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Biomedical subjects

K Manton

Publications and source records attributed to K Manton.

11 recordsLinked to original sources
PubMed2006

Cumulative index of health disorders as an indicator of aging-associated processes in the elderly: results from analyses of the National Long Term Care Survey.

BACKGROUND: We employ an approach based on the elaborated frailty index (FI), which is capable of taking into account variables with mild effect on the aging, health and survival outcomes, and investigate the connections between the FI, chronological age and the aging-associated outcomes in the elderly. METHODS: Cross-sectional analysis of pooled data from the National Long Term Care Survey (NLTCS) assessing health and functioning of the U.S. elderly in 1982, 1984, 1989, 1994, and 1999. RESULTS: Distributions of frequency, residual life span, mortality rate, and relative risk of death are remarkably similar over age and FI. Coefficients of correlation between FI and age are low both for males (0.127, p<.01) and females (0.221, p<.01). The FI-specific age patterns show deceleration at advanced ages. The FI can provide order of magnitude better resolution in estimating mean remaining life span compared to age. Males have smaller FI than females while males' mortality risks are higher. For short-time horizons, the FI and age are largely independently associated with mortality risks. CONCLUSIONS: The FI: (i) can be considered as an adequate sex-specific indicator of the aging-associated processes in the elderly, (ii) can characterize these processes independently of age, and (iii) is a better characteristic of the aging phenotype than chronological age.

Age Factors↗
PubMed2004

Modeling nonlinear effects in longitudinal survival data: implications for the physiological dynamics of biological systems.

Despite the wealth of longitudinal data on the health dynamics of human populations, information on covariates (risk factors) changes in those studies has not been systematically and fully exploited. In this work we use the 46-year follow-up of the Framingham Heart Study to analyze dynamics of these risk factors in survival models that go far beyond the standard linear dynamic formulation. We focus on improving the inferences about the physiology of human aging processes and its plasticity and on modeling state trajectories for individuals considering the effect of nonlinear interactions among covariates. We find that using standard statistical methods to construct models describing the age dependence of health status might give rise to surprising results with highly "diluted" dynamics, but with significantly improved statistical criteria. It is found that problems with the dynamics are a consequence of the intrinsic nonlinear nature of these models. We show that evolution of the risk factors measured in the Framingham study is more complicated for females than for males (i.e., female health status is more sensitive to nonlinear interactions among risk factors). We suggest that this is due to the rapid rate of decline of estrogen production after menopause.

Aging↗
PubMed1995

Case mix controlled service use and expenditures in the social/health maintenance organization demonstration.

BACKGROUND: The social health maintenance organization (S/HMO) demonstration was implemented, in part, to determine if the presumed integration of acute and chronic care in these plans could produce sufficient savings to allow plans to offer expanded and chronic care benefits without increased cost to the Medicare program. METHODS: S/HMO members and a sample of fee-for-service (FFS) recipients were tracked over three years to assess their utilization experience. Analyses controlled for case mix, using Grade of Membership procedures. RESULTS: In 1987, the last year of risk sharing, S/HMOs reported higher total expenditures than FFS in each health status class. For the "healthy," differences were largest for physician care. In other classes, differences in nonskilled nursing or home care use were noted. In 1988, the first year of full risk, Seniors Plus had equivalent or lower expenditures relative to FFS for all classes. Elderplan had lower expenditures in four of six classes and provided more service to the "frail" and the "acutely ill." SHP had higher expenditures in all classes because of higher hospital and nursing home expenditures. Medicare Plus II had higher expenditures in all classes, for physician, nonskilled nursing home, and home care expenditures. CONCLUSIONS: Overall plan losses and higher expenditures among a number of case mix groups suggest a need for refinement of S/HMO operations--especially in case management relationships to medical care and in the selection of "high risk" cases.

Diagnosis-Related Groups↗
PubMed1993

Catastrophic acute and long-term care costs: risks faced by disabled elderly persons.

This article presents an empirical analysis of the extent to which acute and long-term care cause disabled elderly persons to incur catastrophic costs. We found that the proportion of those people whose out-of-pocket costs exceed 20% of income rises from 20% (when only acute care costs are measured) to 30% (when long-term care costs are included).

Age Factors↗
PubMed1991

Nursing home length of stay and spenddown in Connecticut, 1977-1986.

A study of lifetime nursing home use was conducted with data from Connecticut for a 9-year period, 1977-1986. By linking stays for individuals, we were able to make life table estimates of the total amount of time after age 65 expected to be spent by persons in nursing homes. Because these data were linked to Medicaid eligibility records, it was possible to determine the total amount of nursing home use that is paid for by Medicaid and to produce estimates of the risk of Medicaid spenddown. The lifetime risk of spenddown in nursing homes was estimated to be 21.5%, with a 14.4% incidence of spenddown in any given episode. The amount of time it took to spend down was longer than reported in several other studies.

Aged↗
PubMed1990

Medicaid spenddown in nursing homes.

This paper employs information from nationally representative surveys to examine the incidence and causes of Medicaid spenddown among disabled elderly persons. About 10% of nursing home discharges experience "asset spenddown," the process of converting from private pay to Medicaid. In contrast, over 50% of nursing home patients remain private pay throughout their stays. In addition, becoming a Medicaid patient is more common among community residents than among nursing home residents. Implications of findings for health care policies are discussed.

Aged↗
PubMed1989

Black/white differences in health status and mortality among the elderly.

Grade of membership (GOM) representations are used to characterize and compare the health status of a very heterogeneous sample of blacks and whites in an elderly cohort of 2,806 noninstitutionalized men and women living in New Haven, Connecticut. They were interviewed in 1982 as part of the Established Populations for the Epidemiologic Study of the Elderly (EPESE). Ideal profiles based on functional disabilities, chronic diseases, and selected biomedical and behavioral risk factors are constructed empirically. Each individual in the sample is represented by a set of GOM scores, interpreted as degrees of similarity of his or her health record to each of the profiles. Four profiles emerge from GOM analyses: healthy elderly, elderly with cognitive impairment, elderly with impairment in mobility function and physical performance and with selected chronic conditions, and elderly with major limitations in activities of daily living and multiple chronic conditions. Although elderly blacks and whites generally have similar configurations of profiles, there are important differences, especially when chronic conditions are related to specific types of functional impairments. Questions about and claims for black/white mortality crossovers at older ages, usually addressed with aggregate data, are examined conditional on GOM scores that correspond to diverse combinations of disabilities (or lack thereof) together with housing characteristics of cohort members (e.g., whether they live in public housing for the elderly or in owned or rented housing in the community).

Activities of Daily Living↗
PubMed1987

Malignant melanoma in the elderly.

Advancing age is associated with poorer prognosis in malignant melanoma. We studied 3,872 cases of malignant melanoma to evaluate whether the effect of age could be analyzed relative to sex, tumor depth, primary site, and other clinical and pathologic variables. The sex distribution by age shows a slight female predominance in the early and late decades but male predominance in the middle years. The percentage of patients with metastatic disease at initial diagnosis did not vary with age, despite greater diameter and depth of lesions in the older patients. In fact, in the older age groups, initial nodal metastasis occurred slightly less frequently. Trunk primaries decreased in frequency with increasing age, while extremity lesions remained relatively constant, and face, nose, and ear lesions increased. This was in part related to the histopathologic type, as lentigo maligna lesions increased in frequency with age, superficial spreading lesions were somewhat less frequent in the older age group and nodular types were fairly constant. On the basis of both Clark's level and Breslow thickness, there was an increasing proportion of deeper penetrating lesions in the older age group. The mean diameter of these lesions on the skin surface was also greater for the older patients. This would suggest that lesions in the older individual remain confined to the local site longer, penetrate and spread, but do not necessarily metastasize more rapidly. Cox model regression analysis of survival time within stage showed that age was highly significant as a poor prognostic factor. Though the adverse relation of advancing age with survival was partially explained by predominance of other unfavorable factors, such as primary site, depth of lesion, or histologic type, age remained an independent poor prognostic factor (chi 2 = 5.3; P = .02) for death due to melanoma.

Adolescent↗