Variation in expenditure for common, high cost surgical procedures in a working age population: implications for reimbursement reform

BACKGROUND

In the move toward value-based care, bundled payments are believed to reduce waste and improve coordination. Some commercial insurers have addressed this through the use of bundled payment, the provision of one fee for all care associated with a given index procedure. This system was pioneered by Medicare, using a population generally over 65 years of age, and despite its adoption by mainstream insurers, little is known of bundled payments' ability to reduce variation or cost in a working-age population. This study uses a universally-insured, nationally-representative population of adults aged 18-65 to examine the effect of bundled payments for five high-cost surgical procedures which are known to vary widely in Medicare reimbursement: hip replacement, knee replacement, coronary artery bypass grafting (CABG), lumbar spinal fusion, and colectomy.

METHODS

Five procedures conducted on adults aged 18-65 were identified from the TRICARE database from 2011 to 2014. A 90-day period from index procedure was used to determine episodes of associated post-acute care. Data was sorted by Zip code into hospital referral regions (HRR). Payments were determined from TRICARE reimbursement records, they were subsequently price standardized and adjusted for patient and surgical characteristics. Variation was assessed by stratifying the HRR into quintiles by spending for each index procedure.

RESULTS

After adjusting for case mix, significant inter-quintile variation was observed for all procedures, with knee replacement showing the greatest variation in both index surgery (107%) and total cost of care (75%). Readmission was a driver of variation for colectomy and CABG, with absolute cost variation of $17,257 and $13,289 respectively. Other post-acute care spending was low overall (≤$1606, for CABG).

CONCLUSIONS

This study demonstrates significant regional variation in total spending for these procedures, but much lower spending for post-acute care than previously demonstrated by similar procedures in Medicare. Targeting post-acute care spending, a common approach taken by providers in bundled payment arrangements with Medicare, may be less fruitful in working aged populations.

Minimally invasive surgery and its impact on 30-day postoperative complications, unplanned readmissions and mortality

BACKGROUND

A critical appraisal of the benefits of minimally invasive surgery (MIS) is needed, but is lacking. This study examined the associations between MIS and 30-day postoperative outcomes including complications graded according to the Clavien-Dindo classification, unplanned readmissions, hospital stay and mortality for five common surgical procedures.

METHODS

Patients undergoing appendicectomy, colectomy, inguinal hernia repair, hysterectomy and prostatectomy were identified in the American College of Surgeons National Surgical Quality Improvement Program database. Non-parsimonious propensity score methods were used to construct procedure-specific matched-pair cohorts that reduced baseline differences between patients who underwent MIS and those who did not. Bonferroni correction for multiple comparisons was applied and P < 0·006 was considered significant.

RESULTS

Of the 532 287 patients identified, 53·8 per cent underwent MIS. Propensity score matching yielded an overall sample of 327 736 patients (appendicectomy 46 688, colectomy 152 114, inguinal hernia repair 59 066, hysterectomy 59 066, prostatectomy 10 802). Within the procedure-specific matched pairs, MIS was associated with significantly lower odds of Clavien-Dindo grade I-II, III and IV complications (P ≤ 0·004), unplanned readmissions (P < 0·001) and reduced hospital stay (P < 0·001) in four of the five procedures studied, with the exception of inguinal hernia repair. The odds of death were lower in patients undergoing MIS colectomy (P < 0·001), hysterectomy (P = 0·002) and appendicectomy (P = 0·002).

CONCLUSION

MIS was associated with significantly fewer 30-day postoperative complications, unplanned readmissions and deaths, as well as shorter hospital stay, in patients undergoing colectomy, prostatectomy, hysterectomy or appendicectomy. No benefits were noted for inguinal hernia repair.

Subjects' views of obligations to ensure post-trial access to drugs, care and information: qualitative results from the Experiences of Participants in Clinical Trials (EPIC) study

OBJECTIVES

To report the attitudes and opinions of subjects in US clinical trials about whether or not, and why, they should receive post-trial access (PTA) to the trial drug, care and information.

DESIGN

Focus groups, short self-administered questionnaires.

SETTING

Boston, Dallas, Detroit, Oklahoma City.

PARTICIPANTS

Current and recent subjects in clinical trials, primarily for chronic diseases.

RESULTS

93 individuals participated in 10 focus groups. Many thought researchers, sponsors, health insurers and others share obligations to facilitate PTA to the trial drug, if it benefited the subject, or to a therapeutic equivalent. Some thought PTA obligations include providing transition care (referrals to non-trial physicians or other trials, limited follow-up, short-term drug supply) or care for long-term adverse events. Others held, in contrast, that there are no PTA obligations regarding drugs or care. However, there was agreement that former subjects should receive information (drug name, dosage received, market approval date, long-term adverse effects, trial results). Participants frequently appealed to health need, cost, relationships, reciprocity, free choice and sponsor self-interest to support their views. Many of their reasons overlapped with those commonly discussed by bioethicists.

CONCLUSION

Many participants in US trials for chronic conditions thought there are obligations to facilitate PTA to the trial drug at a "fair" price; these views were less demanding than those of non-US subjects in other studies. However, our participants' views about informational obligations were broader than those of other subjects and many bioethicists. Our results suggest that the PTA debate should expand beyond the trial drug and aggregate results.

Quantitative genetic analysis in Saccharomyces cerevisiae using epistatic miniarray profiles (E-MAPs) and its application to chromatin functions

The use of the budding yeast Saccharomyces cerevisiae as a simple eukaryotic model system for the study of chromatin assembly and regulation has allowed rapid discovery of genes that influence this complex process. The functions of many of the proteins encoded by these genes have not yet been fully characterized. Here, we describe a high-throughput methodology that can be used to illuminate gene function and discuss its application to a set of genes involved in the creation, maintenance and remodeling of chromatin structure. Our technique, termed E-MAPs, involves the generation of quantitative genetic interaction maps that reveal the function and organization of cellular proteins and networks.

The action of molecular chaperones in the early secretory pathway

The endoplasmic reticulum (ER) serves as a way-station during the biogenesis of nearly all secreted proteins, and associated with or housed within the ER are factors required to catalyze their import into the ER and facilitate their folding. To ensure that only properly folded proteins are secreted and to temper the effects of cellular stress, the ER can target aberrant proteins for degradation and/or adapt to the accumulation of misfolded proteins. Molecular chaperones play critical roles in each of these phenomena.

Market competition and patient-oriented research: the results of a national survey of medical school faculty

PURPOSE

To understand the effect of market competition on patient-oriented research at U.S. medical schools and teaching hospitals.

METHOD

From a multi-stage stratified, random sample, the authors surveyed 3,804 research faculty at 117 U.S. medical schools. The questionnaire assessed five variables, the type of research conducted by the respondent, changes in patient-oriented and non-clinical research in the preceding three years, amount of time spent on patient care, market stage of the respondent's institution, and research productivity.

RESULTS

Of the 2,336 faculty who responded (62%), 84% of those conducting patient-oriented research and 80% of those engaged in non-clinical research reported conducting the same amount of research or more in 1996-1997 than in the preceding three years. However, both patient-oriented and non-clinical researchers in the most competitive health care markets and those with high levels of patient care duties were most likely to report decreases in the amounts of such research conducted in the previous three years. Further, researchers reporting such decreases had been as productive in recent years and over their careers as had those who did not report a decrease.

CONCLUSIONS

This study provides additional evidence of the negative relationships that exist between high levels of market competition and patient care services on the patient-oriented and non-clinical research missions of teaching hospitals.

The ins and outs of GroEL-mediated protein folding

Two papers recently published in Cell investigate the role of protein encapsulation by GroEL in assisting folding. The first shows how encapsulation can "smooth" the folding landscape, accelerating folding of some proteins. The second defines a confinement-independent pathway, which allows GroEL to assist folding of substrates too large to be encapsulated.

Preparedness for clinical practice: reports of graduating residents at academic health centers

CONTEXT

Medical educators are seeking improved measures to assess the clinical competency of residents as they complete their graduate medical education.

OBJECTIVE

To assess residents' perceptions of their preparedness to provide common clinical services during their last year of graduate medical education.

DESIGN, SETTING, AND PARTICIPANTS

A 1998 national survey of residents completing their training in 8 specialties (internal medicine, pediatrics, family practice, obstetrics/gynecology, general surgery, orthopedic surgery, psychiatry, and anesthesiology) at academic health centers in the United States. A total of 2626 residents responded (response rate, 65%).

MAIN OUTCOME MEASURES

Residents' reports of their preparedness to perform clinical and nonclinical tasks relevant to their specialties.

RESULTS

Residents in all specialties rated themselves as prepared to manage most of the common conditions they would encounter in their clinical career. However, more than 10% of residents in each specialty reported that they felt unprepared to undertake 1 or more tasks relevant to their disciplines, such as caring for patients with human immunodeficiency virus/acquired immunodeficiency syndrome or substance abuse (family practice) or nursing home patients (internal medicine); performance of spinal surgery (orthopedic surgery) or abdominal aortic aneurysm repair (general surgery); and management of chronic pain (anesthesiology).

CONCLUSIONS

Overall, residents in their last year of training at academic health centers rate their clinical preparedness as high. However, opportunities for improvement exist in preparing residents for clinical practice.

Racial differences in cardiac revascularization rates: does "overuse" explain higher rates among white patients?

BACKGROUND

Coronary artery bypass graft (CABG) surgery and percutaneous transluminal coronary angioplasty (PTCA) are well-established treatments for symptomatic coronary artery disease. Previous studies have documented racial differences in rates of use of these cardiac revascularization procedures. Other studies suggest that these procedures are overused: that is, they are done for patients with clinically inappropriate indications.

OBJECTIVE

To test the hypothesis that the higher rate of cardiac revascularization among white patients is associated with a higher prevalence of overuse (revascularization for clinically inappropriate indications) among white patients than among African-American patients.

DESIGN

Observational cohort study using Medicare claims and medical record review.

SETTING

173 hospitals in five U.S. states.

PARTICIPANTS

A stratified, weighted, random sample of 3960 Medicare beneficiaries who underwent coronary angiography during 1991 and 1992; 1692 of these patients underwent 1711 revascularization procedures within 90 days.

MEASUREMENTS

The proportion of CABG and PTCA procedures rated appropriate, uncertain, and inappropriate according to RAND criteria, and the multivariate odds of undergoing inappropriate revascularization among African-American patients and white patients.

RESULTS

After angiography, rates of PTCA (23% vs. 19%) and CABG surgery (29% vs. 17%) were significantly higher among white patients than among African-American patients. The respective rates of inappropriate PTCA and CABG surgery were 14% and 10%. Among the study states, rates of inappropriate use ranged from 4% to 24% for PTCA and 0% to 14% for CABG surgery. White patients were more likely than African-American patients to receive inappropriate PTCA (15% vs. 9%; difference, 6 percentage points [95% CI, -0.4 to 12.7 percentage points]), and difference by race was statistically significant among men (20% vs. 8%; difference, 12 percentage points [CI, 1.2 to 21.7 percentage points]). Rates of inappropriate CABG surgery did not differ by race (10% in both groups).

CONCLUSIONS

Among a large and diverse sample of Medicare beneficiaries in five U.S. states, overuse of PTCA was greater among white men than among other groups, but this difference did not fully account for racial disparities in revascularization. Overuse of cardiac revascularization varied significantly by geographic region.

Residents' preferences and preparation for caring for underserved populations

Access to care by low-income persons and residents of rural and poor inner-city areas is a persistent problem, yet physicians tend to be maldistributed relative to need. The objectives were to describe preferences of resident physicians to locate in underserved areas and to assess their preparedness to provide service to low-income populations. A national survey was made of residents completing their training in eight specialties at 162 US academic health center hospitals in 1998, with 2,626 residents responding. (Of 4,832 sampled, 813 had invalid addresses or were no longer in the residency program. Among the valid sample of 4,019, the response rate was 65%.) The percentage of residents ranking public hospitals, rural areas, and poor inner-city areas as desirable employment locations and the percentage feeling prepared to provide specified services associated with indigent populations were ascertained. Logistic regressions were used to calculate adjusted percentages, controlling for sex, race/ethnicity, international medical graduate (IMG) status, plans to subspecialize, ownership of hospital, specialty, and exposure to underserved patients during residency. Only one third of residents rated public hospitals as desirable settings, although there were large variations by specialty. Desirability was not associated with having trained in a public hospital or having greater exposure to underserved populations. Only about one quarter of respondents ranked rural (26%) or poor inner-city (25%) areas as desirable. Men (29%, P <.01) and noncitizen IMGs (43%, P <.01) were more likely than others to prefer rural settings. Residents who were more likely to rate poor inner-city settings as desirable included women (28%, P =.03), noncitizen IMGs (35%, P =.01), and especially underrepresented minorities (52%, P <.01). Whereas about 90% or more of residents felt prepared to treat common clinical conditions, only 67% of residents in four primary care specialties felt prepared to counsel patients about domestic violence or to care for human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) or substance abuse patients (all 67%). Women were more likely than men to feel prepared to counsel patients about domestic violence (70% vs. 63%, P =.002) and depression (83% vs. 75%, P <.01). Underrepresented minority residents were more likely than other residents to feel prepared to counsel patients about domestic violence (P <.01) and compliance with care (P =.04). Residents with greater exposure to underserved groups were more prepared to counsel patients about domestic violence (P =.01), substance abuse (P =.01), and to treat patients with HIV/AIDS (P =.01) or with substance abuse problems (P <.01). This study demonstrates the need to expose graduate trainees to underserved populations and suggests a continuing role of minorities, women, and noncitizen physicians in caring for low-income populations.

Status of clinical research in academic health centers: views from the research leadership

CONTEXT

The changing state of the health care system in the United States may be adversely affecting clinical research conducted in academic health centers (AHCs). Few formal data have been gathered about the nature and extent of the problems facing clinical research or the effects of remedies undertaken by AHCs.

OBJECTIVES

To assess the perceived quality and health of the clinical research enterprise and to determine challenges and adaptations to current environmental pressures.

DESIGN, SETTING, AND PARTICIPANTS

Mailed survey conducted between December 1998 and March 1999 of a subsample of department chairs and senior research administrators (SRAs) in all US medical schools. Of the 712 potential respondents, 478 completed a questionnaire, yielding an overall response rate of 67.1% (64.8% for SRAs and 67.8% for department chairs).

MAIN OUTCOME MEASURES

Ratings of overall health/robustness of clinical research, quality of research in 5 domains, extent of challenges to performing research, and sense of urgency in responding to research challenges; formal strategies for research-related tasks and their effects.

RESULTS

Slightly more than half (52%) of all respondents rated the health of the clinical research enterprise as good or excellent compared with 63% for nonclinical research (P<.001). Respondents were most likely to rate nonclinical research as high in quality (79%) compared with 70% for phase 3 clinical trials, 67% for translational research, 65% for phase 1 and 2 trials, and 57% for health services research (for all comparisons with nonclinical research, P<.001). Pressure on clinical faculty to see patients was perceived as a moderate-to-large problem for clinical research by the largest percentage of respondents (93%), followed by insufficient clinical revenues (89%), recruiting trained researchers (75%), lack of external support for clinical research (72%), competition from contract research organizations (48%), problems introduced by the institutional review board process (38%), and finding research participants (37%). In total, 81% of respondents considered the challenges facing clinical research in AHCs to be urgent or extremely urgent.

CONCLUSIONS

Academic leaders perceive clinical research activities in AHCs to be less healthy, of poorer quality, and facing greater challenges than nonclinical research activities. Many AHCs do not have policies or mechanisms to address challenges facing the clinical research mission. Even among those with such policies, more than half do not believe these policies have had large positive effects. Our findings support the view that the clinical research workforce and infrastructure may need to be expanded and strengthened to keep pace with advances in basic research.

Multiple Gln/Asn-rich prion domains confer susceptibility to induction of the yeast [PSI(+)] prion

The yeast prion [PSI(+)] results from self-propagating aggregates of Sup35p. De novo formation of [PSI(+)] requires an additional non-Mendelian trait, thought to result from a prion form of one or more unknown proteins. We find that the Gln/Asn-rich prion domains of two proteins, New1p and Rnq1p, can control susceptibility to [PSI(+)] induction as well as enhance aggregation of a human glutamine expansion disease protein. [PSI(+)] inducibility results from gain-of-function properties of New1p and Rnq1p aggregates rather than from inactivation of the normal proteins. These studies suggest a molecular basis for the epigenetic control of [PSI(+)] inducibility and may reveal a broader role for this phenomenon in the physiology of protein aggregation.

Conformational diversity in a yeast prion dictates its seeding specificity

A perplexing feature of prion-based inheritance is that prions composed of the same polypeptide can evoke different phenotypes (such as distribution of brain lesions), even when propagated in genetically identical hosts. The molecular basis of this strain diversity and the relationship between strains and barriers limiting transmission between species remain unclear. We have used the yeast prion phenomenon [PSI+]4 to investigate these issues and examine the role that conformational differences may have in prion strains. We have made a chimaeric fusion between the prion domains of two species (Saccharomyces cerevisae and Candida albicans) of Sup35, the protein responsible for [PSI+]. Here we report that this chimaera forms alternate prion strains in vivo when initiated by transient overexpression of different Sup35 species. Similarly, in vitro the purified chimaera, when seeded with different species of Sup35 fibres, establishes and propagates distinct amyloid conformations. These fibre conformations dictate amyloid seeding specificity: a chimaera seeded by S. cerevisiae fibres efficiently catalyses conversion of S. cerevisiae Sup35 but not of C. albicans Sup35, and vice versa. These and other considerations argue that heritable prion strains result from self-propagating conformational differences within the prion protein itself. Moreover, these conformational differences seem to act in concert with the primary structure to determine a prion's propensity for transmission across a species barrier.

Understanding the relationship between market competition and students' ratings of the managed care content of their undergraduate medical education

PURPOSE

The increase in managed care has led to questions about the inadequacy of instruction undergraduate medical students receive in curricular areas related to managed care. This study examined (1) the percentages of graduating medical students who felt they had received inadequate instruction in six curricular content areas (CCAs): primary care, care of ambulatory patients, health promotion and disease prevention, medical care cost control, teamwork with other health professionals, and cost-effective medical practice; and (2) whether the market competitiveness of these students' medical schools affected their reports of inadequacy of instruction in these CCAs.

METHOD

Data from the Association of American Medical Colleges' Graduation Questionnaires (GQs) from 1994 to 1997 were analyzed. The GQ asked graduating students to rate the adequacy of instruction they had received in the six CCAs. Students' ratings were collapsed into the dichotomous variables "inadequate" and "not inadequate." The market competitiveness of medical schools was determined using the four-stage Market Evolution Model developed by the University HealthSystem Consortium. Only responses from students graduating from medical schools that could be staged for all four years of the study were analyzed. Statistical analyses were performed to determine trends for each CCA by year, across the entire study period, by market stage, and by market stage across the entire study period.

RESULTS

A total of 39,136 respondents from 86 medical schools were used in the study. The percentages of graduating medical students who reported inadequate instruction decreased over the study period for five of the six CCAs: primary care (27.6% in 1994 to 13.7% in 1997), ambulatory care (37.4% to 23. 9%), medical care cost control (62.9% to 52.9%) cost-effectiveness of medical practice (62.7% to 53.9%), and health promotion and disease prevention (44.4% to 23.7%); all at p <0.001. The responses for inadequacy of instruction for teamwork with other health professionals remained steady from 1994 to 1996 (10.2% to 10.6%), then increased 21.8% in 1997. Over the course of the study, students graduating from schools in more competitive markets (Stage 3 or Stage 4) were more likely to report inadequate instruction in three CCAs, primary care, ambulatory care, and health promotion and disease prevention, than were those graduating from schools in less competitive markets (Stage 1 and Stage 2). Conversely, students graduating from schools in the more competitive health care markets were less likely to report inadequate instruction in cost-effectiveness and cost control than were students from schools in less competitive markets.

CONCLUSION

Graduating students' reports of inadequacy of instruction decreased over the study period for five of the six CCAs, increasing only for teamwork with other professionals. Findings were mixed with regard to the relationship of medical schools' market competitiveness and graduating students' reports of inadequacy of instruction. More research is needed to confirm graduating students' perceptions of the inadequacy of their instruction in CCAs related to managed care, particularly once they have gained experience treating patients in managed care environments.

Biochemical basis of oxidative protein folding in the endoplasmic reticulum

The endoplasmic reticulum (ER) supports disulfide bond formation by a poorly understood mechanism requiring protein disulfide isomerase (PDI) and ERO1. In yeast, Ero1p-mediated oxidative folding was shown to depend on cellular flavin adenine dinucleotide (FAD) levels but not on ubiquinone or heme, and Ero1p was shown to be a FAD-binding protein. We reconstituted efficient oxidative folding in vitro using FAD, PDI, and Ero1p. Disulfide formation proceeded by direct delivery of oxidizing equivalents from Ero1p to folding substrates via PDI. This kinetic shuttling of oxidizing equivalents could allow the ER to support rapid disulfide formation while maintaining the ability to reduce and rearrange incorrect disulfide bonds.

Racial disparities in access to renal transplantation--clinically appropriate or due to underuse or overuse?

BACKGROUND

Despite abundant evidence of racial disparities in the use of surgical procedures, it is uncertain whether these disparities reflect racial differences in clinical appropriateness or overuse or underuse of inappropriate care.

METHODS

We performed a literature review and used an expert panel to develop criteria for determining the appropriateness of renal transplantation for patients with end-stage renal disease. Using data from five states and the District of Columbia on patients who had started to undergo dialysis in 1996 or 1997, we selected a random sample of 1518 patients (age range, 18 to 54 years), stratified according to race and sex. We classified the appropriateness of patients as data on candidates for transplantation and analyzed rates of referral to a transplantation center for evaluation, placement on a waiting list, and receipt of a transplant according to race.

RESULTS

Black patients were less likely than white patients to be rated as appropriate candidates for transplantation according to appropriateness criteria based on expert opinion (71 blacks [9.0 percent] vs. 152 whites [20.9 percent]) and were more likely to have had incomplete evaluations (368 [46.5 percent] vs. 282 [38.8 percent], P<0.001 for the overall chi-square). Among patients considered to be appropriate candidates for transplantation, blacks were less likely than whites to be referred for evaluation, according to the chart review (90.1 percent vs. 98.0 percent, P=0.008), to be placed on a waiting list (71.0 percent vs. 86.7 percent, P=0.007), or to undergo transplantation (16.9 percent vs. 52.0 percent, P<0.001). Among patients classified as inappropriate candidates, whites were more likely than blacks to be referred for evaluation (57.8 percent vs. 38.4 percent), to be placed on a waiting list (30.9 percent vs. 17.4 percent), and to undergo transplantation (10.3 percent vs. 2.2 percent, P<0.001 for all three comparisons).

CONCLUSIONS

Racial disparities in rates of renal transplantation stem from differences in clinical characteristics that affect appropriateness as well as from underuse of transplantation among blacks and overuse among whites. Reducing racial disparities will require efforts to distinguish their specific causes and the development of interventions tailored to address them.

Unmet health needs of uninsured adults in the United States

CONTEXT

In 1998, 33 million US adults aged 18 to 64 years lacked health insurance. Determining the unmet health needs of this population may aid efforts to improve access to care.

OBJECTIVE

To compare nationally representative estimates of the unmet health needs of uninsured and insured adults, particularly among persons with major health risks.

DESIGN AND SETTING

Random household telephone survey conducted in all 50 states and the District of Columbia through the Behavioral Risk Factor Surveillance System.

PARTICIPANTS

A total of 105,764 adults aged 18 to 64 years in 1997 and 117,364 in 1998, classified as long-term (>/=1 year) uninsured (9.7%), short-term (<1 year) uninsured (4.3%), or insured (86.0%).

MAIN OUTCOME MEASURES

Adjusted proportions of participants who could not see a physician when needed due to cost in the past year, had not had a routine checkup within 2 years, and had not received clinically indicated preventive services, compared by insurance status.

RESULTS

Long-term- and short-term-uninsured adults were more likely than insured adults to report that they could not see a physician when needed due to cost (26.8%, 21.7%, and 8.2%, respectively), especially among those in poor health (69.1%, 51.9%, and 21.8%) or fair health (48.8%, 42.4%, and 15.7%) (P<.001). Long-term-uninsured adults in general were much more likely than short-term-uninsured and insured adults not to have had a routine checkup in the last 2 years (42.8%, 22.3%, and 17.8%, respectively) and among smokers, obese individuals, binge drinkers, and people with hypertension, elevated cholesterol, diabetes, or human immunodeficiency virus risk factors (P<.001). Deficits in cancer screening, cardiovascular risk reduction, and diabetes care were most pronounced among long-term-uninsured adults.

CONCLUSIONS

In our study, long-term-uninsured adults reported much greater unmet health needs than insured adults. Providing insurance to improve access to care for long-term-uninsured adults, particularly those with major health risks, could have substantial clinical benefits. JAMA. 2000;284:2061-2069

A census of glutamine/asparagine-rich regions: implications for their conserved function and the prediction of novel prions

Glutamine/asparagine (Q/N)-rich domains have a high propensity to form self-propagating amyloid fibrils. This phenomenon underlies both prion-based inheritance in yeast and aggregation of a number of proteins involved in human neurodegenerative diseases. To examine the prevalence of this phenomenon, complete proteomic sequences of 31 organisms and several incomplete proteomic sequences were examined for Q/N-rich regions. We found that Q/N-rich regions are essentially absent from the thermophilic bacterial and archaeal proteomes. Moreover, the average Q/N content of the proteins in these organisms is markedly lower than in mesophilic bacteria and eukaryotes. Mesophilic bacterial proteomes contain a small number (0-4) of proteins with Q/N-rich regions. Remarkably, Q/N-rich domains are found in a much larger number of eukaryotic proteins (107-472 per proteome) with diverse biochemical functions. Analyses of these regions argue they have been evolutionarily selected perhaps as modular "polar zipper" protein-protein interaction domains. These data also provide a large pool of potential novel prion-forming proteins, two of which have recently been shown to behave as prions in yeast, thus suggesting that aggregation or prion-like regulation of protein function may be a normal regulatory process for many eukaryotic proteins with a wide variety of functions.

Evidence for the prion hypothesis: induction of the yeast [PSI+] factor by in vitro- converted Sup35 protein

Starting with purified, bacterially produced protein, we have created a [PSI(+)]-inducing agent based on an altered (prion) conformation of the yeast Sup35 protein. After converting Sup35p to its prion conformation in vitro, we introduced it into the cytoplasm of living yeast using a liposome transformation protocol. Introduction of substoichiometric quantities of converted Sup35p greatly increased the rate of appearance of the well-characterized epigenetic factor [PSI+], which results from self-propagating aggregates of cellular Sup35p. Thus, as predicted by the prion hypothesis, proteins can act as infectious agents by causing self-propagating conformational changes.

Functional and genomic analyses reveal an essential coordination between the unfolded protein response and ER-associated degradation

The unfolded protein response (UPR) regulates gene expression in response to stress in the endoplasmic reticulum (ER). We determined the transcriptional scope of the UPR using DNA microarrays. Rather than regulating only ER-resident chaperones and phospholipid biosynthesis, as anticipated from earlier work, the UPR affects multiple ER and secretory pathway functions. Studies of UPR targets engaged in ER-associated protein degradation (ERAD) reveal an intimate coordination between these responses: efficient ERAD requires an intact UPR, and UPR induction increases ERAD capacity. Conversely, loss of ERAD leads to constitutive UPR induction. Finally, simultaneous loss of ERAD and the UPR greatly decreases cell viability. Thus, the UPR and ERAD are dynamic responses required for the coordinated disposal of misfolded proteins even in the absence of acute stress.

Molecular basis of a yeast prion species barrier

The yeast [PSI+] factor is inherited by a prion mechanism involving self-propagating Sup35p aggregates. We find that Sup35p prion function is conserved among distantly related yeasts. As with mammalian prions, a species barrier inhibits prion induction between Sup35p from different yeast species. This barrier is faithfully reproduced in vitro where, remarkably, ongoing polymerization of one Sup35p species does not affect conversion of another. Chimeric analysis identifies a short domain sufficient to allow foreign Sup35p to cross this barrier. These observations argue that the species barrier results from specificity in the growing aggregate, mediated by a well-defined epitope on the amyloid surface and, together with our identification of a novel yeast prion domain, show that multiple prion-based heritable states can propagate independently within one cell.

Quality of care by race and gender for congestive heart failure and pneumonia

BACKGROUND

Variations in the rates of major procedures by race and gender are well described, but few studies have assessed the quality of care by race and gender for basic hospital services.

OBJECTIVE

To assess quality of care by race and gender.

RESEARCH DESIGN

Retrospective review of medical records.

SUBJECTS

Stratified random sample of 2,175 Medicare beneficiaries hospitalized for congestive heart failure or pneumonia in Illinois, New York, and Pennsylvania during 1991 and 1992.

MEASURES

Explicit process criteria and implicit review by physicians.

RESULTS

In adjusted analyses, black patients with congestive heart failure or pneumonia received lower quality of care overall than other patients with these conditions by both explicit process criteria and implicit review (P < 0.05). On explicit measures, overall quality of care did not differ by gender for either condition, but significant differences were noted on explicit subscales. Women received worse cognitive care than men from physicians for both conditions, better cognitive care from nurses for pneumonia, and better therapeutic care for congestive heart failure (P < 0.05). Women received worse quality of care than men by implicit review (P = 0.03) for congestive heart failure but not pneumonia.

CONCLUSIONS

Consistent racial differences in quality of care persist in basic hospital services for two common medical conditions. Physicians, nurses, and policy makers should strive to eliminate these differences. Gender differences in quality of care are less pronounced and may vary by condition and type of provider or service.

The effect of patients' preferences on racial differences in access to renal transplantation

BACKGROUND

In the United States, black patients undergo renal transplantation less often than white patients, but few studies have directly assessed the association between race and patients' preferences with respect to transplantation.

METHODS

To assess preferences with respect to transplantation and experiences with medical care, we interviewed 1392 (82.9 percent) of 1679 eligible patients with end-stage renal disease (age range, 18 to 54 years) approximately 10 months after they had begun maintenance treatment with dialysis. Participants were selected from a stratified random sample of patients undergoing dialysis in four regions of the United States (Alabama, southern California, Michigan, and the mid-Atlantic region of Maryland, Virginia, and the District of Columbia) in 1996 and 1997. Patients were followed until March 1999.

RESULTS

The interviews were conducted with 384 black women, 354 white women, 337 black men, and 317 white men. Black patients were less likely than white patients to want a transplant (76.3 percent of black women reported such a preference, vs. 79.3 percent of white women, and 80.7 percent of black men vs. 85.5 percent of white men), and they were less likely to be very certain about this preference (58.3 percent vs. 65.3 percent and 64.1 percent vs. 75.7 percent, respectively; P<0.01 for each comparison with both sexes combined). However, much larger differences were evident in rates of referral for evaluation at a transplantation center (50.4 percent for black women vs. 70.5 percent for white women, and 53.9 percent for black men vs. 76.2 percent for white men; P<0.001 for each comparison) and placement on a waiting list or transplantation within 18 months after the start of dialysis therapy (31.3 percent for black women vs. 56.5 percent for white women, and 35.3 percent for black men vs. 60.6 percent for white men; P<0.001). These racial differences remained significant after adjustment for patients' preferences and expectations about transplantation, sociodemographic characteristics, the type of dialysis facility, perceptions of care, health status, the cause of renal failure, and the presence or absence of coexisting illnesses.

CONCLUSIONS

In the United States, the preferences and expectations with respect to renal transplantation among patients with end-stage renal disease differ according to race. These differences, however, explain only a small fraction of the substantial racial differences in access to transplantation. Physicians should ensure that black patients who desire renal transplantation are fully informed about it and are referred for evaluation.

Academic health centers on the front lines: survival strategies in highly competitive markets

The authors describe approaches that five academic health centers (AHCs) have taken to reduce costs, enhance quality, or improve their market positions since the onset of price competition and managed care. The five AHCs, all on the West Coast, were selected for study because they (1) are located in markets that had been highly competitive for the longest time; (2) are committed to all the major missions of AHCs; and (3) own or substantially control their major clinical teaching facilities. The study findings reflect the status of the five AHCs during the fall of 1998. Although some findings may no longer be current (especially in light of ongoing implementation of the Balanced Budget Act of 1997), they still provide insights into the options and opportunities available to many AHCs in highly competitive markets. The authors report on the institutions' financial viability (positive), levels of government support (advantageous), and competition from other AHCs (modest). They outline the study AHCs' survival strategies in three broad areas: increasing revenues via exploiting market niches, reducing costs, and reorganizing to improve internal governance and decision making. They also report how marketplace competition and the strategies the AHCs used to confront it have affected the AHCs' missions. The authors summarize the outstanding lessons that all AHCs can learn from the experiences of the AHCs studied, although adding that AHCs in other parts of the country should use caution in looking to the West Coast AHCs for answers.

Income levels of bad-debt and free-care patients in Massachusetts hospitals

This study disputes the common notion that many hospitalized patients whose expenses are written off to bad debt are able to pay their bills. By matching 1996 state tax returns to more than 350,000 bad-debt and free-care claims at seven Massachusetts hospitals, we found that most patients involved had incomes below the federal poverty level and thus were presumably eligible for either public programs or hospital-based free care. This suggests that hospitals and public officials need to investigate further why low-income, uninsured patients are not receiving benefits for which they are eligible. Our results also suggest that measurements of indigent care levels in hospitals for purposes of research or regulation should include some portion of bad debt.

Hospital readmissions and quality of care

BACKGROUND

Readmission rates are often proposed as markers for quality of care. However, a consistent link between readmissions and quality has not been established.

OBJECTIVE

To test the relation of readmission to quality and the utility of readmissions as hospital quality measures.

SUBJECTS

One thousand, seven hundred and fifty-eight Medicare patients hospitalized in four states between 1991 to 1992 with pneumonia or congestive heart failure (CHF).

DESIGN

Case control.

MEASURES

Related adverse readmissions (RARs), defined as readmissions that indicate potentially sub-optimal care during initial hospitalization, were identified from administrative data using readmission diagnoses and intervening time periods designated by physician panels. We used linear regression to estimate the association between implicit and explicit quality measures and readmission status (RARs, non-RAR readmissions, and nonreadmissions), adjusting for severity. We tested whether RARs were associated with inferior care and performed simulations to determine whether RARs discriminated between hospitals on the basis of quality.

RESULTS

Compared with nonreadmitted pneumonia patients, patients with RARs had lower adjusted quality measured both by explicit (0.25 standardized units, P = 0.004) and implicit methods (0.17, P = 0.047). Adjusted differences for CHF patients were 0.17 (P = 0.048) and 0.20 (P = 0.017), respectively. In some analyses, patients with non-RAR readmissions also experienced lower quality. However, rates of inferior quality care did not differ significantly by readmission status, and simulations identified no meaningful relationship between RARs and hospital quality of care.

CONCLUSIONS

RARs are statistically associated with lower quality of care. However, neither RARs nor other readmissions appear to be useful tools for identifying patients who experience inferior care or for comparing quality among hospitals.

Market forces and unsponsored research in academic health centers

CONTEXT

Increased competitive pressures on academic health centers may result in reduced discretionary funds from patient care revenues to support the performance of unsponsored research, including institutionally funded and faculty-supported activities.

OBJECTIVE

To measure the amount and distribution of unsponsored research activities and their outcomes.

DESIGN AND SETTING

Survey conducted in academic year 1996-1997 of 2336 research faculty in 117 medical schools. Responses were weighted to provide national estimates.

MAIN OUTCOME MEASURES

Institutionally funded research as a proportion of total direct costs of research was compared across stages of market competition. Logistic regression was used to assess the relationship of performing unsponsored research to faculty characteristics and market stage.

RESULTS

Overall, 43% of faculty received institutional funding for research. Young faculty were more likely than others to receive institutional support (adjusted odds ratio [OR], 1.4; 95% confidence interval [CI], 1.1-1.9; P = .004). The amount of institutional support as a proportion of total funding was more than twice as high in less competitive markets (6.1%) compared with the most competitive markets (2.5%; P = .05). Most faculty (55%) performed faculty-supported research. Clinical researchers (OR, 1.6; 95% CI, 1.1-2.3), principal investigators (OR, 4.3; 95% CI, 2.8-7.0), faculty with high levels of research effort (OR, 6.2; 95% CI, 4.0-9.5) or institutional funding (OR, 1.9; 95% CI, 1.4-2.6), and faculty in the most competitive markets (OR, 1.9; 95% CI, 1.4-2.5) were more likely than others to conduct faculty-supported research. When undertaken by clinical researchers, these activities were supported by clinical income, extra hours worked, and discretionary funds, and often led to publications (76%) or grant awards (51%).

CONCLUSIONS

Many academic health center faculty receive institutional support to conduct their research or fund the research themselves. Market pressures may be affecting the level of institutional funding available to faculty.

Termination from Medicaid: how does it affect access, continuity of care, and willingness to purchase insurance?

Welfare reform has raised fears that Medicaid recipients will lose coverage, yet efforts to insure the poor via waiver programs may fall short. A telephone sample of 351 enrolled and terminated members of a Medicaid managed care plan based in community health centers were asked about insurance status, source of care, willingness to purchase new insurance, and access. Of terminated families, 78 percent had one member without insurance, 93 percent retained a regular source of care (vs. 96 percent enrolled), and 86 percent retained the same source as before losing coverage. Only 11 percent of uninsured respondents were willing to pay $200 per month and 57 percent to pay $50 per month for replacement coverage, and they were more likely to report problems getting prescription medications and obtaining treatment for serious symptoms and to go without care because of the expense. Access to care is diminished for those who lose Medicaid coverage, even for persons attending community health centers.

The stability of preferences for life-sustaining care among persons with AIDS in the Boston Health Study

BACKGROUND

Clinicians recognize the importance of eliciting patient preferences for life-sustaining care, yet little is known about the stability of those preferences for patients with serious disease.

OBJECTIVES

To examine the stability of preferences for life-sustaining care among persons with AIDS and to assess factors associated with changes in preferences.

DESIGN

Two patient surveys and medical record reviews, administered four months apart in 1990-1991.

SETTING

Three health care settings in Boston.

PATIENTS

252 of 505 eligible persons with AIDS who participated in both baseline and follow-up surveys.

MAIN OUTCOME MEASURES

A single question assessing desire for cardiac resuscitation and a scale of preferences for life-extending treatment conditional on hypothetical health states.

RESULTS

Approximately one-fourth of the respondents changed their minds about life-sustaining care during a four-month period. Of patients who initially desired cardiac resuscitation, 23% decided to forego it four months later, and of those who initially said they would decline care, 34% later said they would accept it. Of those who initially desired any of the life-extending treatments, 25% decided to forego them four months later, and of those who initially said they would decline life-extending care, 24% later said they would accept some treatment. Patients reporting changes in physical function, pain, or suicide ideation were more likely to modify their desires to be resuscitated (all p< or =0.05). Patients lacking an advance directive, not completing high school, or becoming more severely ill were more likely to change their preferences on the Life Extension scale (p< or =0.05). Patients who discussed their preferences with at least one physician were just as likely as others to change desires for cardiac resuscitation. Age, gender, race, emotional health, clinical severity, social support, and site of care were not significant correlates of change for either measure.

CONCLUSIONS

Health care providers should periodically reassess preferences for life-sustaining care, particularly for patients with progressive disease, given the instability in patient preferences. However, predictors of instability may vary with how preferences are measured. In particular, changes in health status may be related to instability of preferences for certain types of treatments.

Quality of care for two common illnesses in teaching and nonteaching hospitals

Teaching hospitals are recognized for treating rare diseases, but their value in caring for common illnesses is less clear. To assess quality of care for congestive heart failure and pneumonia, we reviewed the medical records of Medicare beneficiaries in major teaching, other teaching, and nonteaching hospitals in four states. Overall quality was rated better in major and other teaching hospitals than in nonteaching hospitals by physician reviewers and explicit process criteria, but the results varied for different subsets of explicit measures. Future studies should assess whether outcomes differ between teaching and nonteaching hospitals.

GroEL-GroES-mediated protein folding requires an intact central cavity

The chaperonin GroEL is an oligomeric double ring structure that, together with the cochaperonin GroES, assists protein folding. Biochemical analyses indicate that folding occurs in a cis ternary complex in which substrate is sequestered within the GroEL central cavity underneath GroES. Recently, however, studies of GroEL "minichaperones" containing only the apical substrate binding subdomain have questioned the functional importance of substrate encapsulation within GroEL-GroES complexes. Minichaperones were reported to assist folding despite the fact that they are monomeric and therefore cannot form a central cavity. Here we compare directly the folding activity of minichaperones with that of the full GroEL-GroES system. In agreement with earlier studies, minichaperones assist folding of some proteins. However, this effect is observed only under conditions where substantial spontaneous folding is also observed and is indistinguishable from that resulting from addition of the nonchaperone protein alpha-casein. By contrast, the full GroE system efficiently promotes folding of several substrates under conditions where essentially no spontaneous folding is observed. These data argue that the full GroEL folding activity requires the intact GroEL-GroES complex, and in light of previous studies, underscore the importance of substrate encapsulation for providing a folding environment distinct from the bulk solution.

A critical role for amino-terminal glutamine/asparagine repeats in the formation and propagation of a yeast prion

The yeast [PSI+] factor propagates by a prion-like mechanism involving self-replicating Sup35p amyloids. We identified multiple Sup35p mutants that either are poorly recruited into, or cause curing of, wildtype amyloids in vivo. In vitro, these mutants showed markedly decreased rates of amyloid formation, strongly supporting the protein-only prion hypothesis. Kinetic analysis suggests that the prion state replicates by accelerating slow conformational changes rather than by providing stable nuclei. Strikingly, our mutations map exclusively within a short glutamine/asparagine-rich region of Sup35p, and all but one occur at polar residues. Even after replacement of this region with polyglutamine, Sup35p retains its ability to form amyloids. These and other considerations suggest similarities between the prion-like propagation of [PSI+] and polyglutamine-mediated pathogenesis of several neurodegenerative diseases.

Costs and outcomes of AIDS care: comparing a health maintenance organization with fee-for-service systems in the Boston Health Study

OBJECTIVE

A 4-month observational cohort study was performed to compare the performance of one health maintenance organization (HMO) with two fee-for-service (FFS) systems in Boston, Massachusetts in treating 255 patients with AIDS.

MAIN OUTCOME MEASURES

Total 4-month costs; cost subcomponents, including inpatient, outpatient, home care, and zidovudine costs; functional status (difficulties with activities of daily living); and satisfaction with care.

RESULTS

Compared with FFS patients, HMO patients were better educated, more often white, less often on Medicaid, and more often reported homosexual or bisexual behaviors as HIV risk factors (all factors, p = .001). Both groups had similar duration of AIDS, baseline hemoglobin levels, and leukocyte counts. Total 4-month costs at the HMO were significantly lower than those in the FFS settings ($4799 U.S. versus $8540 U.S.; p = .013), as were outpatient costs ($1131 U.S. versus $1614 U.S.; p = .001), after adjustment for sociodemographic factors, baseline functioning, main HIV risk factor, and other clinical variables. Adjusted physical functioning (p = .32) and patient satisfaction (p = .82). were similar between systems.

CONCLUSIONS

The HMO had significantly lower total costs without any observable decrement in functional outcomes or patient satisfaction. The largest component of these cost savings came from reduced spending on inpatient care, but the HMO also spent less on outpatient and home care. Better coordination of care at the HMO may have been responsible for these lower costs.

Ero1p: a novel and ubiquitous protein with an essential role in oxidative protein folding in the endoplasmic reticulum

The structure of many proteins entering the secretory pathway is dependent on stabilization by disulfide bonds. To support disulfide-linked folding, the endoplasmic reticulum (ER) must maintain a strongly oxidizing environment compared to the highly reduced environment of the cytosol. We report here the identification and characterization of Ero1p, a novel and essential ER-resident protein. Mutations in Ero1p cause extreme sensitivity to the reducing agent DTT, whereas overexpression confers DTT resistance. Strikingly, compromised Ero1p function results in ER retention of disulfide-stabilized proteins in a reduced, nonnative form, while not affecting structural maturation of a disulfide-free protein. We conclude that there exists a specific cellular redox machinery required for disulfide-linked protein folding in the ER and that Ero1p is an essential component of this machinery.

The Boston AIDS Survival Score (BASS): a multidimensional AIDS severity instrument

OBJECTIVES

This study developed a new acquired immunodeficiency syndrome (AIDS) severity system by including diagnostic, physiological, functional, and sociodemographic factors predictive of survival.

METHODS

Three-hundred five persons with AIDS in Boston were interviewed; their medical records were reviewed and vital status ascertained.

RESULTS

Overall median (+/- SD) survival for the cohort from the first interview until death was 560 +/- 14.4 days. The best model for predicting survival, the Boston AIDS Survival Score, included the Justice score (stage 2 relative hazard [RH] = 1.25, 95% confidence interval [CI] = 0.80, 1.96; stage 3 RH = 1.76, 95% CI = 1.15, 2.70), a newly developed opportunistic disease score (Boston Opportunistic Disease Survival Score; stage 2 RH = 1.35, 95% CI = 0.90, 2.02; stage 3 RH = 2.10, 95% CI = 1.38, 3.18), and measures of activities of daily living (any intermediate limitations, RH = 1.84, 95% CI = 1.05, 3.21; any basic limitations, RH = 2.60, 95% CI = 1.44, 4.69). This model had substantially greater predictive power (R2 = .17, C statistic = .68) than the Justice score alone (R2 = .09, C statistic = .61).

CONCLUSIONS

Incorporating data on clinically important events and functional status into a physiologically based system can improve the prediction of survival with AIDS.

The influence of health-related quality of life and social characteristics on hospital use by patients with AIDS in the Boston Health Study

OBJECTIVES

The authors examine whether health-related quality of life (HRQL) and social factors were independent predictors of future hospital use for persons with acquired immunodeficiency syndrome (AIDS).

METHODS

A panel of 305 patients with AIDS treated at three provider settings in the Boston, Massachusetts area were enrolled during 1990 and 1991. Data were collected at baseline study enrollment and again 4 months later. Patient interviews, hospital bills, and medical charts were used to measure hospital use (admissions and days during the 4 months after enrollment), sociodemographic characteristics (age, gender, race, education, insurance, homelessness, alcohol use, and AIDS risk factors), disease burden (patient severity and a three-level opportunistic diseases and complications score), HRQL (patient-reported symptoms, activities of daily living, neuropsychological status, and global health assessment), system of care, and use of prophylactic drugs. Logistic regression was used to estimate the odds of admission. Total days of hospital care by patients with at least one admission were analyzed using multiple linear regression. Clinical models of hospital use were developed first from the variables measuring disease burden and system of care. Models estimating the associations between hospital use and all other predictor variables measured at baseline then were estimated using stepwise techniques, controlling for variables in the core model.

RESULTS

Patients were more likely than their reference groups to be hospitalized if they had serious opportunistic diseases (adjusted odds ratio [OR] = 2.7), had poorer neuropsychological status (OR = 1.9), were non-white (OR = 2.0), or were homeless (OR = 3.3) (all P < or = 0.05). Activities of daily living were associated moderately (OR = 1.3; P = 0.07). Only system of care and neuropsychological status predicted total hospital days.

CONCLUSIONS

The results indicate that future hospital use by persons with AIDS may be influenced by social and other health-related factors in addition to the more clinically related characteristics that are recorded in a medical chart. It therefore may be appropriate to assess these factors when considering options for intervention or when comparing patterns of use among patient groups or settings.

Release of both native and non-native proteins from a cis-only GroEL ternary complex

Protein folding by the double-ring chaperonin GroEL is initiated in cis ternary complexes, in which polypeptide is sequestered in the central channel of a GroEL ring, capped by the co-chaperonin GroES. The cis ternary complex is dissociated (half-life of approximately 15 s) by trans-sided ATP hydrolysis, which triggers release of GroES. For the substrate protein rhodanese, only approximately 15% of cis-localized molecules attain their native form before hydrolysis. A major question concerning the GroEL mechanism is whether both native and non-native forms are released from the cis complex. Here we address this question using a 'cis-only' mixed-ring GroEL complex that binds polypeptide and GroES on only one of its two rings. This complex mediates refolding of rhodanese but, as with wild-type GroEL, renaturation is quenched by addition of mutant GroEL 'traps', which bind but do not release polypeptide substrate. This indicates that non-native forms are released from the cis complex. Quenching of refolding by traps was also observed under physiological conditions, both in undiluted Xenopus oocyte extract and in intact oocytes. We conclude that release of non-native forms from GroEL in vivo allows a kinetic partitioning among various chaperones and proteolytic components, which determines both the conformation and lifetime of a protein.

The validity of self-reported health-care utilization by AIDS patients

OBJECTIVES

To examine the validity of self-reported health-care utilization among persons with AIDS.

DESIGN

A comparison of survey data with information collected from medical and financial records.

METHODS

Personal interviews provided information on utilization within a 4-month period for inpatient admissions (n = 296), ambulatory visits (n = 284), and hours of homecare (n = 106). Risk group, socioeconomic characteristics, disease stage, functional status, memory, and respondent's recall ability were also measured. Reporting error was defined as the difference between self reports and medical/financial records. Variations among subgroups of patients were examined using t tests and multiple regression. To determine whether reporting errors affected analysis of utilization data, we compared coefficients from parallel utilization models using each data source to predict use/non-use and total utilization.

RESULTS

Mean overall reporting errors were small and not significantly different from zero. Reporting errors were lowest for hospital admissions and highest for homecare. High utilizers underreported all types of services. The interviewer evaluation of recall was an independent and significant predictor of reporting errors for admissions and ambulatory visits. Reporting errors varied by selected subgroup characteristics, but the direction and significance of the error depended on the type of utilization measured. In the parallel utilization models, few differences appeared between models using self-reports and medical/financial records to identify correlates of use/non-use, but some differences between the models of total utilization were apparent.

CONCLUSIONS

Self-reports of utilization by AIDS patients with a recall period of 4 months or less provide, on average, valid data for analytic purposes. However, caution should be applied to reports by high or low users or by respondents judged by interviewers to have major recall problems.