3-hydroxykynurenine is a ROS-inducing cytotoxic tryptophan metabolite that disrupts the TCA cycle

Tryptophan is an essential amino acid that is extensively characterized as a regulator of cellular function through its metabolism by indoleamine 2,3-deoxygenase (IDO) into the kynurenine pathway. However, despite decades of research on tryptophan metabolism, the metabolic regulatory roles of it and its metabolites are not well understood. To address this, we performed an activity metabolomics screen of tryptophan and most of its known metabolites in cell culture. We discovered that treatment of human colon cancer cells (HCT116) with 3-hydroxykynurenine (3-HK), a metabolite of kynurenine, potently disrupted TCA cycle function. Citrate and aconitate levels were increased, while isocitrate and all downstream TCA metabolites were decreased, suggesting decreased aconitase function. We hypothesized that 3HK or one of its metabolites increased reactive oxygen species (ROS) and inhibited aconitase activity. Accordingly, we observed almost complete depletion of reduced glutathione and a decrease in total glutathione levels. We observed a dose-dependent decrease in cell viability after 48 hours of 3HK treatment. These data suggest that raising the intracellular levels of 3HK could be sufficient to induce ROS-mediated apoptosis. We modulated the intracellular levels of 3HK by combined induction of IDO and knockdown of kynureninase (KYNU) in HCT116 cells. Cell viability decreased significantly after 48 hours of KYNU knockdown compared to controls, which was accompanied by increased ROS production and Annexin V staining revealing apoptosis. Finally, we identify xanthommatin production from 3-HK as a candidate radical-producing, cytotoxic mechanism. Our work indicates that KYNU may be a target for disrupting tryptophan metabolism. Interestingly, many cancers exhibit overexpression of IDO, providing a cancer-specific metabolic vulnerability that could be exploited by KYNU inhibition.

Malic Enzyme 1 Absence in Synovial Sarcoma Shifts Antioxidant System Dependence and Increases Sensitivity to Ferroptosis Induction with ACXT-3102

PURPOSE

To investigate the metabolism of synovial sarcoma (SS) and elucidate the effect of malic enzyme 1 absence on SS redox homeostasis.

EXPERIMENTAL DESIGN

ME1 expression was measured in SS clinical samples, SS cell lines, and tumors from an SS mouse model. The effect of ME1 absence on glucose metabolism was evaluated utilizing Seahorse assays, metabolomics, and C13 tracings. The impact of ME1 absence on SS redox homeostasis was evaluated by metabolomics, cell death assays with inhibitors of antioxidant systems, and measurements of intracellular reactive oxygen species (ROS). The susceptibility of ME1-null SS to ferroptosis induction was interrogated in vitro and in vivo.

RESULTS

ME1 absence in SS was confirmed in clinical samples, SS cell lines, and an SS tumor model. Investigation of SS glucose metabolism revealed that ME1-null cells exhibit higher rates of glycolysis and higher flux of glucose into the pentose phosphate pathway (PPP), which is necessary to produce NADPH. Evaluation of cellular redox homeostasis demonstrated that ME1 absence shifts dependence from the glutathione system to the thioredoxin system. Concomitantly, ME1 absence drives the accumulation of ROS and labile iron. ROS and iron accumulation enhances the susceptibility of ME1-null cells to ferroptosis induction with inhibitors of xCT (erastin and ACXT-3102). In vivo xenograft models of ME1-null SS demonstrate significantly increased tumor response to ACXT-3102 compared with ME1-expressing controls.

CONCLUSIONS

These findings demonstrate the translational potential of targeting redox homeostasis in ME1-null cancers and establish the preclinical rationale for a phase I trial of ACXT-3102 in SS patients. See related commentary by Subbiah and Gan, p. 3408.

Disrupting Mitochondrial Pyruvate Uptake Directs Glutamine into the TCA Cycle away from Glutathione Synthesis and Impairs Hepatocellular Tumorigenesis

Hepatocellular carcinoma (HCC) is a devastating cancer increasingly caused by non-alcoholic fatty liver disease (NAFLD). Disrupting the liver Mitochondrial Pyruvate Carrier (MPC) in mice attenuates NAFLD. Thus, we considered whether liver MPC disruption also prevents HCC. Here, we use the N-nitrosodiethylamine plus carbon tetrachloride model of HCC development to test how liver-specific MPC knock out affects hepatocellular tumorigenesis. Our data show that liver MPC ablation markedly decreases tumorigenesis and that MPC-deficient tumors transcriptomically downregulate glutathione metabolism. We observe that MPC disruption and glutathione depletion in cultured hepatomas are synthetically lethal. Stable isotope tracing shows that hepatocyte MPC disruption reroutes glutamine from glutathione synthesis into the tricarboxylic acid (TCA) cycle. These results support a model where inducing metabolic competition for glutamine by MPC disruption impairs hepatocellular tumorigenesis by limiting glutathione synthesis. These findings raise the possibility that combining MPC disruption and glutathione stress may be therapeutically useful in HCC and additional cancers.

Tompkins et al. utilize stable glutamine isotope tracers in vivo and ex vivo to demonstrate hepatocyte MPC disruption increases TCA cycle glutamine utilization at the expense of glutathione synthesis and decreases hepatocellular tumorigenesis.

Mitochondrial Pyruvate Carrier Function in Health and Disease across the Lifespan

As a nodal mediator of pyruvate metabolism, the mitochondrial pyruvate carrier (MPC) plays a pivotal role in many physiological and pathological processes across the human lifespan, from embryonic development to aging-associated neurodegeneration. Emerging research highlights the importance of the MPC in diverse conditions, such as immune cell activation, cancer cell stemness, and dopamine production in Parkinson’s disease models. Whether MPC function ameliorates or contributes to disease is highly specific to tissue and cell type. Cell- and tissue-specific differences in MPC content and activity suggest that MPC function is tightly regulated as a mechanism of metabolic, cellular, and organismal control. Accordingly, recent studies on cancer and diabetes have identified protein–protein interactions, post-translational processes, and transcriptional factors that modulate MPC function. This growing body of literature demonstrates that the MPC and other mitochondrial carriers comprise a versatile and dynamic network undergirding the metabolism of health and disease.

Scale and structure of capitated physician organizations in California

Physician organizations in California broke new ground in the 1980s by accepting capitated contracts and taking on utilization management functions. In this paper we present new data that document the scale, structure, and vertical affiliations of physician organizations that accept capitation in California. We provide information on capitated enrollment, the share of revenue derived by physician organizations from capitation contracts, and the scope of risk sharing with health maintenance organizations (HMOs). Capitation contracts and risk sharing dominate payment arrangements with HMOs. Physician organizations appear to have responded to capitation by affiliating with hospitals and management companies, adopting hybrid organizational structures, and consolidating into larger entities.

Simulating the impact of medical savings accounts on small business

OBJECTIVE

To simulate whether allowing small businesses to offer employer-funded medical savings accounts (MSAs) would change the amount or type of insurance coverage.

STUDY SETTING

Economic policy evaluation using a national probability sample of nonelderly non-institutionalized Americans from the 1993 Current Population Survey (CPS).

STUDY DESIGN

We used a behavioral simulation model to predict the effect of MSAs on the insurance choices of employees of small businesses (and their families). The model predicts spending by each family in a FFS plan, an HMO plan, an MSA, and no insurance. These predictions allow us to compute community-rated premiums for each plan, but with firm-specific load fees. Within each firm, employees then evaluate each option, and the firm decides whether to offer insurance-and what type-based on these evaluations. If firms offer insurance, we consider two scenarios: (1) all workers elect coverage; and (2) workers can decline the coverage in return for a wage increase.

PRINCIPAL FINDINGS

In the long run, under simulated conditions, tax-advantaged MSAs could attract 56 percent of all employees offered a plan by small businesses. However, the fraction of small-business employees offered insurance increases only from 41 percent to 43 percent when MSAs become an option. Many employees now signing up for a FFS plan would switch to MSAs if they were universally available.

CONCLUSIONS

Our simulations suggest that MSAs will provide a limited impetus to businesses that do not currently cover insurance. However, MSAs could be desirable to workers in firms that already offer HMOs or standard FFS plans. As a result, expanding MSA availability could make it a major form of insurance for covered workers in small businesses. Overall welfare would increase slightly.

Simulating the effects of employer contributions on adverse selection and health plan choice

OBJECTIVE

To investigate the effect of employer contribution policy and adverse selection on employees' health plan choices.

STUDY DESIGN

Microsimulation methods to predict employees' choices between two health plan options and to track changes in those choices over time. The simulation predicts choice given premiums, healthcare spending by enrollees in each plan, and premiums for the next period.

DATA SOURCES

The simulation model is based on behavioral relationships originally estimated from the RAND Health Insurance Experiment (HIE). The model has been updated and recalibrated. The data processed in the simulation are from the 1993 Current Population Employee Benefits Supplement sample.

PRINCIPAL FINDINGS

A higher fraction of employees choose a high-cost, high-benefit plan if employers contribute a proportional share of the premium or adjust their contribution for risk selection than if employees pay the full cost difference out-of-pocket. When employees pay the full cost difference, the extent of adverse selection can be substantial, which leads to a collapse in the market for the high-cost plan.

CONCLUSIONS

Adverse selection can undermine the managed competition strategy, indicating the importance of good risk adjusters. A fixed employer contribution policy can encourage selection of more efficient plans. Ironically, however, it can also further adverse selection in the absence of risk adjusters.

Structure-based design and synthesis of a novel class of Src SH2 inhibitors

The structure-based design and synthesis of a novel class of 2,4-disubstituted thiazoles as Src SH2 inhibitors is described. Initial results are presented, including the X-ray and NMR analysis of one thiazole inhibitor bound to Lck and Src SH2.

Structure-activity relationships of a novel class of Src SH2 inhibitors

The structure-activity relationships (SAR) of a novel class of Src SH2 inhibitors are described. Variation at the pY+1 and pY+3 side chain positions using 2,4- and 2,5-substituted thiazoles and 1,2,4-oxadiazoles as scaffolds resulted in inhibitors that bound as well as the standard tetrapeptide Ac-pYEEI-NH2.

Who gains and who loses with community rating for small business?

This paper compares community rating with experience rating for small businesses using a microsimulation model to determine what firms offer and who within these firms purchases insurance. We generate four years of data and find that our results are remarkably stable through time. Both offer and purchase rates are about five percentage points higher under experience rating, but community rating leads to more stable offerings. Under community rating, high-risk firms and families purchase insurance, whereas under experience rating, it is the low-risk firms and families who are the purchasers. Young families and poor families have the lowest purchase rates, with these rates being disproportionately low under community rating.

Health services research in workers' compensation medical care: policy issues and research opportunities

OBJECTIVE

To describe some of the unique aspects of medical care offered under workers' compensation insurance systems and discuss the major policy considerations relevant to health services researchers undertaking investigations in this area.

BACKGROUND AND FINDINGS

State-based workers' compensation (WC) insurance systems requiring employers to pay for medical care and wage replacement for workplace injuries and illnesses were first developed between 1910 and 1920 in the United States. Employers are generally required to purchase state-regulated workers' compensation insurance that includes first-dollar payment for all medical and rehabilitative services and payment of lost wages to workers with work-related illness or injury. Injured workers have variable but usually limited latitude in choosing their health care provider. Employers and workers' compensation insurers have incentives for controlling both the cost of medical care and lost wages.

CONCLUSION

The major policy issues in WC medical care--the effect of patient choice of provider and delivery system structure, the ensuring of high-quality care, the effect of integrating benefits, and investigation of the interrelationships between work, health, and productivity--can be informed by current studies in health services research and by targeted future studies of workers' compensation populations. These studies must consider the extent of patient choice of physician, the regulatory environment, the unique role of the workplace as a risk and modifying factor, and the complex interaction between health and disability insurance benefits.

Primary care of long-stay nursing home residents: approaches of three health maintenance organizations

OBJECTIVE

To describe the innovative programs of three health maintenance organizations (HMOs) for providing primary care for long-stay nursing home (NH) residents and to compare this care with that of fee-for-service (FFS) residents at the same NHs.

DESIGN

Cross-sectional interviews and case-studies, including retrospective chart reviews for 1 year.

SETTING

The programs were based in 20 community-based nursing homes in three regions (East, West, Far West).

PARTICIPANTS

Administrative and professional staff of HMOs in three regions and 20 NHs; 215 HMO and 187 FFS residents at these homes were studied.

MAIN OUTCOME MEASURES

Emergency department (ED) and hospital utilization.

RESULTS

All HMO programs utilized nurse practitioner/physician's assistants (NP/PA), but the structural configuration of physicians' (MD) practices differed substantially. At nursing homes within each region, all three HMO programs provided more total (MD plus NP/PA) visits per month than did FFS care (2.0 vs 1.1, 1.3 vs .6, and 1.4 vs .8 visits per month; all P < .05). The HMO that provided the most total visits had a significantly lower percentage of residents transferred to EDs (6% vs 16%, P = .048), fewer ED visits per resident (0.1 vs .4 per year, P = .027), and fewer hospitalizations per resident (0.1 vs .5 per year, P = .038) than FFS residents; these differences remained significant in multivariate analyses. However, the other two programs did not achieve the same benefits on healthcare utilization.

CONCLUSIONS

HMO programs for NH residents provide more primary care and have the potential to reduce ED and hospital use compared with FFS care. However, not all programs have been associated with decreased ED and hospital utilization, perhaps because of differences in structure or implementation problems.

Life-sustaining treatment decisions for nursing home residents: who discusses, who decides and what is decided?

OBJECTIVE

To evaluate whether nursing home residents and their families reported discussions about life-sustaining treatment with their physicians, the relationship between such discussions and orders to limit therapy, and predictors of physician-patient communication about life-sustaining treatment.

DESIGN

Cross-sectional interviews and retrospective chart abstraction.

SETTING

Three regions: West Coast, New England, Western.

SAMPLE

A total of 413 nursing home residents, 363 family/surrogate interviews, and 192 resident interviews.

MAIN OUTCOME MEASURES

Measured were (1) physician-resident communication about life-sustaining treatment and (2) presence of an advance directive or do not resuscitate (DNR) order in resident's chart.

RESULTS

Seventy-four percent of residents had DNR orders, and 32% had advance directives; only 29% of residents reported discussions about life-sustaining treatment. Of residents with DNR orders who could have participated in discussions about life-sustaining treatment, nearly half reported they had not discussed CPR with their caregivers. Older age, longer duration of time living in nursing home, location in a New England nursing home, physician-family member discussion, and the presence of an advance directive in the medical chart were positively associated with having DNR orders. Physician-resident discussion was not associated with having a DNR order. For the subsample of interviewed residents, age and a diagnosis of cognitive impairment were negatively associated with a physician-resident discussion about life-sustaining treatment, whereas the likelihood of having a discussion increased with increasing numbers of medical diagnoses.

CONCLUSIONS

Chart orders to limit therapy are common, but physician-resident discussions about life-sustaining treatments are not. Far more family members than residents report such discussions with the resident's physicians.

Redistributional consequences of community rating

OBJECTIVE

To predict the geographical effects of community rating of health insurance premiums on the amount individuals pay for insurance.

DATA SOURCES

We estimate premiums and health expenditures for a 5 percent sample of Californians from the 1990 U.S. Census (the Public Use Microdata Sample) and use data from Blue Cross of California to adjust for regional price differences in services.

STUDY DESIGN

We use an episodic health simulation model to estimate health expenditures for 975,074 Californians. Because the simulations do not reflect expenditure differences due to price variation in cost of services, we adjust these data for relative price differences by county. This leaves us with a sample of Californians for whom we have estimated health expenditures. We then compute average expenditures within areas of different sizes (all California, two regions, within counties) to estimate community-rated premiums. We then compare these premiums with actual expenditures on a county-by-county basis.

PRINCIPAL FINDINGS

With a single California-wide premium, rural residents pay premiums that exceed their use of care, while urban residents pay premiums that are less than their use of care. These transfers are substantial. Dividing California into regional risk pools at the county level still results in poorer communities providing substantial subsidies to their more wealthy counterparts.

CONCLUSIONS

Mandated community rating of premiums in a heterogeneous state such as California results in large unintended transfers of wealth from poorer, rural communities to urban, wealthier communities. Allowing premiums to vary with the regional cost of medical care would eliminate some of the transfers without sacrificing the benefits of community rating. Subsidies to low-income families could also effectively mitigate this redistribution. UTILITY: This article points out some potentially regressive consequences of geographic community rating and suggests ways to mitigate them.

Can medical savings accounts for the nonelderly reduce health care costs?

OBJECTIVE

To understand how medical savings account (MSA) legislation for the nonelderly would affect health care costs.

DESIGN

Economic policy evaluation based on the RAND Health Expenditures Simulation Model.

SETTING

National probability sample of nonelderly noninstitutionalized households.

PARTICIPANTS

Persons in 23 157 sampled households from the 1993 Current Population Survey.

INTERVENTIONS

Medical savings account legislation would allow all Americans who are covered only by a catastrophic health care plan to set up a tax-exempt account that they can use to pay medical bills not covered by their health insurance. The interventions we evaluate differ in the deductibles of the catastrophic plan and in whether the employee or employer funds the MSA.

MAIN OUTCOME MEASURES

Changes in national health expenditures and net societal benefits of health care.

RESULTS

If all insured nonelderly Americans switched to MSAs, their health care expenditures would decline by between 0% and 13%, depending on how the MSAs are designed. However, not all nonelderly Americans would choose MSAs; taking into account selection patterns, health spending would change by + 1% to -2%.

CONCLUSIONS

Medical savings account legislation would have little impact on health care costs of Americans with employer-provided insurance. However, depending on the size of the catastrophic limit, waste from the excessive use of generously insured care could be reduced, and MSAs would be attractive to both sick and healthy people.

Charges for outpatient rehabilitation: growth and differences in provider types

OBJECTIVE

This study compares Medicare program charges through time for outpatient rehabilitation services across different types of institutional providers.

DESIGN

Observational study of Medicare Part B claims. The analytic methods include a decomposition analysis and analysis of variance via regression.

SETTING

Data come from six different institutional providers types: community hospital outpatient departments, rehabilitation hospital outpatient departments, skilled nursing facilities, independent rehabilitation agencies, comprehensive outpatient rehabilitation facilities, and home health agencies.

PATIENTS

Five percent random sample of Medicare beneficiaries who used any institutionally based Part B physical, occupational, or speech therapy during the calendar years 1987 to 1990.

MAIN OUTCOME MEASURE

Charges for Medicare Part B rehabilitation therapies (physical and occupational therapy, speech pathology).

RESULTS

Charges for rehabilitation services grew more than 86% during this period across all provider types. Both the likelihood of using rehabilitation services and the average annual charges per patient grew rapidly. We found large differences in average annual per person charges and in the growth in charges across the six institutional provider types. Analyses that controlled for patient demographic characteristics and diagnoses across five provider types did not explain observed differences. Hospital outpatient departments were consistently the least costly type of institutional provider and independent rehabilitation agencies the most expensive. Diagnostic data were not available for home health agency claims, so these were omitted from the multivariate analysis of annual charges.

CONCLUSIONS

The large increases in charges cannot be explained by increases in the Medicare eligible population, aging, or inflation. The level and differential in growth is highest among new provider types and those dominated by proprietary ownership. These observations suggest that therapy services are profitable and that provider incentives may be an important component in overall growth.

Medicaid health maintenance organizations. Can they reduce program spending?

A randomized trial to evaluate the Florida site of the Program for Prepaid Managed Care showed that the plan, a staff model health maintenance organization, was successful in attracting Medicaid enrollees. The evaluation established that the health maintenance organization was able to limit members' utilization. The savings were in the form of lower likelihood of using care. The amount of services received, once care was initiated, was the same in both fee-for service Medicaid and health maintenance organizations. The authors detected no differences in inpatient use or costs. Additionally, they found evidence that the plan attracted sicker than average enrollees, so this reduced utilization translates into Medicaid program savings.

Rationing or rationalizing children's medical care: comparison of a Medicaid HMO with fee-for-service care

OBJECTIVES

This paper examines how medical care obtained by children enrolled in a Medicaid health maintenance organization (HMO) differs from that obtained by similar children who receive care from fee-for-service Medicaid providers.

METHODS

In a randomized trial, some Medicaid households were assigned to remain in a traditional fee-for-service arrangement and others were randomly selected to join a Medicaid prepaid plan (an HMO). Participating households recorded data on children's health status and use of medical care.

RESULTS

The prepaid plan members and the fee-for-service recipients received equivalent numbers of checkup visits, but the children in the prepaid plan made significantly fewer acute care visits. This plan appeared to target its services to children with the greatest health care needs. However, the content of health visits in the two systems did not differ, nor did prepaid and fee-for-service enrollees use the emergency room differently.

CONCLUSIONS

It is possible to design a Medicaid HMO that achieves financial savings without reducing services to the most vulnerable patients. However, these findings alone do not provide a basis for widespread policy change in the direction of Medicaid HMOs. Further research is needed to establish whether the children treated in the HMO differed in health outcomes from those treated by fee-for-service care.

How will changes in health insurance tax policy and employer health plan contributions affect access to health care and health care costs?

OBJECTIVE

To understand how changes in federal taxation of and employer contributions to health insurance benefits affect the decisions of firms to offer insurance, the willingness of households to purchase different health plans, and the resultant health expenditures.

DESIGN

Economic policy simulation.

SETTING

Secondary data analysis.

PARTICIPANTS

A total of 18,343 sampled families (representing 77 million total families throughout the United States) with a working household head from the 1988 Current Population Survey who were not covered by either Medicare, Medicaid, or CHAMPUS (Civilian Health and Medical Program of the Uniformed Services) insurance.

INTERVENTIONS

One intervention limits the amounts of tax-free employer contributions to health insurance premiums to 80% of our estimate of the base plan in the market and assumes that employer contributions will also be limited to this maximum. A second intervention eliminates the favorable tax treatment of employer-paid premiums altogether and assumes that employees will pay the full price of insurance.

MAIN OUTCOME MEASURES

Change in the number of working families offered employment-based insurance, change in insurance plan choice, and change in medical spending.

RESULTS

Capping the favorable tax treatment and employer contributions decreases the number of families offered employment-based insurance by approximately 91,000, increases the number of families selecting the least generous insurance plan from 20% under the current situation to 33%, and reduces overall health spending by less than 2%. By eliminating the tax exemption altogether, the number of families offered employment-based insurance decreases by approximately half a million families, the number of families selecting the least generous plan goes from 20% to 40%, and overall spending falls by about $16 billion.

CONCLUSIONS

Eliminating the tax subsidy and limiting employer-paid contributions to the low-cost plan substantially increases the number of low-income uninsured under a voluntary insurance system, decreases overall spending only modestly, but would raise tax revenues by $36 billion. These tax revenues could be used to assist low-income families to obtain insurance coverage.

Differences between nursing home admissions and residents

The use of a cross-sectional sample of nursing home residents rather than a sample of admissions to estimate admission characteristics carries a potential bias. The purpose of this study was to fill this void by comparing abstracted records data for an admissions cohort (n = 1,118) and a residents cohort (n = 830) residing in the same nursing homes. Compared to residents, admissions were significantly more dependent in their ability to get around and to dress themselves, received more clinical services, and had a higher rate of medication use. Over a 12-month period, admissions had a fivefold greater likelihood of being discharged to community, but about the same mortality rate as residents. Within both groups, those discharged to the community as well as those who died had expenditures that were almost twice as high as those of their counterparts who remained alive in the nursing home.

A randomized trial to evaluate the effectiveness of a Medicaid HMO

The value of health-care services used by AFDC Medicaid patients receiving care in a voluntary enrollment HMO is contrasted with that of health care services used by Medicaid patients receiving fee-for-service (FFS) care. The randomized assignment of Medicaid recipients to the HMO or to FFS allows the authors to conclude that the apparent lower use of HMO enrollees results from the HMO's selection of patients with lower needs for care rather than from technical efficiency. Patients had lower use while in the HMO, but disenrollees and those who refused enrollment had significantly higher use than FFS participants. In contrast to the effect of HMOs on non-Medicaid populations, the Medicaid HMO studied provided significantly fewer outpatient services, but the same level of inpatient services as the FFS sector. Overall, voluntary enrollment of Medicaid eligibles into the HMO resulted in higher state expenditures for Medicaid because of favorable selection.

Improving primary care in nursing homes

We conducted a quasi-experiment to evaluate the impact of a Medicare waiver which allowed the use of nurse practitioners (NPs) and physicians assistants (PAs) to deliver primary care to Massachusetts nursing home patients and removed the limits on the reimbursable numbers of visits per month. A carefully matched set of 1,327 Medicaid patients from 95 non-participating homes in the same areas of Massachusetts was compared to 1,324 Medicaid demonstration patients from 75 homes. Information came from specially designed record reviews and the Medicaid and Medicare information systems. Separate analyses were done for newly admitted cases and rollovers. Comparisons of quality of care suggested that the medical groups using NPs and PAs provided as good or better care than did the physicians in the control group. There were no differences in functional status changes or in the use of medications. The demonstration patients received more attention, as reflected in more orders written and an average of one additional visit a month. Demonstration patients showed higher scores on three of seven specially designed quality tracers, congestive heart failure and hypertension for both new administrations and rollovers, and new urinary incontinence for new admissions. Rollovers had significantly fewer emergency and total hospital days. A cost analysis suggests that the use of NPs and PAs saves at least as much as it costs and may save additional money with more sustained use.

Impact of geriatric nurse practitioners on nursing-home residents' functional status, satisfaction, and discharge outcomes

This study evaluated the impact of geriatric nurse practitioners (GNP) employed by nursing homes on quality of patient care and residents' outcomes during a 12-month study period. Quality of care was assessed in standardized interviews of 525 residents in five nursing homes with GNPs and 323 residents in five other nursing homes without GNPs. Each resident was interviewed up to four times during the study period (at baseline, and 3, 6, and 12 months later) to determine functional status, satisfaction with care, and physical condition at each of these points. The only significant difference between groups was that fewer newly admitted residents were hospitalized from GNP homes than from those without a GNP. The results of this interview study showed that the GNP as a nursing home employee had little impact on residents' functional status, physical condition, or satisfaction.

Setting capitations for Medicaid: a case study

This article examines the methodology New York State used to set capitation rates for a Medicaid health maintenance organization. By examining the methods used and the assumptions made in a particular case, some general lessons are drawn about the ratesetting process. Greater reliance on statewide data to assure fair and statistically stable estimates is needed. Although the article focuses on one State and its ratesetting for one particular plan (Health Care Plus), the issues raised have general interest for other plans and for other States concerned with the setting of capitation rates for Medicaid enrollees in prepaid plans.

Assessing cost effects of nursing-home-based geriatric nurse practitioners

Employment of geriatric nurse practitioners (GNPs) is one strategy to improve nursing home care. The effects of GNPs on costs and profitability of nursing homes and on costs of patient medical service use outside the nursing home are examined. Employment of GNPs does not adversely affect nursing home costs or significantly affect profits. There is some evidence of cost savings in medical service use for newly admitted patients but no evidence of savings for continuing residents. GNPs reduce the use of hospital services for both groups, and the reduction is statistically significant for newly admitted patients.

Effects of a geriatric nurse practitioner on process and outcome of nursing home care

We compared measures of quality of care and health services utilization in 30 nursing homes employing geriatric nurse practitioners with those in 30 matched control homes. Information for this analysis came from reviews of samples of patient records drawn at comparable periods before and after the geriatric NPs were employed. The measures of geriatric nurse practitioner impact were based on comparisons of changes from pre-NP to post-NP periods. Separate analyses were done for newly admitted and long-stay residents; a subgroup of homes judged to be best case examples was analyzed separately as well as the whole sample. Favorable changes were seen in two out of eight activity of daily living (ADL) measures: five of 18 nursing therapies; two of six drug therapies; six of eight tracers. There was some reduction in hospital admissions and total days in geriatric NP homes. Overall measures of medical attention showed a mixed pattern with some evidence of geriatric NP care substituted for physician care. These findings suggest that the geriatric NP has a useful role in nursing home care.

Effects of room reflectance and background noise on perceived auditory distance

Perceptions of egocentric auditory distance were investigated within an environment for which the reverberation time could be systematically varied without changes in the size or shape of the room. Two levels of wide-band background noise, differing by 20 dB, were used as a masking stimulus. Target sounds were presented from distances between 0.75 and 6.0 m and verbal reports of distance were collected from 288 listeners in two separate experiments. Changes in physical distance produced variation in reported distance in each configuration. Reported distance was generally proportional to real distance, but considerably underestimated when room reflectance was low. When room reflectance was high (T60 approximately 1.7 s for the range of frequencies used), initial reports of distance were often overestimates; upon repeated presentation, judgments in the high reflectance room became more nearly veridical. The effect of increasing the background noise level was to decrease the perceived distance. These findings are in accord with expectations based upon the importance of reverberation cue(s) to distance and upon previous analyses from this laboratory.

Risk selection of families electing HMO membership

This study analyzes the health plan selection history of approximately 30,000 employees of a large aerospace corporation. The data show that families selecting HMOs were younger, had lower income, and had less time on the job. HMOs attracted families with lower annual claimed expenditures, and these families' claimed expenses were lower still in the year immediately prior to switching into the HMO. Lower costs among families switching into the HMOs are partly explained by the composition of these families compared with families who stayed in the FFS plan. However, the selection pattern persisted even after adjusting for the size of the family, the age and sex of family members, and other family characteristics, such as race and income. Families switching out of HMOs had higher total annual claims during their first year back in the FFS sector compared with families about to switch into HMOs. However, recent HMO exiters did not always differ from families who never left the FFS plan.