Meta-analysis and endocrinology

Halitosis and helicobacter pylori infection: A meta-analysis

BACKGROUND

Halitosis is used to describe any disagreeable odor of expired air regardless of its origin. Numerous trials published have investigated the relation between Helicobacter pylori (H pylori) infection and halitosis, and even some regimes of H pylori eradication have been prescribed to those patients with halitosis in the clinic. We conducted a meta-analysis to define the correlation between H pylori infection and halitosis.

OBJECTIVES

To evaluate whether there is a real correlation between H pylori infection and halitosis, and whether H pylori eradication therapy will help relieve halitosis.

METHODS

We searched several electronic databases (The Cochrane Library, MEDLINE, EMBASE, PubMed, Web of Science, and Wanfangdata) up to December 2015. Studies published in English and Chinese were considered in this review. After a final set of studies was identified, the list of references reported in the included reports was reviewed to identify additional studies. Screening of titles and abstracts, data extraction and quality assessment was undertaken independently and in duplicate. All analyses were done using Review Manager 5.2 software.

RESULTS

A total of 115 articles were identified, 21 of which met the inclusion criteria and presented data that could be used in the analysis. The results showed that the OR of H pylori infection in the stomach between halitosis-positive patients and halitosis-negative patients was 4.03 (95% CI: 1.41-11.50; P = 0.009). The OR of halitosis between H pylori-positive patients and H pylori-negative patients was 2.85 (95% CI: 1.40-5.83; P = 0.004); The RR of halitosis after successful H pylori eradication in those H pylori-infected halitosis-positive patients was 0.17 (95% CI: 0.08-0.39; P <0.0001), compared with those patients without successful H pylori eradication. And the RR of halitosis before successful H pylori eradication therapy was 4.78 (95% CI: 1.45-15.80; P = 0.01), compared with after successful H pylori eradication therapy.

CONCLUSIONS

There is clear evidence that H pylori infection correlates with halitosis. H pylori infection might be important in the pathophysiological mechanism of halitosis, and H pylori eradication therapy may be helpful in those patients with refractory halitosis.

Clostridium difficile-associated diarrhea and proton pump inhibitor therapy: a meta-analysis

OBJECTIVES

Clostridium difficile-associated diarrhea (CDAD) is a major cause of morbidity and increasing health-care costs among hospitalized patients. Although exposure to antibiotics remains the most documented risk factor for CDAD, attention has recently been directed toward a plausible link with proton pump inhibitors (PPIs). However, the results of studies on the association between CDAD and PPIs remain controversial. We have conducted a meta-analysis to summarize the association between PPIs and CDAD among hospitalized patients.

METHODS

A systematic search of published literature on studies that investigated the association between PPIs and CDAD from 1990 to 2010 was conducted on Medline and PubMed. The identified articles were reviewed for additional references. The most adjusted risk estimates were extracted by two authors and summarized using random effects meta-analysis. We also conducted a subgroup analysis by study design. Publication bias was evaluated using the Begg and Egger tests. A sensitivity analysis using the Duval and Tweedie "trim-and-fill" method has also been performed.

RESULTS

Twenty-three studies including close to 300,000 patients met the inclusion criteria. There was a 65% (summary risk estimate 1.69 with a 95% confidence interval (CI) from 1.395 to 1.974; P<0.000) increase in the incidence of CDAD among patients on PPIs. By study design, whether case-control study (17) or cohort study (6), there was still a significant increase in the incidence of CDAD among PPI users. The risk estimates were 2.31 (95% CI from 1.72 to 3.10; P<0.001) and 1.48 (95% CI from 1.25 to 1.75; P<0.001) for cohort and case-control studies, respectively.

CONCLUSIONS

There is sufficient evidence to suggest that PPIs increase the incidence of CDAD. Our meta-analysis shows a 65% increase in the incidence of CDAD among PPI users. We recommend that the routine use of PPIs for gastric ulcer prophylaxis should be more prudent. Establishing a guideline for the use of PPI may help in the future with the judicious use of PPIs. Further studies, preferably prospective, are needed to fully explore the association between PPIs and CDAD.

A comparison of label-based review and ALE meta-analysis in the Stroop task

Meta-analysis is an important tool for interpreting results of functional neuroimaging studies and is highly influential in predicting and testing new outcomes. Although traditional label-based review can be used to search for agreement across multiple studies, a new function-location meta-analysis technique called activation likelihood estimation (ALE) offers great improvements over conventional methods. In ALE, reported foci are modeled as Gaussian functions and pooled to create a statistical whole-brain image. ALE meta-analysis and the label-based review were used to investigate the Stroop task in normal subjects, a paradigm known for its effect of producing conflict and response inhibition due to subjects' tendency to perform word reading as opposed to color naming. Both methods yielded similar activation patterns that were dominated by response in the anterior cingulate and the inferior frontal gyrus. ALE showed greater involvement of the anterior cingulate as compared to that in the label-based technique; however, this was likely due to the increased spatial level of distinction allowed with the ALE method. With ALE, further analysis of the anterior cingulate revealed evidence for somatotopic mapping within the rostral and caudal cingulate zones, an issue that has been the source of some conflict in previous reviews of the anterior cingulate cortex.

A meta-analysis comparing eradication, healing and relapse rates in patients with Helicobacter pylori-associated gastric or duodenal ulcer

AIM

To compare the effectiveness of Helicobacter pylori eradication in curing peptic ulcer disease in trials involving both gastric ulcer and duodenal ulcer.

METHODS

Twenty-four relevant randomized controlled trials and randomized comparative trials met the predefined selection criteria. Only proton pump inhibitor-based eradication trials were considered for the evaluation of eradication efficacy and ulcer healing. For the determination of relapse rates, all trials independent of the eradication therapy regimen were considered.

RESULTS

Data from 2102 patients were analysed comparing gastric ulcer with duodenal ulcer. No statistical differences between gastric ulcer and duodenal ulcer patients were found with regard to eradication rates (summarized odds ratio, 1.23; 95% confidence interval, 0.98-1.55) or ulcer relapse rates, whether in successfully H. pylori eradicated patients (summarized odds ratio, 0.69; 95% confidence interval, 0.26-1.84) or unsuccessfully H. pylori eradicated patients (summarized odds ratio, 1.48; 95% confidence interval, 0.85-2.56). Owing to heterogeneity, healing rates were not comparable.

CONCLUSIONS

The eradication of H. pylori infection cures both gastric and duodenal ulcer, and the cure rates are similar. This suggests that H. pylori is the key factor in peptic ulcer disease independent of the ulcer site.

Beyond the single study: function/location metanalysis in cognitive neuroimaging

Cognitive neuroimaging maps the brain locations of mental operations. This process is iterative, as no single study can fully characterize a mental operation or its brain location. This iterative discovery process, in combination with the location-reporting standard (i.e. spatial coordinates) of the cognitive neuroimaging community, has engendered a new form of metanalysis. Response locations from multiple studies have been analyzed collectively so as to better describe the spatial distribution of brain activations, with promising results. New hypotheses regarding elementary mental operations and their respective brain locations are being generated and refined via metanalysis. These hypotheses are being tested and confirmed by subsequent, prospective experiments. Function/location metanalysis is an important new tool for hypothesis generation in cognitive neuroimaging. This form of metanalysis is fundamentally different from the effect-size metanalyses prevalent in other literatures, with unique advantages and challenges.