Gestational weight gain in twin gestations and pregnancy outcomes: a systematic review and meta-analysis.

BACKGROUND: Data on the association of inappropriate gestational weight gain (GWG) and adverse outcomes in twin pregnancies are limited and inconsistent. OBJECTIVES: To perform a systematic review and meta-analysis on the association between GWG and adverse outcomes in twin pregnancies. SEARCH STRATEGY: Ovid, Medline, EMBASE and Cochrane Central databases from 1 January 1990 until 23 September 2020. SELECTION CRITERIA: Interventional and observational studies evaluating the association between GWG and adverse outcomes in twin pregnancies. DATA COLLECTION AND ANALYSIS: Data were extracted by two independent reviewers. Summary odds ratios (OR) were calculated using a random-effects model in a subset of studies that analysed GWG as a categorical variable in relation to the Institute of Medicine (IOM) recommendations. The primary outcome was preterm birth. MAIN RESULTS: From 277 citations, 19 studies involving 36 023 women with twin pregnancies were included in the qualitative analysis, of which 14 were included in the meta-analysis. Overall, 56.8% of women experienced inappropriate GWG: 35.4% (95% CI 30.0-41.0%) gained weight below and 21.4% (95% CI 14.2-29.5%) gained weight above IOM recommendations. Compared with GWG within IOM guidelines, GWG below IOM guidelines was associated with preterm birth before 32 weeks of gestation (OR 3.38; 95% CI 2.05-5.58), and a reduction in the risk of pre-eclampsia (OR 0.68; 95% CI 0.48-0.97). GWG above IOM guidelines was associated with an increased risk of pre-eclampsia that was consistent across all body mass index categories. CONCLUSIONS: Inappropriate GWG affects over half of twin pregnancies, so is a common and potentially modifiable risk factor for preterm birth and pre-eclampsia.

The role of skin testing for penicillin allergy.

Skin testing for penicillin allergy is an imperfect predictor of severe allergic reactions. We used decision analysis to identify the types of allergy history for which skin testing should alter management. The treatment threshold, the probability of a serious allergic reaction at which point one should switch from penicillin to another antibiotic, depends on the quality of life associated with the clinical outcomes. We measured 12 physicians' attitudes toward the outcomes of treatment with penicillin or vancomycin for Streptococcus viridans endocarditis in patients with a history of penicillin allergy. The clinicians' threshold probabilities ranged from .00010 to .00210 (median, .00013). Given the sensitivity (89% to 96%) and specificity (89% to 96%) of skin testing and our clinicians' median threshold, test results could alter the choice of antibiotic when the probability of a severe allergic reaction is between .00001 and .001. This range corresponds to a weak history of penicillin allergy. Although the decision should be individualized, our study suggests that skin testing is unnecessary when the patient has a convincing history of a severe allergic reaction to penicillin.

Assessing the clinical importance of symptomatic improvements. An illustration in rheumatology.

OBJECTIVE: To estimate when a difference in disability symptoms is sufficiently large to be important to individual patients. DESIGN: Cross-sectional analysis of two groups: derivation set (n = 46) and validation set (n = 57). SETTING: The Arthritis Foundation, Northern California Chapters. PARTICIPANTS: Volunteer sample of patients with arthritis who live in the community. MAIN OUTCOME MEASURES: We applied the Stanford Health Assessment Questionnaire to assess the functional status of individuals. Participants then conducted one-on-one conversations with each other and rated whether their disability was "much better" "somewhat better," "about the same," "somewhat worse," or "much worse" relative to each person they met. For every conversation we calculated the difference between the two participants' health assessment questionnaire scores and linked the difference to the subjective comparison ratings of each individual in the pair. RESULTS: Health assessment questionnaire score differences were significantly correlated with subjective comparison ratings (correlation coefficient, .41; 95% confidence interval, 0.31 to 0.50). We estimated that health assessment questionnaire scores needed to differ by about 0.19 units for average respondents to stop rating themselves as "about the same" and start rating themselves as "somewhat better" (95% confidence interval, 0.10 to 0.28). Analysis of a second group of patients revealed a similar threshold (mean, 0.23 units; 95% confidence interval, 0.13 to 0.23). In both groups, health assessment questionnaire score differences were imperfect predictors of individual ratings and the threshold for less disabled participants tended to be lower than the threshold for more disabled participants. CONCLUSIONS: Some statistically significant differences in functional status scores may be so small that they represent trivial degrees of symptom relief. An awareness of the smallest difference in symptom scores that is important to patients can provide a rough guide to help clinicians interpret the medical literature.

Charges for medical care at different hospitals.

BACKGROUND: The United States has a high proportion of people without health insurance (15%) and a low proportion of people without employment (5%), resulting in millions who lack insurance but have some ability to pay. We tested whether hospitals charge similar prices for well-specified elective services to individuals paying out-of-pocket for medical care. METHODS: We surveyed the 2 largest general hospitals from every large city (population >500 000) in the United States and Canada. At each hospital we evaluated 5 diagnostic, 7 therapeutic, and 3 nonclinical services to determine the total charge to patients who pay directly. RESULTS: Overall, 66 hospitals were included (average, 758 beds; not-for-profit, 97% [n = 64]; teaching, 80% [n = 53]). The range in charges was substantial; for example, a screening mammogram was $40 at one hospital in Los Angeles, Calif, and $346 at one hospital in Quebec City. Charges for a screening mammogram were relatively stable between 1996 and 1997 (r=0.79; 95% confidence interval, 0.68-0.87) and unrelated to the hospital's location or charges for other services. The relative amount of variation in charges was similar for high-priced and low-priced services, similar for diagnostic and therapeutic services, and similar for the United States and Canada. CONCLUSIONS: Charges for the same hospital service vary substantially. Greater visibility might reduce some variation by bringing outliers into closer scrutiny. Patients seeking care and paying out-of-pocket could save financially by comparison shopping.

Preventing Mycobacterium avium complex in patients who are using protease inhibitors: a cost-effectiveness analysis.

BACKGROUND: Practice guidelines recommending Mycobacterium avium complex (MAC) prophylaxis for patients with HIV disease were based on clinical trials in which individuals did not receive protease inhibitors. OBJECTIVE: To estimate the cost-effectiveness of strategies for MAC prophylaxis in patients whose treatment regimen includes protease inhibitors. DESIGN: Decision analysis with Markov modelling of the natural history of advanced HIV disease. Five strategies were evaluated: no prophylaxis, azithromycin, rifabutin, clarithromycin and a combination of azithromycin plus rifabutin. MAIN OUTCOME MEASURES: Survival, quality of life, quality-adjusted survival, health care costs and marginal cost-effectiveness ratios. RESULTS: Compared with no prophylaxis, rifabutin increased life expectancy from 78 to 80 months, increased quality-adjusted life expectancy from 50 to 52 quality-adjusted months and increased health care costs from $233000 to $239800. Ignoring time discounting and quality of life, the cost-effectiveness of rifabutin relative to no prophylaxis was $44300 per life year. Adjusting for time discounting and quality of life, the cost-effectiveness of rifabutin relative to no prophylaxis was $41500 per quality-adjusted life year (QALY). In comparison with rifabutin, azithromycin was associated with increased survival, increased costs and an incremental cost-effectiveness ratio of $54300 per QALY. In sensitivity analyses, prophylaxis remained economically attractive unless the lifetime chance of being diagnosed with MAC was less than 20%, the rate of CD4 count decline was less than 10 x 10(6) cells/l per year, or the CD4 count was greater than 50 x 10(6) cells/l. CONCLUSION: MAC prophylaxis increases quality-adjusted survival at a reasonable cost, even in patients using protease inhibitors. When not contraindicated, starting azithromycin or rifabutin when the patient's CD4 count is between 50 and 75 x 10(6) cells/l is the most cost-effective strategy. The main determinants of cost-effectiveness are CD4 count, viral load, place of residence and patient preference.

Improved diagnostic accuracy of inferior petrosal sinus sampling over imaging for localizing pituitary pathology in patients with Cushing's disease.

The majority of patients with Cushing's disease can be cured by transsphenoidal microsurgery; however, precise localization of the pituitary source of ACTH is not always possible by standard imaging techniques. Bilateral venous sampling from the inferior petrosal sinuses (IPSS) is also useful for diagnosing Cushing's disease, but the interpretation of discordant findings between IPSS and imaging remains problematic. We tested the ability of imaging and IPSS to localize an ACTH-secreting pituitary lesion in comparison to definitive histopathological examination of the pituitary in patients with Cushing's disease (n = 37). Bilateral IPS catheterization was technically feasible in 32 patients and provided evidence of lateralization in 31 patients. Histological examination confirmed a corticotropic adenoma in 28 patients and corticotropic hyperplasia in 2 patients; Crooke's hyaline change was found in 7 patients, among whom 1 subsequently was found to have an ectopic sphenoid corticotropic adenoma, and the remainder had suspected microadenomas that were not identified microscopically. Accurate localization of the pituitary lesion was more frequent when based on IPSS results than on imaging studies (70% vs. 49%, P < 0.06). The 2 tests provided directly discrepant results for 8 patients; among these, IPSS was more likely than imaging to agree with final pathology (63% vs. 13%, P < 0.10). Imaging was entirely normal for another 9 patients, in whom IPSS accurately localized the lesion for the majority (89%; 95% confidence interval: 50-99%). We suggest that IPSS is an effective tool for localizing pituitary pathology and planning surgery for patients with Cushing's disease.

Acromegaly. Clinical and biochemical features in 500 patients.

This prospective study defines the clinical and biochemical features of acromegaly in a large cohort of patients. There was no difference in sex distribution, and for men and women the mean ages at diagnosis (40 +/- 12 and 40 +/- 14 yr, respectively) were similar. Nearly three-quarters of patients were overweight and some 12% severely overweight; the frequency and severity of obesity also was not different between the sexes. Half of patients were hypertensive or were taking anti-hypertensive drugs. Neither GH nor insulin levels were significantly different between normotensive and hypertensive patients. Acral growth and facial coarsening, soft tissue swelling, and excessive perspiration were present in the majority (98%) of patients. Mean serum GH, Sm-C, and PRL levels did not differ between the sexes. Sm-C levels correlated with mean GH concentration (r = 0.31, p < 0.001), both variables inversely related to age. With each decade of life, mean GH and Sm-C levels declined by 7.6 +/- 0.2 ng/mL and 0.5 +/- 0.2 U/mL, respectively. Impaired glucose tolerance was diagnosed in 36% and frank diabetes mellitus in 30% of patients. Hyperprolactinemia was noted in 18% of patients. Galactorrhea was noted in 43 (9%) patients, most of whom were female; the mean GH levels of patients with galactorrhea (60.1 +/- 13 ng/mL) were higher than those of patients without (35.4 +/- 2.6 ng/mL, p = 0.02). Acromegaly appears to afflict men and women equally with a preponderance of presentation in the fourth decade of life.(ABSTRACT TRUNCATED AT 250 WORDS)

Quality of life and utility in irradiated laryngeal cancer patients.

PURPOSE: To determine quality of life (QOL) and health utility in irradiated laryngeal cancer survivors. MATERIALS AND METHODS: Over 6 months, consecutive follow-up patients at a comprehensive cancer centre completed the QOL questionnaire FACT-H&N and the time trade-off (TTO) utility instrument. RESULTS: Inclusion criteria were met by 339 patients, of whom 269 were eligible, 245 were approached, and 120 agreed to participate. Most participants were men (83%) who had received radiotherapy (97%) for Stage I disease (53%) of the glottis (75%); 7% had undergone total laryngectomy. Participants differed from nonparticipants only in being younger (mean age, 65 vs. 68 years, p = 0.0049) and having higher performance status (Karnofsky 88 vs. 84, p = 0.0012). The average scores for FACT-H&N and the TTO were 124/144 (SD, 14) and 0.90/1.0 (SD, 0.16) respectively. FACT-H&N score was more highly correlated with Karnofsky score (r = 0.43, p = 0.001) than with the TTO (r = 0.29, p = 0.002). Gender predicted QOL (means: M = 125, F = 118), while natural speech, no relapses, and more time since initial treatment predicted higher utility. CONCLUSION: The QOL of irradiated laryngeal cancer survivors was reasonably high and independent of initial disease variables. The QOL questionnaire correlated more strongly with performance status than with utility, suggesting that QOL and utility measures may be perceived differently by patients.

In vivo responsiveness of morphological variants of growth hormone-producing pituitary adenomas to octreotide.

The somatostatin analog, octreotide, is an inhibitor of growth hormone (GH) secretion that has been used to treat patients with GH-producing pituitary tumors. In this study we investigated the in vivo responsiveness to treatment with this analog in patients harboring different morphological types of GH-producing pituitary adenomas. Both GH and insulin-like growth factor I (IGF-I) plasma levels in 30 patients treated with octreotide (300 micrograms/day) for 4 months preoperatively were compared with those from 30 patients who did not receive treatment preoperatively. Tissue samples were studied using ultrastructural and immunohistochemical techniques. Amongst patients harboring densely granulated (DG) adenomas, mean GH levels were reduced to 32 +/- 9% by octreotide, to 30 +/- 7% by surgery and to 26 +/- 9% of baseline by both interventions. Surgery was equally as effective in lowering GH levels in patients with sparsely granulated (SG) adenomas as it was in those with DG adenomas; in patients with SG adenomas, GH levels were reduced by surgery alone to 37 +/- 16% and to 24 +/- 15% when performed following octreotide pretreatment. In contrast, treatment with octreotide alone in patients harbouring SG adenomas reduced GH levels to only 70 +/- 13% of baseline (p < 0.02 compared to surgery alone, or surgery and octreotide). We conclude that the GH inhibitory effects of octreotide are significantly better in patients harboring DG somatotroph adenomas compared with those harboring SG adenomas.

Interpretation and bias in case-crossover studies.

The case-crossover design is an innovative epidemiologic technique with distinct strengths and limitations. We review the fundamental logic of this self-matching non-randomized design and direct attention to 15 concerns related to the available data, unavailable data, analytic technique, quantitative statistics, and etiologic model. Implications for each concern are discussed in the context of a recent report on whether cellular telephone calls are associated with an increased risk of a motor vehicle collision. We suggest that an understanding of the case-crossover design may help investigators explore selected questions in behavioral medical research.

Variability among methods to assess patients' well-being and consequent effect on a cost-effectiveness analysis.

Cost-effectiveness analysis is emerging as an approach for determining the relative value of health care programs, technologic innovations, and clinical decisions. Increasingly, patients' stated values for quality of life are applied as adjustment in these analyses; the results may vary depending on how individuals assess their well-being. We interviewed 58 patients with chronic renal failure to determine the level of agreement among six methods for assessing well-being, and to determine the effects of variation in assessed well-being on the results of a cost-effectiveness analysis of in-center hemodialysis. Patients reported well-being using the Sickness Impact Profile, Campbell Index of Well-being, Kaplan-Bush Index of Well-being, categorical scaling, standard gamble, and time trade-off. We found that patient well-being was substantially higher as evaluated by the Sickness Impact Profile compared to the other five methods. The Sickness Impact Profile and the Kaplan-Bush Index of Well-being provided much narrower distributions of assessed values relative to other measures. Correlations among assessment methods were poor (Spearman rank-correlation coefficients range: 0.094-0.519). Discrepancies among indices were particularly vivid when we evaluated data at the individual level; many patients reported a high level of well-being according to one index and a low level of well-being according to a different index. The cost effectiveness of in-center hemodialysis varied from $34,893 to $45,254 per quality-adjusted life-year saved according to the Sickness Impact Profile and standard-gamble technique respectively. The substantial variability in patients' stated quality of life may preclude the use of a single method to analyze the cost effectiveness of a health program.

Assessing predictive accuracy: how to compare Brier scores.

Several investigators have used the Brier index to measure the predictive accuracy of a set of medical judgments; the Brier scores of different raters who have evaluated the same patients provides a measure of relative accuracy. However, such comparisons may be difficult to interpret because of the lack of a statistical test for differentiating between two Brier scores. To demonstrate a method for addressing this issue we analyzed the judgments of five medical students, each of whom independently evaluated the same 25 patients with recurrent chest pain. Using the method we determined that two of the students gave judgments that were incompatible with the actual observed outcomes (p less than 0.05); of the three remaining students we detected a significant difference between two (p less than 0.05). These results differed from receiver operating characteristic curve area analysis, another technique used to evaluate predictive accuracy. We suggest that the proposed method can provide a useful tool for investigators using the Brier index to compare how well clinicians express uncertainty using probability judgments.

Assessing the minimal important difference in symptoms: a comparison of two techniques.

We have developed a method for estimating the minimally important difference (MID) for health status measures. Whereas the conventional approach requires patients to judge themselves relative to their memories, our method requires patients to judge themselves relative to others with the same condition. In this study we examined whether our method (based on between-patient differences) and the conventional method (based on within-patient changes) provides comparable estimates of the MID for one health status measure: the Chronic Respiratory Questionnaire. Patients with chronic obstructive pulmonary disease who were participating in a supervised respiratory rehabilitation program were included if they were in stable health (n = 112). Their mean score per question in the Chronic Respiratory Questionnaire was 4.5 (range, 1 to 7; where bigger values indicate better health). Our method estimated that the MID was 0.5 (95% confidence interval 0.4 to 0.7). This estimate was similar to the MID previously found using the conventional method. These observations support the role of the Chronic Respiratory Questionnaire for measuring patient's symptoms, the validity of our approach for assessing the MID, and an estimate on the order of 0.5 as the threshold for this particular health status measure.

Spirometry and dyspnea in patients with COPD. When small differences mean little.

OBJECTIVE: To determine when a difference in FEV1 is sufficiently large to be associated with a noticeable difference in dyspnea symptoms for patients with chronic lung disease. DESIGN: Cross-sectional analysis of 15 groups (n = 112 patients, 832 contrasts). SETTING: Respiratory rehabilitation program. PATIENTS: Patients with COPD (mean FEV1 = 35% predicted). MEASURES: Patients' perspectives assessed through subjective comparison ratings of dyspnea and of overall health. Relation between the FEV1 and patients' perspectives determined the smallest difference in spirometry that was associated with a noticeable difference in patients' symptoms. RESULTS: The FEV1 was moderately correlated with patients' ratings of dyspnea (r = 0.29; 95% confidence interval (CI), 0.22 to 0.35). In contrast, the FEV1 was minimally correlated with patients' ratings of overall health (r = 0.10; 95% CI, 0.03 to 0.17). The FEV1 needed to differ by 4% predicted for the average patient to stop rating his or her dyspnea as "about the same" and start rating his or her dyspnea as either "a little bit better" or "a little bit worse" relative to other patients (95% CI, 1.5 to 6.5). This was equivalent to the average patient's FEV1 increasing by 112 mL (starting from 975 mL and ending at 1,087 mL). CONCLUSIONS: Some statistically significant differences in the FEV1 are so small that they may not represent important differences in symptoms for the average patient with severe COPD; an awareness of the smallest difference in FEV1 that is noticeable to patients can help clinicians interpret the effectiveness of symptomatic treatments.

Diffuse pulmonary arteriovenous malformations: characteristics and prognosis.

OBJECTIVE: To study the clinical characteristics and prognosis of patients with diffuse pulmonary arteriovenous malformations (AVMs). DESIGN: Retrospective chart review of all patients (n = 16) with diffuse pulmonary AVMs seen at Yale New Haven Hospital, Johns Hopkins Hospital, and St. Michael's Hospital. Up-to-date follow-up information was obtained in all living patients. RESULTS: All patients were severely hypoxic. Neurologic complications (stroke or brain abscess) had occurred in 70% of patients by the time of diagnosis. During the follow-up period (mean, 6 years), three patients died and two others developed new neurologic complications. One of the deaths occurred perioperatively during lung transplantation. All patients underwent transcatheter embolotherapy of any large pulmonary AVMs. A selected group underwent pulmonary flow redistribution, a novel technique. Oxygenation did not improve significantly with embolotherapy of the larger AVMs, but there was a small significant improvement in those patients who underwent pulmonary flow redistribution. The majority (85%) of the living patients are currently working or studying full-time. CONCLUSIONS: Patients with diffuse pulmonary AVMs are at increased risk of neurologic complications. Transcatheter embolotherapy does not significantly improve the profound hypoxia, but it may reduce the risk of neurologic complications. Antibiotic prophylaxis is recommended for bacteremic procedures to prevent brain abscess. These patients can live for many years and lead productive lives. We do not recommend lung transplantation because survival with disease is difficult to predict and we have observed a perioperative transplant death.

Cost-effectiveness of regulations against using a cellular telephone while driving.

PURPOSE: To evaluate the cost-effectiveness of regulations that prohibit using a cellular telephone while driving a motor vehicle. DESIGN: Decision analysis of risks and benefits related to cellular telephones and driving. SETTING: United States population in 1997. MEASURES: Health benefits measured as the quality-adjusted life years potentially saved. Financial benefits measured as health care and other services potentially averted. Costs of regulation measured as the lost productivity derived from willingness to pay for cellular telephone calls. RESULTS: Under base-case conditions, cellular telephone calls in the United States each day accounted for about 984 reported collisions, 1,729 total collisions, 2 deaths, 317 persons with injuries, 99 lost years of life expectancy, 161 lost quality-adjusted life years, $1 million in health care costs, and $4 million in property damage and other costs. This reflected a total of about 35 million telephone calls while driving, 70 million calling minutes, and $33 million in total value to society. The estimated cost-effectiveness ratio for a regulation restricting cellular telephone usage while driving was $300,000 per quality-adjusted life year saved, but ranged from $50,000 to $700,000 under alternative assumptions and interpretations of data. Regulations applied to teenage males could be cost-saving to society if the value of a call fell below 37 cents per minute. CONCLUSIONS: Regulations restricting cellular telephone usage while driving are less cost-effective for society than other safety measures. Nevertheless, regulations may be justifiable because the benefits and harms do not always involve the individual who has the cellular telephone. Increasing the price of a call (or adding a supplementary tax) might decrease the number of discretionary calls, be cost-saving for society, and be life-saving for individuals.

Decision analysis with cumulative prospect theory.

BACKGROUND: Individuals sometimes express preferences that do not follow expected utility theory. Cumulative prospect theory adjusts for some phenomena by using decision weights rather than probabilities when analyzing a decision tree. METHODS: The authors examined how probability transformations from cumulative prospect theory might alter a decision analysis of a prophylactic therapy in AIDS, eliciting utilities from patients with HIV infection (n = 75) and calculating expected outcomes using an established Markov model. They next focused on transformations of three sets of probabilities: 1) the probabilities used in calculating standard-gamble utility scores; 2) the probabilities of being in discrete Markov states; 3) the probabilities of transitioning between Markov states. RESULTS: The same prophylaxis strategy yielded the highest quality-adjusted survival under all transformations. For the average patient, prophylaxis appeared relatively less advantageous when standard-gamble utilities were transformed. Prophylaxis appeared relatively more advantageous when state probabilities were transformed and relatively less advantageous when transition probabilities were transformed. Transforming standard-gamble and transition probabilities simultaneously decreased the gain from prophylaxis by almost half. Sensitivity analysis indicated that even near-linear probability weighting transformations could substantially alter quality-adjusted survival estimates. CONCLUSION: The magnitude of benefit estimated in a decision-analytic model can change significantly after using cumulative prospect theory. Incorporating cumulative prospect theory into decision analysis can provide a form of sensitivity analysis and may help describe when people deviate from expected utility theory.

Time preference in medical decision making and cost-effectiveness analysis.

Cost-effectiveness analyses usually quantify peoples' attitudes towards delayed outcomes using the exponential discount model. The authors examined three assumptions of this model by assessing the time preferences of individuals towards hypothetical health states and calculating implicit annual discount rates. Of a random sample of medical students, house officers, and attending physicians, 121 participated, reflecting a response rate of 81%. The participants considered three temporary events (colostomy, blindness, depression) that were destined to occur at five sequentially distant times in the future (one day, six months, one year, five years, and ten years). The utility of each prospect was measured using two elicitation techniques (standard gamble and categorical scaling), and 1,394 implicit discount rates were calculated. Of all the discount rates, 62.1% equalled zero, 10.0% were less than 0.00, and 15.7% were greater than 0.10. Mean discount rates for relatively proximal time intervals tended to be larger than those for relatively more distant intervals (0.041 vs. 0.025, p < 0.01). Mean discount rates for blindness tended to be smaller than those for colostomy or depression (0.023 vs. 0.039 vs 0.037, respectively, p < 0.005). Hence, peoples' implicit discount rates are not always small positive numbers that are constant over time and the same for all settings. The authors suggest that the conventional exponential discount model may not fully characterize the time preferences held by individuals.

The beguiling pursuit of more information.

BACKGROUND: The authors tested whether clinicians make different decisions if they pursue information than if they receive the same information from the start. METHODS: Three groups of clinicians participated (N=1206): dialysis nurses (n=171), practicing urologists (n=461), and academic physicians (n=574). Surveys were sent to each group containing medical scenarios formulated in 1 of 2 versions. The simple version of each scenario presented a choice between 2 options. The search version presented the same choice but only after some information had been missing and subsequently obtained. The 2 versions otherwise contained identical data and were randomly assigned. RESULTS: In one scenario involving a personal choice about kidney donation, more dialysis nurses were willing to donate when they first decided to be tested for compatibility and were found suitable than when theyknew they were suitable from the start (65% vs. 44%, P= 0.007). Similar discrepancies were found in decisions made by practicing urologists concerning surgery for a patient with prostate cancer and in decisions of academic physicians considering emergency management for a patient with acute chest pain. CONCLUSIONS: The pursuit of information can increase its salience and cause clinicians to assign more importance to the information than if the same information was immediately available. An awareness of this cognitive bias may lead to improved decision making in difficult medical situations.