Duplicate breath testing to confirm eradication of Helicobacter pylori: incremental benefit and cost in 419 patients

Helicobacter Pylori-Associated Gastritis in Middle Eastern Patients: A Case Series

Helicobacter pylori (H. pylori) infection is a common chronic infection responsible for upper gastrointestinal symptoms such as indigestion, belching, heartburn, and abdominal fullness along with nausea and vomiting. It is considered a transmissible infection, although the exact chain of transmission is not clear. H. pylori-associated infection is a major pathogenic factor for gastroduodenal ulcers and gastric carcinoma in most patients, which can be prevented with eradication therapy. Transmission of the bacterium occurs mainly between family members and during childhood. Others may remain asymptomatic or may present with atypical symptoms such as headache, fatigue/weakness, anxiety, and bloating. We present five interesting cases of H. pylori-positive patients who had variable presentations and were successfully treated with first-line therapy and salvage therapy.

Tablet and oral liquid L-thyroxine formulation in the treatment of naïve hypothyroid patients with Helicobacter pylori infection

To compare the clinical efficacy of tablet and oral liquid L-thyroxine (LT4) formulation in naïve hypothyroid subjects with Helicobacter pylori infection. Forty-seven adult naïve hypothyroid subjects with dyspeptic symptoms were investigated with upper endoscopy and divided into: 28 patients with Helicobacter pylori infection (Group A); 15 patients without gastric alterations (group B); 4 patients with autoimmune gastritis were excluded from the study. Subjects were randomly treated with a same dose of LT4 tablet (TAB) or oral liquid formulation (SOL), for 9 months on group A and 6 months on group B. Helicobacter pylori infection was eradicated after 3 months of LT4 treatment. On group A, after 3 months (before Helicobacter pylori eradication), subjects treated with SOL showed a greater thyroid-stimulating hormone reduction (ΔTSH_3-0: TAB = -4.1 ± 4.6 mU/L; SOL = -7.7 ± 2.5 mU/L; p = 0.029) and a greater homogeneity in the thyroid-stimulating hormone values (TSH_3mo: TAB = 5.7 ± 4.9 mU/L; SOL = 4.1 ± 2.0 mU/L; p = 0.025), compared to LT4 tablet. At 9 months (after 6 months of Helicobacter pylori eradication) mean thyroid-stimulating hormone values were lower in subjects treated with LT4 tablet (TSH_9mo: TAB = 1.8 ± 1.2 mU/L; SOL = 3.2 ± 1.7 mU/L; p = 0.006). On group B no difference were observed, at each time point, in the mean thyroid-stimulating hormone values and thyroid-stimulating hormone variations between two LT4 formulations. LT4 liquid formulation may produce a better clinical response compared to the tablet formulation in hypothyroid subjects with Helicobacter pylori infection.

Cost-effectiveness analysis of universal noninvasive testing for post-treatment confirmation of Helicobacter pylori eradication and the impact of patient adherence

BACKGROUND

The treatment failure rate for Helicobacter pylori eradication therapy is ~20% due to poor patient compliance and increased antibiotic resistance. This analysis assessed the cost-effectiveness of universal post-treatment testing to confirm eradication of H. pylori infection in adults.

METHODS

Decision-analytic models evaluated the cost-effectiveness of universal post-treatment testing (urea breath test [UBT] or monoclonal fecal antigen test [mFAT]) vs no testing (Model 1), and UBT vs mFAT after adjusting for patient adherence to testing (Model 2) in adults who previously received first-line antimicrobial therapy. Patients testing positive received second-line quadruple therapy; no further action was taken for those testing negative or with no testing (Model 1) or for those nonadherent to testing (Model 2). In addition to testing costs, excess lifetime costs and reduced quality-adjusted life-years (QALYs) due to continuing H. pylori infection were considered in the model.

RESULTS

Expected total costs per patient were higher for post-treatment testing (UBT: US$325.76; mFAT: US$242.12) vs no testing (US$182.41) in Model 1 and for UBT (US$336.75) vs mFAT (US$326.24) in Model 2. Expected QALYs gained per patient were 0.71 and 0.72 for UBT and mFAT, respectively, vs no testing (Model 1), and the same was 0.37 for UBT vs mFAT (Model 2). The estimated incremental costs per QALY gained for post-treatment testing vs no testing were US$82.90-US$202.45 and, after adjusting for adherence, US$28.13 for UBT vs mFAT.

CONCLUSION

Universal post-treatment testing was found to be cost-effective for confirming eradication of H. pylori infection following first-line therapy. Better adherence to UBT relative to mFAT was the key to its cost-effectiveness.

Population genetic analyses of Helicobacter pylori isolates from Gambian adults and children

The gastric pathogen Helicobacter pylori is one of the most genetically diverse of bacterial species. Much of its diversity stems from frequent mutation and recombination, preferential transmission within families and local communities, and selection during persistent gastric mucosal infection. MLST of seven housekeeping genes had identified multiple distinct H. pylori populations, including three from Africa: hpNEAfrica, hpAfrica1 and hpAfrica2, which consists of three subpopulations (hspWAfrica, hspCAfrica and hspSAfrica). Most detailed H. pylori population analyses have used strains from non-African countries, despite Africa's high importance in the emergence and evolution of humans and their pathogens. Our concatenated sequences from seven H. pylori housekeeping genes from 44 Gambian patients (MLST) identified 42 distinct sequence types (or haplotypes), and no clustering with age or disease. STRUCTURE analysis of the sequence data indicated that Gambian H. pylori strains belong to the hspWAfrica subpopulation of hpAfrica1, in accord with Gambia's West African location. Despite Gambia's history of invasion and colonisation by Europeans and North Africans during the last millennium, no traces of Ancestral Europe1 (AE1) population carried by those people were found. Instead, admixture of 17% from Ancestral Europe2 (AE2) was detected in Gambian strains; this population predominates in Nilo-Saharan speakers of North-East Africa, and might have been derived from admixture of hpNEAfrica strains these people carried when they migrated across the Sahara during the Holocene humid period 6,000–9,000 years ago. Alternatively, shared AE2 ancestry might have resulted from shared ancestral polymorphisms already present in the common ancestor of sister populations hpAfrica1 and hpNEAfrica.

How long will it take to reduce gastric cancer incidence by eradicating Helicobacter pylori infection?

Helicobacter pylori (H. pylori) is the most important risk factor for the development of gastric cancer. The objective of this article is to estimate how the number of clinically diagnosed cases caused by H. pylori would reduce in the years after the eradication of the infection from a population. It is assumed that the eradication of H. pylori will prevent the start of some new gastric tumors, but those that have passed the "point of no return" will continue to develop until diagnosed clinically. The observed reduction in the number of clinically diagnosed cases of gastric cancer will depend on the form and parameters of the distribution of the time t taken for tumor to develop into a clinical case after passing the "point of no return." This analysis assumes that the time t follows normal and log-normal distributions with means 5, 10, and 15 years. If the mean value of time t were 5 years, H. pylori caused cases should be almost eliminated after 10 years, whereas if the mean were 10 years, the number of cases should be halved. If the mean were 15 years, the reduction would only be about 15% after 10 years. The eradication of H. pylori from a population will reduce the incidence of gastric cancer, but the follow-up time needed to show and evaluate the reduction may be longer than that that has been used in studies published so far.

Culture-based selection therapy for patients who did not respond to previous treatment for Helicobacter pylori infection

BACKGROUND & AIMS

Eradication of Helicobacter pylori using empiric therapy has become difficult as a result of increasing resistance to antibiotics. We evaluated the efficacy of specific treatments, selected based on response of bacterial samples to culture with clarithromycin, levofloxacin, and metronidazole, for patients infected with resistant strains of H pylori.

METHODS

We performed a prospective study at a single center of 236 consecutive patients with persistent H pylori infection, despite 1 or more treatment attempts, and documented resistance to at least 1 antimicrobial agent (based on bacterial culture tests). Biopsy samples were collected by endoscopy and cultured in selective media. Patients received either 10 days of levofloxacin (250 mg twice daily for 131 patients with susceptible infections) or 12 days of rifabutin (150 mg once daily for 105 patients resistant to levofloxacin) in combination with amoxicillin (1 g twice daily) and esomeprazole (40 mg twice daily). Efficacy of eradication was determined by the (13)C-urea breath test, 6 to 8 weeks after therapy. Compliance and side effects were determined via personal interviews at the end of therapy. Rifabutin toxicity was monitored by analysis of blood samples.

RESULTS

H pylori infection was cured in 118 of the patients who received levofloxacin triple therapy (90%; 95% confidence interval, 85%-95%) and 93 of the patients who received rifabutin triple therapy (88.6%; 95% confidence interval, 82%-95%). In each group, the cure rate did not differ significantly between patients infected with H pylori strains resistant to single or multiple antibiotics. Mild side effects occurred in 15.5% and 14.9% of patients resistant to single or multiple antibiotics, respectively, and self-limiting neutropenia was observed in 1 (0.7%) case.

CONCLUSIONS

Selection of triple therapy with either levofloxacin or rifabutin, based on results from bacterial culture tests, cures H pylori infection in about 90% who did not previously respond to antibiotics.

Does low dose13C-urea breath test maintain a satisfactory accuracy in diagnosing Helicobacter pylori infection?

CONTEXT: The standard doses of 13C-urea in 13C-urea breath test is 75 mg. OBJECTIVE: To assess the diagnostic accuracy of 13C-urea breath test containing 25 mg of 13C-urea comparing with the standard doses of 75 mg in the diagnosis of Helicobacter pylori infection. METHODS: Two hundred seventy adult patients (96 males, 174 females, median age 41 years) performed the standard 13C-urea breath test (75 mg 13C-urea) and repeated the 13C-urea breath test using only 25 mg of 13C-urea within a 2 week interval. The test was performed using an infrared isotope analyzer. Patients were considered positive if delta over baseline was >4.0‰ at the gold standard test. RESULTS: One hundred sixty-one (59.6%) patients were H. pylori negative and 109 (40.4%) were positive by the gold standard test. Using receiver operating characteristic analysis we established a cut-off value of 3.4% as the best value of 25 mg 13C-urea breath test to discriminate positive and negative patients, considering the H. pylori prevalence (95% CI: 23.9-37.3) at our setting. Therefore, we obtained to 25 mg 13C-urea breath test a diagnostic accuracy of 92.9% (95% CI: 88.1-97.9), sensitivity 83.5% (95% CI: 75.4-89.3), specificity 99.4% (95% CI: 96.6-99.9), positive predictive value 98.3% (95% CI: 92.4-99.4), and negative predictive value 93.0% (95% CI: 88.6-96.1). CONCLUSIONS: Low-dose 13C-urea breath test (25 mg 13C-urea) does not reach accuracy sufficient to be recommended in clinical setting where a 30% prevalence of H. pylori infection is observed. Further studies should be done to determine the diagnostic accuracy of low doses of 13C-urea in the urea breath test.

Diagnosis of Helicobacter pylori infection

The articles published this last year in the field of Helicobacter pylori diagnosis reported the development of in vivo histology, small improvements in some invasive methods (urease test, culture, and histology) and new kits for the stool antigen tests. They also contributed to increasing our knowledge, by further exploration into specific conditions for the urea breath test and into the significance of cagA antibodies. The role of serum markers of atrophy was also confirmed. Molecular methods are still being developed for direct genotyping, detection of H. pylori and its clarithromycin resistance, either by polymerase chain reaction or fluorescent in-situ hybridization. For the first time, there was a report on a possible interest of magnetic resonance spectroscopy.