| 1. |
- Backlund, Lars G., et al.
(författare)
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Improving Fast and Frugal Modeling in Relation to Regression Analysis : Test of 3 Models for Medical Decision Making
- 2009
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Ingår i: Medical decision making. - : Sage Publications. - 0272-989X .- 1552-681X. ; 29:1, s. 140-148
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Tidskriftsartikel (refereegranskat)abstract
- Background. A matching heuristic (MH) model of decision makinghas been evaluated previously in a series of studies on medicaldecision making. The authors' purpose is to evaluate an extendedMH model that considers the prevalence of cue values. Methods.Data from 2 previous studies were reanalyzed, one on judgmentsregarding drug treatment of hyperlipidemia and the other ondiagnosing heart failure. The original MH model and the extendedMH model were compared with logistic regression (LR) in termsof fit to actual judgments, number of cues, and the extent towhich the cues were consistent with clinical guidelines. Results. There was a slightly better fit with LR compared with MH. Theextended MH model gave a significantly better fit than the originalMH model in the drug treatment task. In the diagnostic task,the number of cues was significantly lower in the MH modelscompared to LR, whereas in the therapeutic task, LR could beless or more frugal than the matching heuristic models dependingon the significance level chosen for inclusion of cues. Forthe original MH model, but not for the extended MH model orLR, the most important cues in the drug treatment task wereoften used in a direction contrary to treatment guidelines.Conclusions. The extended MH model represents an improvementin that prevalence of cue values is adequately taken into account,which in turn may result in better fit and in better agreementwith medical guidelines in the evaluation of cues.
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| 2. |
- Kerimi, Neda, 1980-, et al.
(författare)
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Do We Really Need Medical Experts when modelling in Judgment Analysis? : Lack of Difference Between Expert and Non-Expert models in Judgment Analysis
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Tidskriftsartikel (refereegranskat)abstract
- It is assumed that in judgment analysis, experts provide better models than non-experts. In this study we challenge this view by showing that data from non-experts might be equally suitable for building models. We show this by modeling the decisions of 21 medical students, 27 general practitioners, and 22 cardiologists on real patient vignettes regarding diagnosing heart failure. The models used were logistic regression and fast and frugal models. Results showed that there were no differences between any of the expertise groups in terms of fit, prediction, information searched, or percent of actual diagnosis in any of the models. Therefore, it seems, at least for the studied conditions, using models built on decision data from non-experts versus experts might be equally valid in judgment analysis.
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| 3. |
- Kerimi, Neda, 1980-, et al.
(författare)
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Judgment Analysis in the Medical Domain : Making a Fair Comparison Between Logistic Regression and Fast & Frugal Models
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Tidskriftsartikel (refereegranskat)abstract
- Using participant data from the medical domain, the robustness of logistic regression (LR) with different cue inclusion levels and two fast and frugal (F&F) models in terms of predictive accuracy and frugality were tested. Two data sets based on judgments of verbally described patients were used: Heart failure (66 analysts), and Hyperlipidemia (38 analysts). In both data sets, when the models were cross-validated, there was a significant decrease in predictive accuracy for all models, especially when all cues were used in LR. The other models had about equal predictive accuracy, also when comparisons were made with actual diagnoses, with a slight advantage for LR in the Heart failure study. LR using the 5% inclusion level was more frugal than F&F. These results emphasize the importance of using cross-validation and of choosing the proper significance levels for cue inclusion and when comparing different judgment models.
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| 4. |
- Skånér, Ylva
(författare)
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Diagnosing heart failure in primary health care
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Diagnosing chronic heart failure (CHF) is difficult. General practitioners (GPs) have an important role in the management of heart failure patients, and the purpose of the studies was to examine their judgements of patients with suspected CHF. Two methods from cognitive psychology were used, Clinical Judgement Analysis (CJA) in Studies I-IV, and think-aloud technique in Study V. Written case vignettes based on authentic patients were presented either in a paper format (Studies 1-111) or on a computer screen (Study V). In Study IV, theoretical and practical problems concerning how to construct suitable case vignettes for CJA studies were discussed, with reference to experiences from Studies I-II. In Study I, 27 GPs assessed the probability of CHF for 45 case vignettes, five of which were duplicates. Each GP's diagnostic strategy was defined as the set of statistical regression weights for the different variables (cues) describing the patient. Both judgements and strategies varied widely among the GPs, but according to analysis of the duplicate cases, the GPs were consistent in their judgements. The most important cues were pulmonary congestion and cardiac volume. In Study 11, 27 GPs, 22 cardiologists and 21 medical students assessed the probability of CHF for 40 case vignettes. Since the diagnoses were based on thorough investigations and cardiologists' judgements ("gold standard"), diagnostic accomplishment could be analysed. The variation was large regarding strategies and diagnostic accomplishment between individuals, but not between the groups. The most important cues were cardiac volume and pulmonary congestion. Using cluster analysis, three main strategies were identified. Cardiac volume dominated in the first, pulmonary congestion in the second, and in the third the weights were more evenly distributed. The first cluster, comprising a third of the participants, had the best diagnostic accomplishment. In Study III, the same data were analysed for characteristics of the case vignettes causing the most and the least diagnostic agreement among the participants. Increased cardiac volume and presence of atrial fibrillation contributed to the diagnostic agreement between the participants, as well as a larger number of cues indicative of CHF. The starting point for Study IV was the recommendation in the CJA literature to use representative case vignettes. The concept of representativity and its consequences for the construction of case vignettes were discussed. Two factors above all turned out to be problematic: the incomplete information in the patient records and the necessity of keeping the number of case vignettes low. These two factors necessitated compromises regarding, for example, the choice of cues and the number of cues. In Study V, 15 GPs judged six case vignettes, selected from Study 11, and the data were analysed regarding how different kinds of information were used in the diagnostic judgements. Although echocardiography (not included in the previous studies) was the most frequently used information, it was not used in a third of the judgement situations. Cardiac volume and pulmonary congestion were also important information. Information about other relevant diseases was frequently used in the diagnostic reasoning, but this is not reflected in the guidelines. Both of the two methodological approaches to diagnostic judgements and reasoning in this thesis are useful tools for studying clinical decision-making. One possible application area is the study of expert doctors and medical students, which can give insights useful for teaching. Other application areas involve the development and testing of different decision support systems integrated in electronic patient records, and the development of guidelines.
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| 5. |
- Skånér, Ylva, et al.
(författare)
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General practitioners’ reasoning when considering the diagnosis heart failure : A think-aloud study.
- 2005
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Ingår i: BMC Family Practice. - : Springer Science and Business Media LLC. - 1471-2296. ; 6:4
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Tidskriftsartikel (refereegranskat)abstract
- Diagnosing chronic heart failure is difficult, especially in mild cases or early in the course of the disease, and guidelines are not easily implemented in everyday practice. The aim of this study was to investigate general practitioners' diagnostic reasoning about patients with suspected chronic heart failure in comparison with recommendations in European guidelines. The think-aloud technique was used. Fifteen general practitioners reasoned about six case vignettes, representing authentic patients with suspected chronic heart failure. Information about each case was added successively in five steps. The general practitioners said their thoughts aloud while reasoning about the probability of the patient having chronic heart failure, and tried to decide about the diagnosis. Arguments for and against chronic heart failure were analysed and compared to recommendations in guidelines. Information about ejection fraction was the most frequent diagnostic argument, followed by information about cardiac enlargement or pulmonary congestion on chest X-ray. However, in a third of the judgement situations, no information about echocardiography was utilized in the general practitioners' diagnostic reasoning. Only three of the 15 doctors used information about a normal electrocardiography as an argument against chronic heart failure. Information about other cardio-vascular diseases was frequently used as a diagnostic argument. It was concluded that the clinical information was not utilized to the extent recommended in guidelines. Some implications of our study are that 1) general practitioners need more information about how to utilize echocardiography when diagnosing chronic heart failure, 2) guidelines ought to give more importance to information about other cardio-vascular diseases in the diagnostic reasoning, and 3) guidelines ought to treat the topic of diastolic heart failure in a clearer way.
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| 6. |
- Vancheri, Federico, et al.
(författare)
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Coronary risk estimates and decisions on lipid-lowering treatment in primary prevention : Comparison between general practitioners, internists, and cardiologists
- 2009
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Ingår i: European journal of internal medicine. - : Elsevier. - 0953-6205 .- 1879-0828. ; 20:6, s. 601-606
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Tidskriftsartikel (refereegranskat)abstract
- Background: Quantitative assessment of an individual's absolute cardiovascular risk is essential for primary prevention. Although risk-scoring tools have been developed for this task, risk estimates are usually made subjectively. We investigated whether general practitioners (GPs), internists and cardiologists differ in their quantitative estimates of cardiovascular risk and their recommendations about lipid-lowering treatment for the same set of patients. Methods: Mail survey. Nine written clinical vignettes, four rated high-risk and five rated low-risk according to the Framingham equation, were mailed to 90 randomly selected GPs and to the same number of internists and cardiologists in Sicily. The doctors were then asked to estimate the 10-year coronary risk in each case and to decide whether they would recommend a lipid-lowering treatment. Results: In the majority of the nine cases, the cardiologists' risk estimates were significantly lower than those of the other two groups. A higher proportion of internists (mean value 0.68) decided to start treatment than GPs (0.54) or cardiologists (0.57). In all three groups, the doctors' willingness to begin treatment was over 90% when their risk estimate was above 20%, and less than 50% when it fell below this level. Internists were more prone to treat than the other two groups even when their patients' estimated risk was below 20%. Conclusion: When presented with the same set of clinical cases, GPs, internists and cardiologists make different quantitative risk estimates and come to different conclusions about the need for lipid-lowering treatment. This may result in over- or under-prescription of lipid-lowering drugs and inconsistencies in the care provided by different categories of doctors.
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| 7. |
- Vancheri, Federico, et al.
(författare)
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General practitioners’ coronary risk assessments and lipid-lowering treatment decisions in primary prevention : Comparison between two European areas with different cardiovascular risk levels
- 2008
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Ingår i: Primary Health Care Research and Development. - : Cambridge University Press. - 1463-4236 .- 1477-1128. ; 9:4, s. 248-256
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Tidskriftsartikel (refereegranskat)abstract
- Aim: To investigate whether general practitioners (GPs) in countries with different levels of cardiovascular risk would make different risk estimates and choices about lipid-lowering treatment when assessing the same patients. Background: Primary prevention of coronary heart disease should be based on the quantitative assessment of an individual’s absolute risk. Risk-scoring charts have been developed, but in clinical practice risk estimates are often made on a subjective basis. Methods: Mail survey: Nine written case simulations of four cases rated by the Framingham equations as high risk, and five rated as low-risk were mailed to 90 randomly selected GPs in Stockholm, as a high-risk area, and 90 in Sicily as a low-risk area. GPs were asked to estimate the 10-year coronary risk and to decide whether to start a lipid-lowering drug treatment. Findings: Overall risk estimate was lower in Stockholm than in Sicily for both high-risk cases (median 20.8; interquartile range (IQR) 13.5–30.0 versus 29.1; IQR 21.8–30.6; P = 0.033) and low-risk cases (6.4; IQR 2.2–9.6 versus 8.5; IQR 6.0–14.5; P = 0.006). Swedish GPs were less likely than Sicilian GPs to choose to treat when their estimate of risk was above the recommended cut-off limit for treatment, both for the entire group (means of GPs’ decision proportions: 0.64 (0.45) and 0.92 (0.24), respectively, P = 0.001) and for high-risk cases (0.65 (0.45) and 0.93 (0.23), P = 0.001). Conclusions: The cardiovascular risk level in the general population influences GPs’ evaluations of risk and subsequent decisions to start treatment. GPs’ risk estimates seem to be inversely related to the general population risk level, and may lead to inappropriate over- or under-treatment of patients.
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