Comparing trends in esophageal adenocarcinoma incidence and lifestyle factors between the United States, Spain, and the Netherlands.

OBJECTIVES: The incidence of esophageal adenocarcinoma (EAC) in the western world has been rapidly increasing. The trends in obesity and other lifestyle-associated factors have been hypothesized to be important drivers of this increase. We tested this hypothesis by comparing changes in these factors with changes in EAC incidence over time between three western countries. METHODS: Data on EAC incidence trends were abstracted from the SEER-9 registry (1975-2009) for the United States, from multiple cancer registries (1980-2004) in Spain, and from Eindhoven Cancer Registry in the Netherlands (1974-2010). In addition, we collected trend data on obesity, smoking, and alcohol consumption. The trend data were analyzed using log-linear regression. RESULTS: In 1980, the EAC incidence was similar among the three countries ((0.46-0.63) per 100,000). EAC incidence increased in all, with the largest increase observed in the Netherlands, followed by the United States and Spain (estimated annual percentage of change=9.7%, 7.4%, 4.3%, respectively). However, this pattern was not observed in lifestyle factors associated with EAC. With regards to obesity, the United States clearly has had the highest prevalence rates both in the past and in the present. For alcohol, the highest consumption rates are seen in Spain. Smoking showed a reverse trend compared with EAC among all three countries in the last 20 years. CONCLUSIONS: International trends in EAC incidence do not match corresponding trends in lifestyle-associated factors including obesity. Our findings suggest that factors other than obesity must be the important drivers for the increase in EAC incidence.

Oesophageal hypersensitivity is associated with features of psychiatric disorders and the irritable bowel syndrome.

BACKGROUND: Twenty per cent of patients with heartburn do not respond to proton pump inhibitors (PPIs). Many have normal oesophageal acid exposure. We hypothesized that such PPI non-responders have heightened oesophageal sensation, and that oesophageal hypersensitivity is associated with psychiatric features including somatization and anxiety. AIM: To compare oesophageal sensation in subjects with heartburn categorized by response to PPI, and to correlate oesophageal sensation with psychiatric features. METHODS: Twenty-one PPI responders, nine PPI non-responders and 20 healthy volunteers completed questionnaires of psychiatric disorders and gastrointestinal symptoms. Subjects underwent oesophageal sensory testing with acid perfusion and balloon distension. RESULTS: Healthy volunteers displayed higher thresholds for sensation and discomfort from balloon distension than heartburn subjects (sensation P = 0.04, discomfort P = 0.14). Psychiatric disorders were associated with increased intensity of sensation (P = 0.02) and discomfort from acid (P = 0.01). Somatization was associated with increased discomfort from balloon distension (P = 0.006). Features of irritable bowel syndrome were associated with increased sensation and discomfort. CONCLUSIONS: Heartburn subjects tend to have heightened oesophageal sensation, suggesting that oesophageal hypersensitivity may persist despite therapy with PPI. Oesophageal hypersensitivity is associated with features of psychiatric disease and with the irritable bowel syndrome, which might partly explain the aetiology of heartburn symptoms that are refractory to PPI.

Primary care physician perceptions of non-steroidal anti-inflammatory drug and aspirin-associated toxicity: results of a national survey.

AIM: To assess primary care physician perceptions of non-steroidal anti-inflammatory drug (NSAID) and aspirin-associated toxicity. METHODS: A group of gastroenterologists and internal medicine physicians created a survey, which was administered via the Internet to a large number of primary care physicians from across the US. RESULTS: One thousand primary care physicians participated. Almost one-third of primary care physicians recommended 325 mg rather than 81 mg of aspirin/day for cardioprotection. Fifty-nine percent thought enteric-coated or buffered aspirin reduced the risk of upper gastrointestinal (GI) bleeding. Seventy-six percent believed that Helicobacter pylori infection increased the risk of NSAID ulcers but fewer than 25% tested NSAID users for this infection. More than two-thirds were aware that aspirin co-therapy decreased the GI safety benefits of the cyclo-oxygenase 2 selective NSAIDs. However, 84% felt that aspirin with a cyclo-oxygenase 2 selective NSAID was safer than aspirin with a non-selective NSAID. When presented a patient at high risk for NSAID-related GI toxicity, almost 50% of primary care physicians recommended a proton pump inhibitor and cyclo-oxygenase 2 selective NSAID. CONCLUSIONS: This survey has identified areas of misinformation regarding the risk-benefit of NSAIDs and aspirin and the utilization of gastroprotective strategies. Further education on NSAIDs for primary care physicians is warranted.

The cost-effectiveness of biomarkers for predicting the development of oesophageal adenocarcinoma.

BACKGROUND: The recommended surveillance strategy for oesophageal adenocarcinoma may prevent as few as 50% of cancer deaths. Tissue biomarkers have been proposed to identify high-risk patients. AIM: To determine performance characteristics of an ideal biomarker, or panel of biomarkers, that would make its use more cost-effective than the current surveillance strategy. METHODS: We created a Markov model using data from published literature, and performed a cost-utility analysis. The population consisted of 50-year-old Caucasian men with gastro-oesophageal reflux, who were monitored until age 80. We examined strategies of observation only, current practice (dysplasia-guided surveillance), surveillance every 3 months for patients with a positive biomarker (biomarker-guided surveillance), and oesophagectomy immediately for a positive biomarker (biomarker-guided oesophagectomy). The primary outcome was the threshold cost and performance characteristics needed for a biomarker to be more cost-effective than current practice. RESULTS: Regardless of the cost, the biomarker needs to be at least 95% specific for biomarker-guided oesophagectomy to be cost-effective. For biomarker-guided surveillance to be cost-effective, a $100 biomarker could be 80% sensitive and specific. CONCLUSIONS: Biomarkers predicting the development of oesophageal adenocarcinoma would need to be fairly accurate and inexpensive to be cost-effective. These results should guide the development of biomarkers for oesophageal adenocarcinoma.

Relationship between diabetes mellitus and adenocarcinoma of the oesophagus and gastric cardia.

BACKGROUND: Obesity is a risk factor for adenocarcinomas of the oesophagus and gastric cardia. Diabetes mellitus might mediate that association. AIM: To estimate the risk of diabetes mellitus on the development of adenocarcinoma of distal oesophagus and gastric cardia beyond that of gastro-oesophageal reflux disease. METHODS: A case-control study was performed using a national administrative database of the Veterans Administration. RESULTS: A total of 311 cases of cancer and 10,154 controls were identified. Gender, age, and race were risks for cancer. Diabetes was diagnosed in 36% of cases, and 32% of controls (P = 0.15). Diabetic complications were diagnosed in 14% of cases and 13% of controls (P = 0.60). Multiple logistic regression confirmed the absence of an association between cancer and diabetes (odds ratio 1.1, 95% confidence interval 0.8-1.5) or diabetic complications (odds ratio 0.8, 95% confidence interval 0.6-1.3), adjusting for age, gender, and race. CONCLUSIONS: Within the limitations of this case-control study, there is no evidence of an association between diabetes and adenocarcinoma of the oesophagus or gastric cardia among US veterans with gastro-oesophageal reflux disease.

Review article: Medical decision models of Helicobacter pylori therapy to prevent gastric cancer.

The aim of the present article is to study the utility of Helicobacter pylori eradication programmes in decreasing the incidence of gastric cancer. Three types of decision models are employed to pursue this aim, i.e. decision tree, present value, and declining exponential approximation of life expectancy (DEALE). 1) A decision tree allows one to model the interaction of multiple variables in great detail and to calculate the marginal cost, as well as the marginal cost-benefit ratio, of a preventive strategy. The cost of gastric cancer, the efficacy of H. pylori therapy in preventing cancer, and the cumulative probability of developing gastric cancer exert the largest influence on the marginal cost of cancer prevention. The high cost of future gastric cancer and a high efficacy of therapy make screening for H. pylori and its eradication the preferred strategy. 2) The present value is an economic method to adjust future costs or benefits to their current value using a discount rate and the length of time between now and a given time point in the future. It accounts for the depreciation of money and all material values over time. During childhood, the present value of future gastric cancer is very low. Vaccination of children to prevent gastric cancer would need to be very inexpensive to be practicable. Cancer prevention becomes a feasible option, only if the time period between the preventive measures and the occurrence of gastric cancer can be made relatively short. 3) The DEALE provides a means to calculate the increase in life expectancy that would occur, if death from a particular disease became preventable. Life expectancy of the general population is hardly affected by gastric cancer. For life expectancy to increase appreciably by vaccination or antibiotic therapy directed against H. pylori infection, these interventions would need to be focused towards a sub-population with an a priori high risk for gastric cancer.

Systematic review: the economic impact of irritable bowel syndrome.

BACKGROUND: Although little mortality is associated with irritable bowel syndrome, curative therapy does not exist and thus the economic impact of this disorder may be considerable. METHODS: A systematic review of the literature was performed. Studies were included if their focus was irritable bowel syndrome, and direct and/or productivity (indirect) costs were reported. Two investigators abstracted the data independently. RESULTS: One hundred and seventy-four studies were retrieved by the search; 11 fulfilled all criteria for entry into the review. The mean direct costs of irritable bowel syndrome management were reported to be UK pound sterling90, Canadian$259 and US$619 per patient annually, with total annual direct costs related to irritable bowel syndrome of pound sterling45.6 million (UK) and $1.35 billion (USA). Direct resource consumption of all health care for irritable bowel syndrome patients ranged from US$742 to US$3166. Productivity costs ranged from US$335 to US$748, with total annual costs of $205 million estimated in the USA. Annual expenditure for all health care, in addition to expenditure limited to gastrointestinal disorders, was significantly higher in irritable bowel syndrome patients than in control populations. CONCLUSIONS: Despite the lack of significant mortality, irritable bowel syndrome is associated with high direct and productivity costs. Irritable bowel syndrome patients consume more gastrointestinal-related and more total health care resources than non-irritable bowel syndrome controls, and sustain significantly greater productivity losses.

Economic analysis of step-wise treatment of gastro-oesophageal reflux disease.

BACKGROUND: To expose patients with gastro-oesophageal reflux disease (GERD) to the least amount of medication and to reduce health expenditures, it is recommended that their treatment is started with a small dose of an antisecretory or prokinetic medication. If patients fail to respond, the dose is increased in several consecutive steps or the initial regimen is changed to a more potent medication until the patients become asymptomatic. Although such treatment strategy is widely recommended, its impact on health expenditures has not been evaluated. METHODS: The economic analysis compares the medication costs of competing medical treatment strategies, using two different sets of cost data. Medication costs are estimated from the average wholesale prices (AWP) and from the lowest discount prices charged to governmental health institutions. A decision tree is used to model the step-wise treatment of GERD. In a Monte Carlo simulation, all transition probabilities built into the model are varied over a wide range. A threshold analysis evaluates the relationship between the cost of an individual medication and its therapeutic success rate. RESULTS: In a governmental health care system, a step-wise strategy saves on average $916 per patient every 5 years (range: $443-$1628) in comparison with a strategy utilizing only the most potent medication. In a cost environment relying on AWP, the average savings amount to $256 (-$206 to +$1561). The smaller the cost difference between two consecutive treatment steps, the longer one needs to follow the patients to reap the benefit of the small cost difference. However, even a small cost difference can turn into tangible cost savings, if a large enough fraction of GERD patients responds to the initial step of a less potent but also less expensive medication. CONCLUSIONS: The economic analysis suggests that a step-wise utilization of increasingly more potent and more expensive medications to treat GERD would result in appreciable cost savings.

The laparoscopic evaluation of ascites.

Laparoscopy is an invaluable technique for the evaluation of ascites in subgroups of patients with ascites. Indications for laparoscopic examination include determination of the causes of ascites when routine tests fail to disclose the source, evaluation for the presence of multiple causes of ascites formation, or histopathologic verification of malignancy within the peritoneal cavity. Several reported series have illustrated the efficacy of laparoscopy for the diagnosis of peritoneal carcinomatosis, tuberculous peritonitis, or unsuspected cirrhosis, securing its role in the management of selected patients with ascites.

Reliability block diagrams to model disease management.

BACKGROUND AND OBJECTIVES: Studies of diagnostic or therapeutic procedures in the management of any given disease tend to focus on one particular aspect of the disease and ignore the interaction between the multitude of factors that determine its final outcome. The present article introduces a mathematical model that accounts for the joint contribution of various medical and non-medical components to the overall disease outcome. METHODS: A reliability block diagram is used to model patient compliance, endoscopic screening, and surgical therapy for dysplasia in Barrett's esophagus. RESULTS: The overall probability of a patient with a Barrett's esophagus to comply with a screening program, be correctly diagnosed with dysplasia, and undergo successful therapy is 37%. The reduction in the overall success rate, despite the fact that the majority of components are assumed to function with reliability rates of 80% or more, is a reflection of the multitude of serial subsystems involved in disease management. Each serial component influences the overall success rate in a linear fashion. Building multiple parallel pathways into the screening program raises its overall success rate to 91%. Parallel arrangements render systems less sensitive to diagnostic or therapeutic failures. CONCLUSIONS: A reliability block diagram provides the means to model the contributions of many heterogeneous factors to disease outcome. Since no medical system functions perfectly, redundancy provided by parallel subsystems assures a greater overall reliability.

Cost-effectiveness of colorectal cancer surveillance in ulcerative colitis.

Key issues concerning colorectal cancer in inflammatory bowel disease include determination of the risk of colorectal cancer and assessment of interventions to increase survival. No randomized, controlled trials of colonoscopic surveillance compared to no surveillance exist; however, retrospective studies illustrate that surveillance is associated with improved survival, probably as a result of detection of cancer at earlier stages of disease. In the absence of prospective clinical trials of either prophylactic colectomy or surveillance colonoscopy to detect dysplasia, quantitative analysis has been utilized to estimate the impact of competing management strategies on costs and benefits. Published analyses show that while prophylactic colectomy will likely save the greatest number of life-years, quality of life is not optimal, and thus shared decision-making between provider and patient is recommended. Surveillance colonoscopy to detect early cancer and dysplasia appears to be cost-effective, although the risk of colorectal cancer must be substantial in order for this to hold true. It is estimated that the incidence of cancer in ulcerative colitis must exceed 27% over a 30-year period in order for surveillance colonoscopy every 2 years to be cost-effective. Determination of the optimal interval between surveillance procedures is also a contentious issue. Although annual surveillance colonoscopy may not be cost-effective, 3-4 year intervals yield cost-effectiveness ratios comparable to other medical practices deemed worthwhile by society, while 5-year interval produce an incremental cost-effectiveness similar to screening strategies in other diseases.

Greater loss of productivity among Japanese workers with gastro-esophageal reflux disease (GERD) symptoms that persist vs resolve on medical therapy.

BACKGROUND: Gastro-esophageal reflux disease (GERD) impairs quality of life; however, the association between GERD and work productivity has not been well investigated in Japan. This study was designed to compare the impact of GERD on productivity between Japanese workers with GERD symptoms that persisted vs resolved on medical therapy. METHODS: A cross-sectional Web-based survey was conducted in workers. The impact of GERD on work and daily productivity was evaluated using a Web-reported Work Productivity and Activity Impairment Questionnaire for patients with GERD and a GERD symptom severity Questionnaire. Demographic information, clinical history, and satisfaction with GERD medication were also ascertained. KEY RESULTS: A total of 20 000 subjects were invited to the survey. After the exclusion of patients with a history of gastrointestinal (GI) malignancy, peptic ulcer, upper GI surgery, and unemployment, 650 participants were included in the analysis. Participants with persistent GERD symptoms reported a significantly greater losses of work productivity (11.4 ± 13.4 h/week), absenteeism (0.7 ± 3.1 h/week), presenteeism (10.7 ± 12.6 h/week), costs (20 100 ± 26 800 JPY/week), and lower daily productivity (71.3% [95% confidence interval, 69.0-73.7]) than those whose symptoms were alleviated with medications. The level of dissatisfaction with GERD medications among participants with persistent GERD symptoms was significantly correlated with loss of work and daily productivity (p < 0.001). CONCLUSIONS & INFERENCES: GERD places a significant burden on work and daily productivity despite medical therapy. Ineffective GERD therapy is associated with greater productivity loss.

Classification of functional dyspepsia based on concomitant bowel symptoms.

BACKGROUND: Functional dyspepsia (FD) is a heterogeneous disease, and categorized into postprandial distress syndrome (PDS) and epigastric pain syndrome (EPS). However, many FD patients have overlap of both PDS and EPS. The present study was designed to examine whether FD could be categorized based on the presence of concomitant gastrointestinal symptoms. METHODS: A web survey comprised of the Gastrointestinal Symptom Rating Scale (GSRS), Rome III criteria of FD, and demographic information was sent to public participants who have no history of severe illness. Factor and cluster analyses were conducted to identify sub-categories of FD based on GSRS. KEY RESULTS: A total of 8038 participants completed the survey. A total of 563 participants met the criteria for FD, whereas 6635 participants did not have dyspepsia symptoms. The remainder had either organic disease (377) or uninvestigated dyspepsia (463). The cluster analysis categorized participants as constipation predominant (cluster C), diarrhea predominant (cluster D), or having neither diarrhea nor constipation (cluster nCnD). Cluster C and D were significantly associated with the presence of FD [odds ratio (OR) 2.57, 95% confidence interval (CI) 2.06-3.21; OR 2.80; 95% CI 2.27-3.45, respectively]. In FD, especially in PDS cases, the scores of upper gastrointestinal symptoms were higher in cluster C or D than in cluster nCnD. CONCLUSIONS & INFERENCES: The severity of dyspepsia symptoms is associated with the presence of bowel symptoms especially in PDS. This novel categorization of FD based on concomitant constipation or diarrhea may improve classification of patients.

Japanese herbal medicine in functional gastrointestinal disorders.

Management of functional gastrointestinal disorders is hindered by both poor efficacy and adverse effects of traditional pharmacological therapy. Herbal medicine may be an attractive alternative based on the perception of its 'natural' approach and low risk of side effects; however, the lack of standardization of drug components has limited the ability to perform rigorous clinical studies in Western countries. Japanese herbal medicine (JHM) is a standardized form of herbal medicine with regards to the quality and quantities of ingredients. While extensively studied and widely used in Asia, there is a paucity of data upon which physicians in other parts of the world may draw conclusions regarding the effectiveness of herbal medicine for gastrointestinal disorders. The aim of this study was to summarize the most recent developments in JHM for treatment of functional gastrointestinal disorders. Animal and human studies were systematically reviewed to identify published data of JHM used for treatment of gastrointestinal disorders. The herbal components of JHM were examined. Results describing the physiological and clinical effects of JHM were abstracted, with an emphasis on functional gastrointestinal disorders. JHM are associated with a variety of beneficial physiological on the gastrointestinal system. Patient-based clinical outcomes are improved in several conditions. Rikkunnshi-to reduces symptoms and reverses physiological abnormalities associated with functional dyspepsia, while dai-kenchu-to improves symptoms of postoperative ileus and constipation in children. This updated summary of JHM in the field of gastrointestinal disorders illustrates the potential for herbal medication to serve a valuable role in the management of patients with functional gastrointestinal disorders.

Ascites improves upon [corrected] serum sodium plus [corrected] model for end-stage liver disease (MELD) for predicting mortality in patients with advanced liver disease.

BACKGROUND: The clinical impact of ascites has historically been well recognized; however, its value is unclear in the context of current prognostic models. AIM: To determine whether ascites can improve risk discrimination beyond model for end-stage liver disease (MELD) and serum sodium (MELDNa). METHODS: Consecutive cirrhotic patients were evaluated for ascites on the basis of an outpatient CT along with concurrent MELD and Na values. Cox models were used to determine the added value of ascites for predicting 1-year mortality. Increases in the C-index, integrated discrimination improvement (IDI) and the net reclassification index (NRI) were used to assess improvements in discrimination after the addition of ascites. RESULTS: A total of 1003 patients had Na and MELD scores available within 30 days of the CT scan. A total of 60 deaths occurred within 1 year, with mortality higher in patients with ascites (21.4% vs. 4.0%, HR 6.08, 95% CI 3.62-10.19, P < 0.0005). In the presence of ascites, the MELD and MELDNa scores underestimated mortality risk when the scores were less than 21. The addition of ascites to the MELDNa model substantially improved discrimination by the C-index (0.804 vs. 0.770, increase of 3.4%, 95% CI 0.2-9.9%), IDI (1.8%, P = 0.016) and NRI (15.8%, P = 0.0006). CONCLUSION: The incorporation of radiographic ascites significantly improves upon MELDNa for predicting 1-year mortality. The presence of ascites may help identify patients at increased risk for mortality, not otherwise captured by either MELD or MELDNa.

NIH consensus development statement on management of hepatitis B.

OBJECTIVE: To provide health care providers, patients, and the general public with a responsible assessment of currently available data on the management of hepatitis B. PARTICIPANTS: A non-DHHS, nonadvocate 12-member panel representing the fields of hepatology and liver transplantation, gastroenterology, public health and epidemiology, infectious diseases, pathology, oncology, family practice, internal medicine, and a public representative. In addition, 22 experts from pertinent fields presented data to the panel and conference audience. EVIDENCE: Presentations by experts and a systematic review of the literature prepared by the Minnesota Evidence-based Practice Center, through the Agency for Healthcare Research and Quality. Scientific evidence was given precedence over anecdotal experience. CONFERENCE PROCESS: The panel drafted its statement based on scientific evidence presented in open forum and on published scientific literature. The draft statement was presented on the final day of the conference and circulated to the audience for comment. The panel released a revised statement later that day at http://consensus.nih.gov. This statement is an independent report of the panel and is not a policy statement of the NIH or the Federal Government. CONCLUSIONS: The most important predictors of cirrhosis or hepatocellular carcinoma in persons who have chronic HBV are persistently elevated HBV DNA and ALT levels in blood. Other risk factors include HBV genotype C infection, male sex, older age, family history of hepatocellular carcinoma, and co-infection with HCV or HIV. The major goals of anti-HBV therapy are to prevent the development of progressive disease, specifically cirrhosis and liver failure, as well as hepatocellular carcinoma development and subsequent death. To date, no RCTs of anti-HBV therapies have demonstrated a beneficial impact on overall mortality, liver-specific mortality, or development of hepatocellular carcinoma. Most published reports of hepatitis therapy use changes in short-term virologic, biochemical, and histologic parameters to infer likelihood of long-term benefit. Approved therapies are associated with improvements in intermediate biomarkers, including HBV DNA, HBeAg loss or seroconversion, decreases in ALT levels, and improvement in liver histology (Table). Although various monitoring practices have been recommended, no clear evidence exists for an optimal approach. The most important research needs include representative prospective cohort studies to define the natural history of the disease and large RCTs of monotherapy and combined therapies, including placebo-controlled trials, that measure the effects on clinical health outcomes. Table. Criteria Useful in Determining for Whom Therapy is Indicated: Patients for whom therapy is indicated: Patients who have acute liver failure, cirrhosis and clinical complications, cirrhosis or advanced fibrosis and HBV DNA in serum, or reactivation of chronic HBV after chemotherapy or immunosuppression; Infants born to women who are HBsAg-positive (immunoglobulin and vaccination). Patients for whom therapy may be indicated: Patients in the immune-active phase who do not have advanced fibrosis or cirrhosis. Patients for whom immediate therapy is not routinely indicated: Patients with chronic hepatitis B in the immune-tolerant phase (with high levels of serum HBV DNA but normal serum ALT levels or little activity on liver biopsy); Patients in the inactive carrier or low replicative phase (with low levels of or no detectable HBV DNA in serum and normal serum ALT levels); Patients who have latent HBV infection (HBV DNA without HBsAg). We recommend routine screening for hepatitis B of newly arrived immigrants to the United States from countries where the HBV prevalence rate is greater than 2%. Screening will facilitate the provision of medical and public health services for infected patients and their families and provide public health data on the burden of disease in immigrant populations. The screening test should not be used to prohibit immigration.

The impact of colorectal cancer screening on life expectancy.

METHODS: The purpose of this study was to assess the effect of screening for colorectal cancer on life expectancy and estimate the number of colonoscopies needed per life year saved. The declining exponential approximation of life expectancy was used to calculate the effect of colorectal cancer screening on expected remaining lifetime. The annual number of deaths from colorectal cancer and the size of the population were obtained from the vital statistics of the United States. Published reports were consulted to determine the decrease in mortality from colorectal cancer achieved by fecal occult blood testing, screening sigmoidoscopy or colonoscopy. A Markov chain analysis was used to determine the endoscopic resources required to screen and survey the entire population of U.S. residents age 50 years until death or age 85 years. RESULTS: Colorectal cancer decreases the life expectancy of U.S. residents aged 50 to 54 years by 292 days and those aged 70 to 74 years by 70 days. Screening with fecal occult blood tests extends expected lifetime of the 2 age groups by 51 and 12 days, respectively, whereas screening with sigmoidoscopy leads to increases of 86 and 21 days. Colonoscopic screening increases expected lifetime by 170 and 41 days, respectively. The number of colonoscopies needed to save 1 year of expected life ranges from 2.9 to 6.0, depending on the type of screening regimen used. CONCLUSIONS: The extension of life through screening colonoscopy is two or three times longer than the extension achieved through flexible sigmoidoscopy or fecal occult blood test, respectively. Although a large number of colonoscopies are required to screen the U.S. population, relatively few colonoscopies need to be invested per year of life expectancy saved.

The impact of peptic ulcer disease and infection with Helicobacter pylori on life expectancy.

OBJECTIVE: Knowledge about the influence of H. pylori-related disease on life expectancy might affect physician behavior in dealing with such disease. The aim of this study was to assess how life expectancy is influenced by H. pylori infection and peptic ulcer disease. METHODS: The declining exponential approximation of life expectancy was used to model the effects of H. pylori and various peptic ulcer disease conditions on life expectancy. Deaths from peptic ulcer and gastric cancer were determined from the Vital Statistics of the United States. H. pylori prevalence rates were derived from the existing literature. RESULTS: Cure of active peptic ulcer increases life expectancy by 2.3 yr in persons aged 40-44 yr and 121 days in persons aged 70-74 yr. More substantial impact occurs in complicated ulcer, with increases in life expectancy ranging between 26.1 and 6.3 yr. Primary prevention of H. pylori could increase life expectancy by 190 days in those aged 40-44 yr and 26 days in 70-74-yr-old subjects. CONCLUSION: The benefit of ulcer cure or H. pylori prevention diminishes as age advances. Cure of ulcers in young patients or in those who have sustained complications results in an appreciable increase in life expectancy. Successful primary prevention of H. pylori in selected populations could substantially increase life expectancy.

Reliability block diagrams to model the management of colorectal cancer.

The present study aims to show how various medical and nonmedical components contribute to success and failure in the management of colorectal cancer. The first encounter, subsequent diagnosis, and surgical therapy of a patient with Dukes B sigmoid cancer is modeled as a reliability block diagram with a serial and parallel arrangement of various components. The overall probability of a patient with new-onset colorectal cancer to visit a physician, be correctly diagnosed, and undergo successful therapy is 69%. The reduction in the overall success, despite the fact that the majority of components are assumed to function with failure rates of 5% or less, is a reflection of the multitude of serial subsystems involved in the management of the patient. In contrast, the parallel arrangement of subsystems results in a relative insensitivity of the overall system to failure, a greater stability, and an improved performance. Since no medical system functions perfectly, redundancy associated with parallel subsystems assures a better overall outcome. System analysis of health care provides a means to improve its performance.