Thomas G. Tape

Clinical Prediction Rule for Pulmonary Infiltrates

OBJECTIVE To derive and validate a clinical rule for predicting pneumonic infiltrates in adult patients with acute respiratory illness. DESIGN Prevalence studies in three settings. SETTING Emergency departments of the University of Illinois Hospital at Chicago, the University of Nebraska Medical Center at Omaha, and the Medical College of Virginia at Richmond. PATIENTS Symptoms, signs, comorbidity data, and chest roentgenogram results were recorded for 1134 patients from Illinois (the derivation set), 150 patients from Nebraska, and 152 patients from Virginia (the validation sets). All patients presented to the emergency department and had a chest roentgenogram to evaluate fever or respiratory complaints. MEASUREMENTS AND MAIN RESULTS Within the training set, temperature greater than 37.8 degrees C, pulse greater than 100 beats/min, rales, decreased breath sounds, and the absence of asthma were identified as significant predictors of radiographically proved pneumonia in a stepwise logistic regression model (P = 0.001). The logistic rule discriminated patients with and without pneumonia in the training set with a receiver operating characteristic (ROC) area of 0.82. In the validation sets, the rule discriminated pneumonia and nonpneumonia with ROC areas of 0.82 and 0.76 after adjusting for differences in disease prevalence (P greater than 0.2 compared with the training set). The predicted probability of having pneumonia for patients with different clinical findings corresponded closely with the incidence of pneumonia among patients with such findings in the three settings. CONCLUSIONS Among adults presenting with acute respiratory illness, a prediction rule based on clinical findings accurately discriminated patients with and without radiographic pneumonia, and was used in two other samples of patients without significant decrement in discriminatory ability. This rule can be used by physicians to develop more effective strategies for detecting pneumonia and for helping to determine the need for radiologic study among patients with acute respiratory disease.

Computerized medical records and preventive health care: success depends on many factors.

OBJECTIVE To study the effect of a computerized medical record and other practice factors on the delivery of preventive health care. DESIGN Prospective, controlled trial. SETTING University general internal medicine teaching clinic. PARTICIPANTS Forty-five internal medicine residents and their 4 supervising attending physicians. INTERVENTION The study group used a computerized ambulatory medical record system that included health care maintenance reminders. The control group used a conventional paper record with a health care maintenance flow sheet. MEASUREMENTS AND MAIN RESULTS The computer reminders significantly increased health care maintenance recommendations made to patients for proctosigmoidoscopy, tetanus vaccination, influenza vaccination, and pneumococcal vaccination, but not for fecal occult blood testing, mammography, Pap smears, or serum thyroxine screening in the elderly. First-year residents were nearly twice as successful as third-year residents in overall health care maintenance. Success scores varied markedly depending on which attending physician was supervising the residents. We found a strong interaction among group assignment, supervising attending, and level of training such that the reminders doubled success scores among first-year residents supervised by two of the attending physicians but had little effect on other subgroups. The time of year and the format of the reminder also had important effects for some of the maneuvers. CONCLUSIONS Although computerized medical records markedly improved the performance of prevention maneuvers by committed physicians, many physicians using computer systems failed to make use of the resource. The reasons for this were complex. Future work in this area should carefully control for personal behaviors and focus upon administrative changes that more effectively implement these potentially powerful tools.

Quantitative culture of bronchoalveolar lavage fluid for the diagnosis of bacterial pneumonia.

PURPOSE A prospective study to determine the usefulness of quantitative bacterial cultures of fluid obtained via fiberoptic bronchoscopy and bronchoalveolar lavage as an aid in the diagnosis of bacterial pneumonia. PATIENTS AND METHODS All patients undergoing fiberoptic bronchoscopy with bronchoalveolar lavage during a 6 1/2-month period. Presence of pneumonia was determined using clinical, radiographic, laboratory, and histologic data. Quantitative bacterial cultures of bronchoalveolar lavage fluid were determined using a 1-microL culture loop. RESULTS Quantitative bacterial cultures of bronchoalveolar lavage (BAL) fluid were sensitive and specific predictors of bacterial pneumonia. Using 10(3) colony-forming units (cfu)/mL as the threshold value for a positive culture, we determined the sensitivity and specificity to be 90% and 97%, respectively. The data were also analyzed for the subgroups of patients who were intubated or were receiving antibiotics. The sensitivity and specificity were 78% and 96% for the group of patients receiving antibiotics and 100% and 82% for the group of patients intubated for more than 24 hours at the time of BAL. Values for the area under the receiver operating characteristic curve for the 3 groups were 0.94, 0.88, and 0.96, respectively. CONCLUSIONS Quantitative bacterial cultures of BAL fluid are sensitive and specific in the diagnosis of bacterial pneumonia. The use of antibiotics at the time of BAL reduces the sensitivity of the test, and prolonged intubation reduces the specificity of the test.

Variation by specialty in the treatment of urinary tract infection in women

To determine practicing physicians’ strategies for diagnosing and managing uncomplicated urinary tract infection, we surveyed physicians in general internal medicine, family practice, obstetrics and gynecology, and emergency medicine in four states, Responses differed significantly by respondents’ specialty. For example, nitrofurantoin was the antibiotic of first choice for 46% of obstetricians, while over 80% in the other specialties chose trimethoprim-sulfamethoxazole. Most surveyed said they do not usually order urine culture, but the percentage who do varied by specialty. Most use a colony count of 105 colony-forming units or more for diagnosis although evidence favors a lower threshold, and 70% continue antibiotic therapy even if the culture result is negative. This survey found considerable variation by specialty and also among individual physicians regarding diagnosis and treatment of urinary tract infection and also suggests that some of the new information from the literature has not been translated to clinical practice.

How useful are routine chest x-rays of preoperative patients at risk for postoperative chest disease?

The authors studied the value of routine chest x-rays in the management of patients admitted for vascular surgery, a population likely to have comorbid chest disease. Patient records from 341 admissions were reviewed to determine the relationship between chest x-ray results and postoperative chest complications. Patients who had major abnormalities had a 40% postoperative complication rate, compared with 9% for those with normal x-rays; but only 13% of the complications occurred in patients with major abnormalities. Nine patients had x-ray findings that led to clinical action: three with potentially beneficial management changes (congestive heart failure in 2, fibrosis in 1) and six with potentially detrimental clinical action (false diagnosis of tuberculosis in 2, false diagnosis of nodules in 2, falsely normal chest x-ray in 2). None of 50 surgical cancellations occurred as a result of an abnormal x-ray. All the beneficial effects attributable to preoperative chest x-rays accrued to patients who had clinical evidence of chest disease. The authors conclude that routine chest x-rays were not helpful in improving patient outcomes. They recommend ordering preoperative chest x-rays based on clinical indications so that the likelihood of false positives and false negatives and their associated detrimental effects can be minimized.

Cardiac screening with electrocardiography, stress echocardiography, or myocardial perfusion imaging: advice for high-value care from the American College of Physicians.

BACKGROUND Cardiac screening in adults with resting or stress electrocardiography, stress echocardiography, or myocardial perfusion imaging can reveal findings associated with increased risk for coronary heart disease events, but inappropriate cardiac testing of low-risk adults has been identified as an important area of overuse by several professional societies. METHODS Narrative review based on published systematic reviews; guidelines; and articles on the yield, benefits, and harms of cardiac screening in low-risk adults. RESULTS Cardiac screening has not been shown to improve patient outcomes. It is also associated with potential harms due to false-positive results because they can lead to subsequent, potentially unnecessary tests and procedures. Cardiac screening is likely to be particularly inefficient in adults at low risk for coronary heart disease given the low prevalence and predictive values of testing in this population and the low likelihood that positive findings will affect treatment decisions. In this patient population, clinicians should focus on strategies for mitigating cardiovascular risk by treating modifiable risk factors (such as smoking, diabetes, hypertension, hyperlipidemia, and overweight) and encouraging healthy levels of exercise. HIGH-VALUE CARE ADVICE Clinicians should not screen for cardiac disease in asymptomatic, low-risk adults with resting or stress electrocardiography, stress echocardiography, or stress myocardial perfusion imaging.

Echocardiography, Endocarditis, and Clinical Information Bias

Although clinical information provided to the interpreter of imaging tests may improve disease detection, it may also bias the interpreter towards certain diagnoses, increasing the chance of false positives. To determine the possibility of this bias, the authors studied patients who were referred for echocardiography with a clinical suspicion of endocarditis. Hospital charts from a two-year period were reviewed to determine clinical data available to the echocardiographer, echocardiogram results, and the final diagnosis. Four clinical features, when present at the time of echocardiography, were associated with increased numbers of false-positive results. Test specificity was 97% (34/35) for patients without any of these features, but dropped to 80% (16/20) when two or more features were present. The authors conclude that clinical information may bias echocardiogram interpretations such that both test specificity and the posttest probability of disease may be overestimated when tests are used in clinical practice.

The effects of proficiency and bias on residents' interpretation of the microscopic urinalysis

Objective . This study aims to determine whether residents are influenced by clinical information when interpreting microscopic urinalysis (UA) and estimating the probability of a urinary tract infection (UTI), and to determine the accuracy and reliability of UA readings. Design . Residents estimated the UA white blood cell count and the probability of a UTI in vignettes using a fractional factorial design, varying symptoms, gender, and the white blood cell count on preprepared urine slides. Results . Individual-level results indicated a clinical information bias and poor accuracy. Seventeen of 38 residents increased the white blood cell count in response to female gender; 14 increased the white blood cell count in response to UTI symptoms. Forty-nine percent of the readings were inaccurate; agreement ranged from 50% to 67% for white and red blood cells and bacteria. Conclusion . Many residents gave inaccurate UA readings, and many readings varied with clinical information. A significant portion of residents needs assistance in objectively and accurately interpreting the UA.

Thyroid disease awareness is associated with high rates of identifying subjects with previously undiagnosed thyroid dysfunction

BackgroundConventional screening for hypothyroidism is controversial. Although hypothyroidism is underdiagnosed, many organizations do not recommend screening, citing low disease prevalence in unselected populations. We studied attendees at a thyroid health fair, hypothesizing that certain patient characteristics would enhance the yield of testing.MethodsWe carried out an observational study of participants at a Michigan health fair that focused on thyroid disease. We collected patient-reported symptoms and demographics by questionnaire, and correlated these with the TSH values obtained through the health fair.Results794 of 858 health fair attendees participated. Most were women, and over 40% reported a family history of thyroid disease. We identified 97 (12.2%) participants with previously unknown thyroid dysfunction. No symptom or combination of symptoms discriminated between hypothyroid and euthyroid individuals. Hypothyroid and euthyroid participants in the health fair reported each symptom with a similar prevalence (p > 0.01), a prevalence which was very high. In fact, when compared with a previously published case-control study that reported symptoms, the euthyroid health fair participants reported a higher symptom prevalence (range 3.9% to 66.3%, mean 31.5%), than the euthyroid individuals from the case-control study (range 2% to 54%, mean 17.4%).ConclusionsA high proportion of previously undiagnosed thyroid disease was identified at this health fair. We initially hypothesized symptoms would distinguish between thyroid function states. However, this was not the case in this health fair screening population. The prevalence of reported symptoms was similar and high in both euthyroid and hypothyroid participants. Because attendees were self-selected, it is possible that this health fair that focused on thyroid disease attracted participants specifically concerned about thyroid health. Despite the lack of symptom discrimination, the much higher prevalence of hypothyroidism in this study (12%) compared with the general population (<2%) suggests that screening may be appropriate and effective in certain circumstances such as thyroid health fairs.

The relationship between treatment objectives and practice patterns in the management of urinary tract infections

Objective. To describe physicians’ goals when treating uncomplicated urinary tract infections (UTIs) and the relationship between goals and practice patterns. Study design. Analysis of survey results. Population. Primary care physicians. Outcomes measured. Self-reported treatment objectives and practice patterns. Results. Most physicians reported their UTI management was convenient for the patient (81.3%). Fewer stated they minimized patients’ costs (53.4%), made an accurate diagnosis (56.7%), or avoided unnecessary antibiotics (40.9%). Physicians who stressed convenience or minimizing patient expenses were less likely to use many resources (urine culture, microscopic urinalysis, followup visits and tests, and prolonged antibiotic treatment) and more likely to use telephone treatment. Physicians who stressed accurate diagnoses or avoiding unnecessary antibiotics were more likely to use the same resources and less likely to use telephone treatment. Conclusion. UTI management goals vary across physicians and are associated with different clinical approaches. Differences in treatment objectives may help explain variations in practice patterns.