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Biomedical subjects

G Riley

Publications and source records attributed to G Riley.

At least 55 records · Page 3Linked to original sources
PubMed1996

Health status of Medicare enrollees in HMOs and fee-for-service in 1994.

We compared the health status of 863 health maintenance organization (HMO) enrollees with that of 4,576 non-enrollees, controlling for demographics and area of residence, using 1994 data from the Medicare Current Beneficiary Survey (MCBS). HMO respondents were less likely to report fair or poor health, functional impairment, or heart disease. Average predicted costs based on various health-status measures were substantially lower for HMO respondents than for respondents in fee-for-service (FFS) arrangements. The Medicare payment formula for HMOs does not adequately adjust for the better health and consequent lower expected costs of HMO enrollees. The addition of health-status measures would improvement payment accuracy and reduce average HMO payments significantly below current levels.

Activities of Daily Living↗
PubMed1995

A positron emission tomography [18F]deoxyglucose study of developmental stuttering.

Positron emission tomography using [18F]deoxyglucose (FDG) as a marker of regional brain metabolism was used to investigate the neural substrate of stuttering. Four patients with severe developmental stuttering were studied while reading aloud to another person (stuttering condition) and while reading aloud in unison with someone else (non-stuttering condition). The patients were also compared with four normal controls reading aloud by themselves. In the stuttering condition, significant decreases in regional glucose metabolism in Broca's area, Wernicke's area and frontal pole were seen compared with themselves while not stuttering. These differences were also seen in stuttering condition compared with normal controls. Significantly lower left caudate metabolism was seen in patients during both stuttering and non-stuttering conditions compared with normal controls. A circuit for stuttering is proposed based on these findings.

Adult↗
PubMed1994

Evaluation of cold-adapted, reassortant influenza B virus vaccines in elderly and chronically ill adults.

The safety and immunogenicity of two recent cold-adapted reassortant influenza B viruses were evaluated in persons at high risk for influenza-related morbidity and mortality. Ambulatory adults > 65 years old or with chronic high-risk conditions were randomly assigned to receive parenteral trivalent inactivated influenza vaccine containing either influenza B/Ann Arbor/86 or B/Yamagata/88 hemagglutinin antigens, cold-adapted reassortant influenza B/Ann Arbor/1/86 or B/Yamagata/16/88 viruses (10(7.2) TCID50), or placebo in double-blind fashion. Cold-adapted vaccine viruses were well tolerated, with similar rates of respiratory symptoms in all groups. There were no changes in spirometry or oxygen saturation following vaccination. Immune responses to both types of vaccine were modest, with serum antibody responses occurring significantly more frequently and with higher magnitude in those receiving inactivated than in those receiving cold-adapted vaccine. Cold-adapted, reassortant influenza B vaccines are safe in the elderly and those with chronic illness but are not optimally immunogenic in this group.

Aged↗
PubMed1994

Antimicrobial susceptibility of pathogenic Yersinia enterocolitica isolated in Canada from 1972 to 1990.

Yersinia enterocolitica has emerged as an enteropathogen associated with several types of human infections that often require antimicrobial therapy, but little is known about the antimicrobial susceptibilities of pathogenic strains isolated from humans in Canada. To determine the present patterns of antimicrobial susceptibility, to identify changes in these patterns that occurred during the past two decades, and to investigate the relationships between O serotypes and patterns of susceptibility, we tested a total of 1,105 pathogenic Y. enterocolitica strains isolated during 1972 to 1976, 1980, 1985, and 1990 for their susceptibilities to 22 antimicrobial agents. Susceptibility testing was performed by using a single breakpoint concentration in agar procedure. The results showed that all strains were susceptible to ciprofloxacin and piperacillin, and 98% or more of the strains from each period were susceptible to trimethoprim, sulfamethoxazole, cotrimoxazole, tetracycline, chloramphenicol, cefamandole, cefotaxime, aztreonam, and four aminoglycosides. In contrast, all strains were nonsusceptible to erythromycin, furazolidone, and clindamycin and 90% or more of the strains from each period were nonsusceptible to ampicillin, carbenicillin, ticarcillin, and cephalothin. Strains belonging to serotypes O:3, O:5,27, and O:8 had different patterns of susceptibility to ampicillin, carbenicillin, ticarcillin, and amoxicillin-clavulanic acid. No major difference in susceptibility was observed between any of the groups of human or animal strains included in the study, but nonsusceptibility to tetracycline increased from 0.4% in 1985 to 2% in 1990 in human strains isolated in those years. Our results indicate that between 1972 and 1990 there was no marked decrease in susceptibility to agents commonly used for therapy among pathogenic Y. enterocolitica strains isolated in Canada.

Animals↗
PubMed1993

Medicare beneficiaries: adverse outcomes after hospitalization for eight procedures.

Rehospitalization following surgery is widely recognized as an important outcome measure. The purpose of this study was to identify rehospitalizations for adverse events following 8 procedures, using diagnosis and procedure codes contained in Medicare claims files. Adverse events were broadly defined as: 1) complications; 2) failure of the procedure to achieve its therapeutic goal; and 3) untoward events associated with the natural history of the disease being treated with the procedure. Expert panels identified specific diagnosis and procedure codes that might indicate an adverse event if they appeared on the Medicare record of a rehospitalization. Among patients undergoing percutaneous transluminal coronary angioplasty, almost 36% were rehospitalized for an adverse event within a year of surgery; among patients undergoing coronary artery bypass graft surgery, 20% were rehospitalized for an adverse event. Following the other 6 procedures (cholecystectomy, partial excision of the large intestine, total knee replacement, total hip replacement, replacement of the head of the femur, and reduction of fracture of the femur) between 4% and 9% of patients were rehospitalized for an adverse event. Findings from this exploratory study indicate that rehospitalizations for adverse events appear to be a useful outcome measure for the cardiac procedures; they appear to be less useful for the other procedures, at least at the individual hospital or small area level, because of their relative rarity. Future studies should investigate procedures associated with more frequent rehospitalizations, and medical admissions, which often tend to be associated with higher rehospitalization levels.

Aged↗
PubMed1992

Localization of the immunologic activity in the superantigen Staphylococcal enterotoxin B using truncated recombinant fusion proteins.

The exotoxins of certain strains of Staphylococcus aureus strains are able both to stimulate potent proliferation and induce anergy in T lymphocytes expressing the appropriate T cell Ag receptor V beta gene elements. Although T cell activation by the S. aureus enterotoxins requires the presence of accessory cells bearing class II Ag of the MHC, unlike the peptide fragments of nominal Ag, they contact the external surfaces of both the class II MHC and TCR molecules. This paper investigates the immunologically active domains of S. aureus enterotoxin B (SEB) using truncated fragments of rSEB expressed as a fusion protein with protein A. The results of the experiments reported here indicate that the minimal fragment of SEB able to stimulate and induce anergy in hemagglutinin-reactive human T cells expressing V beta 3.1 gene elements is located in the amino-terminal portion of the molecule within residues 1-138. Deletion of the first 30 amino acid residues renders rSEB unable to stimulate T cells expressing V beta 3.1, whereas polyclonal T cells still respond to this molecule. This implies that the stimulation of several TCR-V beta families may be caused by the interaction with different regions of the toxin. The localization of immunologically active sites in the bacterial enterotoxins is needed to investigate both their biology and potential application as immunomodulatory agents.

Antigens, Bacterial↗
PubMed1992

Prostatic abscess: diagnosis and treatment.

We present a series of 25 men with prostatic abscesses studied during an 11-year interval in whom prostatic fluctuation upon digital rectal examination was the most characteristic sign. Transrectal ultrasound was the most reliable method for diagnosis and transurethral drainage under antibiotic coverage was the ideal treatment for this disease.

Abscess↗
PubMed1992

Satisfaction with medical care among elderly people in fee-for-service care and an HMO.

This study investigates satisfaction with care among elderly Medicare beneficiaries enrolled in a health maintenance organization (HMO) and beneficiaries in fee-for-service (FFS) care in the same geographic area. Satisfaction with two dimensions of care, access/quality and costs, are examined, to investigate differences in enrollee/FFS evaluation of these dimensions of care as well as predictors of satisfaction with care. In addition, satisfaction among healthy and chronically ill elderly people in these two care settings is explored. Results indicate higher satisfaction with access/quality of care among those in FFS and higher satisfaction with costs among HMO enrollees. These relationships hold controlling for other variables and among the chronically ill elderly. Sources of variation in satisfaction are somewhat different among the HMO and FFS elderly. Satisfaction with paperwork and ease of getting to care, however, influences satisfaction with other aspects of care in both populations.

Aged↗
PubMed1991

U.S. initiatives and approaches for outcomes and effectiveness research.

This paper provides an overview of the new Federal initiative underway to promote research in outcomes and effectiveness of services provided in the U.S. It discusses the factors that stimulated the U.S. government ot undertake this initiative and summarizes past research and current efforts to advance knowledge about utilization and outcomes of care. A focal point of this initiative is to take advantage of information in large, administrative data bases to monitor the use, costs and outcomes of medical services. As part of this initiative, the Federal Government for the first time assembled detailed data, by geographic area and by demographic groups, on the hospitalization, mortality and rehospitalization experience of the entire Medicare population. The paper describes this project and illustrates uses of these data.

Aged↗
PubMed1991

Enrollee health status under Medicare risk contracts: an analysis of mortality rates.

Previous studies comparing the health status of Medicare beneficiaries enrolled under HMO risk contracts to that of Medicare beneficiaries in fee-for-service (FFS) have generally focused on demonstration projects conducted before 1985. This study examines mortality rates in 1987 for approximately 1 million aged Medicare beneficiaries enrolled in 108 HMOs. We estimated adjusted mortality ratios (AMR) for each HMO and across all HMOs, by dividing the actual number of deaths among HMO enrollees by the "expected" number of deaths. The expected number of deaths was based on death rates among local FFS populations, adjusting for age, sex, Medicaid buy-in status, and institutional status. The AMR for all HMO enrollees pooled together was 0.80. For persons newly enrolled in 1987, the AMR was 0.69; in general, AMRs were higher for beneficiaries who had been enrolled for longer periods of time. Among individual HMOs, none exhibited an AMR substantially above 1.00. Regression analysis indicated lower AMRs for staff model HMOs than for either IPA or group models. Low mortality among Medicare HMO enrollees is consistent with favorable selection or with improvements in the health status of enrollees due to better access or quality of care in HMOs. In either case, health status differences between HMO enrollees and FFS beneficiaries have implications for the appropriateness of Medicare's Adjusted Average Per Capita Cost (AAPCC) payment formula for HMOs.

Aged↗
PubMed1989

Biased selection and regression toward the mean in three Medicare HMO demonstrations: a survival analysis of enrollees and disenrollees.

Mortality of aged Medicare enrollees in three demonstration health maintenance organizations (HMOs) was compared with that of three cohorts of local fee-for-service (FFS) beneficiaries as a measure of group differences in health status. Mortality of the HMO and FFS cohorts was tracked via life-table analysis for 6 years after enrollment to measure the persistence of health status differences existing at enrollment. After adjustment for age, sex, Medicaid-eligibility, and institutional status, HMO enrollee mortality was lower than FFS at all three plans in the first year after enrollment. Enrollee mortality at two plans increased to near FFS levels in year 2 and remained relatively stable thereafter. Enrollee mortality at the third plan increased toward FFS levels more gradually and was significantly below FFS levels for the first 5 years of follow-up. Mortality of disenrollees in the 2 years after disenrollment was significantly higher than that of the continuously enrolled in one plan and marginally significantly higher in a second. These findings suggest a pattern of favorable selection at enrollment, followed by different rates of decay in the favorable health status of enrollees. Other health status measures may exhibit different patterns, however. Selection effects may cause payments based on Medicare's AAPCC to be too high or low, in some cases for several years after enrollment.

Aged↗