Permanent Supportive Housing Receipt and Health Care Use Among Adults With Disabilities

This study assessed whether permanent supportive housing (PSH) participation is associated with health service use among a population of adults with disabilities, including people transitioning into PSH from community and institutional settings. Our primary data sources were 2014 to 2018 secondary data from a PSH program in North Carolina linked to Medicaid claims. We used propensity score weighting to estimate the average treatment effect on the treated of PSH participation. All models were stratified by whether individuals were in institutional or community settings prior to PSH. In weighted analyses, among individuals who were institutionalized prior to PSH, PSH participation was associated with greater hospitalizations and emergency department (ED) visits and fewer primary care visits during the follow-up period, compared with similar individuals who largely remained institutionalized. Individuals who entered PSH from community settings did not have significantly different health service use from similar comparison group members during the 12-month follow-up period.

Permanent Supportive Housing Tenure Among a Heterogeneous Population of Adults with Disabilities

People with disabilities can face substantial barriers to living stably in community settings. Evidence shows that permanent supportive housing (PSH), which combines subsidized housing with individualized support services, can improve housing stability among subpopulations of people with disabilities, including those with behavioral health conditions. PSH has also been shown to improve some health outcomes among people with severe mental illness or substance use disorder, but effects varied by participants' program tenure. This study assessed retention in a PSH program serving a broad population of adults with disabilities and identified factors associated with program tenure. Administrative data from 2093 individuals who began participating in a North Carolina PSH program between 2015 and 2018 were analyzed. Participants' unadjusted probability of remaining in a PSH placement at specific time points was estimated, with censoring due to death or the end of the study period (July 2020). Using Cox regression, program tenure was modeled as a function of participant and PSH placement location characteristics. Participants had a 71% probability of remaining in PSH after 2 years. Older age, female gender, and non-Hispanic Black race/ethnicity were associated with lower hazard of PSH departure. Having a severe mental illness diagnosis was associated with greater departure hazard. Level of socioeconomic deprivation and rurality of the PSH placement ZIP code were not associated with departure hazard. PSH programs may be able to successfully retain a heterogeneous population of adults with disabilities, although tenure may vary by participant demographic and clinical characteristics.

Preventive Services by Medical and Dental Providers and Treatment Outcomes

OBJECTIVE

Nearly all state Medicaid programs reimburse nondental primary care providers (PCPs) for providing preventive oral health services to young children; yet, little is known about how treatment outcomes compare with children visiting dentists. This study compared the association between the provider of preventive services (PCP, dentist, or both) with Medicaid-enrolled children before their third birthday and subsequent dental caries-related treatment (CRT) and CRT payment.

METHODS

We conducted a retrospective study of young children enrolled in North Carolina Medicaid during 2000 to 2006. The annual number of CRT and CRT payments per child between the ages of 3 and 5 yr were estimated with a zero-inflated negative binomial regression and a hurdle model, respectively. Models were adjusted for relevant child- and county-level characteristics and used propensity score weighting to address observed confounding.

RESULTS

We examined 41,453 children with > 1 preventive oral health visit from a PCP, dentist, or both before their third birthday. Unadjusted annual mean CRT and payments were lowest among children who had only PCP visits (CRT = 0.87, payment = $172) and higher among children with only dentist visits (CRT = 1.48, payment = $234) and both PCP and dentist visits (CRT = 1.52, payment = $273). Adjusted results indicated that children who had dentist visits (with or without PCP visits) had significantly more CRT and higher CRT payments per year during the ages of 3 and 4 yr than children who had only PCP visits. However, these differences attenuated each year after age 3 yr.

CONCLUSIONS

Because of children's increased opportunity to receive multiple visits in medical offices during well-child visits, preventive oral health services provided by PCPs may lead to a greater reduction in CRT than dentist visits alone. This study supports guidelines and reimbursement policies that allow preventive dental visits based on individual needs.

Systematic review of the long-term effects and economic consequences of treatments for obesity and implications for health improvement

OBJECTIVES

To undertake a systematic review of the long-term effects of obesity treatments on body weight, risk factors for disease, and disease.

METHODS

The study encompassed three systematic reviews that examined different aspects of obesity treatments. (1) A systematic review of obesity treatments in adults where the methods of the Cochrane Collaboration were applied and randomised controlled trials (RCTs) with a follow-up of at least 1 year were evaluated. (2) A systematic epidemiological review, where studies were sought on long-term effects of weight loss on morbidity and/or mortality, and examined through epidemiological modelling. (3) A systematic economic review that sought reports with both costs and outcomes of treatment, including recent reports that assessed the cost-effectiveness of pharmaceutical and surgical interventions. A Markov model was also adopted to examine the cost-effectiveness of a low-fat diet and exercise intervention in adults with obesity and impaired glucose tolerance.

RESULTS

The addition of the drugs orlistat or sibutramine was associated with weight loss and generally improved risk factors, apart from diastolic blood pressure for sibutramine. Metformin was associated with decreased mortality after 10 years in obese people with type 2 diabetes. Low-fat diets were associated with continuing weight loss for 3 years and improvements in risk factors, as well as prevention of type 2 diabetes and improved control of hypertension. Insufficient evidence was available to demonstrate the benefits of low calorie or very low calorie diets. The addition of an exercise or behaviour programme to diet was associated with improved weight loss and risk factors for at least 1 year. Studies combining low-fat diets, exercise and behaviour therapy suggested improved hypertension and cardiovascular disease. Family therapy was associated with improved weight loss for 2 years compared to individual therapy. There was insufficient evidence to conclude that individual therapy was more beneficial than group therapy. Weight lost more quickly (within 1 year), from the epidemiology review, may be more beneficial with respect to the risk of mortality. The effects of intentional weight loss need further investigation. Weight loss from surgical and non-surgical interventions for people suffering from obesity was associated with decreased risk of development of diabetes, and a reduction in low-density lipoprotein cholesterol, total cholesterol and blood pressure, in the long term. Targeting high-risk individuals with drugs or surgery was likely to result in a cost per additional life-year or quality-adjusted life-year (QALY) of no more than 13,000 British pounds. There was also suggestive evidence of cost saving from treatment of people with type 2 diabetes with metformin. Targeting surgery on people with severe obesity and impaired glucose tolerance was likely to be more cost-effective at 2329 British pounds per additional life-year. Economic modelling over 6 years for diet and exercise for people with impaired glucose tolerance was associated with a high initial cost per additional QALY, but by the sixth year the cost per QALY was 13,389 British pounds. Results did not include cost savings from diseases other than diabetes, and therefore may be conservative.

CONCLUSIONS

The drugs orlistat and sibutramine appear beneficial for the treatment of adults with obesity, and metformin for obese patients with type 2 diabetes. Exercise and/or behaviour therapy appear to improve weight loss when added to diet. Low-fat diets with exercise, or with exercise and behaviour therapy are associated with the prevention of type 2 diabetes and hypertension. Long-term weight loss in epidemiological studies was associated with reduced risk of type 2 diabetes, and may be beneficial for cardiovascular disease. Low-fat diets and exercise interventions in individuals at risk of obesity-related illness are of comparable cost to drug treatments. Long-term pragmatic RCTs of obesity treatments in populations with obesity-related illness or at high risk of developing such illness are needed (to include an evaluation of risk factors, morbidity, quality of life and economic evaluations). Drug trials that include dietary advice, plus exercise and/or behaviour therapy are also needed. Research exploring effective types of exercise, diet or behaviour and also interventions to prevent obesity in adults is required.

A randomised controlled trial of a tailored multifaceted strategy to promote implementation of a clinical guideline on induced abortion care

OBJECTIVE

To evaluate the effectiveness and efficiency of a tailored multifaceted strategy, delivered by a national clinical effectiveness programme, to implement a guideline on induced abortion.

DESIGN

Cluster randomised controlled trial.

SETTING AND PARTICIPANTS

All 26 hospital gynaecology units in Scotland providing induced abortion care.

INTERVENTION

Following the identification of barriers to guideline implementation, intervention units received a package comprising audit and feedback, unit educational meetings, dissemination of structured case records and promotion of a patient information booklet. Control units received printed guideline summaries alone.

MAIN OUTCOME MEASURES

Compliance with five key guideline recommendations (primary outcomes) and compliance with other recommendations, patient satisfaction and costs of the implementation strategy (secondary outcomes).

RESULTS

No effect was observed for any key recommendation: appointment with a gynaecologist within five days of referral (odds ratio 0.89; 95% confidence interval 0.50 to 1.58); ascertainment of cervical cytology history (0.93; 0.36 to 2.40); antibiotic prophylaxis or screening for lower genital tract infection (1.70; 0.71 to 5.99); use of misoprostol as an alternative to gemeprost (1.00; 0.27 to 1.77); and offer of contraceptive supplies at discharge (1.11; 0.48 to 2.53). Median pre-intervention compliance was near optimal for antibiotic prophylaxis and misoprostol use. No intervention benefit was observed for any secondary outcome. The intervention costs an average of pound 2607 per gynaecology unit.

CONCLUSIONS

The tailored multifaceted strategy was ineffective. This was possibly attributable to high pre-intervention compliance and the limited impact of the strategy on factors outside the perceived control of clinical staff.

Evolution in health and disease: work in progress

This article surveys progress in Darwinian medicine since 1991. Evolutionary thinking has been providing an increasing flow of fresh ideas into medical science, ideas that would not be suggested by other perspectives. Recent contributions have shed new light on the evolution of virulence, of antibiotic resistance, of oocytic atresia, of menopause, of the timing of the expression of genetic disease, of links between mate choice and disease resistance, and of genomic conflict between mother and fetus over resource provisioning. An important consequence of changes from the environment of evolutionary adaptedness concerns reproductive cancers; the incidence of reproductive cancers may be linked to changes in the frequency of menstruation in postindustrial societies. Other intriguing developments include some unanticipated and undesirable consequences of good hygiene, hope from an unexpected quarter for progress on nerve and muscle regeneration, evolutionary interpretations of mental disease, and insights from functional genomics into the nature of tradeoffs. The application of evolutionary thinking to problems in medical research and practice has thus yielded an abundant and growing harvest of insights. Some are well founded, others remain speculative. The field is moving from an initial phase dominated by speculation and hypothesis formation into a more rigorous phase of experimental testing of explicit alternatives. Currently the most promising areas, those in which experimental rigor can be applied efficiently, include experimental evolution and functional genomics. The pioneers can be proud of what they have set in motion.

Treatment outcomes and costs of dental sealants among children enrolled in Medicaid

OBJECTIVES

This retrospective cohort analysis of children enrolled in the North Carolina Medicaid program compared the likelihood of restorative treatments and associated cumulative Medicaid expenditures for teeth with or without dental sealants.

METHODS

We assessed the dental experience of the cohort of 15 438 children from 1985 to 1992 on the basis of enrollment and claims files. We conducted regression analyses for outcomes (caries-related services involving the occlusal surface [CRSOs] of permanent first molars) and cumulative expenditures, controlling for characteristics of the child, the treating dentist, and the child's county of residence.

RESULTS

Overall, 23% of children received at least 1 sealant and 33% at least 1 CRSO. Sealants were effective in preventing CRSOs, although the degree of effectiveness was highest for children with the greater levels of CRSOs before sealant placement. Estimated cumulative Medicaid expenditures indicated expenditure savings from sealants within 2 years of application for children with 2 or more prior CRSOs.

CONCLUSIONS

Sealant placement was associated with expenditure savings to Medicaid for certain high-risk children, so Medicaid and, more broadly, society will benefit by providing for sealant placement in these children.

Decline in offspring viability as a manifestation of aging in Drosophila melianogaster

The evolutionary explanation of senescence proposes that selection against alleles with deleterious effects manifested only late in life is weak because most individuals die earlier for extrinsic reasons. This argument also applies to alleles whose deleterious effects are nongenetically transmitted from mother to progeny, that is, that affect the performance of progeny produced at late ages rather than of the aging individuals themselves. We studied the effect of maternal age on offspring viability (egg hatching success and larva-to-adult survival) in two sets of Drosophila melanogaster lines (HAM/LAM and YOUNG/OLD), originating from two long-term selection experiments. In each set, some lines (HAM and YOUNG, respectively) have been selected for early reproduction, whereas later reproduction was favored in their counterparts (LAM and OLD). In the HAM and LAM lines, both egg hatching success and larval viability declined with mother's age and did so with accelerating rates. The hatching success declined significantly faster with maternal age in HAM than in LAM lines, according to one of two statistical approaches used. Egg hatching success also declined with maternal age in YOUNG and OLD lines, with no difference between the selection regimes. However, the relationship between mother's age and offspring larva-to-adult viability differed significantly between these two selection regimes: a decline of larval viability with maternal age occurred in YOUNG lines but not in OLD lines. This suggests that the rate with which offspring viability declines with mother's age responded to selection for early versus late reproduction. We suggest broadening the evolutionary concept of senescence to include intrinsically caused declines in offspring quality with maternal age.

Life history evolution: successes, limitations, and prospects

Life history theory tries to explain how evolution designs organisms to achieve reproductive success. The design is a solution to an ecological problem posed by the environment and subject to constraints intrinsic to the organism. Work on life histories has expanded the role of phenotypes in evolutionary theory, extending the range of predictions from genetic patterns to whole-organism traits directly connected to fitness. Among the questions answered are the following: Why are organisms small or large? Why do they mature early or late? Why do they have few or many offspring? Why do they have a short or a long life? Why must they grow old and die? The classical approach to life histories was optimization; it has had some convincing empirical success. Recently non-equilibrium approaches involving frequency-dependence, density-dependence, evolutionary game theory, adaptive dynamics, and explicit population dynamics have supplanted optimization as the preferred approach. They have not yet had as much empirical success, but there are logical reasons to prefer them, and they may soon extend the impact of life history theory into population dynamics and interspecific interactions in coevolving communities.

Access to care for rural Medicare beneficiaries

This paper examines variations between urban and rural Medicare beneficiaries in three measures of access to care: self-reported access to care, satisfaction with care received and use of services. The assessment focuses on these measures and their relationship to adjacency to metropolitan areas. Comparisons are also provided for the relative effects of adjacency versus broader access barriers such as income. Data from the 1993 Medicare Current Beneficiary Survey are used. The analyses offer several new perspectives on access in rural areas. First, as perceived by respondents, rural residence does not indicate access problems; instead, Medicare beneficiaries in rural counties that are adjacent to urban areas and that have their own city of at least 10,000 people report higher levels of satisfaction and fewer self-reported access problems than do residents of urban counties. These results may stem either from differences in rural residents' expectations regarding access or willingness to accept appropriate substitutions. Preventive vaccination rates in rural areas are on par with or better than rates by beneficiaries in urban areas. The only services where utilization in rural areas was limited relative to urban areas were preventive cancer screening for women and dental care. Development of policies to address these specific service gaps may be warranted. Low income has a more pervasive and problematic relationship to self-reported access, satisfaction and utilization than does rural residence per se.

The economic implications of self-care: the effect of lifestyle, functional adaptations, and medical self-care among a national sample of Medicare beneficiaries

OBJECTIVES

Self-care includes actions taken by individuals to promote or ensure their health, to recover from diseases or injuries, or to manage their effects. This study measured associations between self-care practices (lifestyle practices, adaptations to functional limitations, and medical self-care) and Medicare expenditures among a national sample of adults 65 years and older.

METHODS

Regression models of Medicare use and expenditures were estimated by using the National Survey of Self-Care and Aging and Medicare claims for 4 years following a baseline interview.

RESULTS

Lifestyle factors (swimming and walking) and functional adaptations (general home modifications) were associated with reductions in monthly Medicare expenditures over a 12-month follow-up period. Expenditure reductions were found over the 48-month follow-up period for participation in active sports, gardening, and medical self-care. Practices associated with increases in expenditures included smoking, physical exercise (possibly of a more strenuous nature), and specific home modifications.

CONCLUSIONS

Certain self-care practices appear to have significant implications for Medicare expenditures and presumptively for the health status of older adults. Such practices should be encouraged among older adults as a matter of national health policy.

Life-history correlates of evolution under high and low adult mortality

Life-history theory predicts evolutionary changes in reproductive traits and intrinsic mortality rates in response to differences in extrinsic mortality rates. Trade-offs between life- history traits play a pivotal role in these predictions, and such trade-offs are mediated, at least in part, by physiological allocations. To gain insight into these trade-offs, we have been performing a long-term experiment in which we allow fruitflies, Drosophila melanogaster, to evolve in response to high (HAM) and low (LAM) adult mortality rates. Here we analyze the physiological correlates of the life-history trade-offs. In addition to changing development time and early fecundity in the direction predicted, high adult mortality affected three traits expressed early in life-body size, growth rate, and ovariole number-but had little or no effect on body composition (relative fat content), viability, metabolic rate, activity, starvation resistance, or desiccation resistance. Correlations among lines revealed trade-offs between early fecundity, late fecundity, and starvation resistance, which appear to be mediated by differential allocation of lipids.

The effects of Medicaid expansions and reimbursement increases on dentists' participation

North Carolina Medicaid increased nominal Medicaid reimbursement to dentists 23% from 1988 to 1991 and doubled enrollment through eligibility expansions from 1985 to 1991. Using Medicaid claims data and panel data techniques, this analysis investigates the effect of these policy changes on the probability that a dentist participated in Medicaid, and on the number of Medicaid children seen per provider per quarter. The results suggest that eligibility expansions and reimbursement rate increases were only marginally effective in increasing access to dental services for the Medicaid population.

Experimental evolution of aging, growth, and reproduction in fruitflies

We report in this paper an evolutionary experiment on Drosophila that tested life-history theory and the evolutionary theory of aging. As theory predicts, higher extrinsic mortality rates did lead to the evolution of higher intrinsic mortality rates, to shorter lifespans, and to decreased age and size at eclosion; peak fecundity also shifted earlier in life. These results confirm the key role of extrinsic mortality rates in the evolution of growth, maturation, reproduction, and aging, and they do so with a selection regime that maintained selection on fertility throughout life while holding population densities constant.

Competitive behavior in local physician markets

Competition often is viewed as a mechanism for controlling cost. Competition may work well in urban areas with many providers; competition may not exist in rural areas with few providers. The authors use the empirical framework developed by Bresnahan and Reiss to analyze the entry behavior of physicians into local markets to determine the level of physician supply consistent with competitive behavior. The study estimates entry patterns for total and specialty physicians located in nonmetropolitan health service areas using longitudinal data. The authors find a surprising drop in the population increments necessary for entry by the second provider, possibly due to the unattractiveness of being the solo physician in an area. Subsequent population increments stabilize at three to five physicians. Since more than 93 percent of the U.S. population lives in areas that can support three to five physicians, competition between physicians through mechanisms such as managed care may be feasible.

A tale of two bounties: the impact of competing fees on physician behavior

This study examines how the volume of privately insured services provided in hospital inpatient and outpatient departments changes in response to reductions in Medicare physician payments. We hypothesize that physicians consider relative payment rates when choosing which patients to treat in their practices. When Medicare reduces its payments for surgical procedures, as it did in the late 1980s, physicians are predicted to treat more privately insured patients because they become more lucrative. We use data from 182 hospitals for seventeen major procedures groups, covering a forty-five-month period between 1988 and 1991 that encom passes a twenty-four-month period before the reduction in Medicare fees and twenty-one months after the reduction. Our findings are consistent with the predictions for a number of procedure groups, but not for all of them. One implication of the findings is that societal savings from Medicare fee reductions are overstated if one does not also consider spillover effects in the private insurance market.

The experimental evolution of aging in fruitflies

The evolutionary theory of aging suggests that the level of repair will evolve to an intermediate optimum that permits the accumulation of random damage to cells. This, in turn, causes a decline in essential functions during the life span of an organism. The central claim of the life history theory of aging is that intrinsic mortality rates evolve in response to changes in extrinsic mortality rates. To prove this central claim, it must be evaluated experimentally. Experimental evolution is an approach that has been yielding interesting results from both a variety of questions posed and organisms examined. In this article the organism chosen for study is the fruitfly (Drosophilia melanogaster) in which the evolutionary effects of high and low adult mortality rates are compared. It has been found that higher extrinsic mortality rates lead to the evolution of higher intrinsic mortality rates and a shorter life span. This is the first clear experimental demonstration of the central claim of the evolutionary theory of aging.

Volume responses to Medicare payment reductions with multiple payers: a test of the McGuire-Pauly model

The effects of changing financial incentives on physician's practice behaviour have long been of interest to researchers and policy makers. We test a model of physician volume response within the context of multiple payers developed by Thomas McGuire and Mark Pauly. A panel data set covering discharges from about 200 hospitals in the US over 45 months is used to carry out the empirical investigation. A fixed-effect model with generalized least squares and instrumental variable specifications is used to compute empirical evidence of volume responses from eight specialties experiencing varying degrees of Medicare payment reductions following the implementation of Omnibus Budget Reconciliation Acts of 1989 and 1990. The empirical findings are compared with McGuire and Pauly's simulated predictions. We note that in examining physician responses to Medicare payment reductions in the context of a multi-payer environment, it becomes evident that only fixing one payer's reimbursement policy is at best a partial solution to cost containment. We echo observations made by other analysts that physician responses to payment changes can be quite complex. Physicians do not all respond to payment reduction in the same way.

Reductions in hospital use from self management training for chronic asthmatics

The purpose of this study was to assess the impact of asthma Self Management Training on the health status and resource use of patients with chronic asthma. The study consisted of a randomized control design of chronic asthmatic patients in a tertiary care center in India. The intervention group (153 patients) received four training sessions in addition to the regular care provided to the control group (150 patients). Health status and resource use were measured at baseline and over a one year follow-up period. The intervention group had significantly better health status (measured by breathing ability), fewer productive days lost, and lower resource use (hospitalizations and emergency room visits) than the control group. Total annual costs (direct and indirect) were also lower, though physician costs were not included in the assessment. Therefore, incorporation of asthma Self Management Training as part of clinical management of asthma can result in improvements in health status and reductions in hospital use.

Psychosocial and educational outcomes associated with home- and clinic-based pretest education and cystic fibrosis carrier testing among a population of at-risk relatives

We report on the psychosocial and knowledge outcomes of two different approaches to cystic fibrosis (CF) gene pretest education and carrier testing offered to 288 proactively recruited first-, second-, and third-degree relatives of people with CF. One group received pretest education and gene testing in a clinical setting from a certified genetic counselor. The other group received pretest education in their homes from a specially prepared pamphlet and were asked to send in a buccal cell sample for genotyping. No statistically significant differences between groups were noted on measures of CF knowledge, anxiety, and positive or negative affect, either while waiting for their test results or within a few weeks after they had learned their results. At both measurement points, participants who had received home education and testing reported that the testing was more convenient, but that they had received less information than they would have liked, and they were more likely to report being confused by the testing, although their level of CF knowledge was comparable to that of people who had been seen by a genetic counselor. In light of the increasing interest in home-based medical testing of all kinds, this study suggests that CF carrier testing in the home warrants further consideration as one possible approach to facilitating access to testing.

The structure and experience of state risk pools: 1988-1994

State risk pools are state-sponsored plans for persons who want to buy health insurance but are medically uninsurable or unable to find policies at reasonable cost. This article reviews the structure of all pools and describes in more detail the experiences of eight pools. Although pools grew in number and size in the late 1980s, most pools subsequently stabilized in size. The eight risk pools studied had high enrollee turnover; and a small proportion of enrollees accounted for a large proportion of expenditures. All pools experienced losses, and the current methods of financing losses embody undesirable incentives. Continued use or expansion of these pools may require broader methods of covering losses.

P-element inserts in transgenic flies: a cautionary tale

The fruitfly, Drosophila melanogaster, can be transfected with P-elements and induced to overexpress a transfected gene whose impact on lifespan can be measured. Here, it is reported that in previous experiments a transfected gene was not expressed. This suggested a new statistical analysis indicating that (1) the size of the insert, the position and the interactions of the insert with the genetic backgrounds into which the P-element are inserted have effects on lifespan similar to those attributed to overexpression; (2) these effects occur without expression of the transfected gene; and (3) effects of interactions with backgrounds and effects of positions are as large as responses to six generations of strong directional artificial selection. Reports of effects of overexpression of transfected genes on lifespan in Drosophila melanogaster may be experimental artefacts. Credible experiments on the phenotypic effects of transgenesis need proper controls for the effects of insert size and position and should estimate the magnitudes of interactions of treatment with genetic backgrounds.

A prospective study of the impact of patient preferences on life-sustaining treatment and hospital cost

OBJECTIVES

Ethicists advise that life-sustaining treatment decisions should be made in keeping with patient preferences. Until recently, there has been little systematic study of the impact of patient preferences on the use of various life-sustaining treatments or the consequent cost of hospital care. This prospective study was designed to answer the following questions: a) Do patient treatment preferences about the use of life-sustaining treatment influence the treatments they receive? and b) Do patient treatment preferences influence the total cost of their hospitalization?

DESIGN

A prospective, cohort study.

SETTING

A university teaching hospital.

PATIENTS

Hospitalized patients, at least 50 yrs of age, with short life expectancy due to end-stage heart, lung, or liver disease, metastatic cancer, or lymphoma.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Patients were interviewed to determine their desire for life-sustaining treatment and other characteristics and then were followed for 6 months to determine life-sustaining treatment use and costs during hospitalization. Two hundred forty-four patients were interviewed. Fifty-eight percent of patients expressed a desire for life-sustaining treatments to prolong life for 1 wk. During 245 subsequent hospitalizations, there were 20 episodes of mechanical ventilation, 63 episodes of intensive care, and 66 cancer treatments given. Bivariate and multivariate analyses showed no significant association between patient desire to receive treatment to prolong life and either life-sustaining treatment use (p = .59) or hospital costs (p = .20).

CONCLUSION

In a university teaching hospital setting, there is no systematic evidence that patient preferences determine life-sustaining treatment use or hospital costs.

Innovative strategies using SUDAAN for analysis of health surveys with complex samples

Large-scale health surveys provide a wealth of information for addressing problems in health sciences research. Designed for multiple purposes, these surveys frequently have large sample sizes and extensive measurements of demographic and socioeconomic characteristics, risk factors, disease outcomes and health care service use and costs. Complex features of the sampling design typically employed to select the survey sample, coupled with the vast amount of information available from the survey database, underlie issues that must be addressed during data processing and analysis. Numerous articles in the literature have focused on the debate of whether or not, and how, to control for features of the sample design during data analysis. Traditional statistical methods for simple random samples and the software that accompanies them have historically not had the capacity to account for the survey design. Recent advancements in statistical methodology for survey data analysis have greatly expanded the analytical tools available to the survey analyst. Commercial software packages that incorporate these methods offer the analyst convenient ways for applying such tools to large survey databases in an easy and efficient manner. We present an overview of analysis strategies for survey data and illustrate their application via the SUDAAN software system. Examples for analyses are provided through data from two large US health surveys, the National Health Interview Survey and the Longitudinal Study of Aging. Questions of both a cross-sectional and longitudinal nature are addressed. The examples involve logistic regression, time-to-event analysis, and repeated measures analysis.

Estimating confidence intervals for cost-effectiveness ratios: an example from a randomized trial

Cost-effectiveness ratios usually appear as point estimates without confidence intervals, since the numerator and denominator are both stochastic and one cannot estimate the variance of the estimator exactly. The recent literature, however, stresses the importance of presenting confidence intervals for cost-effectiveness ratios in the analysis of health care programmes. This paper compares the use of several methods to obtain confidence intervals for the cost-effectiveness of a randomized intervention to increase the use of Medicaid's Early and Periodic Screening, Diagnosis and Treatment (EPSDT) programme. Comparisons of the intervals show that methods that account for skewness in the distribution of the ratio estimator may be substantially preferable in practice to methods that assume the cost-effectiveness ratio estimator is normally distributed. We show that non-parametric bootstrap methods that are mathematically less complex but computationally more rigorous result in confidence intervals that are similar to the intervals from a parametric method that adjusts for skewness in the distribution of the ratio. The analyses also show that the modest sample sizes needed to detect statistically significant effects in a randomized trial may result in confidence intervals for estimates of cost-effectiveness that are much wider than the boundaries obtained from deterministic sensitivity analyses.

Risk indicators for hospitalization during the last year of life

OBJECTIVE

High levels of hospital expenditures for older people during their last year of life are widely documented. However, evidence of the association between prospectively measured indicators and subsequent hospitalization is sparse. This article investigates the pattern of hospitalization for a sample of Medicare enrollees during their last year of life.

DATA SOURCES

Data from the Longitudinal Study of Aging, a national study of persons age 70 and older, are used. Only data on decedents are used.

STUDY DESIGN

We determine individual characteristics (including functional status, evidence of disease, living arrangement, and prior hospitalization) shortly before the last year of life. A distinction is made between terminal and nonterminal admissions. National estimates and regression analyses using survey weights are conducted.

PRINCIPAL FINDINGS

The likelihood of any use is high regardless of age, functional status, or the presence of major diseases. Although only a few indicators are associated with having a terminal stay, a number of indicators are associated with nonterminal use. Nonterminal stays and total nights hospitalized are positively associated with prior evidence of disease, prior hospitalization, and age, although the probability of nonterminal use decreases with age for persons over 82 years old. The relationship between use and functional status depends on whether persons lived alone, were institutionalized, or had private health insurance.

CONCLUSIONS

This study demonstrates that while it is difficult to predict who will be admitted to the hospital at the time of death, a number of characteristics existing before the last year of life are associated with nonterminal hospitalization and total nights hospitalized during the last year of life.

Diagnosing senescence: inferring evolutionary causes from phenotypic patterns can be misleading

Based on the predictions of two theories for the evolution of senescence, the 'antagonistic pleiotropy' and the 'mutation accumulation' theory, an age-specific increase in mortality and a decrease in fecundity are widely used criteria to diagnose senescence in natural, and laboratory populations. In this study we question the reliability of these criteria. Using a simple model we show that similar phenotypic patterns result from optimal life histories without senescence. With a tradeoff between reproduction and period survival, optimal life histories produce patterns of increasing mortality and decreasing fecundity as organisms age, even if the tradeoff does not deteriorate with age, so that we are not forced to invoke genetic effects such as antagonistic pleiotropy or accumulation of deleterious mutations to explain such patterns. Furthermore, if optimal life history theory is applied to senescent organisms, phenotypic patterns can result that are usually not associated with senescence. We conclude that the reliability of a diagnosis of senescence based on phenotypic patterns and the comprehension of the phenomenon senescence depends critically on understanding to what extent tradeoffs are determined by the effects of segregating genes.

Increasing Medicaid child health screenings: the effectiveness of mailed pamphlets, phone calls, and home visits

OBJECTIVES

A randomized controlled trial was conducted to test the effectiveness and cost effectiveness of three outreach interventions to promote well-child screening for children on Medicaid.

METHODS

In rural North Carolina, a random sample of 2053 families with children due or overdue for screening was stratified according to the presence of a home phone. Families were randomly assigned to receive a mailed pamphlet and letter, a phone call, or a home visit outreach intervention, or the usual (control) method of informing at Medicaid intake.

RESULTS

All interventions produced more screenings than the control method, but increases were significant only for families with phones. Among families with phones, a home visit was the most effective intervention but a phone call was the most cost-effective. However, absolute rates of effectiveness were low, and incremental costs per effect were high.

CONCLUSIONS

Pamphlets, phone calls, and home visits by nurses were minimally effective for increasing well-child screenings. Alternate outreach methods are needed, especially for families without phones.

The effect of channeling on home care utilization and satisfaction with care

This study examined the relationship between participation in two home and community-based long-term care case management interventions (collectively known as the Channeling demonstration), use of formal in-home care, and satisfaction with care. Maximum likelihood estimation techniques were used to analyze the National Long-Term Care Demonstration data set. It was hypothesized that participation in the two Channeling interventions would indirectly (rather than directly) enhance satisfaction by operating through the increased use of formal in-home care. However, both Channeling models were found to have favorable direct and indirect effects on patient satisfaction.

State risk pools and mental health care use

State risk pools provide an opportunity for persons with mental health and substance abuse (MH/SA) problems to purchase health insurance. This study uses data from eight risk pools during the period 1988-1991 to analyze the utilization and enrollment experience for persons who submit claims for MH/SA treatment. Special consideration is given to the effect of variation in inpatient benefits across risk pools. The experience of Connecticut's risk pool differs markedly from that of the other risk pools. Given that two states (Connecticut and Florida) have restricted MH/SA benefits over time, we discuss the ability of risk pools to maintain comprehensive MH/SA benefits.

The effect of Channeling on in-home utilization and subsequent nursing home care: a simultaneous equation perspective

OBJECTIVE

This study explored the relationship between participation in a home/community-based long-term care case management intervention (known as the Channeling demonstration), use of formal in-home care, and subsequent nursing home utilization.

STUDY DESIGN

Structural analysis of the randomized Channeling intervention was conducted to decompose the total effects of Channeling on nursing home use into direct and indirect effects.

DATA COLLECTION METHOD

Secondary data analysis of the National Long-Term Care Data Set.

PRINCIPAL FINDINGS

The use of formal in-home care, which was increased by the Channeling intervention, was positively associated with nursing home utilization at 12 months. However, the negative direct effect of Channeling on nursing home use was of sufficient magnitude to offset this positive indirect effect, so that a small but significant negative total effect of Channeling on subsequent nursing home utilization was found.

CONCLUSIONS

This study shows why Channeling did not have a large total impact on nursing home utilization. The analysis did not provide evidence of direct substitution of in-home care for nursing home care because the direct reductions in nursing home utilization due to other aspects of Channeling (including, but not limited to case management) were substantially offset by the indirect increases in nursing home utilization associated with additional home care use.

Selection against inbred song sparrows during a natural population bottleneck

The genetic and demographic consequences of population subdivision have received considerable attention from conservation biologists. In particular, losses of genetic variability and reduced viability and fecundity due to inbreeding (inbreeding depression) are of concern. Studies of domestic, laboratory and zoo populations have shown inbreeding depression in a variety of traits related to fitness. Consequently, inbreeding depression is widely accepted as a fact. Recently, however, the relative impact of inbreeding on the viability of natural populations has been questioned. Work on the cheetah (Acinonyx jubatus), for example, has emphasized the overwhelming importance of environmental factors on mortality in the wild. Here we report that song sparrows (Melospiza melodia) that survived a severe population bottleneck were a non-random subset of the pre-crash population with respect to inbreeding, and that natural selection favoured outbred individuals. Thus, inbreeding depression was expressed in the face of an environmental challenge. Such challenges are also likely to be faced by inbred populations of endangered species. We suggest that environmental and genetic effects on survival may interact and, as a consequence, that their effects on individuals and populations should not be considered independently.

A retrospective analysis of the cost-effectiveness of dental sealants in a children's health center

A retrospective patient record analysis was conducted to study the cost-effectiveness of dental sealants placed under routine, unrestricted practice condition in a fluoridated community. The 26 dentists who provided care at the clinic over the period of the study used their own clinical judgement to determine sealant placement or alternative treatment. Dental services for 275 patients at a children's dental clinic for low-income families were evaluated. All children had at least 3 years between their first and last dental visit (mean = 5.8 years). A lifetable analysis was conducted to compare the probability of survival (restoration-free tooth years) and costs incurred to first molars of children who did not receive sealants, received any sealants, or received sealants on all first molars. Among the children with sealants, comparisons were also made between sealed and unsealed teeth in children who did and did not have a first molar restoration prior to sealant placement. Costs included the costs of sealants and restorative treatments for these teeth over time. Depending on the conditions under which sealants were placed, cost-savings or improving cost-effectiveness with time were found. A strategy of identifying children with prior restorations and sealing the remaining molars showed cost-savings within 4-6 years. For other comparisons, incremental cost-effectiveness ratios became more favorable over time.

The effects of enhanced expression of elongation factor EF-1 alpha on lifespan in Drosophila melanogaster. IV. A summary of three experiments

This paper summarizes three experiments on the genetic manipulation of fitness components involved in the evolution of lifespan through the introduction of an additional copy of the gene for elongation factor EF-1 alpha into the genome of Drosophila melanogaster. The first experiment checked a prior claim that enhanced expression of elongation factor increased the lifespan of virgin male fruitflies. It used inbred stocks; three treatment and three control lines were available. The second experiment put one treatment and one control insert into different positions on the third chromosome, then measured the influence of six genetic backgrounds on treatment effects in healthier flies. The third experiment put six treatment and six control inserts into the genetic background whose lifespan was most sensitive to the effects of treatment in the second experiment, then measured the influence of insert positions on treatment effects in healthy flies. The treatment never increased the lifespan of virgin males. It increased the lifespan of mated females in inbred flies reared to eclosion at 25 degrees, reduced it in the positions experiment, and made no difference to lifespan in the backgrounds experiment. When it increased lifespan, it reduced fecundity. In inbred flies and in the positions experiment, the treatment reduced dry weight at eclosion of females. Marginal effects of gene substitutions on tradeoffs were measured directly. The results suggest that enhanced expression of elongation factor makes local changes within the bounds of tradeoffs that are given by a pre-existing physiological structure whose basic nature is not changed by the treatment.

Phenotypic plasticity for life-history traits in Drosophila melanogaster. III. Effect of the environment on genetic parameters

We estimated genetic and environmental variance components for developmental time and dry weight at eclosion in Drosophila melanogaster raised in ten different environments (all combinations of 22, 25 and 28 degrees C and 0.5, 1 and 4% yeast concentration, and 0.25% yeast at 25 degrees C). We used six homozygous lines derived from a natural population for complete diallel crosses in each environment. Additive genetic variances were consistently low for both traits (h2 around 10%). The additive genetic variance of developmental time was larger at lower yeast concentrations, but the heritability did not increase because other components were also larger. The additive genetic effects of the six parental lines changed ranks across environments, suggesting a mechanism for the maintenance of genetic variation in heterogenous environments. The variance due to non-directional dominance was small in most environments. However, there was directional dominance in the form of inbreeding depression for both traits. It was pronounced at high yeast levels and temperatures but disappeared when yeast or temperature were decreased. This meant that the heterozygous flies were more sensitive to environmental differences than homozygous flies. Because dominance effects are not heritable, this suggests that the evolution of plasticity can be constrained when dominance effects are important as a mechanism for plasticity.

Hospital discharge decisions, health outcomes, and the use of unobserved information on case-mix severity

Although implementation of the Medicare prospective payment system has been accompanied by significant decreases in hospital length of stay, the early discharge of some patients may lead to worse health outcomes, particularly if sufficient aftercare services following hospitalization are not available. This article develops an empirical model of the relationship between the choice of length of stay and patient outcome. The model incorporates information on the severity of a patient's medical condition known by the physician who chooses length of stay for a patient but generally not known by a researcher interested in the factors that affect length of stay and health outcome. Joint estimation of equations for length of stay and health outcome controls for unmeasured aspects of case severity that affect both variables. The ratio of nursing home beds to Medicare enrollees in the county is included as an exogenous variable in both equations to assess whether variation in nursing home bed availability is correlated with length of stay or health outcome. The model is estimated using billing data for Medicare patients admitted with congestive heart failure to New Jersey hospitals during 1982 and 1983. Two measures of outcome are used: (1) a discrete measure of survival time following admission, and (2) a categorical measure of whether or not the patient was discharged dead or died within six months after discharge. Empirical results show no evidence that longer lengths of stay for congestive heart failure patients lead to lower postadmission mortality. However, greater availability of nursing home beds may reduce length of stay and may shift the provision of terminal care away from a hospital setting. Therefore, policies to expand the nursing home bed supply may enable further decreases in hospital length of stay without deleterious effect on patient outcome.

The selection-arena hypothesis

The selection arena hypothesis offers one answer to a puzzling question. Why do some organisms produce many more fertilized zygotes than are actually reared to hatching, birth, or release-then neglect, discard, resorb, or eat some of them, or allow them to eat each other? It makes four assumptions: (1) zygotes are cheap; (2) after conception the investment of parental time, energy, or risk into offspring continues; (3) offspring vary in fitness; (4) variation in offspring fitness can be identified by the mother at an early stage of the life cycle. If these assumptions hold, then one general prediction follows: the parent should overproduce zygotes, identify those with lower expected fitness, then either kill and reabsorb them, let them be eaten by sibs, or simply stop feeding them in order to invest in more promising offspring. The explanation appears to apply to a wide range of phenomena whose common cause had not previously been appreciated. These include: (1) polyovulation in some bats, tenrecs, the plains viscacha, and the pronghorn antelope; (2) cases of recurrent, consecutive, spontaneous abortions in humans; (3) some cases of surplus flower production and fruit abortion; (4) sex-ratio adjustment in red deer, mice, and coypus; (5) some types of cannibalism, including possible cases in mice, sharks, and wasps. Some cases that might be explained by the selection arena hypothesis are also plausibly explained by other causes, including bet-hedging reproductive investment in the face of unpredictable food supplies, and inter-specific or inter-familial aggression as an alternative to parent-offspring or sib-sib cannibalism.

On inference in ecology and evolutionary biology: the problem of multiple causes

If one investigates a process that has several causes but assumes that it has only one cause, one risks ruling out important causal factors. Three mechanisms account for this mistake: either the significance of the single cause under test is masked by noise contributed by the unsuspected and uncontrolled factors, or the process appears only when two or more causes interact, or the process appears when there are present any of a number of sufficient causes which are not mutually exclusive. In ecology and evolutionary biology, experiments usually test single factor hypotheses, and many scientists apparently believe that hypotheses incorporating several factors are so much more difficult to test that to do so would not be practical. We discuss several areas in ecology and evolutionary biology in which the presupposition of simple causation has apparently impeded progress. We also examine a more mature field, the study of atherosclerosis, in which single factor studies did significantly delay progress towards understanding what now appears to be a multifactor process. The problem has three solutions: either factorial experiments, dynamic models that make quantitative predictions, response-surface methods, or all three. In choosing a definition for 'cause', we make a presupposition that profoundly influences subsequent observations and experimental designs. Alternative definitions of causation should be considered as contributing to potential cures for research problems.