Anne B. Newman

Ankle-arm index as a marker of atherosclerosis in the Cardiovascular Health Study. Cardiovascular Heart Study (CHS) Collaborative Research Group.

BACKGROUND Peripheral arterial disease measured noninvasively by the ankle-arm index (AAI) is common in older adults, largely asymptomatic, and associated with clinically manifest cardiovascular disease (CVD). The criteria for an abnormal AAI have varied in previous studies. To determine whether there is an inverse dose-response relation between the AAI and clinical CVD, subclinical disease, and risk factors, we examined the relation of the AAI to cardiovascular risk factors, other noninvasive measures of subclinical atherosclerosis using carotid ultrasound, echocardiography and electrocardiography, and clinical CVD. METHODS AND RESULTS The AAI was measured in 5084 participants > or = 65 years old at the baseline examination of the Cardiovascular Health Study. All subjects had detailed assessment of prevalent CVD, measures of cardiovascular risk factors, and noninvasive measures of disease. Participants were stratified by baseline clinical CVD status and AAI (< 0.8, > or = 0.8 to < 0.9, > or = 0.9 to < 1.0, > or = 1.0 to < 1.5). Analyses tested for a dose-response relation of the AAI with clinical CVD, risk factors, and subclinical disease. The cumulative frequency of a low AAI was 7.4% of participants < 0.8, 12.4% < 0.9, and 23.6% < 1.0. participants with an AAI < 0.8 were more than twice as likely as those with an AAI of 1.0 to 1.5 to have a history of myocardial infarction, angina, congestive heart failure, stroke, or transient ischemic attack (all P < .01). In participants free of clinical CVD at baseline, the AAI was inversely related to history of hypertension, history of diabetes, and smoking, as well as systolic blood pressure, serum creatinine, fasting glucose, fasting insulin, measures of pulmonary function, and fibrinogen level (all P < .01). Risk factor associations with the AAI were similar in men and women free of CVD except for serum total and low-density lipoprotein cholesterol, which were inversely associated with AAI level only in women. Risk factors associated with an AAI of < 1.0 in multivariate analysis included smoking (odds ratio [OR], 2.55), history of diabetes (OR, 3.84), increasing age (OR, 1.54), and nonwhite race (OR, 2.36). In the 3372 participants free of clinical CVD, other noninvasive measures of subclinical CVD, including carotid stenosis by duplex scanning, segmental wall motion abnormalities by echocardiogram, and major ECG abnormalities were inversely related to the AAI (all P < .01). CONCLUSIONS There was an inverse dose-response relation of the AAI with CVD risk factors and subclinical and clinical CVD among older adults. The lower the AAI, the greater the increase in CVD risk; however, even those with modest, asymptomatic reductions in the AAI (0.8 to 1.0) appear to be at increased risk of CVD.

Physical disability in older adults: A physiological approach

Measures of physical function have been developed primarily to assess health status, prognosis, and service needs. They are now, increasingly, being used as outcome measures in studies seeking to determine the causes of disability. However, the extent to which these standardized measures, as they currently are constituted, are meaningful for the evaluation of underlying pathophysiology is not defined. To assess evidence for an etiologic rationale for these measures, we evaluated self-report of difficulty in physical function in the Cardiovascular Health Study, a study of 5201 men and women 65 years and older in four U.S. communities. We determined (by factor analysis) that self-reported difficulty with each of 17 tasks of daily life aggregates in four groups; i.e. difficulty in one task is associated with having difficulty in the other tasks in the group. These groups include (1) activities primarily dependent on mobility and exercise tolerance; (2) complex activities heavily dependent on cognition and sensory input; (3) selected basic self-care activities; and (4) upper extremity activities. Groups 2 and 3 are similar, but not identical, to Instrumental Activities of Daily Living (IADL) and Activities of Daily Living (ADL), respectively. We then tested whether these groupings were associated with different underlying impairments. Multiple logistic regression analyses indicate that there are constellations of physiologic and disease characteristics significantly (p < 0.01) associated with difficulty in each of these four groups of activities, among 15 chronic diseases and conditions ascertained. Some diseases are uniquely associated with difficulty in one group of tasks; some overlap, and are associated with 2, 3 or 4 groups of tasks. The associations found with difficulty in performing tasks in groups 2 and 3 were frequently stronger than those with the larger groups of ADL or IADL tasks, suggesting increased specificity of associations found with these new groupings. These results suggest that re-grouping of tasks of daily life may provide a more refined physiologically-based outcome measure for use in evaluating causes of disability. The ability to define risk factors for disability may be enhanced by choosing outcome measures with a demonstrated physiologic rationale.

Bundling Preventive Services for Community-Dwelling Seniors: Rationale for Multi-Faceted Public Health Interventions

Background: Many older adults do not obtain important preventive services, which are critical for avoiding disease and disability. This is due in part to guidelines and interventions that take a “one disease at a time” approach, a lack of strategies to promote adherence to key services, and fragmented delivery systems. Many conditions common in older adults have overlapping risk factors; therefore, preventive services may be delivered more effectively as a “bundle,” especially given limited resources available for such programs. Methods and results: We outline a rationale for bundled preventive interventions by describing 5 “Ps”: priorities (preventive services of greatest benefit in older adults), place (clinical vs. community settings for delivery of services, including the integration of the public health system); package (rationale for bundled interventions, including examples), population/promotion (reaching those in greatest need); and policy implications. Conclusions: We conclude that new approaches to delivery of prevention and adherence to prevention for older adults are needed, and suggest an agenda for future comparative effectiveness research in this area.