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Biomedical subjects

K G Manton

Publications and source records attributed to K G Manton.

At least 127 records · Page 7Linked to original sources
PubMed1984

Life table methods for assessing the dynamics of U.S. nursing home utilization: 1976-1977.

One likely consequence of the aging of the U.S. population is the growth of the number of persons in nursing homes. As the numbers of persons in nursing homes increase so will the amount of resources required to keep them in those homes. This will make it increasingly important to understand the dynamics of nursing home utilization so that we can more effectively plan the allocation of resources. Unfortunately, we lack direct information on the dynamics of nursing home utilization both because of the expense of implementing longitudinal studies to gather such information and because the available data on current residents are inappropriate to study the dynamics of utilization because of several types of bias. Demographic methods are presented that can be applied to survey data to remove sample biases from the data and permit study of the dynamics of the utilization of facilities for the total U.S. nursing home population and for various of its components.

Actuarial Analysis↗
PubMed1984

Projecting chronic disease prevalence.

Health and long-term care planning for an aging population is an important and necessary function for both the public and private sector. Unfortunately, efforts at planning have often been limited by difficulties in making estimates and forecasts of chronic disease prevalence in the population. These difficulties are a direct result of the natural history of chronic diseases that normally have long presymptomatic stages. Because of this characteristic, predictions of the magnitude of chronic disease prevalence in the United States often fail to reflect an important dimension of the health state of the population: that there is a sizeable proportion of chronic disease prevalence and risk existing in the population in a preclinical phase. The authors present a strategy for obtaining more complete estimates of chronic disease prevalence. This approach entails the creation of an illness--death model representing the natural history of individual chronic diseases and the application of the model to infer morbidity incidence and prevalence patterns from national mortality statistics. They illustrate the approach with an example of lung cancer and discuss the applications of the outputs of the modeling strategy for health care resource planning.

Actuarial Analysis↗
PubMed1984

The use of Grade of Membership analysis to evaluate and modify diagnosis-related groups.

A classification methodology is presented that can be used to evaluate the heterogeneity of reimbursement categories and service groups in multivariate terms. This methodology, called Grade of Membership analysis, has several properties that are particularly important in such assessments. First, simultaneously with the determination of the multivariate profile of characteristics that describe a group, the methodology determines the degree to which each case is described by that profile, which means that the model can explicitly represent the heterogeneity of individual cases in any derived classification scheme. Second, the estimates of the model's parameters are produced by maximum likelihood procedures; hence, the classification and group descriptions generated by the model can be statistically evaluated. Third, because of the way the group profiles are constructed, the results of the analysis will be reasonably robust to the selection of new samples. The analysis is illustrated using data on hospital discharges for the state of Maryland in 1981. The purpose of the analysis is to examine the association between the patterns of clinical and service attributes identified by the procedures with DRG category assignments.

Aged↗
PubMed1984

Mortality patterns in developed countries.

The implications of recent demographic trends in developed countries are considered. The emphasis is on the increase in life expectancy, and particularly in the rate of growth of the numbers of the very old (those aged 85 and over). "To evaluate the impact of recent mortality reductions on the social security and health service systems of developed countries [the author analyzes] the mortality conditions of 11 developed countries over the period 1950 to 1978." The countries concerned are the United States, Canada, Japan, Norway, Sweden, Denmark, Czechoslovakia, Hungary, the United Kingdom, the Federal Republic of Germany, and France. "The results of [the] analyses show that major increases in life expectancy have occurred at advanced ages for females and that the cross-country differences in the cause of death structure indicate that advances were achieved through a variety of mechanisms. Thus, it appears that no single uniform model of biological aging will currently explain cause specific mortality trends in countries with historically high life expectancies. This implies that further mortality reductions are possible in these countries by achieving cause specific mortality reductions observed to have occurred in another country." This is a revised version of a paper originally presented at the 1983 Annual Meeting of the Population Association of America (see Population Index, Vol. 49, No. 3, Fall 1983, p. 413).

Adult↗
PubMed1984

Methods and issues in the projection of population health status.

The discussion of strategies for forecasting health status changes in human populations often becomes immersed in efforts to utilize simple projection strategies that will produce crude projections. The motivation behind this effort is that simple projection strategies have limited data requirements and the crude projection strategies will be, in some ill-defined sense, robust (i.e., insensitive to assumptions). Actually there is a wide range of projection tools available. It seems appropriate to appraise the nature and attributes of each when considering the uses to which the projections will be put. For example, simple models are not necessarily more robust than more sophisticated procedures, especially for longer term temporal projections. Clearly we have many examples in developed countries where the use of simple actuarial or demographic projections has underestimated the true cost of a health programme by factors of 200-300%. The reason why the failures of such simple projection efforts become so rapidly manifest is that the programmes, once implemented, are expanded to meet the population's needs. In projecting only health services or utilization one has nearly a self-fulfilling prophecy--that resource constraints or the actual organization of the programme will directly determine the course of the level and mixture of health services consumption. Therefore failure to base the projections on a detailed model of underlying population needs leads in such cases to grossly inaccurate results. Clearly, projecting a population's health needs requires even more data than projecting health service requirements. Such information constraints require the use of a model to organize data from multiple objective and subjective sources, and to reflect the best scientific understanding of the processes involved. This article briefly discussed the application of 2 such models. One was designed for the analysis of discrete state health changes using population and vital statistics data, the other described both discrete and continuous changes using data from longitudinally followed community populations. One is designed to work only with detailed aggregate data with heavy inputs from scientific experts; the other deals with relatively information-rich measurements. Both can be modified on the basis of expert judgement to deal with simulations of a multiplicity of possible interventions. Both appropriately calculate the relative costs and benefits of select health initiatives.(ABSTRACT TRUNCATED AT 400 WORDS)

Actuarial Analysis↗
PubMed1983

A mathematical model of the physiological dynamics of aging and correlated mortality selection. I. Theoretical development and critiques.

A number of theoretical models of aging and human mortality have been proposed. Only a few of these theoretical models, however, have been translated into statistical procedures and applied to data. In this paper we outline a theoretical model of human aging and mortality and compare it with models developed by Sacher and Trucco and Forbes and Brown. The ways in which this new model can be viewed as a generalization of these other formulations are discussed as are ways in which this model can be translated into a statistical model for empirical application.

Aging↗
PubMed1983

A mathematical model of the physiological dynamics of aging and correlated mortality selection: II. Application to the Duke Longitudinal Study.

Given that mortality risks at advanced ages (over 85) due to circulatory diseases have decreased recently and that it is likely that the effects of risk factors change with age, it is important to study the age dynamics of circulatory disease and circulatory risk factors in elderly populations. Analysis of chronic disease risks, however, is complicated at advanced ages because of the prominence of natural age increases in risk and the rapid rate at which health status changes at those ages. As a consequence, to identify the effects of putative risk factors at advanced ages one must employ appropriate analytic procedures to isolate risk factor effects from aging dynamics. Special risk assessment procedures developed to represent age-related biological processes aare applied to an analysis of circulatory disease risk in a study population with a mean age at study entry of over 70 years--the first Duke University Longitudinal Study of Aging population.

Aged↗
PubMed1983

The length-of-stay pattern of nursing home admissions.

The length of stay (LOS) pattern of nursing home admissions has not been directly measured because the long duration of stay of some patients (e.g., 25% of persons admitted reside in homes for longer than 1 year) makes it impractical to follow specific admission cohorts until the members have been discharged. By applying life-table methods to data on current and discharged residents from the 1977 National Nursing Home Survey, the authors were able to generate estimates of this distribution. They estimated that the typical nursing home admission initially has an expected LOS of 456 days, but, more interesting, the remaining LOS is expected to increase, in the intermediate term, with the amount of time spent in the facility. They also examined LOS distributions of subsets of the national nursing home population, and illustrated potential applications for this new information for policy formulation.

Actuarial Analysis↗
PubMed1983

The contribution of hypertension to mortality in the US: 1968, 1977.

The contribution of hypertension to total mortality in the United States in 1968 and 1977 is assessed through multiple cause death rates for all mentions of hypertension and the death certificate prevalence of hypertension. Age-adjusted declines in the hypertension death rates were 32.8 per cent for non-White females, 30.4 per cent for non-White males, 30.3 per cent for White females, and 25.2 per cent for White males. Declines for younger non-Whites were the greatest, about 50 per cent, although their rates were more than twice the White rates in both years. Death certificate prevalence also declined for all four groups with the greatest (16.5 per cent) for non-White males and the least (10.4 per cent) for White males, who only showed declines at older ages. The age trajectory of death certificate prevalence reached a peak at ages 50-69 for non-Whites and ages 60-79 for Whites, with lower prevalence at the most advanced ages. Large declines in the contribution of hypertension to mortality observed in death certificate data are particularly striking in light of the probability that any bias would be toward better detection and reporting over the 10 years.

Adult↗
PubMed1982

Mortality data analysis using a multiple-cause approach.

Death certificates are the primary source for information used to define general mortality patterns in the United States. Analyses of mortality data generally are restricted to one of the conditions listed on the certificate--the underlying cause of dealth. We review principles related to the use of mortality data and describe a study using mortality tapes ("multiple-cause tapes") that list all conditions recorded on dealth certificates. Using multiple-cause tapes, we found that the number of deaths associated with seven infectious diseases in 1968, 1969, and 1970 was from 24% (diphtheria) to 81% (rubella) greater than that officially reported. Multiple-cause tapes also permitted a review of the association of deaths attributed to measles and varicella and known complications of these diseases. these observations confirm the usefulness of multiple-cause tapes in analyzing mortality data and emphasize the importance of examining all conditions listed on the death certificate.

Death Certificates↗