When to stop the search for an elusive source of gastrointestinal bleeding

BACKGROUND AND STUDY AIMS

This analysis investigates the clinical parameters that should drive decisions about when to continue or stop the search for an elusive source of gastrointestinal bleeding.

PATIENTS AND METHODS

The number of endoscopies necessary to find a source of bleeding was estimated using the geometric distribution. A threshold analysis was used to develop a stop rule for the search for a site of bleeding. Bayes' formula served to estimate changes in the probability of achieving a diagnosis associated with a series of consecutive endoscopic tests.

RESULTS

With decreasing probability of diagnostic success associated with an individual endoscopic procedure, such as P = 50%, 33%, or 25%, the mean (standard deviation [SD]) number of procedures needed to find the source of bleeding increases to 2 (1.41), 3 (2.45), or 4 (3.46), respectively. The threshold analysis suggests that work-up should be discontinued if the expected rise in diagnostic probability does not exceed the ratio of work-up cost to bleeding cost, that is, Δ P < work-up cost/bleeding cost. For instance, a 10-fold higher cost of bleeding than endoscopy would justify continued work-up if it can improve diagnostic probability by 10%. Bayesian analysis shows that after three negative tests the diagnostic probability drops below such a threshold.

CONCLUSIONS

The analysis suggests the following basic rules. The search for a site of gastrointestinal bleeding will take on average 2 procedures with a range of 1 - 4. The search should be continued as long as the diagnostic probability is expected to rise by more than 10 %, which is unlikely after three consecutive negative tests.

Rising trends of gastric cancer and peptic ulcer in the 19th century

BACKGROUND

The risk of dying from gastric cancer appears to have increased among consecutive generations born during the 19th century.

AIM

To follow the time trends of hospitalization for gastric cancer and test whether they confirm such increase.

METHODS

Inpatient records of the last two centuries from four hospitals in Scotland and three US hospitals were analysed. Proportional rates of hospitalization for gastric cancer, gastric ulcer and duodenal ulcer were calculated during consecutive 5-year periods.

RESULTS

The data from all seven cities revealed strikingly similar patterns. No hospital admissions for gastric cancer or peptic ulcer were recorded prior to 1800. Hospital admissions for gastric cancer increased in an exponential fashion throughout the 19th and the beginning of the 20th century. In a majority of cities, the rise in hospitalization for gastric cancer preceded a similar rise in hospitalization for gastric ulcer. Hospitalization for these two latter diagnoses clearly preceded hospitalization for duodenal ulcer by 20-40 years.

CONCLUSIONS

The occurrence of gastric cancer, gastric ulcer and duodenal ulcer markedly increased during the 19th century. Improvements in hygiene may have resulted in the decline of infections by other gastrointestinal organisms that had previously kept concomitant infection by Helicobacter pylori suppressed.

Mitochondrial Haplotype Influences Mycelial Growth of Agaricus bisporus Heterokaryons

We evaluated the influence of mitochondrial haplotype on growth of the common button mushroom Agaricus bisporus. Ten pairs of heterokaryon strains, each pair having the same nuclear genome but different mitochondrial genomes, were produced by controlled crosses among a group of homokaryons of both wild and commercial origins. Seven genetically distinct mitochondrial DNA (mtDNA) haplotypes were evaluated in different nuclear backgrounds. The growth of heterokaryon pairs differing only in their mtDNA haplotypes was compared by measuring mycelial radial growth rate on solid complete yeast medium (CYM) and compost extract medium and by measuring mycelial dry weight accumulation in liquid CYM. All A. bisporus strains were incubated at temperatures similar to those utilized in commercial production facilities (18, 22, and 26(deg)C). Statistically significant differences were detected in 8 of the 10 heterokaryon pairs evaluated for one or two of the three growth parameters measured. Some heterokaryon pairs showed differences in a single growth parameter at all three temperatures of incubation, suggesting a temperature-independent difference. Others showed differences at only a single temperature, suggesting a temperature-dependent difference. The influence of some mtDNA haplotypes on growth was dependent on the nuclear genetic background. Our results show that mtDNA haplotype can influence growth of A. bisporus heterokaryons in some nuclear backgrounds. These observations demonstrate the importance of including a number of mitochondrial genotypes and evaluating different nuclear-mitochondrial combinations of A. bisporus in strain improvement programs.

The influence of environmental risk factors in hospitalization for gastro-oesophageal reflux disease-related diagnoses in the United States

BACKGROUND

The impact of gastro-oesophageal reflux disease on hospitalization is unknown.

AIM

To describe the characteristics of patients hospitalized for diagnoses related to gastro-oesophageal reflux disease (GERD) and find potential environmental influences that affect their hospitalization.

METHODS

Data from the Healthcare Cost and Utilization Project were used to study the demographic characteristics of hospitalizations associated with GERD during 2003-2006. Data from the Centers for Disease Control were used for information about the US prevalence of obesity.

RESULTS

During 2003-2006, 0.5 million patients with a primary and 14.5 million patients with a secondary GERD-related diagnosis became hospitalized in the US. Oesophageal reflux and hiatal hernia were more common in female than in male inpatients, whereas Barrett's oesophagus and oesophageal adenocarcinoma were more common in male than in female inpatients. All GERD-related diagnoses were more common in white people than non-white people. Hospitalizations associated with oesophageal reflux, reflux oesophagitis and Barrett's oesophagus showed resembling geographical distributions among different US states. The prevalence of obesity and the hospitalization for hiatal hernia or reflux oesophagitis were also characterized by similar geographical distributions.

CONCLUSION

The large numbers of inpatients with a discharge diagnosis of GERD-related conditions attest to the frequent occurrence and relevance of GERD in contributing to hospitalization in the US.

Extracellular matrix formation after transplantation of human embryonic stem cell-derived cardiomyocytes

Transplantation of human embryonic stem cell-derived cardiomyocytes (hESC-CM) for cardiac regeneration is hampered by the formation of fibrotic tissue around the grafts, preventing electrophysiological coupling. Investigating this process, we found that: (1) beating hESC-CM in vitro are embedded in collagens, laminin and fibronectin, which they bind via appropriate integrins; (2) after transplantation into the mouse heart, hESC-CM continue to secrete collagen IV, XVIII and fibronectin; (3) integrin expression on hESC-CM largely matches the matrix type they encounter or secrete in vivo; (4) co-transplantation of hESC-derived endothelial cells and/or cardiac progenitors with hESC-CM results in the formation of functional capillaries; and (5) transplanted hESC-CM survive and mature in vivo for at least 24 weeks. These results form the basis of future developments aiming to reduce the adverse fibrotic reaction that currently complicates cell-based therapies for cardiac disease, and to provide an additional clue towards successful engraftment of cardiomyocytes by co-transplanting endothelial cells.

Antiplectin autoantibodies in subepidermal blistering diseases

BACKGROUND

Hemidesmosomal proteins may become targets of autoimmunity in subepidermal blistering diseases. Well-known recognized autoantigens are the intracellular plaque protein BP230, the transmembrane BP180 and its shed ectodomain LAD-1.

OBJECTIVES

To establish the prevalence of autoimmunity against plectin, another intracellular plaque protein, and to investigate its antigenic sites.

METHODS

Two hundred and eighty-two patients with subepidermal blistering diseases, investigated by routine immunoblot analysis for possible antiplectin antibodies, were included in the study. Epitope mapping was performed using recombinantly produced overlapping plectin domains from the actin-binding domain to the rod domain. The COOH-terminal region of plectin was not included in the study.

RESULTS

In 11 of 282 (3.9%) patients an immunoblot staining pattern identical to that of antiplectin monoclonal antibody HD121 was found. Affinity-purified antibodies bound back to normal human skin in a pattern typical for plectin, i.e. to the epidermal basement membrane zone as well as to keratinocytes in the epidermis, and to myocytes. No binding was seen to plectin-deficient skin of a patient with epidermolysis bullosa simplex with muscular dystrophy. Epitope mapping of the plectin molecule showed that the central coiled-coil rod domain is an immunodominant hotspot as 92% of the sera with antiplectin antibodies reacted with it. Most patients with antiplectin antibodies also had antibodies to other pemphigoid antigens.

CONCLUSIONS

Plectin is a minor pemphigoid antigen with an immunodominant epitope located on the central rod domain.

History of dyspepsia in Scotland. Admissions to the Edinburgh Royal Infirmary 1729-1830, doctoral theses 1726-1823, and contemporary British publications

INTRODUCTION

The aim of the study was to assess whether the rise in the occurrence of dyspepsia in Scotland during the eighteenth century was a true epidemiologic phenomenon or just an increase in medical awareness.

METHODS

Admissions for dyspepsia to the Edinburgh Royal Infirmary from 1729 until 1830 were analysed by consecutive five-year time periods. The titles of MD theses on dyspepsia from 1726 to 1823 were extracted from the Edinburgh University index. Monographs and articles on dyspepsia from Britain during the same time period were sought in the Catalogues of the US Surgeon-General's Library.

RESULTS

During the eighteenth century, the annual number of dyspepsia patients admitted to the Edinburgh Royal Infirmary showed an extraordinary increase from none in 1730 to 900 per million population in 1760. About 4000 MD theses were presented to the Edinburgh University between 1726 and 1823. There were none on dyspepsia or gastritis between 1726 and 1749, after when it gradually started to rise. British publications on dyspepsia similarly appeared only in the 1790s and then rapidly increased.

DISCUSSION

We suggest that the rise in MD theses and publications on dyspepsia were responses to a real increase in dyspepsia during the mid eighteenth century.

The lessons learned from randomized clinical trials of GERD

Despite the huge number of randomized controlled clinical trials published on gastro-oesophageal reflux disease, the translation of the information gathered into clinical practice is rather limited. The aim of this article is to summarize the results of pivotal randomized controlled clinical trials and review articles on reflux disease and evaluate to what extent their results can be applied to current clinical practice. We reviewed the most relevant randomized controlled clinical trials and reviews since the publication of the first randomized controlled clinical trial on reflux oesophagitis (1978) to date. Six areas were explored, namely: (1) diagnostic "entry" criteria, (2) efficacy parameters, (3) duration of therapy, (4) degree of antisecretory effect, (5) placebo effect, (6) follow-up data. Gastro-oesophageal reflux disease is now the most frequent upper GI disorder treated by gastroenterologists in Europe and North America. There is still a dearth of information regarding the natural history of the disease. The types of information generated through randomized controlled clinical trials have had only limited applicability to routine clinical practice. In the future, large cooperative databases accumulating the clinical histories of a great variety of gastro-oesophageal reflux disease patients may help to provide us with the much needed insights into the natural history of this common disorder.

Three centuries of stomach symptoms in Scotland

BACKGROUND

Stomach pain and discomfort have been reported since antiquity.

AIM

To follow the time trends since the 18th century of dyspepsia, gastric ulcer, duodenal ulcer, and benign oesophageal disease to test when dyspepsia started to become a major clinical problem.

METHODS

The annual in- and out-patient records of the last three centuries from the Scottish Royal Infirmaries of Edinburgh, Aberdeen, Glasgow and Dundee were analysed. In addition, dispensary attendances, clinicians' casebooks, students' notebooks and medical texts have been scrutinized for historic statistics of upper gastrointestinal disease.

RESULTS

Dyspepsia was first recorded in the 1750s and increased markedly subsequently. Such dyspepsia persisted after gastric and duodenal ulcers appeared in the late 19th century and then declined again in the late 20th century. Non-ulcer dyspepsia has remained the commonest diagnosis made after endoscopy for stomach pain in the beginning of the 21st century.

CONCLUSION

The current commonest diagnosis of stomach pain, dyspepsia dates from the mid-18th century. Any explanations of its causation need to consider this timing.

Personal view: the paradox of runaway competitions in gastroenterology

Occasionally, gastroenterologists harbour reservations about the appropriateness of various procedures and management options, yet find themselves drawn into a competition and forced by outside exigencies to provide such services. The aim of the present analysis was to describe patterns of runaway competitions and factors that influence their occurrence in gastroenterology. The interactions between two physicians or physician and patient are modelled as non-zero-sum games of two players. The outcomes associated with two behavioural strategies of two players are arranged in a two-by-two game matrix. Many scenarios of clinical gastroenterology and social interactions among gastroenterologists are characterized by the underlying game of prisoner's dilemma, where two players can choose to co-operate or compete with each other. Although from their joint perspective co-operation results in a higher joint utility, the perspective of each individual favours competition. Following the inescapable logic of their individual perspective, the players end up with a worse outcome than through co-operation. A runaway competition ensues if the game is played repeatedly with players successively increasing their stakes. Ultimately, each player tries to outdo the opponent while heading in the wrong direction. Recognizing the hallmarks of the game of prisoner's dilemma may help gastroenterologists to avoid such competitions.

Personal view: Why is my GI clinic filled with surgical mishaps? Post-operative syndromes as an externality problem

The aim of the present analysis was to review why gastroenterology clinics appear filled with patients suffering from postsurgical syndromes. The long-term sequelae of gastrointestinal surgery can be modelled as a negative production externality of surgical operations. When seeking to maximize their profits, surgeons are primarily concerned with the price and cost of surgery alone. They tend to ignore parts of the ensuing long-term costs they impose through postsurgical syndromes on other medical specialties. The complication-related rise in the cost of gastroenterology practice reflects parts of the societal costs of surgery that are not included on the surgical balance sheet. To the surgeon, surgery appears cheaper than to the rest of the medical community, because cost shifting from surgery to other medical specialties leads to a favourable surgical outcome with more surgical operations performed than medically needed or economically feasible. The amount of surgical sequelae could drop, if surgeons were forced to care for all their own postsurgical syndromes or if surgery entered a joint enterprise with gastroenterology caring for the same patient pool.

Helicobacter pylori-associated ulcer bleeding: should we test for eradication after treatment?

BACKGROUND

Eradication of Helicobacter pylori after peptic ulcer haemorrhage reduces the risk of recurrence. Because H. pylori treatment is very effective, it is unclear whether testing to confirm eradication is worthwhile.

AIMS

To examine whether patients with H. pylori-associated peptic ulcer haemorrhage should be tested for successful eradication after completion of antibiotic therapy.

METHODS

A Markov cost-effectiveness model was developed to compare testing vs. non-testing of H. pylori eradication in peptic ulcer haemorrhage. Probability estimates and average costs were derived from published information.

RESULTS

Testing for H. pylori eradication resulted in a benefit of 0.07 quality-adjusted life-years and cost 836 US dollars less than the strategy of not confirming eradication. Testing remained the superior strategy when varying the model regarding age, the initial success of eradication, various test and retreatment strategies, and the rate and costs of recurrent bleeding. Assuming a high eradication rate (95%), the test strategy becomes more expensive only if the cost of H. pylori testing reaches 265 US dollars; however, even under these conditions it remains cost-effective.

CONCLUSIONS

Patients with H. pylori-associated peptic ulcer bleeding should be tested to confirm eradiation of H. pylori after completion of antibiotic treatment.

Personal view: passing the buck and taking a free ride -- a game-theoretical approach to evasive management strategies in gastroenterology

BACKGROUND

'Free-riding' physicians enjoy the status, prestige and income of their profession without fully contributing to its overall mission. By shifting the costs of potential medical complications and difficult patient encounters to other physicians, they reap the benefits of their profession without carrying its full weight.

AIM

To describe this phenomenon in terms of decision analysis and characterize the parameters affecting its occurrence.

METHODS

The interaction between two physicians is modeled as a non-zero-sum game. Two strategies of either contributing to patient management or taking a free ride are available to both physicians. The four possible outcomes are arranged in a two-by-two game matrix.

RESULTS

Physicians practice medicine because their personal benefit exceeds their cost. High cost to the physician results in a high probability of taking a free ride and copping out from potentially risky management. Increasing the benefit decreases the probability of free riding. As the number of possible encounters with other physicians increases, the probability of free riding increases and the probability for effective management by each individual physician decreases.

CONCLUSION

If individual gastroenterologists felt less threatened by administrative repercussions and medico-legal consequences of untoward events, each one of them would contribute more to effective patient management.

Personal view: victim blaming as management strategy for the gastroenterologist--a game theoretical approach

BACKGROUND

A multitude of digestive diseases elude simple management strategies. Rather than admit failure of disease management, a gastroenterologist could resort to blaming patients for their own medical conditions. Blaming the patient constitutes an easy exit strategy for otherwise unsolvable disease conditions.

AIM

To shed light on the problem of patient blaming in gastroenterology and provide means for its resolution.

METHODS

The interaction between physician and patient can be formulated in terms of a non-zero-sum game between two adversaries. The outcomes associated with two behavioural strategies available to both adversaries are arranged in a two-by-two game matrix.

RESULTS

Blaming the patient is characterized by the general game pattern of the 'prisoner's dilemma'. If the physician-patient interaction is restricted to one single event, patient blaming represents the management strategy of choice with the highest expected payoff under all foreseeable circumstances. If there is a high probability for repeated physician-patient interactions, however, a physician admitting and a patient accepting the limits of medical performance yield a dominant strategy.

CONCLUSION

Only for single physician-patient encounters does a non-cooperative strategy of blaming one's adversary for a poor medical outcome yield the highest expected outcome. In the long run, the strategy of shifting blame becomes unproductive for both sides alike.

Why do complications of gastrointestinal disease and procedures come as serial rather than singular events?

BACKGROUND

It often appears as if complications arising from gastrointestinal disease and interventional procedures come in 'series' and 'cluster' in individual patients.

AIM

The aim of this study was to analyse the clustering of complications in terms of stochastic modelling and Markov chains.

METHODS

A patient with gastrointestinal disease is simulated to move along either a 'bad track' associated with multiple consecutive complications or a 'good track' free of complications, the transitions within each track and between the two tracks being governed by probability values.

RESULTS

Because the occurrence of a single complication increases the risk of further complications, subjects who encounter their first complication are more likely to experience a second, third or even more complications, before they leave the 'bad track' and their personal chain of cascading complications becomes discontinued. The model of a Markov chain explains why the overall number of complications in the total population of patients with digestive disease remains low even if individual patients are expected to encounter more than a single complication.

CONCLUSIONS

Published complication rates for gastrointestinal procedures underestimate the true risk to the patient, because they do not consider the added vulnerability to cascading complications after the first event.

Personal view: cost and benefit of medical rituals in gastroenterology

BACKGROUND

Unable to resolve a medical problem, gastroenterologists occasionally choose an ineffectual intervention instead. The elusive path to effectual management becomes substituted with an ineffectual but readily available medical ritual. The term 'ritual' refers to the utilization of an ineffectual intervention with little chances of achieving a medically relevant goal.

AIM

The aim of the article is to analyse the cost-benefit relationship of rituals in gastroenterology and the reasons why gastroenterologists utilize them.

METHODS

Ritualistic disease management is described in terms of medical decision and threshold analysis.

RESULTS

If the perceived benefit of a ritual exceeds its cost, the ineffectual path becomes more attractive than expectant management or doing nothing. To engage in an ineffectual intervention, the threshold probability for success needs to exceed its cost-benefit difference divided by the benefit associated with success. In choosing an ineffectual intervention, doctors tend to underestimate the true costs of a ritual and overestimate its probability of success. The availability of an effectual path leads to more stringent conditions for the benefit associated with an ineffectual path.

CONCLUSIONS

A better understanding of their economical underpinnings should lead to more restricted utilization of rituals in gastroenterology, especially, in situations where they drain scarce resources disproportionately to their perceived benefit.

Review article: anti-reflux surgery and endoluminal therapies

In the short term, fundoplication and antisecretory medication are equally effective in the management of gastro-oesophageal reflux disease. However, over the long term, the fundoplication wrap tends to become loose, and many surgical patients continue to take antisecretory medication after surgery. The operation is technically complex and takes a long time to learn. Inexperience of the individual surgeon is a major factor contributing to the occurrence of postsurgical complications. Fundoplication does not prevent the occurrence of Barrett's oesophagus nor its progression to oesophageal adenocarcinoma. There is no evidence to suggest that the procedure is less costly or more cost-effective than long-term maintenance therapy with antisecretory medications, especially if surgical failures and postsurgical complications are taken into account. Fundoplication represents an alternative to medical therapy in patients with gastro-oesophageal reflux disease who cannot or do not want to be on long-term maintenance therapy with antisecretory medication. Endoluminal procedures, such as radiofrequency ablation, endoscopic suturing and injection at the gastro-oesophageal junction, work only in mild forms of reflux disease. They fail to provide complete relief of reflux symptoms and do not heal erosive oesophagitis. All endoluminal procedures would have to undergo major technological improvements before they could become comparable with fundoplication or antisecretory therapy.

Review article: trials on reflux disease -- the role of acid secretion and inhibition

The importance of gastric acid in the pathophysiology of gastro-oesophageal reflux disease is substantiated by the extraordinary therapeutic success of acid inhibition in the management of the disease. The influence of many risk factors for gastro-oesophageal reflux disease is also mediated through their effect on gastric acid secretion and acid reflux. Helicobacter pylori reduces the risk of gastro-oesophageal reflux disease by causing corpus gastritis and reducing gastric acid output. The geographical and temporal trends of H. pylori infection in human populations and its influence on gastric acid secretion are responsible for much of the apparent epidemiology of gastro-oesophageal reflux disease. On average, intra-oesophageal exposure to acid is higher in patients who respond poorly to antisecretory medication. It also tends to increase with increasing severity of reflux disease. However, gastric acid secretion and intra-oesophageal acid exposure vary markedly in reflux patients. The degrees of gastric or intra-oesophageal acidity do not allow the prediction of the presence or severity of gastro-oesophageal reflux disease in the individual subject. The many clinical trials on gastro-oesophageal reflux disease indicate that the reflux of gastric acid constitutes an essential mechanism in the development of this disease, but that additional and partly unknown risk factors must contribute to its aetiology and promote its occurrence in the individual patient.

Ultrastructural localization of integrin subunits alpha3 and alpha6 in capillarized sinusoids of the human cirrhotic liver

Normal liver sinusoids are not lined by a basement membrane (BM). In contrast, in the course of development of liver cirrhosis, a structured BM is formed de novo in the space of Disse. This BM contributes to the inhibition of the metabolic function of the liver but the pathogenic background of the formation of this perisinusoidal BM is still unclear. Integrins of the beta1-class are generally essential for BM stability and some of them (such as alpha2beta1, alpha3beta1 and alpha6beta1) appear de novo in the perisinusoidal space of the cirrhotic liver. Their cellular distribution in capillarized sinusoids as well as the correlation between their cellular distribution and the formation of the microvascular BM in the cirrhotic liver has not been shown at the ultrastructural level. In the present work we aimed to clarify this issue. We focused on integrins alpha3beta1 and alpha6beta1 and localised them ultrastructurally in human cirrhotic liver microvessels using postembedding immunogold which allows the ultrastructural localization of antigens with high resolution in the tissue. The newly formed basement membrane of capillarized sinusoids was visualized by means of fixation with addition of tannic acid, which enables the visualization of structures of the extracellular matrix with the highest resolution. Also, we carried out laminin detection using postembedding immunogold. Our results show that both alpha3beta1 and alpha6beta1 are expressed on the surface of both hepatocytes and endothelial cells, i.e. on both sides of the newly formed basement membrane. This latter shows zones of higher density both in close proximity to the endothelial and to the hepatocytic surfaces which resemble laminae densae. We propose that hepatocytes and endothelial cells may, therefore, by expressing such integrins, contribute to the formation of this pathological BM in the microvessels of the human cirrhotic liver. On stellate cells, which are major producers of BM components, both integrins alpha3beta1 and alpha6beta1 were also localized.

Personal view: 'don't ask, don't tell'--the undesirable consequences of incidental test results in gastroenterology

A gastroenterologist is frequently approached to perform an endoscopic procedure after an incidental test has resulted in an unexpected positive finding. Should the incidental test result be ignored or automatically followed by an endoscopic procedure? The present analysis strives to characterize the common pattern of such scenarios and resolve their underlying dilemma. A model of game theory is used as a mathematical tool to develop general management strategies. Three clinical scenarios are used as examples to demonstrate this approach. The model is based on how doctors rank the various outcomes with which they are confronted by the incidental test results. The ranks of different outcomes are listed in a decision matrix that is converted into a two-by-two, non-zero, ordinal game. All scenarios of incidental test results emerge as a similar type of game that is best played by both parties adhering to the same set of strategies: 'Don't do the test' and 'don't respond to whatever test result it yields'. These two strategies lead to a Nash equilibrium for a non-zero game, where neither party can improve its payoff any further by choosing a different strategy. Although the equilibrium does not provide the individual players with their best possible payoff, it yields the best overall outcome available to both parties given the economic and medical constraints of the situation.

Patient-physician discordance about benefits and risks in gastroenterology decision-making

AIMS

To illustrate the characteristics of situations in gastroenterology when patients and physicians harbour different perspectives of medical costs and benefits, and how such different perspectives affect the outcome of medical decision-making.

METHODS

Two exemplary scenarios are presented, in which threshold analysis yields different results depending on the varying values assigned to identical medical events. The occurrence of varying values is subsequently phrased in economical terms of varying utility functions that characterize patient vs. physician behaviour.

RESULTS

Safety and therapy are the two major preferences that determine patient and physician utility functions. Patients and physicians make medical decisions based on two different utility functions. In comparison with their patients, gastroenterologists are more concerned with safety and inclined to spend more health care resources on safety than therapy because safety and the occurrence of medical complications affect their own professional status. In trying to maximize their own utility, gastroenterologists tend to spend more resources on safety than the patient him/herself might have spent given a free choice of management options.

CONCLUSIONS

In instances of potential complications associated with risky medical interventions, patients may receive less medical therapy in exchange for more procedural safety.

Prersonal view: going around in circles -- circuitous medical management plans

Physicians occasionally embark on a work-up that, after a lengthy path, leads them to a clinical situation similar to that from which they started their original pursuit. This article aims to describe the characteristics of circular medical management and means for its avoidance. The underlying medical problem often presents itself initially as a bewildering array of consecutive outcomes similar to a complex decision tree. On closer inspection, however, few of the outcomes are associated with a high probability, and only one path stands out as the most likely one to take. This path usually ends in such options as expectant management, supportive measures or doing nothing, which are already available at the onset of work-up. If medical management is drawn out and takes a long time to complete, sight of its circular nature is easily lost. If many different specialists care for a patient, little appreciation for circular paths occurs. A prospective outline of the management plan and the elimination of paths with low a priori probability can help to prevent unnecessary medical interventions. The physician may then come to realize that standing still and waiting become as effective and less costly than a lengthy circular work-up.