Life expectancy estimation with breast cancer: bias of the declining exponential function and an alternative to its use.

BACKGROUND: Life expectancy gain (LEG) is an outcome measure commonly estimated with a declining exponential function in a Markov model. The accuracy of such estimates has not been objectively evaluated. PURPOSE: To compare LEGs from declining exponential function estimates with those calculated from population data, using published screening mammography studies as examples. METHOD: SEER-based population data are used to compare LEG calculation with declining exponential function estimation and empiric population data in a new model, the "nested" Markov. RESULTS: Analyses of the LEG of mammographic screening based on the declining exponential function significantly overestimate LEGs for younger women and underestimate them for older women. Because of offsetting errors, all-age analyses paradoxically appear accurate. CONCLUSION: Declining exponential function estimates of LEGs for chronic diseases with low mortality rates and long time horizons are liable to significant bias, especially with limited age cohorts.

Screening for breast cancer: time, travel, and out-of-pocket expenses.

BACKGROUND: We estimated the personal costs to women found to have a breast problem (either breast cancer or benign breast disease) in terms of time spent, miles traveled, and cash payments made for detection, diagnosis, initial treatment, and follow-up. METHODS: We analyzed data from personal interviews with 465 women from four communities in Florida. These women were randomly selected from those with a recent breast biopsy (within 6-8 months) that indicated either breast cancer (208 women) or benign breast disease (257 women). One community was the site of a multifaceted intervention to promote breast screening, and the other three communities were comparison sites for evaluation of that intervention. All P values are two-sided. RESULTS: In comparison with time spent and travel distance for women with benign breast disease (13 hours away from home and 56 miles traveled), time spent and travel distance were statistically significantly higher (P<.001) for treatment and follow-up of women with breast cancer (89 hours and 369 miles). Personal financial costs for treatment of women with breast cancer were also statistically significantly higher (breast cancer = $604; benign breast disease = $76; P < .001) but were statistically significantly lower for detection and diagnosis (breast cancer = $170; benign breast disease = $310; P < .001). Among women with breast cancer, time spent for treatment was statistically significantly lower (P = .013) when their breast cancer was detected by screening (68.9 hours) than when it was detected because of symptoms (84.2 hours). Personal cash payments for detection, diagnosis, and treatment were statistically significantly lower among women whose breast problems were detected by screening than among women whose breast problems were detected because of symptoms (screening detected = $453; symptom detected = $749; P = .045). CONCLUSION: There are substantial personal costs for women who are found to have a breast problem, whether the costs are associated with problems identified through screening or because of symptoms.

Establishing a quality improvement process for identification of psychosocial problems in a primary care practice.

OBJECTIVES: A quality improvement process that will significantly increase the rate of identification of psychosocial problems through routine use of case-finding instruments can be established in a general medicine practice. DESIGN: Two groups of patient examination reports written by physicians were retrospectively compared with the patients' responses on the case-finding database instrument. The samples were obtained by sequential selection in four time periods. SETTING AND PATIENTS: The study occurred in a university general internal medicine practice that utilizes the problem-oriented record. The patients studied were seen for first-time comprehensive examinations designed to identify all important health problems, including psychosocial problems. INTERVENTION: The authors compared performances of the physicians in identification of psychosocial problems before and after the intervention, which consisted of a pilot study audit of psychosocial problem identification, establishment of standards for interpretation of the case-finding instrument, design of a flow sheet to make case-finding data clearly available to the physician at each comprehensive examination, and feedback of physician performance according to practice-adopted standards for identification of psychosocial problems. MEASUREMENT: The result of the intervention was an increase in psychosocial problem identification from 67% to 90% of problems present, p less than 0.05 by chi-square distribution; or a decrease from 33% to 10% in psychosocial problems missed by the physicians. CONCLUSION: The quality improvement process for identification of psychosocial problems described in this report significantly increased the rate of identification of psychosocial problems by general internists.

Ability of dipyridamole-thallium-201 imaging one to four days after acute myocardial infarction to predict in-hospital and late recurrent myocardial ischemic events.

The ability of dipyridamole-thallium-201 imaging to predict in-hospital and late cardiac events when performed very early (62 +/- 21 hours, range 23 to 102) after acute myocardial infarction (AMI) was tested in 50 patients. During hospitalization, 1 patient developed recurrent AMI and 8 patients developed recurrent angina after MI associated with ST-segment depression at 60 +/- 42 hours after the dipyridamole-thallium-201 imaging; of these, 6 required urgent coronary revascularization. No patient died in-hospital. There were no serious adverse effects during the dipyridamole protocol. Using stepwise multivariate logistic regression analysis, the best and only statistically significant predictor of in-hospital ischemic cardiac events was the presence of thallium-201 redistribution within the infarct zone (p = 0.0001). Of 20 patients with infarct zone thallium-201 redistribution, 9 (45%) developed in-hospital ischemic cardiac events compared to 0 of 30 patients without infarct zone thallium-201 redistribution (p less than 0.0001). During a follow-up 12 +/- 7 months after discharge, 3 additional patients with infarct zone thallium-201 redistribution developed recurrent AMI or unstable angina, whereas no patient without infarct zone thallium-201 redistribution developed ischemic cardiac events. These data suggest that dipyridamole-thallium-201 imaging performed very early after AMI may identify a subgroup of patients at high risk for in-hospital and late ischemic cardiac events. Such patients may benefit from early cardiac catheterization and revascularization. Patients without infarct zone thallium-201 redistribution appear to be at very low risk for in-hospital and late ischemic cardiac events and may be candidates for early discharge.

Screening for asymptomatic bacteriuria in pregnancy. A decision and cost analysis.

Screening women for asymptomatic bacteriuria on the first prenatal visit is a standard of obstetric care. Treating women with positive results decreases the risk of pyelonephritis and possible prematurity. This study uses decision and cost analysis to compare the utility of screening for asymptomatic bacteriuria with not screening. Data are based on published reports and average charges for services. Costs are based on 1988 charges, projected for the expected results of outpatient screening, possible suppressive therapy, and risks of pyelonephritis. Screening is based on the combined sensitivities and specificities of the MacConkey and CLED (cysteine-lactose-electrolyte-deficient agar) panels of the dip-slide culture. Under the baseline assumptions, the risk of pyelonephritis is estimated to be 2 cases per 100 screened women vs 3.5 cases per 100 unscreened women. The anticipated cost of screening 100 women is $9,939, compared with $12,824 for not screening 100 women. Screening is cost saving unless the cost of screening is above $26, the length of hospitalization for pyelonephritis is fewer than 2.2 days, the risk of asymptomatic bacteriuria falls below 2%, the risk of pyelonephritis with asymptomatic bacteriuria falls below 13%, or the efficacy of treatment in preventing pyelonephritis falls below 38%.

Decision analysis of treatment options in pyriform sinus carcinoma.

Decision analysis was used to evaluate the current treatment options for stage III squamous cell carcinoma of the pyriform sinus (surgery, radiation therapy, and combined surgery/radiation therapy). Using published data, a decision tree was constructed based on quality-adjusted weeks of survival. With this model the combination of surgery and postoperative radiation therapy is preferred over either primary surgery or the combination of preoperative irradiation and surgery; primary radiation therapy is least favored. The decision is quite sensitive to the augmentation in survival that postoperative radiation therapy seems to provide over primary surgery. The decision is somewhat sensitive to the operative mortality rate and to the probability of disease-free survival following surgery. Quality of life issues emerge as important variables which need to be considered when planning treatment for patients with stage III pyriform sinus carcinoma.

Clinical decision consultation service.

Since 1978, decision analysis consultations have been offered to help physicians manage particularly vexing clinical problems. Consultations were requested for decisions perceived as difficult because: the diagnosis was uncertain; the available therapy had uncertain efficacy or risks; the patient had a short life expectancy that limited the potential benefit of therapy; the risk of a given test or therapy was increased and the usual rules for applying the test or giving the treatment did not apply; the need for a therapeutic procedure was acknowledged, but competing risks created uncertainty about the optimal timing of the procedure; the optimal sequence of multiple necessary procedures could not be discerned readily; explicit patient input into decision-making was required; certain medical information could not be interpreted easily; and a rare, unique, or new problem was encountered. To carry out these consultations, standard techniques were used, including decision tree models, Bayes' theorem, Markov analysis, and utility assessment, but old approaches were modified to adapt decision analysis to individual patient problems. This experience demonstrates that decision analysis can be carried out effectively on a consultative basis for individual patients. A consultation service can also train analysts in decision-making and drive research in medical problem solving.

Clinical pitfalls in the non-invasive thrombolytic approach to presumed acute myocardial infarction.

A 32 year old patient who presented with a clinical and electrocardiographic picture consistent with an acute inferior myocardial infarction was treated with intravenous streptokinase without the aid of acute angiographic study. Subsequent evaluation revealed the initial diagnosis of acute infarction to be incorrect and the patient was found to have acute viral myopericarditis. No adverse sequelae resulted from the administration of the thrombolytic agent. The potential and reported adverse effects of a non-invasive thrombolytic approach to presumed acute infarction are reviewed and considerations related to clinical decision making in this setting are discussed.