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Biomedical subjects

K G Manton

Publications and source records attributed to K G Manton.

At least 109 records · Page 6Linked to original sources
PubMed1986

Patterns of intellectual development in later life.

Temporal changes in 16 measures of cognitive and intellectual functioning (11 Wechsler Adult Intelligence Scale subtests, 3 Wechsler Memory Test subscales, 2 measures of reaction time) were studied in the full data set from the First Duke Longitudinal Study of Aging. Patterns of change in these 16 measures were identified through a 'grade-of-membership' analysis -- a general model for identifying patterns in temporal variation that does not require parametric assumptions about the trajectory of change or assumptions about the homogeneity of the sampled population. The analyses showed that the temporal variation of the 16 measures could be described by five latent patterns that reflected the complex patterning of intellectual functioning in extreme late life. The relation of these five patterns of intellectual ability to age was examined, as were the relationships to measures of mental and physical health. These results underline the needs for comprehensive models of health and functioning in later life that describe changes in a multidimensional form.

Aged↗
PubMed1986

Past and future life expectancy increases at later ages: their implications for the linkage of chronic morbidity, disability, and mortality.

Recently life expectancy increases have been noted at advanced ages in the United States. This means a more rapid growth of the elderly U.S. population in general, and of the "oldest-old" population in particular. Thus it is of considerable social and health policy interest to forecast the direction and magnitude of future changes in life expectancy at later ages and the changes in the prevalence of health and disability at later ages consequent to the increases in life expectancy. In the analysis, several prior efforts to predict life expectancy changes using standard demographic techniques are reviewed and reasons for the limitations of such efforts suggested. Results show that mortality changes at advanced ages have very different relations to risk factors than at earlier ages. The analysis also shows that linking morbidity, disability, and mortality in a complete projection of population health changes will require the extension of standard demographic methodologies to utilize information from multiple data sources.

Adult↗
PubMed1986

Comparison of temporal changes in U.S. and Swedish lung cancer, 1950-51 to 1981-82.

A comparison was made of temporal changes in lung cancer risk for the U.S. white and Swedish populations from 1950-51 to 1981-82 with the use of both life-table- and cohort-specific proportional hazard models to illustrate different features of the time series. Marked differences were noted for the two populations; Swedish lung cancer risks were generally lower than those in the United States. Sex-specific analyses were conducted that showed that Swedish males had a mortality rate roughly half that for U.S. males over the entire period. In contrast, U.S. white female mortality rates, though roughly equal to those for Swedish females in 1950-51, experienced a relatively more rapid increase; their rates were double the Swedish rates by 1980. The factors contributing to these patterns, such as marked cohort differences in risk, are identified by the various stages of analysis.

Age Factors↗
PubMed1986

A multivariate approach for classifying hospitals and computing blended payment rates.

Prospective payment for inpatient hospital care is based on the ideal that hospitals that produce similar outputs, as measured by the types of cases the hospital treats, should be paid similar prices. However, similar output is a multidimensional concept. Thus operationalization of this ideal will ultimately require a more complex framework for determining hospital payment rates than currently employed at either the federal or state level. This article illustrates a multidimensional approach to achieve this objective. This technique, called Grade of Membership, is used to generate a unique type of hospital group and to characterize individual hospitals in terms of their degree of similarity to these groups. In addition, a new concept of grouping is described, a variable set based on hospitals' internal cost structure is developed and used, and ordinary least squares regression is employed to compute prices for these groups. With the use of simulation analysis, these groups are compared with more conventional groups.

Costs and Cost Analysis↗
PubMed1986

Suicide in late life. Review and commentary.

Increasing attention has been directed to recent increases in suicide rates for children, adolescents, and young adults. Nevertheless, persons 65 years and older continue to commit suicide at a higher rate than any other age group in the United States. In this paper various aspects of suicide are examined by analyzing recent trends among young and elderly populations, cohort suicide rates, and future projection of the number of suicides in late life. Data are derived from US death certificates. Consideration of the epidemiologic data and projections may be helpful both to those interested in public policy and to clinicians serving the elderly.

Adolescent↗
PubMed1986

Breast cancer in the elderly. Current patterns of care.

To evaluate age-related differences in the current patterns of presentation and clinical management of breast cancer patients, the authors reviewed 1795 patients referred to a university hospital for their initial treatment. No age-related differences were found with respect to laterality and anatomic site. Age-related differences were seen with respect to histology, with mucinous (colloid) carcinoma being relatively more common with increasing age and medullary and inflammatory carcinoma being more common among young patients. Patients over age 55 presented with more advanced extent of disease, but the proportion did not further increase above age 65. Patients age 75 and older were nearly twice as likely to have surgery as their sole treatment as patients under age 45. The difference in treatment was specifically associated with the differential use of adjuvant chemotherapy between age groups. Sixty percent of patients under 45 with regional node involvement received adjuvant chemotherapy compared with only 27% of those 65 and older. Despite their similar characteristics in regard to laterality, anatomic site, and histology, elderly patients are less frequently given adjuvant chemotherapy in stage II breast cancer.

Adolescent↗
PubMed1986

The complexity of chronic disease at later ages: practical implications for prospective payment and data collection.

The diagnosis related groups system developed to pay for Medicare services under prospective payment has certain built-in constraints, owing to limitations in the data available at the time. To identify additional dimensions potentially relevant to case mix, we used a multivariate grouping model-"Grade of Membership"-on discharge records for patients 65 years of age and older hospitalized in Maryland in 1981 with diagnoses of breast cancer, leukemia, or lung cancer. We found that five dimensions are required to accurately type patients: prognosis, disease severity, the interaction effect of multiple illnesses, admission status, and treatment strategy. We also found that at least three possible stages of treatment can be identified and classified. We discuss the implications of our findings for DRG classification, administrative billing records, and the ICD-9 system.

Aged↗
PubMed1985

Psychiatric disorders. A rural/urban comparison.

We studied rural/urban differences in the prevalence of nine psychiatric disorders from a community survey (part of the Epidemiologic Catchment Area Program) of 3,921 adults living in the Piedmont of North Carolina. Crude comparisons disclosed that major depressive episodes and drug abuse and/or dependence were more common in the urban area, whereas alcohol abuse/dependence was more common in the rural area. When prevalence for these disorders was stratified for age, sex, race, and education (factors that may confound urban/rural comparisons), a number of significant differences were identified, such as higher prevalence of major depression in female and white subjects and higher prevalence of alcohol abuse/dependence in the less educated subjects. A logistic-regression analysis was used to determine if significant urban/rural differences persisted when these potential confounders were controlled. Major depressive disorders were found to be twice as frequent in the urban area in this controlled analysis.

Adolescent↗
PubMed1985

The participant effect: mortality in a community-based study compared to vital statistics.

The 20-year mortality experience of the community-based Evans County Heart Study population is compared to local, regional and national vital statistics. Deficit mortality occurred in the study population at younger ages while at older ages mortality was similar to or greater than vital statistics. This was particularly true for white and nonwhite males, whose mortality patterns were statistically significantly different from Evans Co. vital statistics (P less than 0.005). Nonwhite/white mortality ratios in the study were close to those observed in local vital statistics, particularly for males. Sex mortality ratios in the study population were lower than in vital statistics due to a stronger participant effect (lower mortality) in males. Evans Co. was an area of particularly high mortality for whites in the period 1960-1980 compared to other parts of Georgia and the U.S. Results of this study are similar to other reports of participant effects in epidemiologic follow-up studies; implications for bias in estimates of population levels of disease and of disease/exposure relationships are discussed.

Adult↗
PubMed1985

Mortality and aging in a heterogeneous population: a stochastic process model with observed and unobserved variables.

Various multivariate stochastic process models have been developed to represent human physiological aging and mortality. These efforts are extended by considering the effects of observed and unobserved state variables on the age trajectory of physiological parameters. This is done by deriving the Kolmogorov-Fokker-Planck equations describing the distribution of the unobserved state variables conditional on the history of the observed state variables. Given some assumptions, it is proved that the distribution is Gaussian. Strategies for estimating the parameters of the distribution are suggested based on an extension of the theory of Kalman filters to include systematic mortality selection. Various empirical applications of the model to studies of human aging and mortality as well as to other types of "failure" processes in heterogeneous populations are discussed.

Aging↗
PubMed1985

An analysis of the heterogeneity of U.S. nursing home patients.

Research has shown that the nursing home patient population is quite heterogeneous in terms of both individual patient characteristics and service needs. Furthermore, existing administrative classifications do a poor job of representing this heterogeneity. As a consequence we have conducted an analysis of the individual and service characteristics of two types of patients represented in the National Nursing Home Survey of 1977 (i.e., patients whose primary source of payment was Medicare and patients whose primary payment source was not Medicare). In this analysis we identified patterns of individual characteristics within the two patient groups and showed how these patterns related to their service needs. The logic of the model permitted us both to establish patterns of characteristics within the two payment types and to examine the implications of individual heterogeneity remaining in the classification. This makes the methodology useful both as a research tool for understanding the nature of the nursing home population and as a tool for studying the consequences of various classification schemes for questions of identifying service patterns and needs as well as the evaluation of policy options.

Aged↗
PubMed1985

The black/white mortality crossover: investigation in a community-based study.

The black/white mortality crossover at about age 75, a result of lower white mortality rates at younger ages and lower black rates at the oldest ages, has been observed in U.S. vital statistics since 1900. Though a persistant observation in such data, its validity has been challenged by questions about census enumeration and age reporting on death certificates. Analyses of 20 years experience of all-cause mortality in the community-based Evans County Study using a Weibull model of age specific mortality rates showed a statistically significant black/white mortality crossover for both men (at age 73) and women (at age 85). The finding of a crossover in this longitudinally followed population is significant because the age reporting for both survivors and age at death for nonsurvivors were obtained in the study protocol and did not rely on age reporting either in census data or on the death certificate. Differences in the age and sex patterns of mortality between two populations living in the same geographic region are relevant to questions about the etiology of the major age-related chronic diseases as well as to topics of current interest in health care policy.

Adult↗
PubMed1985

U.S. cancer mortality 1950-1978: a strategy for analyzing spatial and temporal patterns.

There are a number of technical and statistical problems in monitoring the temporal and spatial variation of local area death rates in the United States for evidence of systematically elevated risks. An analytic strategy is proposed to reduce one of the major statistical concerns, i.e., that of identifying areas with truly elevated mortality risks from a large number of local area comparisons. This analytic strategy involves two stages. The first is a procedure for examining the entire distribution of local area death rates instead of simply selecting high risk "outliers." The second is the development of an analytic procedure to relate the temporal changes in the cross-sectional distribution of local area death rates to models of the disease process operating within the populations in those areas. The procedures are applied to data on cancer mortality for the 3050 counties (or county equivalents) of the United States over the period 1950 to 1978. A number of striking mortality patterns, both within the entire United States and within various regions and states, are identified. For example, perhaps the most persistent finding was that the risk increases in the death rates for respiratory cancer mortality were due to a "catching up" of nonmetropolitan county mortality rates with metropolitan area mortality rates.

Adult↗
PubMed1985

Home care expenses for the disabled elderly.

This article presents descriptive statistics from the 1982 Long-Term Care Survey on noninstitutionalized elderly Americans with limitations in activities of daily living (ADL) and instrumental activities of daily living (IADL). The focus of this article is on private expenses for home-based care related to ADL and IADL limitations. We describe the amounts of out-of-pocket payments expended relative to the characteristics of the home-based, disabled elderly population. We also discuss several possible implications of the findings for policymakers and further research.

Activities of Daily Living↗
PubMed1985

Dynamics of health changes in the oldest old: new perspectives and evidence.

Improvement in survival at advanced ages suggests that important changes in health and the natural history of disease processes may be occurring concurrently. a general model based upon cohort and life-course perspectives describes the changing relation of morbidity, disability, and mortality over time. Variability across different social and economic conditions is examined among institutionalized and non-institutionalized elderly, and between the United States and Japan. Future policy must take account of the qualitative, as well as the quantitative, changes in aging.

Aged↗
PubMed1985

Health status and service needs of the oldest old: current patterns and future trends.

The costs--economic and social--of projected increased use of long-term care services by the oldest old will be borne by third-party payers and by their families, who already supply the bulk of personal care services in the community. However, use of health services is concerned among a relatively small group of disabled aged; efficient planning for those aged 85 and over requires early reliable identification of those most in need. Life table models can be used to display health care policy options.

Aged↗