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D A Redelmeier

Publications and source records attributed to D A Redelmeier.

At least 73 records · Page 4Linked to original sources
PubMed1995

A clinician's guide to utility measurement.

The approach described in this article is designed for clinicians who are striving to read utility analyses and understand patients' quality of life. We have introduced six questions to illuminate the complex issues underlying utility measurement and acknowledge the challenges encountered in conducting such research. Although not strict guidelines, the six questions provide a structured approach for recognizing high-quality articles and a swift method for discarding low-quality articles. We recognize that many studies seem poor when judged by these criteria, including some of our own. Yet we encourage clinicians, who are otherwise busy, to be selective in identifying utility analysis that merit attention. Without a structured approach, the temptation is to dismiss all articles as worthless and read nothing. The listed criteria, we hope, will help readers appreciate the merits of utility analyses and the role of patients' quality of life in decision analysis.

Attitude to Health↗
PubMed1994

No place to unload: a preliminary analysis of the prevalence, risk factors, and consequences of ambulance diversion.

STUDY OBJECTIVE: To study the prevalence, risk factors, and consequences of ambulance diversion. DESIGN: Observational cohort analysis from January 1, 1986, to December 31, 1989. SETTING: Population-based study of a large urban region located in Northern California. PATIENTS: Individuals transported by ambulance to any of 13 hospitals in the region (n = 153,167). MEASUREMENTS: Diversion defined as the patient not being transported to their initially intended hospital because the hospital was unable to accept patients because of temporary emergency department closure. Ambulance run time recorded by radio contact was documented in ambulance registry. "Transport-associated deaths" were measured as any deaths occurring in the field, while en route, or soon after arriving at the ED. RESULTS: During the four-year interval, total diversions increased by 453% (n = 718 in 1986 versus 3,973 in 1989; P < .005), thereby affecting one in nine transports during the last quarter of 1989. Diversion was more common in elderly patients (odds ratio, 1.17; 95% confidence interval, 1.11, 1.23), during the winter (odds ratio, 1.36; 95% confidence interval, 1.31, 1.44), and at night (odds ratio, 1.30; 95% confidence interval, 12.4, 1.37). Compared with their nondiverted counterparts, diverted transports had longer times at the scene (13.5 versus 12.4 minutes; P < .005) and greater transport times (13.3 versus 11.6 minutes; P < .005). We did not find a significant increase in the rate of transport-associated deaths (0.460 deaths per 1,000 population in 1986 versus 0.464 deaths per 1,000 population in 1989; P = NS). CONCLUSION: Ambulance diversion is a common and increasing event that delays emergency medical care.

Adult↗
PubMed1994

Acromegaly. Clinical and biochemical features in 500 patients.

This prospective study defines the clinical and biochemical features of acromegaly in a large cohort of patients. There was no difference in sex distribution, and for men and women the mean ages at diagnosis (40 +/- 12 and 40 +/- 14 yr, respectively) were similar. Nearly three-quarters of patients were overweight and some 12% severely overweight; the frequency and severity of obesity also was not different between the sexes. Half of patients were hypertensive or were taking anti-hypertensive drugs. Neither GH nor insulin levels were significantly different between normotensive and hypertensive patients. Acral growth and facial coarsening, soft tissue swelling, and excessive perspiration were present in the majority (98%) of patients. Mean serum GH, Sm-C, and PRL levels did not differ between the sexes. Sm-C levels correlated with mean GH concentration (r = 0.31, p < 0.001), both variables inversely related to age. With each decade of life, mean GH and Sm-C levels declined by 7.6 +/- 0.2 ng/mL and 0.5 +/- 0.2 U/mL, respectively. Impaired glucose tolerance was diagnosed in 36% and frank diabetes mellitus in 30% of patients. Hyperprolactinemia was noted in 18% of patients. Galactorrhea was noted in 43 (9%) patients, most of whom were female; the mean GH levels of patients with galactorrhea (60.1 +/- 13 ng/mL) were higher than those of patients without (35.4 +/- 2.6 ng/mL, p = 0.02). Acromegaly appears to afflict men and women equally with a preponderance of presentation in the fourth decade of life.(ABSTRACT TRUNCATED AT 250 WORDS)

Acromegaly↗
PubMed1993

Understanding patients' decisions. Cognitive and emotional perspectives.

OBJECTIVE: To describe ways in which intuitive thought processes and feelings may lead patients to make suboptimal medical decisions. DESIGN: Review of past studies from the psychology literature. RESULTS: Intuitive decision making is often appropriate and results in reasonable choices; in some situations, however, intuitions lead patients to make choices that are not in their best interests. People sometimes treat safety and danger categorically, undervalue the importance of a partial risk reduction, are influenced by the way in which a problem is framed, and inappropriately evaluate an action by its subsequent outcome. These strategies help explain examples where risk perceptions conflict with standard scientific analyses. In the domain of emotions, people tend to consider losses as more significant than the corresponding gains, are imperfect at predicting future preferences, distort their memories of past personal experiences, have difficulty resolving inconsistencies between emotions and rationality, and worry with an intensity disproportionate to the actual danger. In general, such intangible aspects of clinical care have received little attention in the medical literature. CONCLUSION: We suggest that an awareness of how people reason is an important clinical skill that can be promoted by knowledge of selected past studies in psychology.

Comprehension↗
PubMed1993

Assessing the clinical importance of symptomatic improvements. An illustration in rheumatology.

OBJECTIVE: To estimate when a difference in disability symptoms is sufficiently large to be important to individual patients. DESIGN: Cross-sectional analysis of two groups: derivation set (n = 46) and validation set (n = 57). SETTING: The Arthritis Foundation, Northern California Chapters. PARTICIPANTS: Volunteer sample of patients with arthritis who live in the community. MAIN OUTCOME MEASURES: We applied the Stanford Health Assessment Questionnaire to assess the functional status of individuals. Participants then conducted one-on-one conversations with each other and rated whether their disability was "much better" "somewhat better," "about the same," "somewhat worse," or "much worse" relative to each person they met. For every conversation we calculated the difference between the two participants' health assessment questionnaire scores and linked the difference to the subjective comparison ratings of each individual in the pair. RESULTS: Health assessment questionnaire score differences were significantly correlated with subjective comparison ratings (correlation coefficient, .41; 95% confidence interval, 0.31 to 0.50). We estimated that health assessment questionnaire scores needed to differ by about 0.19 units for average respondents to stop rating themselves as "about the same" and start rating themselves as "somewhat better" (95% confidence interval, 0.10 to 0.28). Analysis of a second group of patients revealed a similar threshold (mean, 0.23 units; 95% confidence interval, 0.13 to 0.23). In both groups, health assessment questionnaire score differences were imperfect predictors of individual ratings and the threshold for less disabled participants tended to be lower than the threshold for more disabled participants. CONCLUSIONS: Some statistically significant differences in functional status scores may be so small that they represent trivial degrees of symptom relief. An awareness of the smallest difference in symptom scores that is important to patients can provide a rough guide to help clinicians interpret the medical literature.

Activities of Daily Living↗
PubMed1993

Hospital expenditures in the United States and Canada.

BACKGROUND: Expenditures per capita for hospitals are higher in the United States than in Canada. If the United States had the same spending pattern as Canada, the annual savings in 1985 would have exceeded $30 billion. METHODS: We used data from published sources, computer files, and institutional reports to compare 1987 costs for acute care hospitals on three levels: national (the United States vs. Canada), regional (California vs. Ontario), and institutional (two California hospitals vs. two Ontario hospitals). Expenditures per admission were adjusted for the case mix of patients, prices of labor and other resources, and outpatients visits. RESULTS: The United States had proportionately fewer hospital beds than Canada (3.9 vs. 5.4 per 1000 population), fewer admissions (129 vs. 142 per 1000 population), and shorter mean stays (7.2 vs. 11.2 days). Higher costs per admission in the United States were explained in part by a case mix that was more complex by 14 percent and by prices for labor, supplies, and other hospital resources that were higher by 4 percent. Hospitals in the United States provided relatively less outpatient care, particularly in emergency departments (320 vs. 677 visits per 1000 population). After all adjustments, the estimate of resources used for inpatient care per admission was 24 percent higher in the United States than in Canada and 46 percent higher in California than in Ontario. The estimated differences between the two pairs of California and Ontario hospitals were 20 and 15 percent. CONCLUSIONS: Canadian acute care hospitals have more admissions, more outpatient visits, and more inpatient days per capita than hospitals in the United States, but they spend appreciably less. The reasons include higher administrative costs in the United States and more use of centralized equipment and personnel in Canada.

California↗
PubMed1993

Survivors of motor vehicle trauma: an analysis of seat belt use and health care utilization.

OBJECTIVE: To determine whether the protective effects of seat belt use on acute injury are followed by corresponding reductions in outpatient health care utilization. DESIGN: Retrospective cohort analysis. SETTING: Northern California Region Kaiser Health Plan hospitals and medical offices. PATIENTS: All Kaiser Foundation Health Plan members injured in motor vehicle crashes in Santa Clara County during one year (total number of patients = 246). MEASUREMENTS AND MAIN RESULTS: 54% of the study participants had been wearing seat belts at the time of injury, and 46% had not been. The belted patients had fewer head injuries (30% vs 50%, p < 0.05), better mean Injury Severity Scale scores (4.3 vs 7.4, p < 0.05), and smaller mean hospital charges ($8,580 vs $16,209, p < 0.05). However, the effects of injury did not end upon discharge from the trauma center; the patients averaged about eight outpatient visits during the subsequent year, a rate almost double their prior use. In contrast to inpatient measures of utilization, the patients who had been wearing seat belts at the time of injury had more outpatient visits during the year after injury than had their unbelted counterparts (9.0 vs 7.1, p < 0.05). This discrepancy was not explained by differences in amounts of utilization during the year before injury, which were similar in the two groups (4.4 vs 4.8, p = NS). Overall, general internists provided the most follow-up care and accounted for the largest discrepancy in utilization between the belted and unbelted patients. CONCLUSIONS: Seat belt use does not result in lower utilization of follow-up outpatient services in the year following injury. However, the beneficial effects on acute care utilization more than offset the marginal effects on subsequent medical services utilization.

Accidents, Traffic↗
PubMed1993

How reliable is peer review of scientific abstracts? Looking back at the 1991 Annual Meeting of the Society of General Internal Medicine.

OBJECTIVE: To evaluate the interrater reproducibility of scientific abstract review. DESIGN: Retrospective analysis. SETTING: Review for the 1991 Society of General Internal Medicine (SGIM) annual meeting. SUBJECTS: 426 abstracts in seven topic categories evaluated by 55 reviewers. MEASUREMENTS: Reviewers rated abstracts from 1 (poor) to 5 (excellent), globally and on three specific dimensions: interest to the SGIM audience, quality of methods, and quality of presentation. Each abstract was reviewed by five to seven reviewers. Each reviewer's ratings of the three dimensions were added to compute that reviewer's summary score for a given abstract. The mean of all reviewers' summary scores for an abstract, the final score, was used by SGIM to select abstracts for the meeting. RESULTS: Final scores ranged from 4.6 to 13.6 (mean = 9.9). Although 222 abstracts (52%) were accepted for publication, the 95% confidence interval around the final score of 300 (70.4%) of the 426 abstracts overlapped with the threshold for acceptance of an abstract. Thus, these abstracts were potentially misclassified. Only 36% of the variance in summary scores was associated with an abstract's identity, 12% with the reviewer's identity, and the remainder with idiosyncratic reviews of abstracts. Global ratings were more reproducible than summary scores. CONCLUSION: Reviewers disagreed substantially when evaluating the same abstracts. Future meeting organizers may wish to rank abstracts using global ratings, and to experiment with structured review criteria and other ways to improve raters' agreement.

Abstracting and Indexing↗
PubMed1993

Minimum important difference between patients with rheumatoid arthritis: the patient's perspective.

OBJECTIVE: To determine the point at which differences in clinical assessment scores on physical ability, pain and overall condition are sufficiently large to correspond to a subjective perception of a meaningful difference from the perspective of the patient. METHODS: Forty patients with a diagnosis of rheumatoid arthritis participated in an evening of clinical assessment and one-on-one conversations with each other regarding their arthritic condition. The assessments included tender and swollen joint counts, clinician and patient global assessments, participant assessment of pain and the Health Assessment Questionnaire (HAQ) on physical ability. After each conversation, participants rated themselves relative to their conversational partner on physical ability, pain and overall condition. These subjective comparative ratings were compared to the differences of the individual clinical assessments. RESULTS: In total there were 120 conversations. Generally participants judged themselves as less disabled than others. They rated themselves as "somewhat better" than their conversation partner when they had a (mean) 7% better score on the HAQ, 6% less pain, and 9% better global assessment. In contrast, they rated themselves as "somewhat worse" when they had a (mean) 16% worse score on the HAQ, 16% more pain, and 29% worse global assessment. CONCLUSIONS: Patients view clinically important differences in an asymmetric manner. These results can provide guidance in interpreting results and planning clinical trials.

Aged↗
PubMed1992

Variability among methods to assess patients' well-being and consequent effect on a cost-effectiveness analysis.

Cost-effectiveness analysis is emerging as an approach for determining the relative value of health care programs, technologic innovations, and clinical decisions. Increasingly, patients' stated values for quality of life are applied as adjustment in these analyses; the results may vary depending on how individuals assess their well-being. We interviewed 58 patients with chronic renal failure to determine the level of agreement among six methods for assessing well-being, and to determine the effects of variation in assessed well-being on the results of a cost-effectiveness analysis of in-center hemodialysis. Patients reported well-being using the Sickness Impact Profile, Campbell Index of Well-being, Kaplan-Bush Index of Well-being, categorical scaling, standard gamble, and time trade-off. We found that patient well-being was substantially higher as evaluated by the Sickness Impact Profile compared to the other five methods. The Sickness Impact Profile and the Kaplan-Bush Index of Well-being provided much narrower distributions of assessed values relative to other measures. Correlations among assessment methods were poor (Spearman rank-correlation coefficients range: 0.094-0.519). Discrepancies among indices were particularly vivid when we evaluated data at the individual level; many patients reported a high level of well-being according to one index and a low level of well-being according to a different index. The cost effectiveness of in-center hemodialysis varied from $34,893 to $45,254 per quality-adjusted life-year saved according to the Sickness Impact Profile and standard-gamble technique respectively. The substantial variability in patients' stated quality of life may preclude the use of a single method to analyze the cost effectiveness of a health program.

Cost-Benefit Analysis↗
PubMed1991

Assessing predictive accuracy: how to compare Brier scores.

Several investigators have used the Brier index to measure the predictive accuracy of a set of medical judgments; the Brier scores of different raters who have evaluated the same patients provides a measure of relative accuracy. However, such comparisons may be difficult to interpret because of the lack of a statistical test for differentiating between two Brier scores. To demonstrate a method for addressing this issue we analyzed the judgments of five medical students, each of whom independently evaluated the same 25 patients with recurrent chest pain. Using the method we determined that two of the students gave judgments that were incompatible with the actual observed outcomes (p less than 0.05); of the three remaining students we detected a significant difference between two (p less than 0.05). These results differed from receiver operating characteristic curve area analysis, another technique used to evaluate predictive accuracy. We suggest that the proposed method can provide a useful tool for investigators using the Brier index to compare how well clinicians express uncertainty using probability judgments.

Chest Pain↗
PubMed1990

The role of skin testing for penicillin allergy.

Skin testing for penicillin allergy is an imperfect predictor of severe allergic reactions. We used decision analysis to identify the types of allergy history for which skin testing should alter management. The treatment threshold, the probability of a serious allergic reaction at which point one should switch from penicillin to another antibiotic, depends on the quality of life associated with the clinical outcomes. We measured 12 physicians' attitudes toward the outcomes of treatment with penicillin or vancomycin for Streptococcus viridans endocarditis in patients with a history of penicillin allergy. The clinicians' threshold probabilities ranged from .00010 to .00210 (median, .00013). Given the sensitivity (89% to 96%) and specificity (89% to 96%) of skin testing and our clinicians' median threshold, test results could alter the choice of antibiotic when the probability of a severe allergic reaction is between .00001 and .001. This range corresponds to a weak history of penicillin allergy. Although the decision should be individualized, our study suggests that skin testing is unnecessary when the patient has a convincing history of a severe allergic reaction to penicillin.

Decision Support Techniques↗
PubMedDate not supplied

Longevity of screenwriters who win an academy award: longitudinal study.

OBJECTIVE: To determine whether the link between high success and longevity extends to academy award winning screenwriters. DESIGN: Retrospective cohort analysis. PARTICIPANTS: All screenwriters ever nominated for an academy award. MAIN OUTCOME MEASURES: Life expectancy and all cause mortality. RESULTS: A total of 850 writers were nominated; the median duration of follow up from birth was 68 years; and 428 writers died. On average, winners were more successful than nominees, as indicated by a 14% longer career (27.7 v 24.2, P=0.004), 34% more total films (23.2 v 17.3, P<0.001), 58% more four star films (4.8 v 3.1, P<0.001), and 62% more nominations (2.1 v 1.3, P<0.001). However, life expectancy was 3.6 years shorter for winners than for nominees (74.1 v 77.7 years, P=0.004), equivalent to a 37% relative increase in death rates (95% confidence interval 10 to 70). After adjustment for year of birth, sex, and other factors, a 35% relative increase in death rates was found (7% to 70%). Additional wins were associated with a 22% relative increase in death rates (3% to 44%). Additional nominations and additional other films in a career otherwise caused no significant increase in death rates. CONCLUSION: The link between occupational achievement and longevity is reversed in screenwriters who win academy awards. Doubt is cast on simple biological theories for the survival gradients found for other members of society.

Achievement↗
PubMedDate not supplied

Decision analysis with cumulative prospect theory.

BACKGROUND: Individuals sometimes express preferences that do not follow expected utility theory. Cumulative prospect theory adjusts for some phenomena by using decision weights rather than probabilities when analyzing a decision tree. METHODS: The authors examined how probability transformations from cumulative prospect theory might alter a decision analysis of a prophylactic therapy in AIDS, eliciting utilities from patients with HIV infection (n = 75) and calculating expected outcomes using an established Markov model. They next focused on transformations of three sets of probabilities: 1) the probabilities used in calculating standard-gamble utility scores; 2) the probabilities of being in discrete Markov states; 3) the probabilities of transitioning between Markov states. RESULTS: The same prophylaxis strategy yielded the highest quality-adjusted survival under all transformations. For the average patient, prophylaxis appeared relatively less advantageous when standard-gamble utilities were transformed. Prophylaxis appeared relatively more advantageous when state probabilities were transformed and relatively less advantageous when transition probabilities were transformed. Transforming standard-gamble and transition probabilities simultaneously decreased the gain from prophylaxis by almost half. Sensitivity analysis indicated that even near-linear probability weighting transformations could substantially alter quality-adjusted survival estimates. CONCLUSION: The magnitude of benefit estimated in a decision-analytic model can change significantly after using cumulative prospect theory. Incorporating cumulative prospect theory into decision analysis can provide a form of sensitivity analysis and may help describe when people deviate from expected utility theory.

AIDS-Related Opportunistic Infections↗