aging, and Body Composition study and free of dementia at baseline. We defined anemia using WHO criteria (hemoglobin concentration <13 g/dL for men and <12 g/dL for women). Dementia diagnosis was determined by dementia medication use, hospital records, or a change in modified mini-mental state (3MS) score of more than 1.5 SD from mean. Discrete time Cox proportional hazard regression models were used to examine the hazard for developing dementia associated with anemia.

Results

Of 2,552 participants, 393 (15.4%) older adults had anemia at baseline [corrected]. Over 11 years of follow-up, 455 (17.8%) participants developed dementia. In the unadjusted model, those with baseline anemia had an increased risk of dementia (23% vs. 17%, hazard ratio = 1.64; 95% confidence interval 1.30, 2.07) compared to those without anemia. The association remained significant after adjusting for demographics, APOE ε4, baseline 3MS score, comorbidities, and renal function. Additional adjustment for other anemia measures (mean corpuscular volume, red cell distribution width), erythropoietin, and C-reactive protein did not appreciably change the results. There was no interaction by sex and race on risk of developing dementia.

Conclusion

Among older adults, anemia is associated with an increased risk of developing dementia. Findings suggest that further study of anemia as a risk factor for dementia and a target for intervention for cognitive health is warranted.

Chronic kidney disease (CKD) is associated with skeletal muscle dysfunction leading to decreased physical functioning. Reduced kidney function leads to impaired muscle mitochondrial oxidative capacity underlying poor physical performance. The link between muscle mitochondrial oxidative capacity and patient-reported and objective measures of physical activity (PA) remains unclear.

Background

Studies suggest that in patients with heart failure (HF), high serum erythropoietin is associated with risk of recurrent HF and mortality. Trials of erythropoietin-stimulating agents in persons with kidney disease have also suggested an increased incidence of adverse clinical events. No large studies of which we are aware have evaluated the association of endogenous erythropoietin levels with clinical outcomes in the community-living older adults.

Methods and results

Erythropoietin concentration was measured in 2488 participants aged 70-79 years in the Health, Aging and Body Composition Study. Associations of erythropoietin with incident HF, coronary heart disease, stroke, mortality, and ≥ 30% decline in estimated glomerular filtration rate were examined using Cox proportional hazards and logistic regression over 10.7 years of follow-up. Mean (SD) age was 75 (3) years and median (quartile 1, quartile 3) erythropoietin was 12.3 (9.0, 17.2) mIU/mL. There were 503 incident HF events, and each doubling of serum erythropoietin was associated with a 25% increased risk of incident HF 1.25 (95% confidence interval 1.13, 1.48) after adjusting for demographics, prevalent cardiovascular disease, cardiovascular disease risk factors, kidney function, and serum hemoglobin. There was no interaction of serum erythropoietin with chronic kidney disease or anemia (P > 0.50). There were 330 incident coronary heart disease events, 161 strokes, 1112 deaths, and 698 outcomes of ≥ 30% decline in estimated glomerular filtration rate. Serum erythropoietin was not significantly associated with these outcomes.

Conclusions

Higher levels of endogenous erythropoietin are associated with incident HF in older adults. Studies need to elucidate the mechanisms through which endogenous erythropoietin levels associate with specific outcomes.

Background

Physical activity (PA) may play a role in preserving kidney health. The purpose of this study was to determine if PA and sedentary behavior are associated with incident chronic kidney disease (CKD) and change in kidney function in older adults.

Methods

The Health, Aging, and Body Composition study is a prospective cohort of 3075 well-functioning older adults. PA and television watching was measured by self-report, and serum cystatin C was used to estimate glomerular filtration rate (eGFR). CKD was defined as an eGFR <60 ml/min/1.73 m(2). Rapid kidney function decline was defined as an annual loss in eGFR of >3 ml/min/1.73 m(2). Discrete survival analysis was used to determine if baseline PA and television watching were related to 10-year cumulative incidence of CKD and rapid decline in kidney function.

Results

Individuals who reported watching television >3 hours/day had a higher risk of incident CKD (HR 1.34; 95% CI, 1.09-1.65) and experiencing a rapid decline in kidney function (HR 1.26; 95% CI, 1.05-1.52) compared with individuals who watched television <2 hours/day. PA was not related to either outcome.

Conclusions

High levels of television watching are associated with declining kidney function; the mechanisms that underlie this association need further study.

Background

Mobility limitation is highly prevalent among older adults and is central to the loss of functional independence. Dynamic isokinetic muscle fatigue testing may reveal increased vulnerability to disability and mortality beyond strength testing.

Methods

We studied community-dwelling older adults enrolled in the Health Aging and Body Composition study (age range: 71-82) free of mobility disability and who underwent isokinetic muscle fatigue testing in 1999-2000 (n = 1,963). Isokinetic quadriceps work and fatigue index was determined over 30 repetitions and compared with isometric quadriceps maximum torque. Work was normalized to leg lean mass accounting for gender-specific differences (specific work). The primary outcome was incident persistent severe lower extremity limitation (PSLL), defined as two consecutive reports of either having a lot of difficulty or being unable to walk 1/4 mile or climb 10 steps without resting. The secondary outcome was all-cause mortality.

Results

There were 608 (31%) occurrences of incident PSLL and 488 (25%) deaths during median follow-up of 9.3 years. After adjustment, lower isokinetic work was associated with significantly greater risks of PSLL and mortality across the full measured range. Hazard ratios per standard deviation lower specific isokinetic work were 1.22 (95% CI 1.12, 1.33) for PSLL and 1.21 (95% CI 1.13, 1.30) for mortality, respectively. Lower isometric strength was associated with PSLL, but not mortality. Fatigue index was not associated with PSLL or mortality.

Conclusions

Muscle endurance, estimated by isokinetic work, is an indicator of muscle health associated with mobility limitation and mortality providing important insight beyond strength testing.