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Biomedical subjects

W P Fisher

Publications and source records attributed to W P Fisher.

17 recordsLinked to original sources
PubMed1997

Kinetic modeling of folate metabolism through use of chronic administration of deuterium-labeled folic acid in men.

This study was conducted as an initial investigation of in vivo folate kinetics in healthy men (n = 4) and made use of a chronic-administration protocol with stable-isotope labeling. Subjects were given 0.453 mumol (200 micrograms) total folic acid in aqueous solution daily throughout the 18-wk study while they consumed self-selected folate-adequate diets. After a 2-wk pretrial period with unlabeled folic acid, subjects were given 0.227 mumol (100 micrograms) pteroyl-L-[2H4]glutamic acid/d ([2H4]folic acid) combined with 0.227 mumol nonlabeled folic acid or [2H2]pteroylhexaglutamic acid/d for the next 8 wk; then for the next 8 wk the [2H4]folic acid was withdrawn and the subjects received only nonlabeled folic acid. Little unmetabolized folic acid was excreted in urine. Isotopic enrichment of urinary folate during [2H4]folic acid administration and withdrawal was consistent with a kinetic model having a rapid turnover pool and a slow turnover pool. In contrast with previous two-pool models, provisions were made for folate turnover by urinary folate excretion (as measured here) and by fecal excretion and catabolic processes. The precision of modeling will be improved in future studies by measurement of enrichment of additional pools. However, this study shows clearly the slow turnover of the whole-body folate pool (< or = 1% per day) and the feasibility of further long-term kinetic analysis.

Adult↗
PubMed1995

Rehabits: a common language of functional assessment.

Probabilistic measurement models offered by Rasch and others can be used to link different functional assessment instruments into a single measurement system. This study assessed 54 subjects (diagnoses: 8 brain injuries, 7 neuromuscular, 22 musculoskeletal, 7 spinal cord, 10 stroke) admitted to a free-standing rehabilitation hospital at admission and discharge using both the Functional Independence Measure (FIM) and the Patient Evaluation and Conference System (PECS). Thirteen FIM and 22 PECS motor skills items were scaled together into a 35-item instrument, providing scale values for all items in the same unit of measurement. Separate FIM and PECS measures produced for each subject correlate .94 and .91 (p < .0001), respectively, with the cocalibration measures, and 0.91 (p < .0001) with each other. Either instrument's ratings are easily and quickly converted into the other's using the common unit of measurement, the rehabit (rehabilitation measuring unit). This article argues that the stability of the PECS and FIM item difficulty estimates over thousands of subjects, dozens of hospitals, hundreds of raters, and years of assessment is convincing evidence in support of the widespread use of their cocalibrated, common scale values as a functionometric ruler.

Calibration↗
PubMed1993

Measurement-related problems in functional assessment.

Occupational therapists, like other rehabilitation professionals, have accepted ordinal raw scores as a sufficient basis for developing evaluation tools. This paper summarizes problems commonly found in evaluation methods based on summing ordinal raw item scores and demonstrates how Rasch measurement models provide a solution to the construction of calibrated (linear) measures. Rasch measurement models are contrasted with Steven's lax definition of measurement and Guttman's unreasonably rigid requirements. The simple Rasch model is a probabilistic formulation of the fundamental requirements for additive linear measurement. This formulation retains Guttman's concept of order, but construes it probabilistically, making it neither too lax (random) nor too rigid. When a measure is based on a theory of what counts as an observation of more or less of something, Rasch measurement models are useful for constructing valid measures.

Activities of Daily Living↗
PubMed1992

Applying psychometric criteria to functional assessment in medical rehabilitation: III. Construct validity and predicting level of care.

A discriminant analysis was performed using Rasch ability estimates derived from four Patient Evaluation and Conference System (PECS) subscales, to distinguish among the functional independence and impairment profiles exhibited by patients admitted into any of three levels of medical rehabilitation delineated by the National Association of Rehabilitation Facilities (NARF): (1) inpatient hospital, (2) atypical nursing home (intermediate), or (3) day program. Two discriminant functions accounted for 91% and 9% of the between-group variance, respectively. Cross-validated classification of patients into one of the three levels of care, based on discriminant function scores, produced 75% correct classification; a 66% improvement over the percentage of correct classification likely by chance alone. Results support the construct validity of the PECS subscales and indicate they may be useful in validating clinically-based admission decisions among three of the levels of care promulgated by NARF.

Activities of Daily Living↗
PubMed1992

Quantifying handicap.

Explore the source record for details and available documents.

Data Interpretation, Statistical↗
PubMed1992

Applying psychometric criteria to functional assessment in medical rehabilitation: II. Defining interval measures.

The use of functional assessment total scores in arithmetic operations has proliferated despite the lack of evidence supporting their use as interval measures of patient ability. Such evidence is minimally necessary to assure the validity of functional assessment total scores for clinical and management decision-making. Two requirements of interval measurement are explained and a set of Rasch analyses of 5,500 assessments using the Patient Evaluation and Conference System (PECS) are presented. The analyses were performed to determine the extent to which four item subsets identified in a previously reported factor analysis of the PECS comprise interval measures of functional independence status. Results indicate that the PECS scales meet these requirements to varying degrees. The analyses also identify areas in which measurement quality can be improved.

Activities of Daily Living↗
PubMed1991

Applying psychometric criteria to functional assessment in medical rehabilitation: I. Exploring unidimensionality.

While rehabilitation providers are facing increasing pressure to document treatment outcomes, critics have warned against the inappropriate use of ordinal functional assessment data in arithmetic operations. Two salient criticisms concern the combination of items representing multidimensional abilities into a single total score, and the indeterminate distances between hierarchical functional assessment scale categories. In this initial study, the factor structure of the Patient Evaluation and Conference System (PECS) was studied to assess the potential for unidimensional measurement. Factor analysis of a multidiagnostic dataset (n = 3,564) yielded eight factors accounting for 60% of the variance among 68 PECS items. The factors indicate that several unidimensional measures may underlie the PECS. These factors are delineated, and further studies of unidimensionality and additivity are recommended.

Activities of Daily Living↗
PubMed1984

Capitation payment for pharmacy services. II. Impact on costs.

Four areas of cost were analyzed in the expanded capitation drug program: total program costs; drug costs, escrow account distribution, and administrative costs. Total program costs were, on average, 9% higher under capitation. Drug costs, however, were 3% lower than under fee-for-service (FFS) reimbursement. This discrepancy is probably because pharmacists were not at financial risk under the program, the capitation rates were higher than intended, there were many emergency claims, and other aspects of the research environment. Although administrative costs were large, almost two thirds of the development cost was for one-time work, which could be transferred to another state at little or no expense. One third of the total administrative costs can be attributed to complying with regulations of the Health Care Financing Administration. Significant refinement of the present capitation model may be necessary before this financing innovation is used elsewhere. Modifications might include limiting the system to nursing home patients, placing pharmacists at partial financial risk, restricting participation to pharmacies that service a large number of Medicaid eligibles, and basing capitation rates in part on the drug use behavior of cash-paying patients.

Capitation Fee↗
PubMed1984

Capitation payment for pharmacy services. I. Impact on drug use and pharmacist dispensing behavior.

Results of a two-county pilot study in Iowa revealed that capitation may have significant advantages over fee-for-service (FFS) reimbursement in the Medicaid drug program. Consequently, the capitation program was expanded to 32 counties on April 1, 1981 and continued through December 31, 1981. Another 32 counties were used as part of a before:after/experimental:control design. Pharmacists were paid 80% of projected drug expenditures in advance based on the types of Medicaid eligibles who chose them as their providers. The remaining 20% was withheld in an escrow account to be used for supplemental, emergency, and bonus payments. Pharmacists who participated in this experiment were guaranteed that their gross profits on Medicaid prescriptions would remain at least equal to what they would have been if they had remained under the current FFS payment system. Major differences in drug use levels and pharmacist dispensing behavior under capitation financing were observed in the pilot study. However, no such changes associated with payment type were noted in the expanded program. Relative to these findings, a discussion of pharmacist attitudes is presented.

Attitude of Health Personnel↗
PubMed1983

A preimplementation assessment of a capitation reimbursement system using simulation.

Capitation is a system of reimbursement for services under which providers are paid a fixed amount per client served per time period. An experiment from April 1981 to December 1981 involved the use of a capitation system of reimbursement to pharmacies participating in the Iowa Medicaid drug program in 32 counties in Iowa. It was essential to demonstrate that cost savings were feasible and pharmacy reimbursement would be adequate before the capitation experiment was begun. An assessment of this issue was developed using simulation and data base management techniques. The positive results of this assessment gave evidence that cost savings due to capitation potentially could be realized by both the Medicaid drug program and pharmacists during the experiment.

Capitation Fee↗
PubMed1981

The effects of an expectancy state on the fate of applications and psychotherapy in an outpatient setting.

This study describes an attempt to influence the outcome of outpatient psychotherapy by offering pretherapy information to application. The sample consisted of more than 1,300 applicants; the pretherapy information, in the form of a printed leaflet, was included with the application blank for alternate cases. The results suggest that the pretherapy information tended to discourage the completing of application blanks. Among those patients who eventually participated in psychotherapy, pretherapy information had no effect on the duration of treatment or on treatment outcomes as rated by the therapists. Incidentally, the data indicate that having health insurance has a strong, positive effect on the number of treatment interviews.

Adjustment Disorders↗
PubMed1980

The effect of a group practice on rural health attitudes and behavior.

The opportunity to join a group practice has been identified as a successful inducement for physicians to locate in rural areas. Less is known of the effects of group practice on the health attitudes, behavior and status of the rural communities in which they are established. A random survey of households was conducted in 1972 in a rural Midwestern area, prior to the establishment of a community-sponsored multispecialty primary care group practice, and again on the same households in 1977, after establishment of this group practice (a total of 292 households representing 829 persons). Perceived access to health services before the establishment of the group practice did not significantly predict use of the group practice. Neither previous use of medical services nor health status measured by several indices was associated with eventual use of the group practice. The apparent impact on the community of the group practice was a significant improvement in access to physician services, shown by shorter average travel time to the place of primary care and a 62 per cent improvement in the ability to make a same-day appointment. Furthermore, a significant shift in the distribution of physician services was noted over the study period. The introduction of physician assistants significantly decreased the prior positive attitudes toward them. Despite improvement in access to care, no changes in population health status or receipt of preventive services were noted. Current users of the group practice appear similar to those utilizing conventional medical care sources in regard to access to services, use of services, as well as health status, attitudes and costs.

Adolescent↗
PubMed1980

Capitation payment for pharmacy services: impact on generic substitution.

This article evaluates changes in the rate of generic substitution as well as the appropriateness of such changes in dispensing behavior when the conventional fee-for-service system for reimbursement of pharmacists is replaced by a capitation system. The fee-for-service system under Medicaid usually covers ingredient costs plus a fixed professional dispensing fee. The capitation system provides a cash payment per Medicaid eligible at the first of each month, which varies by aid category and season of the year. The dispensing behavior of pharmacists in two experimental rural counties is examined during a 1-year preperiod in which the fee-for-service form of reimbursement was employed, as well as a 2-year postperiod in which capitation was used in lieu of fee-for-service payments. The results are compared with pharmacist behavior patterns in two other rural counties which remained on the fee-for-service system over the same 3-year period. The data indicate highly significant increases in both the rate of generic substitution as well as the dollar savings per substitution in the experimental counties after the institution of capitation reimbursement. Using explicit criteria, no substantial differences in the appropriateness of generic substitution were noted between the two financing schemes.

Capitation Fee↗
PubMed1980

Does chiropractic utilization substitute for less available medical services?

In Muscatine, Iowa, a medically underserved rural area, a cohort study of health care utilization was made before and after a significant increase in medical manpower. There was a slight increase, rather than a decrease, in the use of chiropractic services associated with the growth in the physician manpower pool. The level of access to physician services was not a significant predictor of chiropractice utilization.

Adolescent↗
PubMedDate not supplied

Effects of capitation payment for pharmacy services on pharmacist-dispensing and physician-prescribing behavior: I. Prescription quantity and dose analysis.

This paper evaluates changes in quantities and appropriateness of dosages and quantities of prescription in capitation and control pharmacies. The data indicate that, under capitation, changes were made in the quantities of ingredients so that the quantities dispensed were significantly different from those prescribed. However, the number of such modifications to prescriptions was small, and the reader is cautioned against drawing broad conclusions. The analysis, then, considers changes in days' supply of prescription ingredients during the study period. There were significantly increases in the average day's supply of prescription ingredients for maintenance drugs dispensed under the capitation reimbursement scheme; however, no such differences were observed for non-maintenance drugs. Appropriateness of the dosages and quantities of prescriptions were then compared for capitation and fee-for-service pharmacies for the study period, and no significant differences were found. Thus, it is concluded that although capitation was associated with increases in the average days' supply of ingredients dispensed for maintenance prescriptions, such changes did not adversely affect the quality of drug therapy as measured by two sets of criteria.

Capitation Fee↗