On wisdom after the event.
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Adrenergic beta-Antagonists↗
Biomedical subjects
F Harrell
Publications and source records attributed to F Harrell.
Prognoses of seriously ill hospitalized patients on the days before death: implications for patient care and public policy.
Troubling aspects of the experiences of patients at the ends of their lives have fueled interest in special benefits or privileges for this group. There is a presumption that being "at the end of life" is discernible. This study examines this presumption using data from two previously collected databases: the Study to Understand Prognoses and Preferences for Outcomes and Risks of Treatments (SUPPORT) and the Acute Physiology and Chronic Health Evaluation III (APACHE III). Both studies generated multivariable estimates of survival prognosis for hospitalized patients. SUPPORT included 9,105 patients with one of nine serious illnesses in five hospitals over 4 yrs, of whom 2,360 died in the hospital and 4,537 died within 180 days of entry into the study. The APACHE III database describes 2,750 deaths in 16,622 ICU patients in 40 hospitals. The relationship of median estimates with time to death were examined for each source of data, for different diseases, and for ICU settings of care. In SUPPORT, the median predicted chance of survival for 2 months on the day before actual death was .17 (interquartile range, .02-.40) and was .51 (.31-.66) 1 wk before death. Median prognoses varied substantially among diseases: the median for congestive heart failure patients was a .62 chance of living 2 months on the day before death, while lung cancer had only a .17 chance and coma patients only an .11 chance. Median prognostication estimates were not much different when given by physicians and were only a little more pessimistic in APACHE (median estimate for hospital survival on the day before death was .14 and 7 days before was .45). To make plans about care and to optimally support most dying persons and families, conversations must occur while the patient still has a considerable chance of surviving the current episode of illness. Using statistical estimates of prognosis to designate a category of "terminally ill" patients for public policy purposes is unavoidably arbitrary, will often be contested, and will have differential effects upon those dying with differing diseases.
APACHE↗
Regression coefficients and scoring rules.
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Odds Ratio↗
Characterization of Listeria monocytogenes isolates by Southern blot hybridization.
A synthetic deoxyribonucleotide probe for virulent Listeria monocytogenes, designated ADO7, was evaluated for its ability to identify restriction fragments of L. monocytogenes with nucleic acid sequences homologous with the beta-hemolysin gene by Southern blot hybridization of clinical and food isolates. The synthetic probe hybridized with three restriction fragments (approximately 1.1, 0.86, and 0.76 kb) of the serotype 1/2A isolates. Southern blot hybridization of the serogroup 4B isolates indicated that the nucleic acid sequences homologous with the beta-hemolysin gene probe were limited to a single restriction fragment of approximately 1 kb.
Animals↗
Incremental value of the exercise test for diagnosing the presence or absence of coronary artery disease.
To determine the incremental value of the exercise test (ETT) for diagnosing coronary artery disease (CAD), we derived a multivariate logistic regression model for the pre-ETT prediction of CAD using data from 3840 patients at Duke University. We then applied the model to 324 patients at the Brigham and Women's Hospital. Using seven clinical factors, the multivariate model had an 84% overall predictive accuracy on both the training (Duke) and the validation (Brigham) sets of patients. Three ETT factors (ST-segment change in patients not taking digitalis, absence of ST-segment change in patients taking digitalis, ETT stopped because of ECG or blood pressure changes) had incremental, significant predictive power, but overall predictive accuracy based on both clinical and ETT factors improved only to 87%. When the ETT result was important enough to move the probability of CAD across a potential therapeutic threshold, the direction of the change in probability was correct only two-thirds of the time. Thus, the ETT was of limited value in predicting the presence or absence of CAD after other easily obtainable clinical data were taken into account.
Adult↗
Predicting the outcomes of electrophysiologic studies of patients with unexplained syncope: preliminary validation of a derived model.
PURPOSE: To develop and validate a predictive model that would allow clinicians to determine whether an electrophysiologic (EP) study is likely to result in useful diagnostic information for a patient who has unexplained syncope. PATIENTS: One hundred seventy-nine consecutive patients with unexplained syncope who underwent EP studies at two university medical centers comprised the training sample. A test sample to validate the model was made up of 138 patients from the clinical literature who had undergone EP studies for syncope. DESIGN: Retrospective analysis of patients undergoing EP studies for syncope. The data collector was blinded to the study hypothesis; the electrophysiologist assessing outcomes was blinded to clinical and historical data. Clinical predictor variables available from the history, the physical examination, electrocardiography (ECG), and Holter monitoring were analyzed via two multivariable predictive modeling strategies (ordinal logistic regression and recursive partitioning) for their abilities to predict the results of EP studies, namely tachyarrhythmic and bradyarrhythmic outcomes. These categories were further divided into full arrhythmia and borderline arrhythmia groups. RESULTS: Important outcomes were 1) sustained monomorphic ventricular tachycardia (VT) and 2) bradyarrhythmias, including sinus node and atrioventricular (AV) conducting disease. The results of the logistic regression (in this study, the superior strategy) showed that the presence of organic heart disease [odds ratio (OR) = 3.0, p less than 0.001] and frequent premature ventricular contractions on ECG (OR = 6.7, p less than 0.004) were associated with VT, while the following abnormal ECG findings were associated with bradyarrhythmias: first-degree heart block (OR = 7.9, p less than 0.001), bundle-branch block (OR = 3.0, p less than 0.02), and sinus bradycardia (OR = 3.5, p less than 0.03). Eighty-seven percent of the 31 patients with important outcomes at EP study had at least one of these clinical risk factors, while 95% of the patients with none of these risk factors had normal or nondiagnostic EP studies. In the validation sample, the presence of one or more risk factors would have correctly identified 88% of the test VT patients and 65% of the test bradyarrhythmia patients as needing EP study. CONCLUSION: These five identified predictive factors, available from the history, the physical examination, and the initial ECG, could be useful to clinicians in selecting those patients with unexplained syncope who will have a serious arrhythmia identified by EP studies.
Arrhythmias, Cardiac↗