Relationship between long-term use of proton pump inhibitors and risk of gastric cancer: A systematic analysis

Global status and trends of gastric cancer and gastric microbiota research: a bibliometric analysis

Background

Numerous studies have cast light on the relationship between the gastric microbiota and gastric carcinogenesis. In this study, we conducted a bibliometric analysis of the relevant literature in the field of gastric cancer and the gastric microbiota and clarified its research status, hotspots, and development trends.

Materials and methods

Publications were retrieved from the Web of Science Core Collection on 18 July 2023. CiteSpace 6.2.R4, VOSviewer 1.6.19.0, and Biblioshiny were used for the co-occurrence and cooperation analyses of countries, institutions, authors, references, and keywords. A keyword cluster analysis and an emergence analysis were performed, and relevant knowledge maps were drawn.

Results

The number of published papers in this field totaled 215 and showed an increasing trend. The analysis of funding suggested that the input in this field is increasing steadily. China had the highest number of publications, while the United States had the highest betweenness centrality. Baylor College of Medicine published the most articles cumulatively. Both Ferreira RM and Cooker OO had the highest citation frequency. The journal Helicobacter showed the most interest in this field, while Gut provided a substantial research foundation. A total of 280 keywords were obtained using CiteSpace, which were primarily focused on the eradication and pathogenic mechanisms of Helicobacter pylori, as well as the application of the gastric microbiota in the evaluation and treatment of gastric cancer. The burst analysis suggested that in the future, research may focus on the application of gastric microorganisms, particularly Fusobacterium nucleatum, in the diagnosis and treatment of gastric cancer, along with their pathogenic mechanisms.

Conclusion

Current studies have been tracking the eradication of Helicobacter pylori and its pathogenic mechanisms, as well as changes in the gastric microbiota during gastric carcinogenesis. Future research may focus on the clinical application and pathogenesis of stomach microorganisms through bacteria such as Fusobacterium nucleatum.

The central role of gastrin in gastric cancer

The prevalence of gastric cancer has markedly declined, but due to the high mortality rates associated with gastric cancer, it is still a serious disease. The preferred classification of gastric cancer is according to Lauren into either the intestinal type, which has a glandular growth pattern, or the diffuse type, which does not have glandular structures. Both types have been classified as adenocarcinomas, with the latter type based on periodic acid-Schiff (PAS) positivity presumed to reflect mucin. However, the presence of mucin in the diffuse type, in contrast to neuroendocrine/enterochromaffin-like (ECL) cell markers, has not been confirmed by immunohistochemistry and in situ hybridization. The ECL cells are probably prone to becoming cancerous because they do not express E-cadherin. Gastric cancer is unique in that a bacterium, Helicobacter pylori, is thought to be its main cause. H. pylori predisposes infected individuals to cancer only after having caused oxyntic atrophy leading to gastric hypoacidity and hypergastrinemia. No single H. pylori factor has been convincingly proved to be carcinogenic. It is probable that gastrin is the pathogenetic factor for gastric cancer due to H. pylori, autoimmune gastritis, and long-term prolonged inhibition of gastric acid secretion. Hypergastrinemia induces ECL cell hyperplasia, which develops into neuroendocrine tumors (NETs) and then into neuroendocrine carcinomas in rodents, a sequence that has also been described in humans. During carcinogenesis, the tumor cells lose specific traits, requiring that sensitive methods be used to recognize their origin. Gastric cancer occurrence may hopefully be prevented by H. pylori eradication at a young age, and by the reduced use of inhibitors of acid secretion and use of a gastrin antagonist in those with previous long-term H. pylori infection and those with autoimmune gastritis.

Meta-analysis of proton pump inhibitor use and the risk of developing gastric cancer or colorectal cancer

To evaluate the relationship between the use of proton pump inhibitors (PPI) and the risk of gastric cancer and colorectal cancer by using meta-analysis. Computer search PUBMED, EMBASE, Cochrane Library, CNKI and Wanfang database to obtain relevant literature on the use of PPI and the risk of gastric cancer and colorectal cancer, extract relevant data, and use Stata14.0 for Meta-analysis. A total of 24 articles were included, including 12 articles for gastric cancer and 12 articles for colorectal cancer. A total of 5 313 749 persons were included in the study and analysis. Meta-analysis results showed that the risk of gastric cancer in PPI users was significantly increased [risk ratio (RR) = 2.04, 95% confidence interval (CI) (1.33-2.75)], and the regional subgroup analysis results showed that in Europe [RR = 2.01, 95% CI (0.92, 3.09), P < 0.05] and Asia [RR = 2.15, 95% CI (1.16, 3.14), P < 0.05] This risk is higher, and Asia is higher than Europe. The risk of colorectal cancer is slightly increased [RR = 1. 22, 95% CI (1.03, 1.40, P < 0.05], and the regional subgroup analysis results show that in Europe [RR = 1.05 95% CI (0.98, 1.12), P < 0.05] and Asia [RR = 1.18, 95% CI (1.10, 1.27), P < 0.05]. This risk is low, but Asia is higher than Europe. The use of PPI significantly increases gastric cancer However, the risk of colorectal cancer is not significantly increased. The risk of gastric cancer and colorectal cancer in the population using PPI in Asia is higher than that in Europe.

Adverse Effects Associated with Long-Term Use of Proton Pump Inhibitors

Proton Pump Inhibitors are used widely to manage many gastric acid-related conditions such as gastroesophageal disease, gastritis, esophagitis, Barrett's esophagus, Zollinger-Ellison syndrome, peptic ulcer disease, nonsteroidal anti-inflammatory drug-associated ulcers, and Helicobacter pylori eradication, around the globe. This review article focuses on adverse effects associated with the long-term use of proton pump inhibitors. Various observational studies, clinical trials, and meta-analyses have established the adverse effects associated with the long-term use of proton pump inhibitors including renal disorders (acute interstitial nephritis, acute kidney injury, chronic kidney disease, and end-stage renal disease), cardiovascular risks (major adverse cardiovascular events, myocardial infarction, stent thrombosis, and stroke), fractures, infections (Clostridium difficile infection, community-acquired pneumonia, and Coronavirus disease 2019), micronutrient deficiencies (hypomagnesemia, anemia, vitamin B12 deficiency, hypocalcemia, hypokalemia), hypergastrinemia, cancers (gastric cancer, pancreatic cancer, colorectal cancer, hepatic cancer), hepatic encephalopathy, and dementia. Clinicians including prescribers and pharmacists should be aware of the adverse effects of taking proton pump inhibitors for an extended period of time. In addition, the patients taking proton pump inhibitors for long-term should be monitored for the listed adverse effects. The American Gastroenterological association recommends a few non-pharmacological measures and the use of histamine 2 blockers to lessen gastrointestinal symptoms of gastroesophageal reflex disease and the utilization of proton pump inhibitors treatment if there is a definitive indication. Additionally, the American Gastroenterological association's Best Practice Advice statements emphasize deprescribing when there is no clear indication for proton pump inhibitors therapy.

Meta-analysis: Use of proton pump inhibitors and risk of gastric cancer in patients requiring gastric acid suppression

BACKGROUND

Proton-pump inhibitors (PPIs) are suspected to increase the risk of gastric cancer.

AIM

To assess the risk of gastric cancer associated with the use of PPIs.

METHODS

We systematically searched Medline/PubMed, Embase and Scopus databases (until June 1, 2022) for randomised and non-randomised studies (NRS) of the association between PPIs and gastric cancer having considered Histamine-2 receptor antagonists (H2RAs) users as controls. We chose this comparison to minimise confounding by indication, and focus on patients requiring gastric acid suppression. Two authors independently extracted study data and assessed each study's risk of bias. Maximally-adjusted relative risk (RR) estimates were extracted. Heterogeneity and small-study effect were examined, and summary estimates were calculated using random- and fixed-effect models. Stratified analyses and meta-regression were employed to explore heterogeneity. We used GRADE to evaluate the certainty of evidence.

RESULTS

Of 8375 records, 12 NRS (>6 million patients; 11,554 gastric cancers) and two randomised clinical trials (498 patients; 1 gastric cancer) fulfilled the eligibility criteria. Randomised evidence was very imprecise and provided very-low certainty evidence. Meta-analysis of six NRS providing a comprehensive adjustment for confounding (2.5 million patients; 7372 gastric cancers) did not show any association between PPIs and gastric cancer (RR_random  = 1.07, 0.97-1.19; RR_fixed  = 1.05, 0.98-1.12). The certainty of the evidence was low. No convincing evidence of dose-response, or increased risk with long-term use, was found. Lack of or minimal adjustment for confounding was associated with larger effect sizes.

CONCLUSIONS

We found no association between PPIs and gastric cancer in NRS having adequately controlled for confounding. Published studies may suffer residual confounding.

SYSTEMATIC REVIEW REGISTRATION

CRD42022335971.

Exposure to Commonly Used Drugs and the Risk of Gastric Cancer: An Umbrella Review of Meta-Analyses

Recently, attention has been paid to some medications and gastric cancer (GC) risk. This review aimed to evaluate associations between commonly used drugs and GC risk and to grade evidence from published systematic reviews and meta-analyses. This umbrella review was registered in PROSPERO (CRD42022320276). The systematic reviews and meta-analyses of observational studies were retrieved by searching Embase, PubMed, and Web of Science. The evidence strength of commonly used drugs and GC risk was categorized into four grades: weak, suggestive, highly suggestive, and strong. Of 19 associations between commonly used drugs and GC risk and its subtypes, none was supported by convincing or highly suggestive evidence. The risk of GC related to non-steroidal anti-inflammatory drugs (NSAIDs), non-aspirin NSAIDs, and acid-suppressive drugs, as well as the risk of non-cardia GC related to NSAIDs and aspirin, was supported by suggestive evidence. The results showed that a reduced GC risk was associated with two drug types (NSAIDs and non-aspirin NSAIDs), and an increased GC risk was associated with acid-suppressing drugs at the suggestive evidence level. Moreover, NSAIDs and aspirin reduced non-cardia GC risk as supported by suggestive evidence. However, the evidence supporting statins or metformin in reducing GC risk was weak, and thus future studies are required to clarify these associations.

Risk factors for gastric cancer: A comprehensive analysis of observational studies

Background

Multifarious factors have a causal relationship with gastric cancer (GC) development. We conducted a comprehensive analysis to evaluate the strength of the evidence examining non-genetic risk factors for gastric cancer.

Methods

PubMed, Web of Science, and the Cochrane Library were searched from inception to November 10, 2021 to identify meta-analyses of observational studies examining the association between environmental factors and GC risk. For each meta-analysis, the random effect size, 95% confidence interval, heterogeneity among studies, and evidence of publication bias were assessed; moreover, the evidence was graded using predefined criteria, and the methodological quality was evaluated using AMSTAR 2.

Results

A total of 137 associations were examined in 76 articles. Among these meta-analyses, 93 associations yielded significant estimates (p < 0.05). Only 10 associations had strong epidemiologic evidence, including 2 risk factors (waist circumference and bacon), and 8 protective factors (dietary total antioxidant capacity, vegetable fat, cruciferous vegetable, cabbage, total vitamin, vitamin A, vitamin C, and years of fertility); 26 associations had moderate quality of evidence; and the remaining 57 associations were rated as weak. Ninety-four (68.61%) associations showed significant heterogeneity. Twenty-five (18.25%) associations demonstrated publication bias.

Conclusions

In this comprehensive analysis, multiple associations were found between environmental factors and GC with varying levels of evidence. Healthy dietary habits and lifestyle patterns could reduce the risk for GC. However, further high-quality prospective studies are still necessary to draw more definitive conclusions.

Association between proton-pump inhibitors and the risk of gastric cancer: a systematic review and meta-analysis

BACKGROUND

Proton pump inhibitors (PPIs) may be associated with gastric cancer, but studies in recent years have proven still inconsistent results. We conducted a systematic review and meta-analysis to investigate the association between PPI use and gastric cancer.

METHODS

Pubmed, EMBASE, and Cochrane library were searched for studies published up to 15th February 2022. Studies on the association between PPI and the risk of gastric cancer, pooled the odds ratios (ORs) using a random-effects model. The subgroup analysis for study design, site of gastric cancer, and the duration of PPI use was performed. Heterogeneity was assessed using the I² and Cochran's Q statistics.

RESULTS

Sixteen cohorts and case-control studies were included. PPI use was significantly associated with gastric cancer (OR: 1.75, 95% CI: 1.28-2.40). The subgroup analysis found a significant risk increase in non-cardia gastric cancer (OR: 2.14, 95%CI: 1.50-3.07). There was no duration-dependent effect of PPI use and gastric cancer risk (< 1 year: OR: 2.56, 95% CI: 1.41-4.64, I² = 98%; 1-3 years: OR: 1.47, 95% CI: 1.26-1.71, I² = 41%; > 3 years: OR: 1.58, 95% CI: 1.16-2.14, I² = 74%).

CONCLUSIONS

PPIs were significantly associated with an increased risk of gastric cancer. However, this association does not confirm causation. Several well-design studies are needed to confirm the findings in the future.

Use of proton pump inhibitors for the risk of gastric cancer

BACKGROUND

This study aimed to systematically analyze the association between long-term use of proton pump inhibitors (PPIs) and the risk of gastric cancer (GC).

METHODS

We performed a systematic search of articles on the relationship between long-term use of PPIs and the risk of GC from PubMed and EMBASE. We calculated the pooled odds ratio of GC in PPI users compared to non-PPI users using random-effects models.

RESULTS

This meta-analysis included 18 studies from 20 different databases with 4348,905 patients enrolled. In the random effects model, we found that an increased risk of GC among PPI users (OR = 1.94; 95% CI [1.43, 2.64]). The long-term use of PPIs compared with histamine-2 receptor antagonist users did not increase the risk of GC (OR = 1.65; 95% CI [0.92, 2.97]). Stratified analysis showed that PPI users had a significantly increased risk of noncardia GC (OR = 2.53; 95% CI [2.03, 3.15]), but had a relatively small relationship with the risk of gastric cardia cancer. (OR = 1.79; 95% CI [1.06, 3.03]). With the extension of PPI use time, the estimated risk value decreases (<1 year: OR = 6.33, 95% CI [3.76, 10.65]; 1-3 years: OR = 1.82, 95% CI [1.30, 2.55]; >3 years: OR = 1.25, 95% CI [1.00, 1.56]). Despite Helicobacter pylori eradication, the long-term use of PPIs did not alter the increased risk of GC (OR = 2.29; 95% CI [1.57, 3.33]).

CONCLUSION

Our meta-analysis found that PPI use may be associated with an increased risk of GC. Further research on the causal relationship between these factors is necessary.

Biology of cancer; from cellular and molecular mechanisms to developmental processes and adaptation

Cancer research has been largely focused on the cellular and molecular levels of investigation. Recent data show that not only the cell but also the extracellular matrix plays a major role in the progression of malignancy. In this way, the cells and the extracellular matrix create a specific local microenvironment that supports malignant development. At the same time, cancer implies a systemic evolution which is closely related to developmental processes and adaptation. Consequently, there is currently a real gap between the local investigation of cancer at the microenvironmental level, and the pathophysiological approach to cancer as a systemic disease. In fact, the cells and the matrix are not only complementary structures but also interdependent components that act synergistically. Such relationships lead to cell-matrix integration, a supracellular form of biological organization that supports tissue development. The emergence of this supracellular level of organization, as a structure, leads to the emergence of the supracellular control of proliferation, as a supracellular function. In humans, proliferation is generally involved in developmental processes and adaptation. These processes suppose a specific configuration at the systemic level, which generates high-order guidance for local supracellular control of proliferation. In conclusion, the supracellular control of proliferation act as an interface between the downstream level of cell division and differentiation, and upstream level of developmental processes and adaptation. Understanding these processes and their disorders is useful not only to complete the big picture of malignancy as a systemic disease, but also to open new treatment perspectives in the form of etiopathogenic (supracellular or informational) therapies.

Proton Pump Inhibitors and Cancer Risk: An Umbrella Review and Meta-analysis of Observational Studies

OBJECTIVES

Increasing evidence suggested that proton pump inhibitors (PPIs) use might affect the development of cancers, but previous conclusions remain controversial. Therefore, an umbrella review was performed to clarify the associations between PPIs and various types of cancer by summarizing the existing meta-analyses and systematic reviews.

METHODS

We searched PubMed, Cochrane Library, Embase, CNKI, Wanfang, and VIP database up to June 2022 for eligible meta-analyses or systematic reviews. The summary effect size, 95% CI, heterogeneity, small study effect, and 95% prediction interval were considered in the present study. A Measurement Tool to Assess Systematic Review 2 and grading of recommendation, assessment, development, and evaluation were used to assess methodological quality and evidence.

RESULTS

The umbrella review included 21 meta-analyses containing 65 studies and 10 cancer types with 6.8 million subjects. The results showed that PPI use was significantly associated with increased risks of certain types of cancer, including gastric cancer (odds ratio [OR]: 2.07; 95% CI, 1.30 to 3.29), pancreatic cancer (OR: 1.73; 95% CI, 1.23 to 2.44), colorectal cancer (OR: 1.84; 95% CI, 1.26 to 2.67), and liver cancer (OR: 1.80; 95% CI, 1.27 to 2.54), but was not associated with esophageal cancer. In addition, PPI use was associated with decreased risk of breast cancer (OR: 0.69; 95% CI, 0.50 to 0.96).

CONCLUSIONS

These findings suggested that clinicians should pay more attention to the occurrence of gastric cancer, pancreatic cancer, colorectal cancer, and liver cancer in patients who used PPIs, and PPI prescription should be written only when an accurate specific diagnosis has been made. Furthermore, additional PPIs to the treatment regimen may be benefit for women with a higher-than-average risk of breast cancer.

Proton Pump Inhibitor Use and Risk of Gastric Cancer: Current Evidence from Epidemiological Studies and Critical Appraisal

Proton pump inhibitors (PPIs) are used for maintaining or improving gastric problems. Evidence from observational studies indicates that PPI therapy is associated with an increased risk of gastric cancer. However, the evidence for PPIs increasing the risk of gastric cancer is still being debated. Therefore, we aimed to investigate whether long-term PPI use is associated with an increased risk of gastric cancer. We systematically searched the relevant literature in electronic databases, including PubMed, EMBASE, Scopus, and Web of Science. The search and collection of eligible studies was between 1 January 2000 and 1 July 2021. Two independent authors were responsible for the study selection process, and they considered only observational studies that compared the risk of gastric cancer with PPI treatment. We extracted relevant information from selected studies, and assessed the quality using the Newcastle−Ottawa scale (NOS). Finally, we calculated overall risk ratios (RRs) with 95% confidence intervals (CIs) of gastric cancer in the group receiving PPI therapy and the control group. Thirteen observational studies, comprising 10,557 gastric cancer participants, were included. Compared with patients who did not take PPIs, the pooled RR for developing gastric cancer in patients receiving PPIs was 1.80 (95% CI, 1.46−2.22, p < 0.001). The overall risk of gastric cancer also increased in patients with gastroesophageal reflux disease (GERD), H. pylori treatment, and various adjusted factors. The findings were also consistent across several sensitivity analyses. PPI use is associated with an increased risk of gastric cancer in patients compared with those with no PPI treatment. The findings of this updated study could be used in making clinical decisions between physicians and patients about the initiation and continuation of PPI therapy, especially in patients at high risk of gastric cancer. Additionally, large randomized controlled trials are needed to determine whether PPIs are associated with a higher risk of gastric cancer.

Low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols diet versus traditional dietary advice for functional dyspepsia: a randomized controlled trial

BACKGROUND AND AIM

Prospective trials evaluating efficacy of specific diet restriction in functional dyspepsia (FD) are scarce. We aimed to assess efficacy of low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) diet in FD, compared with traditional dietary advice (TDA).

METHODS

In this prospective, single-blind trial, patients with FD (Rome IV) were randomized into low FODMAP diet (LFD) and TDA groups, for 4 weeks (phase I). In phase II (4-12 weeks), LFD group was advised systematic re-introduction of FODMAPs. Symptom severity and quality of life were assessed using "Short-Form Nepean Dyspepsia Index (SF-NDI)." Primary outcome was symptomatic response (symptom score reduction of ≥ 50%), at 4 weeks. Study was registered with CTRI (2019/06/019852).

RESULTS

Of 184 patients screened, 105 were randomized to LFD (n = 54) and TDA (n = 51) groups. At 4 weeks, both groups showed significant reduction in SF-NDI symptom scores compared with baseline, with no significant difference in inter-group response rates [LFD: 66.7% (36/54); TDA: 56.9% (29/51); P = 0.32]. On sub-group analysis, patients with postprandial distress syndrome or bloating had significantly better symptomatic response with LFD (P = 0.04). SF-NDI quality of life scores improved significantly in both groups. On multivariate analysis, factors predicting response to LFD were bloating and male gender. Incidences of adverse events (minor) were similar in both groups.

CONCLUSIONS

In patients with FD, LFD and TDA lead to significant symptomatic and quality of life improvement. Patients with postprandial distress syndrome or bloating respond significantly better to LFD. Therefore, dietary advice for FD should be individualized according to FD subtype.

Association between proton-pump inhibitors and the risk of gastric cancer: a systematic review with meta-analysis

INTRODUCTION

The use of proton-pump inhibitors (PPI) may be associated with an increased risk of gastric cancer (GC).

OBJECTIVE

To review and meta-analyse available literature investigating the association between PPI use and GC risk.

METHODS

Two independent reviewers systematically searched Ovid MEDLINE, EMBASE, and Cochrane Library (inception to July 2020) for case-control and cohort studies assessing the association between PPI use and GC according to a predefined protocol in PROSPERO (CRD42018102536). Reviewers independently assessed study quality, extracted data, and meta-analysed available and newly calculated odds ratios (ORs) using a random-effects model, and stratified for GC site (cardia versus non-cardia) and PPI duration (<1 year, 1-3 years, >3 years).

RESULTS

We screened 2,396 records and included five retrospective cohort and eight case-control studies comprising 1,662,881 individuals in our meta-analysis. In random-effect models, we found an increased GC risk in PPI users [OR: 1.94, 95% confidence interval (95% CI): 1.47-2.56] with high statistical heterogeneity (I ² = 82%) and overall moderate risk of bias. Stratified analyses indicated a significant risk increase in non-cardia (OR: 2.20, 95% CI: 1.44-3.36, I ² = 77%) with a similar non-significant trend in cardia regions (OR: 1.77, 95% CI: 0.72-4.36, I ² = 66%). There was no GC increase with longer durations of PPI exposure (<1 year: OR: 2.29, 95% CI: 2.13-2.47, I ² = 0%; 1-3 years: OR: 1.46, 95% CI: 0.53-4.01, I ² = 35%; >3 years: OR: 2.08, 95% CI: 0.56-7.77, I ² = 61%).

CONCLUSION

We found a twofold increased GC risk among PPI users, but this association does not confirm causation and studies are highly heterogeneous. PPI should only be prescribed when strictly indicated.

Association between proton pump inhibitor use and gastric cancer: a population-based cohort study using two different types of nationwide databases in Korea

OBJECTIVE

The association between proton pump inhibitor (PPI) use and gastric cancer related to Helicobacter pylori eradication has not been fully investigated in geographical regions with high risk of gastric cancer. We aimed to evaluate the association between PPIs and gastric cancer in Korea.

DESIGN

This study analysed the original and common data model versions of the Korean National Health Insurance Service database from 2002 to 2013. We compared the incidence rates of gastric cancer after 1-year drug exposure, between new users of PPIs and other drugs excluding PPIs, by Cox proportional hazards model. We also analysed the incidence of gastric cancer among PPI users after H. pylori eradication.

RESULTS

The analysis included 11 741 patients in matched PPI and non-PPI cohorts after large-scale propensity score matching. During a median follow-up of 4.3 years, PPI use was associated with a 2.37-fold increased incidence of gastric cancer (PPI≥30 days vs non-PPI; 118/51 813 person-years vs 40/49 729 person-years; HR 2.37, 95% CI 1.56 to 3.68, p=0.001). The incidence rates of gastric cancer showed an increasing trend parallel to the duration of PPI use. In H. pylori-eradicated subjects, the incidence of gastric cancer was significantly associated with PPI use over 180 days compared with the non-PPI group (PPI≥180 days vs non-PPI; 30/12 470 person-years vs 9/7814 person-years; HR 2.22, 95% CI 1.05 to 4.67, p=0.036).

CONCLUSION

PPI use was associated with gastric cancer, regardless of H. pylori eradication status. Long-term PPIs should be used with caution in high-risk regions for gastric cancer.

Umbrella review of 42 systematic reviews with meta-analyses: the safety of proton pump inhibitors

BACKGROUND

Proton pump inhibitors (PPIs) are widely used to treat and prevent acid-related disorders. Despite high efficacy, PPI safety has been increasingly scrutinised. However, no comprehensive review summarising investigations of various adverse events is available.

AIMS

To perform an umbrella review to comprehensively assess associations between adverse events and PPI use.

METHODS

In accordance with PRISMA, an umbrella review of systematic reviews with meta-analyses was conducted. PubMed and EMBASE were searched from 2015 to July 2019. AMSTAR 2 and GRADE were used to assess quality and certainty of evidence. Author-reported quality assessments were also reviewed.

RESULTS

Forty-two systematic reviews with meta-analyses, supported predominantly by observational evidence, were included. The most comprehensive studies reported statistically significant associations with PPI use for several outcomes, including: fractures (eg, hip; RR = 1.20; 95% CI = 1.14-1.28; n = 2 103 800), kidney disease (eg, acute kidney injury; RR = 1.61; 95% CI = 1.16-2.22; n = 2 396 640), infections (eg, Clostridioides difficile; OR = 1.99; 95% CI = 1.73-2.30; n = 356 683), gastric cancer (OR = 2.50; 95% CI = 1.74-3.85; n = 943 070) and gastrointestinal events (eg, fundic gland polyps; OR = 2.46; 95% CI = 1.42-4.27; n = 40 218). No associations with non-gastric cancers, or neurological disease were concluded, with conflicting evidence for cardiovascular outcomes. Certainty based on GRADE was very low for most outcomes.

CONCLUSIONS

This review identified several published associations between PPIs and adverse outcomes, however, further investigation is needed to understand their clinical significance and the likelihood of causal relationship. If higher quality evidence is generated substantiating the potential risks, it may be necessary for clinicians to consider alternative treatment strategies, especially when PPI efficacy is suboptimal.

Chemopreventive Effect of Metformin on Gastric Cancer Development

Although Helicobacterpylori infection is the most important causative factor for gastric cancer (GC), H. pylori eradication alone does not completely eliminate the GC risk. In addition to H. pylori eradication, other risk factors for GC should be identified and targeted. Diabetes mellitus (DM) confers a 20% increased risk of GC, which could be mediated via several biological mechanisms including the stimulation of cell proliferation via hyperinsulinemia and increased insulin-growth factor production, the promotion of angiogenesis, and DNA damage. With a current global prevalence of 9.3% and a predicted rise to 10.2% by 2030, DM could contribute substantially to the burden of GC cases worldwide. Emerging evidence showed that metformin possesses chemopreventive effects via both direct (e.g., adenosine monophosphate-activated protein kinase activation and subsequent inhibition of the mammalian target of rapamycin pathway) and indirect (e.g., modulation of the interaction between tumor cells and their microenvironment and gut microbiota) pathways. A recent meta-analysis of observational studies showed that metformin use was associated with 24% lower GC risk. However, many available observational studies related to metformin effects suffered from biases including the failure to adjust for the H. pylori infection status and serial glycemic control and time-related biases. Future prospective studies addressing these pitfalls are needed.

Dose-dependent association of proton pump inhibitors use with gastric intestinal metaplasia among Helicobacter pylori-positive patients

BACKGROUND

Gastric intestinal metaplasia is a pre-cancerous condition associated with multiple factors.

OBJECTIVE

We evaluated whether cumulative proton pump inhibitor dose is associated with the diagnosis of gastric intestinal metaplasia while controlling for multiple variables.

METHODS

We retrospectively identified patients who underwent upper endoscopy with gastric biopsy between 2005 and 2014. Covariate data retrieved included age, sex, ethnicity, smoking status, Helicobacter pylori status (based on clarithromycin-amoxicillin-proton pump inhibitor issued), cumulative proton pump inhibitor issued within 10 years (quartiles [PPI-Q1-4 ] of daily drug dose), anti-parietal cell antibodies, body mass index and comorbidity index.

RESULTS

Of the 14,147 included patients (median age 63.4 years; women 54.4%; Helicobacter pylori-positive 29.0%), 1244 (8.8%) had gastric intestinal metaplasia. Increasing age, Helicobacter pylori infection, smoking, anti-parietal cell antibodies and proton pump inhibitor use were all associated with the diagnosis of gastric intestinal metaplasia. Upper quartiles of cumulative proton pump inhibitor doses (PPI-Q4 and PPI-Q3 vs. PPI-Q1 ) were associated with the diagnosis of gastric intestinal metaplasia: adjusted odds ratios 1.32 (95% confidence interval [CI] 1.111.57) and 1.27 (95% CI 1.07-1.52), respectively, for the whole cohort (Ptotal 0.007, Ptrend 0.013), 1.69 (95% CI 1.23-2.33) and 1.40 (95% CI 1.04-1.89), respectively, for Helicobacter pylori-positive patients (Ptotal 0.004, Ptrend 0.005) and 1.21 (95% CI 0.98-1.49) and 1.20 (95% CI 0.96-1.49), respectively, for Helicobacter pylori-negative patients (Ptotal 0.288, Ptrend 0.018). Upper quartiles of proton pump inhibitor dose were associated with a 5-10-fold increased risk of low-grade dysplasia.

CONCLUSIONS

Among Helicobacter pylori-positive patients, proton pump inhibitor use appears to be associated with a dose-dependent increased likelihood of gastric intestinal metaplasia.

Advances in the diagnosis and management of gastroesophageal reflux disease

Gastroesophageal reflux disease (GERD) is a multifaceted disorder encompassing a family of syndromes attributable to, or exacerbated by, gastroesophageal reflux that impart morbidity, mainly through troublesome symptoms. Major GERD phenotypes are non-erosive reflux disease, GERD hypersensitivity, low or high grade esophagitis, Barrett's esophagus, reflux chest pain, laryngopharyngeal reflux, and regurgitation dominant reflux. GERD is common throughout the world, and its epidemiology is linked to the Western lifestyle, obesity, and the demise of Helicobacter pylori. Because of its prevalence and chronicity, GERD is a substantial economic burden measured in physician visits, diagnostics, cancer surveillance protocols, and therapeutics. An individual with typical symptoms has a fivefold risk of developing esophageal adenocarcinoma, but mortality from GERD is otherwise rare. The principles of management are to provide symptomatic relief and to minimize potential health risks through some combination of lifestyle modifications, diagnostic testing, pharmaceuticals (mainly to suppress or counteract gastric acid secretion), and surgery. However, it is usually a chronic recurring condition and management needs to be personalized to each case. While escalating proton pump inhibitor therapy may be pertinent to healing high grade esophagitis, its applicability to other GERD phenotypes wherein the modulating effects of anxiety, motility, hypersensitivity, and non-esophageal factors may dominate is highly questionable.

Endoscopic grading of gastric intestinal metaplasia on risk assessment for early gastric neoplasia: can we replace histology assessment also in the West?

OBJECTIVES

To assess the value of endoscopic grading of gastric intestinal metaplasia (EGGIM), operative link on gastritis assessment (OLGA) and operative link on gastric intestinal metaplasia (OLGIM) on risk stratification for early gastric neoplasia (EGN) and to investigate other factors possibly associated with its development.

DESIGN

Single centre, case-control study including 187 patients with EGN treated endoscopically and 187 age-matched and sex-matched control subjects. Individuals were classified according to EGGIM, OLGA and OLGIM systems. EGN risk according to gastritis stages and other clinical parameters was further evaluated.

RESULTS

More patients with EGN had EGGIM of ≥5 than control subjects (68.6% vs 13.3%, p<0.001). OLGA and OLGIM stages III/IV were more prevalent in patients with EGN than in control subjects (68% vs 11%, p<0.001, and 61% vs 3%, p<0.001, respectively). The three systems were the only parameters significantly related to the risk of EGN in multivariate analysis: for EGGIM 1-4 (adjusted OR (AOR) 12.9, 95% CI 1.4 to 118.6) and EGGIM 5-10 (AOR 21.2, 95% CI 5.0 to 90.2); for OLGA I/II (AOR 5.0, 95% CI 0.56 to 44.5) and OLGA III/IV (AOR 11.1, 95% CI 3.7 to 33.1); for OLGIM I/II (AOR 11.5, 95% CI 4.1 to 32.3) and OLGIM III/IV (AOR 16.0, 95% CI 7.6 to 33.4).

CONCLUSION

This study confirms the role of histological assessment as an independent risk factor for gastric cancer (GC), but it is the first study to show that an endoscopic classification of gastric intestinal metaplasia is highly associated with that outcome. After further prospective validation, this classification may be appropriate for GC risk stratification and may simplify every day practice by reducing the need for biopsies.

Use of proton pump inhibitors and histamine-2 receptor antagonists and risk of gastric cancer in two population-based studies

BACKGROUND

Studies have shown increased gastric cancer risk in users of proton pump inhibitors (PPI) and histamine-2 receptor antagonists, questioning the safety of gastric acid suppression. Therefore, we conducted a case-control study within the Scottish Primary Care Clinical Informatics Unit (PCCIU) database and a cohort study in the UK Biobank.

METHODS

In PCCIU, five controls were matched to cases diagnosed in 1999-2011, and medications were determined from GP records. Odds ratios (OR) and 95% confidence intervals (CI) were calculated using conditional logistic regression. In the UK Biobank, medications were self-reported at cohort entry 2006-2010, and gastric cancer ascertained from cancer registries until 2014. Hazard ratios (HR) were calculated using Cox regression.

RESULTS

PCCIU contained 1119 cases and 5394 controls. UK Biobank contained 250 cases in 471,779 participants. PPI users had a higher gastric cancer risk in PCCIU and UK Biobank when applying a 1-year lag (adjusted OR = 1.49, 95% CI 1.24, 1.80; adjusted HR = 1.28, 95% CI 0.86, 1.90, respectively), but these associations were attenuated when using a 2-year lag (adjusted OR = 1.13, 95% CI 0.91, 1.40; adjusted HR = 1.15, 95% CI 0.73, 1.82, respectively).

CONCLUSIONS

Overall, we observed little consistent evidence of an increased risk of gastric cancer with PPI use.

Fullerenol Nanoparticles Eradicate Helicobacter pylori via pH-Responsive Peroxidase Activity

Helicobacter pylori (H. pylori) eradication by antibiotics and proton pump inhibitor treatment is limited by the low pH microenvironment in the stomach and can lead to antibiotic resistance. We fabricated fullerenol nanoparticles (FNPs) with varied chemical structures responding to a pinacol rearrangement of vicinal hydroxyl to form carbonyls in low pH environments. An obvious increase in C═O/C-O was induced in low pH and was positively correlated with a peroxidase-like activity. The FNPs exerted an excellent effect on H. pylori eradication in vitro and in vivo because of their peroxidase-like activity. FNP treatment of a H. pylori biofilm revealed that FNPs broke down polysaccharides in cell wall components, resulting in collapse of the bacteria. The cycles of FNPs combining and dissociating with the peroxidase substrate were detected by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and confirmed that FNPs enhance peroxidase-like activity. Further, the isothermal titration calorimetry results showed that FNPs with more C═O/C-O had greater affinity to bind the peroxidase substrates. Therefore, we suggest that varied C═O/C-O serves as a switch to respond to low pH in the stomach to kill H. pylori by inducing a peroxidase-like activity. FNPs can also overcome the challenge of antibiotic resistance to achieve H. pylori eradication in the stomach.

Long-term proton pump inhibitor usage and the association with pancreatic cancer in Sweden

BACKGROUND

The long-term safety of proton pump inhibitors (PPIs) is increasingly questioned. The aim of our study was to assess the risk of pancreatic cancer among long-term PPI users in Sweden.

METHODS

This population-based nationwide Swedish cohort study including 796,492 adult long-term PPI users has been used to calculate the standardized incidence rate ratios (SIRs) and 95% confidence intervals (CI) for pancreatic cancer, stratifying by indications of use, age, sex, and duration of use. The risk among all 20,210 long-term H2-receptor antagonist users was assessed as comparison.

RESULTS

Pancreatic cancer was found in 1733 long-term PPI users, and 25 H2-receptor antagonist users. For PPI users, the risk of pancreatic cancer was increased overall (SIRs = 2.22; 95% CI 2.12-2.32) and in all subgroup analyses, with the highest risk among PPI-users younger than 40 years (SIR = 8.90, 95% CI 4.26-16.37), and among individuals with a history of Helicobacter pylori (SIR = 2.99, 95% CI 2.54-3.49). After the first year after enrolment (during which PPI use may be because of early symptoms of pancreatic cancer), the risk remained increased over time, with SIR = 1.57 (95% CI 1.38-1.76) after 5 years. No associations were found for H2-receptor antagonists (SIR = 1.02, 95% CI 0.66-1.51).

CONCLUSIONS

This large study showed an increased risk of pancreatic cancer in long-term users of PPIs in Sweden, in particular among the youngest users.

An unusual case of proton pump inhibitor induced hyperchromograninemia

Objective: To describe an unusual case of symptomatic hyperchromograninemia associated with proton pump inhibitor (PPI) use.

Case Summary: A 55-year-old man with stage 1 follicular lymphoma and GERD on omeprazole presented with symptoms suggesting carcinoid syndrome. The only positive finding on workup was a markedly elevated level of chromogranin A and no carcinoid tumor was identified. Omeprazole was discontinued, following which his symptoms resolved and chromogranin A levels returned to normal. To the best of our knowledge, no symptoms have been previously reported in association with PPI-induced hyperchromograninemia.

Discussion: The reliability of chromogranin A as a marker for neuroendocrine tumors is of growing concern. The reasons for the associated symptomatology in this case are unclear but could involve physiologic effects of chromogranin A breakdown products. The role of pharmacogenomics in PPI metabolism is discussed as a potential explanation for the significant hyperchromograninemia.

Conclusion: The phenomenon of PPI-induced hyperchromograninemia is highlighted for providers especially in the context of neuroendocrine tumor diagnosis and surveillance. The need for more research into chromogranins is proposed.

Duration of use of proton pump inhibitors and the risk of gastric and oesophageal cancer

BACKGROUND

There is increasing interest in the potential association between proton pump inhibitors (PPIs) and the risk of gastric and oesophageal cancer, yet the effect of duration of treatment needs clarification.

METHODS

This Swedish population-based cohort study assessed the influence of time since initiation of PPI treatment on the risk of gastric and oesophageal cancer, presented as standardised incidence ratios and 95% confidence intervals.

RESULTS

The risk of gastric and oesophageal cancer during the first year was 7-10 times higher than the background population, and remained 24-202% increased without any decrease over time after the first year.

CONCLUSION

PPI use was associated with an increased risk of gastric and oesophageal cancer and the risk remained increased over follow-up. These results support our original hypothesis that use of PPIs may be a risk factor for gastric and oesophageal cancer in the general population of maintenance users, independent of underlying indications.