Patients derogate physicians who use a computer-assisted diagnostic aid.

OBJECTIVE: To ascertain whether a physician who uses a computer-assisted diagnostic support system (DSS) would be rated less capable than a physician who does not. METHOD: Students assumed the role of a patient with a possible ankle fracture (experiment 1) or a possible deep vein thrombosis (experiment 2). They read a scenario that described an interaction with a physician who used no DSS, one who used an unspecified DSS, or one who used a DSS developed at a prestigious medical center. Participants were then asked to rate the interaction on 5 criteria, the most important of which was the diagnostic ability of the physician. In experiment 3, 74 patients in the waiting room of a clinic were randomly assigned to the same 3 types of groups as used in experiment 1. In experiment 4, 131 3rd- and 4th-year medical students read a scenario of a physician-patient interaction and were randomly assigned to 1 of 4 groups: the physician used no DSS, heeded the recommendation of a DSS, defied a recommendation of a DSS by treating in a less aggressive manner, or defied a recommendation of a DSS by treating in a more aggressive manner . RESULTS: The participants always deemed the physician who used no decision aid to have the highest diagnostic ability. CONCLUSION: Patients may surmise that a physician who uses a DSS is not as capable as a physician who makes the diagnosis with no assistance from a DSS.     

Injury to the right A. pulmonalis due to blunt thoracic trauma]

Immediately after a moped accident a 16-year old patient was haemodynamically unstable. Following adequate drainage of a haematopneumothorax in the hospital the patient collapsed into a shock. Thoractomy revealed a tear of the right A. pulmonalis. The hilus was clamped and a lobectomy was performed. After this the patient was haemodynamically stable; due to bone and nerve damage he was transferred to a rehabilitation centre. Laceration of the A. pulmonalis as a consequence of blunt thoracic trauma is rare and mostly fatal. In the case of a patient with a massive haematothorax rapid transport to the nearest hospital is preferable to thorax drainage at the site of the accident.     

"Can you spare an organ?": exploring Hispanic Americans' willingness to discuss living organ donation with loved ones

Living organ donation offers a means of overcoming the shortage of viable organs available for transplant: a shortage particularly problematic among Hispanics. One barrier standing between those in need of a kidney and a successful transplant operation is an inability, and often lack of desire, to talk to loved ones about the need for a living donation. With an eye on future intervention approaches, and guided in part by the theory of planned behavior, this research effort sought to explore the factors associated with a willingness to engage in a conversation about a living donation with loved ones. Study 1, a phone survey of Hispanic Americans drawn from a Hispanic surname list, reveals that while upward of 90% of respondents would be willing to offer a kidney to a family member in need, and a similar percentage would be willing to accept a living donation if offered, only about half of respondents would feel comfortable initiating a conversation with family members if the respondent was in need of a living donation. Study 2, a survey of Hispanic American patients currently in need of a living kidney donation, revealed that perceived behavioral control accounted for 60% of the variance in future intentions to initiate a conversation among those who have yet to speak to a family member about becoming a living donor. Moreover, perceived behavioral control mediated the relationship between perceived asking appropriateness and future intentions to initiate a conversation. Lastly, recipient outcome expectations, asking appropriateness, and subjective norms were revealed to be predictive of perceived behavioral control. Implications for future living donor interventions focusing on increasing recipient-initiated conversations are discussed.     

Child health on a dollar a day: some tentative cross-country comparisons

Children living on a dollar a day-the international extreme poverty line-appear to have radically different chances of dying in childhood and being malnourished, depending on the country in which they live. In Kazakhstan, a child living on a dollar a day, has only a 10% risk of being underweight, while the risk facing a child living on a dollar a day in India is nearly 60%. The Kazakh child has a risk of less than 40 per 1000 of dying before his first birthday, while a child living on a dollar a day in Niger faces a risk of nearly 160 per 1000. Countries where mortality and malnutrition risks at a dollar a day are high are not typically those where there are large gaps in child survival and in malnutrition between the poor and better-off. The two concepts of inequality and health risks at the poverty line are not only conceptually distinct-they are empirically distinct too. The large differences between countries in the risks of mortality and malnutrition in childhood beg the obvious question-what accounts for these differences? Some regression results presented in the paper suggest that these differences may be due to differences across countries in levels of per capita expenditure on the health sector. Regressions find that higher levels of per capita public spending on the health sector are associated with significantly lower levels of mortality and malnutrition amongst children living on a dollar a day.     

Effect of sex of preceding child on birth interval

The study aim was to examine the effect on birth spacing of a prior female child's birth. The study site was a rural health center under observation by staff from the Dayanand Medical College in Ludhiana, India. The sample included 73 pregnant women who were grouped by the sex of the preceding child. The results showed that the average birth interval was significantly shorter for women with a preceding birth of a female child. The average interval in weeks was 90.73 weeks + or - 54.46 weeks for the 41 women who had a prior girl child compared to 133.68 weeks for the male child. When the female child was at a parity of one the birth interval averaged 73.36 weeks, compared to 137.2 weeks for a prior parity of one male child. At parity of two, the average birth interval was 106.2 for a prior girl child and 144.38 for a prior male child. At a parity of three, the average birth interval was 88.22 weeks for a prior girl child and 96.5 weeks for a prior male child. At a parity of four, the average birth interval was 87.66 weeks for a prior girl child and 46.0 weeks for a prior male child. The significant effect of having a prior girl child was evident only at a parity of one. The intervals at a parity of two and three were shorter for girls but not significantly different. The recommendation was that young women and women with low parity be targeted for family planning in order to lengthen the birth interval, regardless of the desire for sons.     

What Is a Valid Mapping Algorithm in Cost-Utility Analyses? A Response From a Missing Data Perspective

ObjectivesAlthough numerous mapping algorithms from a non–preference-based measure to a target health utility measure have been developed and applied in cost-utility analyses (CUAs), conditions for a mapping algorithm to work well in a CUA are still unclear. In this research, we formulate the mapping problem as a missing data problem and clarify these conditions.MethodsWe defined a valid mapping algorithm based on the purpose of mapping (ie, not for prediction but for CUA), and derived a sufficient set of conditions for a valid mapping algorithm. We also conducted a simulation study to investigate properties of a mapping algorithm under situations where the conditions are satisfied and violated.ResultsThe derived sufficient conditions indicate that the complete overlap of the source measure with the target health utility measure is important and that a covariate that is omitted from a mapping algorithm but has an effect on the target health utility measure not captured by the source measure may invalidate a mapping algorithm. The conditions cannot be verified from data in a CUA but can be supported using external data. A simulation study showed that when at least 1 of the 3 conditions was violated, a mapping algorithm provided biased health utility estimates in a CUA, and that prediction accuracy did not necessarily reflect performance of a mapping algorithm in a CUA.ConclusionThe derived conditions provide a fundamental basis for better practices in developing and selecting a mapping algorithm.     

Using performance measures to motivate 'report-averse' and 'report-loving' agents

In designing a quality report, a health plan needs to account for the report's effect on the doctor, hospital or other provider. This paper proposes a simple model of how quality reporting affects a health care provider, using the example of a doctor subject to reporting with a "cut point" that designates the doctor as above or below some standard. Choice of cut point affects the doctor's welfare through the doctor's preferences about income and by affecting market demand for the doctor's services. These factors lead doctors to be "report-averse" or "report-loving," a determination that affects a health plan's cost to enlist a doctor in a contract with reporting and that guides choice of a cut point to maximize the doctors' effort to improve her quality.     

Serious complications following removal of an ingested partial denture

Complications occurred in a 41-year-old woman following an attempt to remove a partial denture by oesophagoscopy. These were: laceration of the oesophagus with subsequent mediastinitis, pneumothorax, and pneumopericardium. At a second oesophagoscopy the denture was removed from the oesophagus using a flexible hood. Following antibiotic treatment the patient recovered. In a 45-year-old man who had also swallowed a denture, the denture could not initially be localized. It was eventually recovered from the antrum using a flexible scope with a flexible hood. The patient was discharged from hospital in a good condition. Psychiatric and mentally handicapped patients run a high risk of denture ingestion. Ingested dental prostheses are often radiolucent, and are difficult to visualize using radiological methods. Extraction of the ingested foreign objects can lead to severe complications. This is why in this type of case, we recommend the use of a flexible scope and a flexible hood attachment.     

Component-Resolved Diagnosis of Hazelnut Allergy in Children

Hazelnuts commonly elicit allergic reactions starting from childhood and adolescence, with a rare resolution over time. The definite diagnosis of a hazelnut allergy relies on an oral food challenge. The role of component resolved diagnostics in reducing the need for oral food challenges in the diagnosis of hazelnut allergies is still debated. Therefore, three electronic databases were systematically searched for studies on the diagnostic accuracy of specific-IgE (sIgE) on hazelnut proteins for identifying children with a hazelnut allergy. Studies regarding IgE testing on at least one hazelnut allergen component in children whose final diagnosis was determined by oral food challenges or a suggestive history of serious symptoms due to a hazelnut allergy were included. Study quality was assessed by the Quality Assessment of Diagnostic Accuracy Studies-2 tool. Eight studies enrolling 757 children, were identified. Overall, sensitivity, specificity, area under the curve and diagnostic odd ratio of Cor a 1 sIgE were lower than those of Cor a 9 and Cor a 14 sIge. When the test results were positive, the post-test probability of a hazelnut allergy was 34% for Cor a 1 sIgE, 60% for Cor a9 sIgE and 73% for Cor a 14 sIgE. When the test results were negative, the post-test probability of a hazelnut allergy was 55% for Cor a 1 sIgE, 16% for Cor a9 sIgE and 14% for Cor a 14 sIgE. Measurement of IgE levels to Cor a 9 and Cor a 14 might have the potential to improve specificity in detecting clinically tolerant children among hazelnut-sensitized ones, reducing the need to perform oral food challenges.     

Identification of mechanisms that may modulate the role of lipoprotein(a) in thrombosis and atherogenesis.

In this report, we review recent findings concerning the identification of mechanisms that may modulate the role of lipoprotein(a), or Lp(a), in thrombosis and atherogenesis. Lp(a) binds to surface-immobilized plasmin-modified fibrin, thus providing a mechanism for incorporating Lp(a) into the vessel wall. We found that homocysteine and other sulfhydryl-containing amino acids markedly increase the binding of Lp(a) to plasmin-modified fibrin. Our results suggest that homocysteine alters the structure of Lp(a) to expose lysine-binding sites on the apolipoprotein(a) portion of the molecule, and thus provide a potential biochemical link between thrombosis and atherogenesis. We also found that transglutaminases catalyze the incorporation of primary amines into Lp(a). Studies in cell culture systems have found that Lp(a) stimulates endothelial cells to synthesize and release plasminogen activator inhibitor-1. Further, Lp(a) inhibits the activation of transforming growth factor-beta in a coculture of bovine endothelial and smooth muscle cells.     

Power and sample size calculations for discrete bounded outcome scores

We consider power and sample size calculations for randomized trials with a bounded outcome score (BOS) as primary response adjusted for a priori chosen covariates. We define BOS to be a random variable restricted to a finite interval. Typically, a BOS has a J- or U-shaped distribution hindering traditional parametric methods of analysis. When no adjustment for covariates is needed, a non-parametric test could be chosen. However, there is still a problem with calculating the power since the common location-shift alternative does not hold in general for a BOS. In this paper, we consider a parametric approach and assume that the observed BOS is a coarsened version of a true BOS, which has a logit-normal distribution in each treatment group allowing correction for covariates. A two-step procedure is used to calculate the power. Firstly, the power function is defined conditionally on the covariate values. Secondly, the marginal power is obtained by averaging the conditional power with respect to an assumed distribution for the covariates using Monte Carlo integration. A simulation study evaluates the performance of our method which is also applied to the ECASS-1 stroke study.     

An analysis of experimenter effects on responses to a sex questionnaire

To test whether responses to sex questionnaires vary as a function of the milieu in which the questionnaires are administered, university and college students were presented with an explicit sex questionnaire by a psychologist or by a member of the clergy. In the first study conducted at a nondenominational university, students generally responded similarly when tested by a psychologist, a rabbi, or a priest. There was some evidence suggesting that a greater number of students tested by members of the clergy, rather than by the psychologist, omitted responses to sensitive questions. In a second study conducted at a Catholic college, responses generally were similar when comparing a priest and a psychologist as testers. On one sensitive item, however, there was evidence of an experimenter effect in the predicted direction. Under testing situations common to a number of studies, responses to sex questionnaires seem relatively unaffected by experimenter effects.     

A rural hospital's impact on a community's economic health.

This research illustrates the importance of a hospital to the economic health of a community. A simulation model of a rural community in Oklahoma is used to demonstrate how the implementation of the DRG reimbursement policy has impacted a rural community, and to project how the closing of the hospital would impact the economy of the community. The results indicate that rural hospitals play a vital role in the economics of their communities. The closing of a rural hospital has a devastating impact on the community, while the DRG reimbursement policy has had a significant impact on the community.     

Management of a traumatic gastric ulcer with a low-profile gastrostomy tube.

Since the advent of percutaneous endoscopic gastrostomy (PEG) tubes in 1980, they have become the device of choice for providing long-term enteral nutrition. Despite their overall safety, a number of complications can occur after PEG placement. Bleeding is usually a minor complication associated with PEG placement that occurs soon after the procedure and is most often caused by puncture of an abdominal wall vessel. More severe bleeding can occur when a branch of one of the gastric arteries is punctured. There are only a few case reports of traumatic gastric ulceration secondary to the internal bolster of a PEG. The internal bolsters are either balloons or dome shaped, and are 1.5-2.0 cm in height. We report a case in which a patient developed hemorrhage from a gastric ulcer induced by a balloon-type PEG tube that was resolved only after replacement with a tube manufactured with a low-profile internal bolster that was only 0.3 mm in height. The protruding tip of a balloon-type gastrostomy tube was believed to have caused traumatic injury to the gastric mucosa in our patient, causing ulceration. Usually, removal of the tube and placement in a different location may solve the problem. However, we believe that the PEG tube fashioned with a low-profile internal bumper is a safer option.     

Serum distribution of lipoprotein(a) in African Americans and Nigerians: Potential evidence for a genotype-environmental effect

Differences in lipoprotein(a) [Lp(a)] levels across populations have been described and blacks are known to have higher Lp(a) values compared to whites. However, environmental factors which influence Lp(a) levels have been difficult to identify. We took advantage of the large environmental contrast which exists against a common genetic background between U.S. and Nigerian blacks to examine the relationship between Lp(a) and apolipoprotein(a) [apo(a)] isoforms. Although the distribution of Lp(a) and apo(a) isoforms was nearly Gaussian in both populations, mean serum Lp(a) values were significantly higher in the United States than in Nigeria (20.5 vs. 12.7 mg/dl; P = 0.0001) and U.S. blacks had a higher frequency of the large molecular weight isoforms compared to Nigerians. Similar trends in the relationship between apo(a) isoform and Lp(a) concentration were seen in both populations; however, the magnitude of the effect was different. Compared to the Nigerians, U.S. blacks had significantly higher mean Lp(a) values for the same apo(a) isoform. The association of Lp(a) with low density lipoprotein-cholesterol (LDL-C) level was not significant after correcting for the contribution of Lp(a) cholesterol to LDL-C in both populations. Surprisingly, the association between Lp(a) and total-C remained significant (r = 0.20, P = 0.04) after similar correction for the contribution of Lp(a) cholesterol in the U.S. sample. Understanding the relationship between other factors including lifestyle characteristics capable of influencing total-C may help explain the unusually high Lp(a) level observed in this U.S. population. Genet. Epidemiol. 14:157–168,1997. © 1997 Wiley-Liss, Inc.     

Lipoprotein(a) levels and apolipoprotein(a) isoforms related to life style risk factors

Lipoprotein(a) [Lp(a)] has been considered to be a predictor of premature coronary heart disease and other cardiovascular diseases. Lp(a) levels are largely genetically determined, but the detailed mechanism of Lp(a) elevation is uncertain. We examined the association between Lp(a) levels and apolipoprotein(a) [apo(a)] phenotypes as well as that of Lp(a) level and other various conditions. The subjects were 280 healthy Japanese (102 males and 178 females) aged 39 to 70 years who were living in a rural community in 1992. We obtained apo(a) phenotypes determined by SDS-PAGE as well as Lp(a) levels and other cardiovascular risk factors. We combined apo(a) phenotypes form 4 groups according to molecular weights (from high apo(a) molecular weight to low: I, II, III and IV). Lp(a) levels were associated with apo(a) phenotype-groups, that is, they were inversely associated with apo(a) molecular weight. Small apo(a) phenotypes were less frequent than large ones. The median Lp(a) level was higher in smoking (29.2 mg/dL) than in non-smoking subjects (18.5 mg/dL) in phenotype-group III. Adjusted means of total cholesterol and fibrinogen levels in apo(a) phenotype-group IV were the highest of all phenotype-groups. Age, apo(a) phenotype, smoking status, total cholesterol and fibrinogen were positively correlated with Lp(a) levels by multiple regression analysis. Lp(a) levels were found to be mainly associated with apo(a) phenotype, but varied broadly within the same apo(a) phenotype at various conditions, such as smoking status and high total cholesterol.     

Robust Bayesian sample size determination in clinical trials

This article deals with determination of a sample size that guarantees the success of a trial. We follow a Bayesian approach and we say an experiment is successful if it yields a large posterior probability that an unknown parameter of interest (an unknown treatment effect or an effects-difference) is greater than a chosen threshold. In this context, a straightforward sample size criterion is to select the minimal number of observations so that the predictive probability of a successful trial is sufficiently large. In the paper we address the most typical criticism to Bayesian methods-their sensitivity to prior assumptions-by proposing a robust version of this sample size criterion. Specifically, instead of a single distribution, we consider a class of plausible priors for the parameter of interest. Robust sample sizes are then selected by looking at the predictive distribution of the lower bound of the posterior probability that the unknown parameter is greater than a chosen threshold. For their flexibility and mathematical tractability, we consider classes of epsilon-contamination priors. As specific applications we consider sample size determination for a Phase III trial.     

Increasing response to mailed questionnaires by including a pencil/pen

Nonmonetary incentives lead to small increases in response rates to mailed questionnaires. However, inclusion of a pen or pencil, which may be a facilitating factor as well as a reward, has not been shown to improve response to health surveys in prior trials. In 2001 and 2002, the authors conducted two US trials in which a study-logo pen or pencil was randomly included in a second questionnaire mailed to nonresponders to a first mailing. In the first study, of 10,686 nonresponders to a cohort recruitment mailing, response to the second mailing was 55% with inclusion of a pen versus 40% without one (p < 0.001). In the second study, of 141 nonresponders to a pilot follow-up survey conducted 2 years after entry into a cohort, response was 43% with inclusion of a pencil versus 24% without one (p = 0.02). This 15-19 percentage point increase for mailing 2 translated to a 5-6 percentage point increase after the two mailings combined. In a simulated study of three mailings based on these studies, the overall response rate increased by 4 percentage points at no added cost through inclusion of a pencil in the second mailing. The additional cost of the pencil was compensated for by the reduced number of nonrespondents sent packets at the third mailing. This study supports including a study-logo pen or pencil in a second questionnaire mailing to nonrespondents as a cost-effective method of increasing response rates.