The epidemiology of hepatitis C virus infection. An update for clinicians

Since the advent of sensitive diagnostic blood tests for the detection of antibody to hepatitis C virus (HCV) in donors, there has been a large decline in the incidence of transfusion-related hepatitis. Globally, the infection has an estimated prevalence of 3%, with a prevailing 1% in Europe while varying geographically within a North-South gradient, ranging from around 0.5% in Northern countries to 2% in Mediterranean area. The incidence is very difficult to estimate accurately as many patients with acute HCV infection are asymptomatic and, thus, do not present for diagnosis. Data from the US report a fall in the annual occurrence of new cases per year from 230,000 in the late 1980s to approximately 35,000 in the 1990s. Therefore, a reduction in incident cases might eventually lead to lower prevalence of HCV infection. Although the incidence of viral infection may be decreasing, the prevalence of liver disease caused by HCV is on the rise. This is due to the significant lag, often 20 years or longer, between the onset of infection and clinical manifestation of liver disease. HCV can be transmitted by a variety of routes. It is most efficiently passed on by large or repeated percutaneous exposures such as through transfusions, transplantation from an infected donor or intravenous drug use. Transmission may also occur from contacts with infected subjects in the household, through perinatal and parenteral exposures in the health care setting. The risk of sexual transmission of HCV is low. Despite this knowledge, nearly half of infected patients do not have a history suggesting a parenteral route of acquisition. Since a prophylactic vaccine is hitherto not available, prevention becomes extremely important: identification of infected persons and of risk factors associated with acquiring HCV allow to develop strategies for preventing the spread of infection as well as its complications, and for planning appropriate care and support services.

Helicobacter pylori and coronary heart disease: which directions for future studies?

Classical risk factors explain the pathogenesis of coronary heart disease (CHD) in only a proportion of cases; therefore, the need to investigate the possible role of "new" agents has incited intense research. Since 1994, a number of studies regarding the possible involvement of Helicobacter pylori (H. pylori) have been published with conflicting results. Establishing a causal link between this infection and CHD would be of major public health importance, since the eradication of the bacterium is easy and much less expensive than long-term treatment of the other risk factors. The main cause of this discordance was the vast heterogeneity of such studies: sufficiently powerful design was found only in few investigations, CHD was defined with a low degree of homogeneity, biases were obvious in the control groups, thus giving room for large variation in the adjustment of potential confounding factors. The present paper attempts to highlight the future directions towards which research should be headed in this area to establish a causal role of H. pylori infection in the pathogenesis of CHD. Future research should take three directions: 1) prospective population-based studies in which the incidence or the recurrence of CHD be evaluated in correlation with H. pylori status, 2) intervention trials, focusing separately on the chronic and acute phases of coronary heart disease and, 3) studies of physiopathology (both in the animal model and humans) to understand the potential biological plausibility.

The epidemiology of gastro-oesophageal reflux disease. A brief review

During the last century, gastro-oesophageal reflux disease (GERD) has become increasingly observed in Western countries. The disorder is chronic and relapsing with a clinically significant impairment in quality of life. Symptoms of GERD are very common in the general population. However, reported symptoms under-represent the true prevalence of the disease, because these do not equate with mucosal damage, and this might lead to a bias in epidemiologic surveys. Several studies have been conducted in endoscopic centres, but these were able to focus on only some consequences of GERD (oesophagitis or Barrett's oesophagus) and not on nonerosive reflux disease (NERD). The latter is a clinical condition characterised by symptoms of reflux and intraesophageal gastric content reflux in the absence of visible endoscopic oesophageal mucosal injury. Moreover, the diffuse use of acid suppressing drugs in the population is able to mask some manifestations of GERD. Other studies have been conducted in the form of questionnaires investigating the presence and the frequency of symptoms typical of GERD. These estimates have taken into consideration and assumed that heartburn is an indicator of the disease. Taking into account the many faces of GERD, and its wide spectrum of manifestations, including atypical symptoms, this could represent a serious limitation. This brief review article fosters understanding of this issue by focusing on the epidemiology of GERD.

The role of gastroesophageal reflux disease in chest pain

Gastroesophageal reflux disease (GERD) is thought to play an important role in the pathogenesis of non-cardiac, unexplained, chest pain. The physiopathological mechanism of this extraesophageal manifestation, remains unclear but it is supposed that the ache could be triggered by the stimulation of acid-sensitive nociceptors of the mucosa. The esophageal origin of the symptom may be identified by an empiric trial of high-dose antisecretory drugs or an abnormal prolonged ambulatory pH monitoring study. Less important is the role of endoscopy especially in subjects without typical symptoms of GERD. The use of manometry or provocative tests can consent to evaluate for esophageal motility abnormalities. It is generally accepted that in clinical practice, in patients with non-cardiac chest pain, the administration of proton pump inhibitors, could serve as a first approach. It is cost-effective in the short-term period, when compared with investigation for gastrointestinal causes, with cost savings persisting beyond a year. In conclusion, patients with non-cardiac chest pain of unknown origin should be carefully screened for the occurrence of GERD, but further research is needed to clarify the role of the latter on the pathogenesis of this symptom.

Diagnosis of Helicobacter pylori infection: validation of a commercial non invasive salivary test against urea breath test and serology

BACKGROUND

Helicobacter pylori (H. pylori) infection plays an important role in the pathogenesis of chronic gastritis, peptic ulcer disease, MALT lymphoma and gastric cancer. Recently Helicobacter spp. infection has been correlated with cirrhosis, hepatocellular carcinoma and acute myocardial infarction. Several invasive and non-invasive tests have been proposed for the detection of the bacterium. In clinical practice, the selection of the appropriate test will depend on the disease and on cost-effectiveness. Aim of the study was to validate a rapid, salivary test for detecting the presence of antibodies against H. pylori in a population of patients undergoing to the 13C-urea breath test (13C-UBT).

METHODS

Saliva and serum samples were obtained from 91 patients (47 females, mean age 53+/-6.7 years) attending the 13C-UBT service between 15 September and 31 November 1999. Thirty-five of them had had a previous diagnosis of peptic ulcer at endoscopy and 46 out of 91 had a diagnosis of histologically confirmed chronic gastritis. 39 out of 91 were dyspeptic patients with no symptoms suspect for peptic ulcer or cancer. Patients were excluded from the 13C-UBT if they had been treated with inhibitors of acid secretion and antibiotics within 30 days before testing. Breath sample were collected at baseline and 30 minutes after the ingestion of orange juice and a 75 mg dose of 13C-labeled urea. The presence in serum of antibodies (IgG) against the bacterium was assessed by means of a commercial enzyme immunosorbent assay with a reported sensitivity of 94% and specificity of 87%. Saliva was collected using a sterile absorbent pad placed between the mandibular gum and the cheek in the mouth and assayed for H. pylori antibodies by an immunochromatographic rapid method.

RESULTS

Thirty-seven of the 91 patients were defined positive by 13C-UBT and serological test. Twenty-nine of these 37 were identified as positive by the salivary test. Fifty-four patients were defined as negative but the salivary test identified 13 of them as positive, thereby sensitivity and specificity were 78.3 and 75.9% respectively. The accuracy was 76.9%. Positive predictive value was 69% and negative predictive value 83.6%.

CONCLUSIONS

The salivary test could be considered in the ambulatory setting, as a non-invasive tool for the screening of H. pylori infection, when more accurate methods are not available.

[Gastroenterologists in ambulatory care. The experience in Turin in the year 2000]

BACKGROUND

Digestive diseases (GI) have a major impact on public health in Italy. Hospital stay for digestive pathologies parallels that due to cardiovascular causes. Total mortality for GI causes is also very high. The management of GI pathologies is therefore a major task for the National Health System. To the experienced gastroenterologist it is clear that a large number of hospitalisation is linked to a lack of careful outpatient follow-up of diseases such as cirrhosis, ulcerative colitis and peptic ulcer.

METHODS

One year of activity of our Gastro-entero-Hepatology outpatient service is examined. The management of the majority of GI diseases is organized in working teams of physicians and surgeons following cohorts of patients suffering of a specific disease.

RESULTS

During the year 2000 not only a statistically significant higher number of patients has been examined (p<0.05), in comparison with 1994, but also the hospitalisation rate was lowered resulting in a very significative cost-containment.

CONCLUSIONS

The specialization of outpatient activities into working teams offers advantages in terms of more appropriate medical care and cost reduction, partly due to a less frequent hospitalisation. The obvious counterpart was an increase of request of such form of follow-up from patients, resulting in longer delay to the access.

The effect of the eradication of Helicobacter pylori infection on hemorrhage because of duodenal ulcer

The cost of a recurrently bleeding duodenal ulcer (DU) is very high, both from a human and an economic point-of-view. Helicobacter pylori infection plays an important role in the pathogenesis of DU disease and its complications, such as bleeding. Cure of H. pylori infection is recommended in patients with DU and its complications, although in the latter case, the most efficient management is not yet a defined issue. In particular, acid secretion inhibitors may not contribute to long-term cure. Our aims were to ascertain whether the recurrence of bleeding because of DU could be prevented by H. pylori eradication and whether long-term inhibition of gastric acid output is needed to prevent recurrence. Eighty-four patients (65 men; mean age, 55.1 years), who had bled because of recurrent DU, were followed after the cure of H. pylori infection. None of the patients were on therapy with nonsteroidal antiinflammatory drugs. Successful cure of H. pylori was determined by gastroscopy, histology, and serology performed at 3, 6, 12, 24, and 48 months after the eradication treatment. A 13C urea breath test was performed when the results of serology were unclear and also at recurrence of DU or bleeding. After the antibiotic treatment, 46 patients stopped all medications, whereas 38 continued long-term therapy with histamine type 2 receptor antagonists. During a mean follow-up period of 47.2 months (range, 37-65 months), recurrence of DU at endoscopy was observed in three patients in each group (p = 0.56), but none bled again. We conclude that H. pylori eradication prevents DU recurrence and rebleeding, that reinfection rate by H. pylori after cure was nil at 4 years, and that long-term inhibition of acid secretion may not improve outcome after cure of H. pylori, even in patients whose DU was complicated by hemorrhage.

Ischemic cardiovascular disease and Helicobacter pylori. Where is the link?

Coronary heart disease (CHD) is the leading cause of death in western countries. Although several major risk factors have been identified, they fail to account for all the epidemiological variants of the disease, thus warranting research into novel causal agents. Cardiovascular diseases have long been associated with chronic infections acting through the activation of inflammatory pathways, and antibiotic therapy has been shown to produce a dramatic decrease in the rate of disease recurrence in patients with a history of myocardial infarction or unstable angina. The link between Helicobacter pylori (H. pylori) infection and CHD, first described by Mendall et al. in 1994, has been the subject of a multitude of epidemiological and clinical studies; however, these have been so heterogeneous that not two of them are based on a comparable selection of patients and focused on the same kind of disease, e.g. stable coronary heart disease or acute myocardial infarction. Evidence from animal studies supports the thesis that H. pylori plays an extremely important role in the acute phase of myocardial infarction: the bacterium causes platelet aggregation and induces pro-coagulant activity in experimentally infected mice. H. pylori may also contribute to atherosclerosis through an auto-immune process against endothelial cells or an increased concentration of homocysteine in the blood due to decreased levels of folic acid and cobalamin. The exact role of H. pylori cannot yet be fully assessed: there is a clear and present need for further studies with appropriate epidemiological and clinical approaches to investigate through prospective and interventional trial the possible causal relationship between H. pylori and CHD.

[Infections and cardiovascular diseases on an ischemic basis. The case of Helicobacter pylori]

Cardiac and cerebrovascular diseases are an important cause of mortality in industrialized countries. "Classical" risk factors cannot fully explain epidemiological variations of these diseases. From several years infections have been linked to ischemic vascular events and recent publications pointed to the role of Helicobacter pylori, a Gram negative bacterium, involved in the pathogenesis of gastritis and peptic ulcer. Results on the association between this bacterium and acute myocardial infarction or stroke are controversial, due to the degree of studies heterogeneity. There is the need for extensive prospectic studies to evaluate the incidence of these diseases in relation to the presence of Helicobacter pylori infection. Interventional randomized studies employing an antibiotic treatment for patients affected by ischemic vascular diseases will rapidly answer the question of wheather Helicobacter pylori has a causal role in the pathogenesis of acute myocardial infarction and ischemic stroke.

[Helicobacter pylori infection in pediatrics. Present knowledge and practical problems]

Helicobacter pylori (H. pylori) infection is acquired in childhood, earlier in developing countries, as a consequence the prevalence of infection is higher in developing countries (70%) than in developed countries (5-15%). H. pylori infection spreads from person-to-person, however the precise mode of transmission (oral-oral, fecal-oral or gastro-oral routes) is as yet, not known. Diagnosis of H. pylori infection can be performed with both invasive endoscopic-based tests, or non-invasive tests, mainly by measurement of IgG antibodies against the bacterium in serum samples or by measurement of 13CO2 in expired air (13C-urea breath test). In clinical practice endoscopy and biopsy is recommended before treatment to determine the presence and the degree of gastritis or ulcer. However, endoscopy is a complicated procedure in children and diagnosis of infection can be based on a non-invasive test. The association of H. pylori infection with recurrent abdominal pain seems evident in a subgroup of children with endoscopic features of gastritis, ulcer or hemorrhage. There is an increasing interest in the extraintestinal manifestations of H. pylori infection in children, i.e. iron-deficiency anemia, growth retardation and migraine, but this domain remains controversial. Since infection at a young age is believed to result in chronic atrophic gastritis and gastric cancer in adult life, it is logical to consider a future massive programme of eradication and immunization. Regimens suggested for H. pylori eradication are a combination of inhibitors of gastric acid secretion plus two antibiotics for 7-10 days.

[Effects of surgical treatment on hypertrophy of the myocardium of the left ventricle in patients with symptomatic arterial hypertension]

A total of 50 patients with arterial hypertension were examined. Group 1 included 28 patients with renovascular hypertension, 18 of them had unilateral renal artery stenosis, the remaining 10 had bilateral renal artery stenosis. Group 2 consisted of 16 patients with primary aldosteronism. Group 3 comprised 6 patients with pheochromocytoma. The examination was made with echocardiograph. Changes in left ventricular myocardial mass (LVMM) were studied 1 and 6 months after surgical intervention. The maximum hypertrophy was observed in the patients with primary aldosteronism, no changes occurred in any of the groups examined 1 month after surgical management. The LVMM was found to be significantly diminished by 13% in the patients with renovascular hypertension and by 23% in patients with adrenal tumors (pheochromocytoma, aldosteroma).