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Biomedical subjects

E F Cook

Publications and source records attributed to E F Cook.

126 records · Page 7Linked to original sources
PubMed1982

A computer-derived protocol to aid in the diagnosis of emergency room patients with acute chest pain.

To determine whether data available to physicians in the emergency room can accurately identify which patients with acute chest pain are having myocardial infarctions, we analyzed 482 patients at one hospital. Using recursive partitioning analysis, we constructed a decision protocol in the format of a simple flow chart to identify infarction on the basis of nine clinical factors. In prospective testing on 468 other patients at a second hospital, the protocol performed as well as the physicians. Moreover, an integration of the protocol with the physicians' judgments resulted in a classification system that preserved sensitivity for detecting infarctions, significantly improved the specificity (from 67 per cent to 77 per cent, P less than 0.01) and positive predictive value (from 34 per cent to 42 per cent, P = 0.016) of admission to an intensive-care area. The protocol identified a subgroup of 107 patients among whom only 5 per cent had infarctions and for whom admission to non-intensive-care areas might be appropriate. This decision protocol warrants further wide-scale prospective testing but is not ready for routine clinical use.

Adult↗
PubMed1982

Evaluation and outcome of emergency room patients with transient loss of consciousness.

We identified 198 patients who presented to our emergency room with transient loss of consciousness. Seizures (29 percent of patients) and vasovagal/psychogenic episodes (40 percent of patients) were the most common presumptive causes of loss of consciousness, but the cause of loss of consciousness remained uncertain even at follow-up in 11 +/- 6 months in 13 percent of the patients. The history and physical examinations were sufficient for diagnosis in 85 percent of the patients in whom a diagnosis could be established. These data guided inpatient and outpatient with potentially dangerous causes of loss of consciousness except for one patient who had pulmonary embolism. In selected patient, diagnostic tests such as blood chemistries (three patients), electrocardiograms (four patients) electroencephalograms (three patients), and Holter monitoring (four patients) provided crucial information, and CT scans identified new brain tumors in four patients with focal neurologic presentations. At the time of follow-up, 7.5 percent of patients had suffered either major morbidity or death related to the cause of the index episode of loss of consciousness. Patients with cardiac causes represented a high risk (33 percent) group for such poor outcome, whereas patients who were under age 30, or who were under age 70 and had loss of consciousness on a vasovagal/psychogenic or unknown basis, constituted a low risk (1 percent) subgroup.

Adult↗
PubMed1982

Pitfalls in the serial assessment of cardiac functional status. How a reduction in "ordinary" activity may reduce the apparent degree of cardiac compromise and give a misleading impression of improvement.

Because the New York Heart Association (NYHA) classification system categorizes patients based on subjective impression of the degree of functional compromise, a reduction in exercise might make a patient seem improved because the new lower level of ordinary activity produced fewer symptoms. To test this hypothesis, we studied three different sets of patients and compared their NYHA classes to their functional classes as determined by a new Specific Activity Scale (SAS) that is based on the metabolic equivalents of oxygen consumption required for activities the patient actually performs. Among ambulatory patients referred for exercise tests, the NYHA class was higher (i.e. indicated the patient was more limited) in 28% of patients and the SAS class was higher in 14% (p less than 0.001). Among patients interviewed at or near the time of catheterization for chest pain, the NYHA was higher in 20% and the SAS class was higher in 20% (p = NS). In both medically and surgically treated patients interviewed 1--3 yr after cardiac catheterization, the NYHA class was higher in only 4%, whereas the SAS class was higher in 28% (p less than 0.001). The SAS class was significantly more likely to be higher in patients who were not working full time and in patients who described their present activity level as sedentary or light. When the NYHA and SAS systems disagreed as to whether a patient was improved, SAS was significantly more likely to correlate with the patient's self-assessment. These findings suggest that some patients restrict their activity as their cardiac disease progresses; the resultant change in the definition of ordinary activity may reduce the apparent degree of cardiac compromise and thus give a false impression of improvement by NYHA criteria.

Activities of Daily Living↗
PubMed1982

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↗
PubMed1982

A multivariate approach to the prediction of no-show behavior in a primary care center.

To predict no-show behavior in a primary care center, we analyzed a wide range of factors in 376 patients. Of 1,181 appointments that were scheduled during a six-month follow-up period and that were not cancelled in advance, 968 (82%) were kept and 213 (18%) were no-shows. By multivariate logistic regression analysis based on two thirds of the patient sample, no-show behavior was independently correlated with the following four factors: the patient's age and race, the presence of any physician-identified psychosocial problems, and the percent of noncancelled and appointments that were kept during the prior 12 months. Neither patient satisfaction nor patient-physician concordance in problem identification were independent correlates of appointment keeping. When our four-factor logistic regression equation was independently tested on the other one third of the patients, it accurately predicted no-show behavior. We suggest that our predicted probability of no-show behavior can be used to guide changes in scheduling patterns or to recognize patients appropriate for interventions to change behavior.

Adult↗
PubMed1981

Confounding: essence and detection.

Confounding is examined from first principles. In follow-up studies a confounder is a predictor of diagnosing the illness--by being either a risk indicator or a determinant of diagnostic errors; in addition, it shows different distributions between the exposed and nonexposed series. In case-referent studies confounding can arise in two ways. A priori confounders are correlates of exposure in the joint source population of cases and reference subjects; also, they are determinants of diagnosing the illness or have different selection implications between cases and referents. In addition, factors bearing on the accuracy of exposure information are confounders if distributed differently between cases and referents. Criteria based singularly on relationships in the data can be misleading. Similarly, a change in the estimate and even a change in the parameter as a result of control is not a criterion rooted in first principles of confounding and can lead to a false conclusion.

Biometry↗
PubMed1981

Comparative reproducibility and validity of systems for assessing cardiovascular functional class: advantages of a new specific activity scale.

Reproducibility and validity are prerequisites for a useful clinical scale. We therefore prospectively tested the reproducibility and validity of the New York Heart Association criteria and the Canadian Cardiovascular Society criteria for the assessment of cardiac functional class and compared these criteria with a new Specific Activity Scale based on the metabolic costs of specific activities. The New York Heart Association estimates made by two physicians had a reproducibility of only 56%, and only 51% of the estimates agreed with treadmill exercise performance. Functional estimates based on the Canadian Cardiovascular Society criteria were significantly more reproducible (73%), but not significantly more valid. The Specific Activity Scale was as reproducible as the Canadian Cardiovascular Society criteria, and its 68% validity was significantly higher than the validities of the other systems. The easily administered Specific Activity Scale was equally reproducible and valid when used by a nonphysician. It was especially better than the other systems for the evaluation of true class II patients and was significantly less likely to underestimate treadmill performance. Although no set of questions can perfectly predict exercise tolerance, the Specific Activity Scale deserves wider prospective testing.

Canada↗
PubMed1981

Impact of a cardiology data bank on physicians' prognostic estimates. Evidence that cardiology fellows change their estimates to become as accurate as the faculty.

To determine whether physicians would be influenced by the prognostic information in a large coronary artery disease data bank, cardiology faculty and fellows made initial estimates of the prognoses of their patients and then made revised final estimates after seeing the outcome of matched patients (OMP) from the data bank. The faculty cardiologists' original estimates proved to be as accurate as those of the data bank's OMP, and the faculty revised their estimates minimally in response to the data bank's OMP. Conversely, the cardiology fellows' original estimates were less accurate than the data bank's OMP, and under all observed circumstances the fellows responded more to the data bank's OMP than did the faculty. As a result, the accuracy of the fellows' final estimates was similar to the accuracies of both the faculty cardiologists and the data bank's OMP. Computerized data banks seem more likely to have impact when their information is provided to physicians who are relatively inexperienced with the disease in question.

Cardiology↗
PubMedDate not supplied

Long-term survival after transient loss of consciousness.

To determine the factors that influenced the long-term outcome of 198 patients who presented to the emergency ward with transient loss of consciousness, the authors followed them for a median of 83 months. Forty-one patients (21%) died, including nine patients who had out-of-hospital sudden cardiac arrest. Compared with age- and sex-adjusted mortality rates for the United States, long-term mortality was not increased among patients with benign causes of syncope. Multivariate analysis revealed that the long-term mortality rate was significantly increased in patients with a prior history of coronary or cerbrovascular disease (RR = 6.7), those who had cancer (RR = 7.3), and those who had drug or metabolic (RR = 5.9), central nervous system (RR = 5.7) or cardiac (RR = 9.2) causes of transient loss of consiousness. Among patients who experience transient losses of consciousness, the cause of the episode is significantly correlated with mortality for at least the next seven years.

Actuarial Analysis↗
PubMedDate not supplied

The characteristics and hospital course of patients admitted for presumed acute pyelonephritis.

To study the characteristics and hospital courses of patients hospitalized for presumed acute pyelonephritis, the authors analyzed 185 cases. Judged by explicit clinical and laboratory criteria, 54% of the patients definitely had pyelonephritis, 22% probably had pyelonephritis, 9% possibly had pyelonephritis, and 16% did not have pyelonephritis. In pretreatment urine cultures, 79% of patients had a single pathogen and 77% had colony counts of 100,000 or more organisms per ml. Non-Escherichia coli infections and positive blood cultures were the only two independent predictors of the concomitant renal stones or genitourinary tract abnormalities that were found in 29% of patients with pyelonephritis. About 15% of all patients continued to have temperatures greater than or equal to 101 degrees F 48 hours after the initiation of antibiotic therapy, but persistent fever did not correlate with a history of prior urinary tract infection, the presence of resistant pathogens, renal stones, or genitourinary tract abnormalities. The authors conclude that many of these patients did not have pyelonephritis, and that certain characteristics correlate with the presence of underlying anatomic abnormalities.

Acute Disease↗
PubMedDate not supplied

Impact of the availability of a prior electrocardiogram on the triage of the patient with acute chest pain.

STUDY OBJECTIVE: To determine whether information from a prior electrocardiogram (ECG) improves diagnostic accuracy in the emergency department (ED) evaluation of patients with acute chest pain. DESIGN: Analysis of prospectively collected data from a cohort study. SETTING: Emergency departments of four community and three university hospitals. PATIENTS: 5,673 patients aged greater than or equal to 30 years who presented to the EDs of participating hospitals for evaluation of acute chest pain, including 772 (14%) with acute myocardial infarction (AMI). MEASUREMENTS AND MAIN RESULTS: After adjusting for clinical characteristics, no significant difference was found in the sensitivities of admission to the hospital or to the coronary care unit (CCU) between AMI patients with and without prior ECGs available for review. However, non-AMI patients with prior ECGs available for review were more likely to avoid CCU admission than were non-AMI patients without prior ECGs. This improvement in specificity was most marked in the 2,024 patients whose current ED ECGs had changes consistent with ischemia or infarction: when a prior ECG was available, non-AMI patients were more than twice as likely to be discharged (26% vs. 12%) and about 1.5 times as likely to avoid CCU admission (39% vs. 27%) (both p less than 0.0001). Admission rates of AMI patients with and without prior ECGs were similar. CONCLUSION: When the current ECG is consistent with ischemia or infarction, the availability of a prior ECG for comparison to determine whether the ECG changes are old or new improves diagnostic accuracy and triage decisions by reducing the admission of patients without AMI or acute ischemic heart disease (increased specificity) without reducing the admission of patients with these diagnoses (unchanged sensitivity).

Aged↗
PubMedDate not supplied

The effect of gender on the probability of myocardial infarction among emergency department patients with acute chest pain: a report from the Multicenter Chest Pain Study Group.

OBJECTIVE: To identify differences in the incidences of myocardial infarction in women and men with chest pain. DESIGN: Prospective multicenter cohort study. SETTING: Emergency rooms of three university and four community hospitals. PATIENTS: 7,734 emergency room patients with acute chest pain. MEASUREMENTS AND MAIN RESULTS: Myocardial infarction was diagnosed in 10% of the 3,896 women, compared with 19% of the 3,838 men, yielding an age-adjusted relative risk of myocardial infarction for women of 0.54 (95% confidence interval 0.48, 0.60). Physicians were equally adept at admitting women and men with myocardial infarctions, but men without myocardial infarction or unstable angina were significantly more likely to be admitted than were women without these diagnoses. Most clinical and electrocardiographic features indicating a risk of myocardial infarction were present in both women and men, but several high-risk features were less commonly present in women. After adjusting for the other factors that correlate with each patient's probability of having acute myocardial infarction, the relative risk of myocardial infarction was the same in women as men when the emergency department electrocardiogram showed the classic changes associated with acute myocardial infarction, but the risk was 40% lower in women when such electrocardiographic changes were not present. CONCLUSIONS: Clinical features that predict myocardial infarction in men predict myocardial infarction in women to a similar extent. However, female gender is associated with about a 40% lower rate of myocardial infarction except when classic electrocardiographic evidence is present on the emergency department electrocardiogram.

Adult↗
PubMedDate not supplied

Blood pressure experience and risk of cardiovascular disease in the elderly.

For the 1254 persons in the Framingham Heart Study who survived to age 65 without prior cardiovascular disease or prior use of antihypertensive medications, significant univariate correlates of the development of cardiovascular disease after age 65 included (1) the systolic blood pressure at age 65, (2) the average systolic blood pressure before age 65, and (3) the slope of blood pressure change up to age 65. After controlling for the systolic blood pressure at age 65, average pre-age 65 blood pressure remained significant (p less than 0.05) and the slope of the pre-age 65 blood pressure was marginally significant (p = 0.06). Even after controlling for the mean of up to three blood pressure measurements at age 65, an average systolic blood pressure of 160 mm Hg or greater before age 65 was an independently significant predictor of the post-age 65 development of cardiovascular disease (rate ratio = 1.79; 95% confidence interval = 1.04, 3.07). These data suggest that even after performing multiple measurements at a single examination, knowledge of past systolic blood pressure history, especially if it averages 160 mm Hg or greater, adds a small but statistically significant increment in predicting future cardiovascular disease in the elderly.

Adult↗
PubMedDate not supplied

Prospective evaluation of a clinical and exercise-test model for the prediction of left main coronary artery disease.

In a multivariate logistic regression analysis of data from 508 patients, only two clinical factors, age and typicality of pain, were independently significant predictors of left main coronary artery disease. The resulting multivariate equation was prospectively applied to another 370 patients to derive pre-exercise-test (ETT) probabilities of left main coronary artery disease, and these pre-ETT probabilities were combined with literature-derived likelihood ratios for various ETT findings to derive post-ETT probabilities. This model, which can be displayed in simple graphic form, accurately predicted the probability of left main coronary artery disease when prospectively evaluated in this independent validation set of patients. The likelihood of left main coronary artery disease was 16% when the ETT increased the probability, and 4% when it decreased the probability (p less than 0.001). While 48% of patients had mid-range (5-15%) probabilities of left main coronary artery disease before the ETT, only 24% fell into this range of probabilities after the ETT (p less than 0.0001), as ETT results moved patients into higher and lower probability ranges. Thus, probability of left main coronary artery disease can be calculated from clinical and ETT data with this model. These estimated pre- and post-ETT probabilities of left main coronary artery disease may aid in the selection of patients for noninvasive testing or for cardiac catheterization.

Age Factors↗
PubMedDate not supplied

Is experience a good teacher? How interns and attending physicians understand patients' choices for end-of-life care. SUPPORT Investigators. Study to Understand Prognoses and Preferences for Outcomes and Risks of Treatments.

BACKGROUND: Recent studies have shown that physicians do not accurately assess patients' health status or treatment preferences. Little is known, however, about how physicians' levels of training or experience relate to their abilities to assess these preferences. To better understand this phenomenon, the authors compared the abilities of medical interns and attending physicians to predict the choices of their adult patients for end-of-life care. METHODS: 230 seriously-ill adult inpatients were surveyed about their desires for cardiopulmonary resuscitation, their current quality of life, and their attitudes toward six other common adverse outcomes. The medical intern and attending physician who cared for these patients were asked to estimate the patient's responses for all of the same items. Agreement was assessed using the kappa statistic. RESULTS: Compared with interns, attending physicians had known patients longer, had talked with patients more frequently about prognosis, and felt they knew more about their patients' preferences (all p < .0001). Despite this, the attending physicians were no more accurate than the interns in assessing patients' preferences. Both interns and attending physicians had only a fair understanding of patients' preferences for cardiopulmonary resuscitation or their quality of life (kappa statistics 0.32 to 0.47), and even less understanding of their willingness to tolerate adverse outcomes (kappa statistics -0.03 to 0.37). CONCLUSIONS: For this cohort of seriously ill patients, neither medical interns nor their attending physicians were consistently accurate in assessing patients' preferences, and attending physicians were not more accurate than medical interns. Attending physicians should not assume that they can infer patients' preferences any better than the interns caring for these hospitalized patients.

Adult↗
PubMedDate not supplied

The association of physician attitudes about uncertainty and risk taking with resource use in a Medicare HMO.

PURPOSE: To explore the association between the attitudes of primary care physicians toward uncertainty and risk taking, as measured by a validated survey, with resource use in a Medicare HMO. DESIGN: All primary-care internists (n=20) in a large, multi-specialty clinic were surveyed to measure their attitudes about uncertainty and risk taking using three previously developed scales. Results were linked with administrative data for 792 consecutive patients in a recently created Medicare HMO. The patients' index visits occurred between April 1, 1995, and November 30, 1995. ANALYSIS: Charges stemming from several claim types (primary care and subspecialty physician, laboratory, radiology, and ambulatory procedures) in the 30 days following the index visit were summed. The physician scales were dichotomized at the median to seek unadjusted associations with charges. Generalized estimation equations were used to account for the correlation of charges resulting from patients' being nested within physicians and adjusted for physician characteristics (age, sex, years in practice) and patient characteristics (age, sex, comorbidity). MAIN RESULTS: The physician response rate was 90%. Most physicians (90%) were male. The mean age of the patients was 74 years, and 69% were female. The mean cost (+/-SD) per patient was $621.61+/-1,737.31. From the unadjusted analysis, high "anxiety due to uncertainty" was associated with higher patient charges ($197.85 vs $158.21, p=0.01). From the multivariable analysis, each standard deviation increase in "anxiety due to uncertainty" (3.5 points) corresponded to a 17% increase in mean charges (p < 0.01) and each similar increase in "reluctance to disclose uncertainty to patients" (1.92 points) corresponded to a 12% increase (p=0.03). However, increasing "reluctance to disclose mistakes to physicians" and increasing physician risk-taking propensity were associated with decreased total charges [-10% per standard deviation (1.34 points), p=0.02, and -8% per standard deviation (3.26 points), p=0.02, respectively]. CONCLUSION: Physician attitudes toward uncertainty were significantly associated with patient charges. Further investigation may improve prediction of patient-care charges, offer insight into the medical decision-making process, and perhaps clarify the relationship between cost, uncertainty, and quality of care.

Aged↗
PubMedDate not supplied

Nosocomial sepsis in the neonatal intensive care unit.

OBJECTIVE: To evaluate the risk factors for nosocomial sepsis among infants hospitalized in 23 neonatal intensive care units. METHODS: Risk factors for nosocomial sepsis among 5760 admissions are analyzed by birth weight groups, <1 kg, 1 to 1.5 kg, and >1.5 kg. A Cox hazard regression model was used to evaluate further detail in the two lower weight groups. RESULTS: Use of corticosteroids had no effect on the incidence of nosocomial sepsis in the two lower weight categories although it was significant among the >1.5 kg infants. In a simple Cox model, significant risk factors included lowest birth weight category, ventilatory support, and presence of a central venous catheter. The complex Cox model revealed that an increase in total days of presence of central arterial catheter, use of antibiotics, and ventilatory support were significant but that total days of presence of a central venous catheter was not. A model for Candida sepsis revealed as a risk factor an increase in total days of use of antibiotics before infection. CONCLUSIONS: The risk for infection associated with presence of a central venous catheter is the same for each day of exposure (i.e., the same risk on day 5 of presence of the line as on day 30), but the risk associated with ventilatory support increases over time. Candida sepsis is associated with prolonged antibiotic use before the first episode of nosocomial sepsis and not with birth weight group.

Candidiasis↗