Using the free-to-total prostate-specific antigen ratio to detect prostate cancer in men with nonspecific elevations of prostate-specific antigen levels.

BACKGROUND: Prostate-specific antigen (PSA) levels between 4.0 to 10.0 ng/ml have poor specificity in prostate cancer screening, leading to unnecessary biopsies. OBJECTIVE: To determine whether the free-to-total PSA ratio (F/T PSA) improved the diagnostic accuracy of these nonspecific PSA levels. MEASUREMENTS AND MAIN RESULTS: MEDLINE searchedwas from 1986 to 1997. Additional studies were identified from article bibliographies and by searching urology journals. Two investigators independently identified English-language studies providing F/T PSA ratio test-operating characteristics data on > or = 10 cancer patients with PSA values between 2.0 and 10.0 ng/ml. Twenty-one of 90 retrieved studies met selection criteria. Two investigators independently extracted data on methodology and diagnostic performance. Investigator-selected cut points for the optimal F/T PSA ratio had a median likelihood ratio of 1.76 (interquartile range, 1.40 to 2.11) for a positive test and 0.27 (0.20 to 0.40) for a negative test. Assuming a 25% pretest probability of cancer, the posttest probabilities were 37% following a positive test and 8% following a negative test. The summary receiver operating characteristic curve showed that maintaining test sensitivity above 90% was associated with false positive rates of 60% to 90%. Methodologic problems limited the validity and generalizability of the literature. CONCLUSIONS: A negative test reduced the posttest probability of cancer to approximately 10%. However, patients may find that this probability is not low enough to avoid undergoing prostate biopsy. The optimal F/T PSA ratio cut point and precise estimates for test specificity still need to be determined.

The paradox of physicians and administrators in health care organizations.

Rapidly changing times in health care challenge both physicians and health care administrators to manage the paradox of providing orderly, high quality, and efficient care while bringing forth innovations to address present unmet problems and surprises that emerge. Health care has grown throughout the past several centuries through differentiation and integration, becoming a highly complex biological system with the hospital as the central attractive force--or "strange attractor"--during this century. The theoretical model of complex adaptive systems promises more effective strategic direction in addressing these chaotic times where the new strange attractor moves beyond the hospital.

A computer alert system to prevent injury from adverse drug events: development and evaluation in a community teaching hospital.

CONTEXT: Adverse drug events (ADEs) are the most common type of iatrogenic injury occurring in hospitalized patients. Errors leading to ADEs are often due to restricted availability of information at the time of physician order writing. OBJECTIVES: To develop, implement, and evaluate a computer alert system designed to correct errors that might lead to ADEs and to detect ADEs before maximum injury occurs. DESIGN: Prospective case series. SETTING: A 650-bed community teaching hospital in Phoenix, Ariz. PATIENTS: Consecutive sample of 9306 nonobstetrical adult patients admitted during the last 6 months of 1997. INTERVENTIONS: Thirty-seven drug-specific ADEs were targeted. Our hospital information system was programmed to generate alerts in clinical situations with increased risk for ADE-related injury. A clinical system was developed to ensure physician notification of alerts. MAIN OUTCOME MEASURES: A true-positive alert was defined as one in which the physician wrote orders consistent with the alert recommendation after alert notification. RESULTS: During the 6-month study period, the alert system fired 1116 times and 596 were true-positive alerts (positive predictive value of 53%). The alerts identified opportunities to prevent patient injury secondary to ADEs at a rate of 64 per 1000 admissions. A total of 265 (44%) of the 596 true-positive alerts were unrecognized by the physician prior to alert notification. CONCLUSIONS: Clinicians can use hospital information systems to detect opportunities to prevent patient injury secondary to a broad range of ADEs.

The effectiveness of implementing the weight-based heparin nomogram as a practice guideline.

OBJECTIVE: To determine the effectiveness of the nomogram in a community hospital that implemented it as a practice guideline. DESIGN: A nonexperimental, retrospective time series. SETTING: A 600-bed community teaching hospital and regional referral center in Phoenix, Ariz. PATIENTS: The study population included 591 consecutive patients with venous thromboembolism, treated over a 5-year study period. METHODS: During this period, the weight-based heparin nomogram was adapted into a preprinted order sheet and distributed to the hospital wards. The main outcome variables were the time to achieve a therapeutic activated partial thromboplastin time and the rate of bleeding complications. RESULTS: Voluntary implementation of the nomogram steadily increased, reaching 94%. Comparison of the periods before and after 50% implementation demonstrated an increase in initial heparin dose (1185 vs 1420 U/h, P < .001), a decrease in time to achieve therapeutic activated partial thromboplastin time (19.6 vs 11.8 hours), a decrease in the variance of this parameter (25 vs 4 hours, P < .001), and no change in bleeding rates. The proportion of patients achieving a therapeutic activated partial thromboplastin time within 24 hours decreased from 97% to 86% when the results from our previous randomized controlled trial (efficacy) are compared with the present results (effectiveness). CONCLUSIONS: The weight-based heparin nomogram was well accepted by clinicians at our institution and led to more aggressive heparin dosing and improvements in intermediate outcomes, without increasing bleeding. Mitigation of benefit is likely to occur when practice guidelines are moved from the realm of efficacy research into clinical practice. Therefore, the effectiveness of such measures requires monitoring.

Integrating stratum-specific likelihood ratios with the analysis of ROC curves.

Data used to construct receiver operating characteristic (ROC) curves and to calculate the area under the curve (ROC AUC) can be used to derive stratum-specific likelihood ratios (SSLRs) with their 95% confidence intervals (95% CIs). The purpose of this study was to determine whether useful information can be obtained by adding SSLRs to the analysis of ROC curves. The authors analyzed four previously reported sets of data: 1) serum creatine kinase (SCK) for diagnosing acute myocardial infarction (AMI) in the coronary care unit (CCU); 2) SCK in the evaluation of chest pain in the emergency center (EC); 3) four predictor variables in the diagnosis of strep throat; and 4) the ordinal assessment of computed tomographic (CT) images. Use of SCK in the CCU produced four strata that had posttest probabilities that were highly discriminating, whereas SCK in the EC resulted in only two strata with limited discriminating ability. In either study the cutpoint at which the SSLR changed from less than to greater than 1.0 was higher than the reported upper normal for the test, thereby quantitating spectrum bias. The maximum number of strata of predictor signs and symptoms for strep throat was three rather than the five used in previous studies. With a larger sample size or pooling, four strata could probably be developed. With CT images, "definitely normal," "probably normal," and "questionable" were collapsed to one negative stratum. "Probably abnormal" became the true "questionable" stratum and "definitely abnormal" was the only positive stratum. The authors conclude that additional useful information is obtained by deriving stratum-specific likelihood ratios as part of the analysis of an ROC curve.

Fine-needle aspiration biopsy of abdominal lesions: diagnostic yield for different needle tip configurations.

Four fine-needle aspiration biopsy needles with different tip configurations were used in 133 patients with abdominal lesions. The 20-gauge needles were used in random sequence by several physicians. The specimen from each of the 522 needle passes was evaluated by two cytopathologists for adequacy to render a diagnosis and for the presence of cell block material. The Franseen needle produced a 16% and 9% better yield for diagnostic material than did the cut biopsy and spinal needles (P less than .05), respectively. The Westcott needle was better than the cut biopsy needle by 13%, and the spinal needle produced an 11% better yield than did the cut biopsy needle. Differences did not exist in liver biopsies but were present in pancreatic biopsies. The spinal needle was the least successful in yielding cell block material. Use of the cut biopsy needle resulted in the largest proportion of inadequate specimens, except its yield in cell blocks in the liver was 25% higher than that of the Westcott needle. The authors conclude that not all unusual designs for 20-gauge needle tips render results superior to those of the simple spinal needle.

1989 ARRS President's Award. The validity and utility of sonography in the diagnosis of appendicitis in the community setting.

Two hundred six patients with suspected appendicitis were examined with sonography over a 6-month period in three community teaching hospitals. Of 41 patients in whom the surgeons judged the clinical findings severe enough to warrant immediate surgery (group A), 34 (83%) had appendicitis, and sonography had a sensitivity of 0.76, a specificity of 0.71, and an accuracy of 0.76. Of 165 patients in whom the surgeons judged the clinical findings severe enough to warrant hospitalization for observation but not immediate surgery (group B), 51 (31%) had appendicitis at subsequent surgery. Sonography had a sensitivity of 0.96, a specificity of 0.94, and an accuracy of 0.95. Of 49 surgeons surveyed, the mean testing threshold (i.e., the probability of appendicitis below which they would send the patient home without further tests or observation) was 0.11, and the mean treatment threshold (i.e., the probability of appendicitis above which they would operate immediately) was 0.82. The posttest probability of appendicitis with findings indicating appendicitis present on sonography was 0.93 in group A and 0.88 in group B, and with findings absent on sonography it was 0.62 in group A and 0.02 in group B. We conclude that in group A patients, the use of sonography remains controversial in the diagnosis of appendicitis, but in group B patients it is both valid and useful.

Barriers to the dissemination of research findings of decision modeling in the management of cardiovascular disease.

The discussion and general conclusions of a working group convened during the Regenstrief Conference are presented. The group was formed to consider issues involved in the dissemination of research findings relative to decision modeling in the management of cardiovascular disease.

Apparently changing patterns of inheritance in Alport's hereditary nephritis: genetic heterogeneity versus altered diagnostic criteria.

With the use of more stringent diagnostic criteria, it has recently been shown that some large pedigrees of Alport's and non-Alport's hereditary nephritis fit sex-linked dominant inheritance (O'Neill et al. 1978). We have used similar diagnostic criteria and have studied a number of Michigan pedigrees in order to see if this hypothesis would be confirmed. We found one small pedigree which definitely shows male-to-male transmission, while one large pedigree is tentatively compatible with sex-linked dominant inheritance. Many of the other pedigrees suggested male-to-male transmission. This Michigan experience is compared to other published reports and found to be consistent, although a trend of fewer reports of male-to-male transmission is seen. We conclude that genetic heterogeneity of Alport's hereditary nephritis is likely.