Comparing the cost-effectiveness of the Otago Exercise Programme among older women and men: A secondary analysis of a randomized controlled trial

Objective

Using stratified analyses, we examined the cost-effectiveness of the Otago Exercise Programme (OEP), from a health care system perspective, among older women and men who have previously fallen.

Methods

This study was a secondary stratified analysis (by women and men), of a 12-month prospective economic evaluation of a randomized clinical trial (OEP compared with usual care). Three hundred and forty four community-dwelling older adults (≥70; 172 OEP (110 women; 62 men), 172 usual care (119 women; 53 men)) who sustained a fall in the past 12 months and received a baseline assessment at the Vancouver Falls Prevention Clinic, Canada were included. A gender by OEP/usual care interaction was examined for the falls incidence rate ratio (IRR). Outcome measures stratified by gender included: falls IRR, incremental cost-per fall prevented (ICER), incremental cost per quality adjusted life year (QALY, ICUR) gained, and mean total health care resource utilization costs.

Results

Men were frailer than women at baseline. Men incurred higher mean total healthcare costs $6794 (SD: $11906)). There was no significant gender by OEP/usual care interaction on falls IRR. The efficacy of the OEP did not vary by gender. The adjusted IRR for the OEP group demonstrated a 39% (IRR: 0.61, CI: 0.40–0.93) significant reduction in falls among men but not women (32% reduction (IRR: 0.69, CI: 0.47–1.02)). The ICER showed the OEP was effective in preventing falls and less costly for men, while it was costlier for women by $42. The ICUR showed the OEP did not impact quality of life.

Conclusion

Future studies should explore gender factors (i.e., health seeking behaviours, gender related frailty) that may explain observed variation in the cost-effectiveness of the OEP as a secondary falls prevention strategy.

Trial registrations

ClinicalTrials.gov Protocol Registration System

Identifier: NCT01029171; URL: https://clinicaltrials.gov/ct2/show/NCT01029171

Identifier: NCT00323596; URL: https://clinicaltrials.gov/ct2/show/NCT00323596

The Effects of Exercise on Cognitive Function in Older Adults With Different Types of Dementia: A Meta-Analysis

Combating dementia is a public health priority, and exercise training is one promising strategy for dementia prevention. However, its efficacy in promoting cognitive outcomes in different types of dementia remains unknown. We conducted a systematic review (N = 27) and meta-analysis (N = 24) of randomized controlled trials with cognitive function as a primary or secondary outcome. We aimed to assess the effect of exercise interventions on the cognitive function of older adults (>60 years) diagnosed with different types of dementia. We synthesized data from 2,441 older adults with dementia. Eleven trials included older adults with multiple types of dementia, eight with Alzheimer's disease, six with unspecified types of dementia, and two with vascular cognitive impairment. We performed random-effects models using robust variance estimation (RVE) and tested potential moderators using the approximate Hotelling-Zhang test (HTZ). Results suggest a small effect of exercise on cognitive function for all-cause dementia (g = 0.18; 95% CI: 0.04, 0.33; p = 0.016); however, the effects did not differ by type of dementia. Moderation analyses showed that trials that did not specify participants' severity of dementia, applied individual-level randomization, and had higher intervention adherence demonstrated larger exercise effects on cognitive function for all-cause dementia. We conclude that exercise promotes small improvements in the cognitive function of older adults with all-cause dementia. More research including different types of dementia is needed if we hope to determine the precise effects of exercise for each type of dementia.

CARDIOVASCULAR RISK MODERATES THE EFFECT OF RESISTANCE TRAINING ON PHYSICAL PERFORMANCE IN OLDER ADULT WOMEN

We aimed to examine whether the Framingham Cardiovascular Risk Profile Score (FCRP) moderates the effect of progressive resistance training (RT) on mobility in older adult women. This is an exploratory analysis of a single-blind, 12-month randomized controlled trial in 155 omen, aged 65 to 75 years old, who were randomized to: 1x/week progressive RT; or 2x/week progressive RT program; or 2x/week balance and tone (BAT). At baseline and trial completion, mobility was measured using the Short Physical Performance Battery (SPPB). The SPPB is a composite measure of usual gait speed, standing balance, and sit to stand performance; scores < 9/12 are indicative of functional decline. Baseline 10-year cardiovascular risk was calculated using the FCRP. Participants were classified as either low risk (<16.5% FCRP score; LCVR) or high risk ≥16.5% FCRP score; HCVR). A complete case analysis (n=126) was conducted using a two-way analysis of covariance (ANCOVA) to evaluate the interaction effect of group by FCRP risk on SPPB scores at trial completion; baseline SPPB scores and age in years were entered as covariates. There was a significant interaction effect (F(1,126)=3.74, p=0.027). At trial completion, both 1x/RT and 2x/RT participants with HCVR demonstrated greater SPPB scores than those with LCVR (11.59 vs. 11.38 for 1x/week; 11.86 vs 11.46 for 2x/week). In contrast, BAT participants with HCVR demonstrated worse SPPB scores than those with LCVR (11.18 vs 11.66). Our data suggest that RT may be more efficacious for improving mobility in older women with higher cardiovascular risk than women with lower risk.

THE ROLE OF S100B IN AEROBIC TRAINING EFFICACY IN OLDER ADULTS WITH MILD VASCULAR COGNITIVE IMPAIRMENT

Aerobic training improves cognitive and brain outcomes across different populations and neurocognitive disorders of aging, including mild subcortical ischemic vascular cognitive impairment (SIVCI). However, little is known of the underlying mechanisms through which aerobic training exerts its beneficial effects on the brain. Recently, S100 calcium-binding protein B (S100B) has been proposed as a possible mediator of aerobic training. At low levels, S100B is neurotrophic but at higher levels it is neurotoxic. Elevated levels of S100B have been associated with decreased performance on measures of global cognitive function. Thus, we conducted a secondary analysis of data collected from the proof-of-concept single-blind randomized controlled trial (NCT01027858) in older adults with mild SIVCI to determine whether the beneficial effects of 6-months, thrice weekly, moderate intensity aerobic training on cognitive performance is related to changes in S100B levels. In a subsample of 45 participants, blood samples were collected both before and after trial completion. Global cognitive function was assessed using Mini Mental State Examination (MMSE). At trial completion, aerobic training decreased circulating levels of S100B compared with usual care plus education (F(1,41) = 6.673, p = 0.013, ηp2 = 0.140; Figure 1). Furthermore, reduced S100B levels were associated with improved global cognitive function in those who received the aerobic exercise intervention (partial r = -0.519, p = 0.023). Together these findings suggest that S100B is a promising target mediating the beneficial effects of moderate-intensity aerobic training on brain health in older adults with mild SIVCI.

AEROBIC TRAINING, THE DEFAULT MODE NETWORK, AND COGNITION IN OLDER ADULTS WITH MILD VASCULAR COGNITIVE IMPAIRMENT

Aerobic training has been shown to be effective at improving cognitive and brain outcomes in older adults with mild subcortical ischemic vascular cognitive impairment (SIVCI). However, uncertainty remains regarding the underlying neurobiological mechanisms by which exercise elicits these improvements in cognition. Increased aberrant functional connectivity of the default mode network has been highlighted as a factor contributing to cognitive decline in older adults with cognitive impairment. Greater connectivity of the DMN at rest is associated with poorer performance on attention-demanding tasks, indicative of a lack of ability to deactivate the network on task. Our previous work on a randomized controlled trial of participants with mild SIVCI, demonstrated that 6-months of thrice weekly aerobic training led to improved global cognitive function, as measured by Alzheimer’s disease Assessment Scale-Cognitive subscale (ADAS-Cog), compared with a health education program. Thus, we conducted secondary analyses to investigate whether these changes in global cognitive function were associated with changes in resting state DMN connectivity. A subsample of 21 participants underwent a resting state functional magnetic resonance imaging (fMRI) scan before and after trial completion. Change in resting state DMN connectivity was found to significantly predict change in ADAS-Cog score (β = -.442, p=.038) after controlling for age, intervention group, and baseline functional capacity (R2=.467, F(4,16)= 3.507, p=.031). These findings suggest that functional connectivity of the DMN may underlie changes in global cognitive function. Furthermore, aerobic exercise is a promising intervention by which to elicit these changes in older adults with mild SIVCI.

MARKERS AND BIOMARKERS OF DEMENTIA BDNF GENOTYPE AND CHANGES IN WHITE MATTER HYPERINTENSITIES AND HIPPOCAMPAL MICROSTRUCTURE IN OLDER MEN AND WOMEN

Brain-derived neurotrophic factor (BDNF) may protect against cerebral gray and white matter impairments in older age. The val66met genetic polymorphism of BDNF is recently emerging as an early marker of brain structural integrity. However, evidence is sparse, cross-sectional, and mostly in men. In a longitudinal cohort study of community-dwelling older adults (N=139, mean age=81.6, 58% female, 58% white, mean follow-up=3.4 years), we estimated the overall and sex-stratified effects of BDNF val66met polymorphism on changes in cognition and gray and white matter macro- and micro-structure. Annualized percent change was computed for volume of white matter (WM) hyperintensities and gray matter (GM), fractional anisotropy of normal appearing WM, and mean diffusivity (MD) of GM in whole brain and memory and executive control function networks. Significant associations were adjusted for variables differing by genotype (race, APOE4, diabetes, triglycerides, smoking). Compared to met carriers, val homozygotes had slower annual whole brain WMH accrual (median (IQR) 31.4% (61.7) vs. 60.7% (92.4)), stronger in women. Met carriers had slower annual accrual of hippocampal MD (median (IQR) 1.26% (0.92) vs. 1.85% (1.09) for right hippocampus, stronger for women, and 1.45% (1.06) vs. 1.97% (1.22) for left hippocampus, stronger for men) compared to val homozygotes. Associations were robust to covariates’ adjustment. BDNF polymorphism was not associated with cognitive changes. BDNF polymorphism may help in early identification of those more likely to resist accrual of WMH and loss of hippocampal microstructural integrity, with effects varying by sex.

Active body, healthy brain: Exercise for healthy cognitive aging

The world's population is aging and promoting healthy cognitive aging is a public health priority and challenge. Physical activity is a modifiable lifestyle factor that has been identified as positively impacting the cognitive health of older adults with and without cognitive impairment. This chapter current evidence from epidemiological and intervention studies (i.e., randomized controlled trials) on the role of physical activity and exercise in promoting cognitive health in older adults both with and without cognitive impairment. Biological sex as a potential moderator of exercise efficacy is also discussed. We conclude with future directions for this rapidly expanding line of research.