Proton pump inhibitor and histamine-2 receptor antagonist use and risk of liver cancer in two population-based studies

Impact of Antibiotics and Chronic Medications on Efficacy of Immune Checkpoint Inhibitors in Patients With Hepatocellular Carcinoma

BACKGROUND AND AIMS

The interaction of immune checkpoint inhibitors (ICI) and concomitant medications such as antibiotics, metformin, statins, beta-blockers, proton pump inhibitors (PPIs), nonsteroidal anti-inflammatory drugs (NSAIDs), and low-dose aspirin has been studied in other malignancies. Our study aims to investigate the relationship between these medications and ICI efficacy in patients with advanced hepatocellular carcinoma (aHCC).

METHODS

A retrospective review of patients who received at least one dose of ICIs between May 2015 and November 2019 was performed. The primary objectives were to compare the overall survival (OS) and progression-free survival (PFS) between patients with and without medication usage. Log rank test was used to assess for differences in survival. Hazard ratios were reported using Cox proportional hazard regression analysis. The data cutoff date was December 31, 2020.

RESULTS

A total of 168 patients were included. Median age was 69 years, 85.7% male, 60.7% ECOG 0, 78.0% Child-Pugh A liver cirrhosis, 57.7% hepatitis B etiology, 8.9% hepatitis C, and 33.3% nonviral. One hundred three patients (61.3%) received ICI monotherapy, while 38.7% received ICI in combination. Sixty-two patients (36.9%) had concomitant antibiotic usage, 26.8% metformin, 30.4% statin, 31.0% beta-blockers, 60.1% PPI, 6.5% NSAIDs, and 11.9% aspirin. Patients with aHCC receiving antibiotics did not have a shorter OS (adjusted HR [aHR] 1.40, 95% CI 0.94-2.09, p = 0.096) or shorter PFS (aHR 0.94, 95% CI 0.66-1.34, p = 0.73), as compared to those who did not receive antibiotics. However, patients with aHCC of viral hepatitis etiology receiving ICI treatment and concurrent antibiotics had shorter OS (5.5 vs. 14.2 months, aHR 1.93, 95% CI 1.17-3.17, p = 0.010) and PFS (1.1 vs. 2.6 months, aHR 2.69, 95% CI 1.28-5.65, p = 0.009), as compared to those who did not receive antibiotics.

CONCLUSIONS

The use of antibiotics may diminish ICI efficacy in patients with aHCC of viral hepatitis etiology, while the use of metformin, statins, beta-blockers, NSAIDs, and aspirin is not associated with significant clinical outcomes.

Proton-Pump Inhibitors and Fat Absorption in Cystic Fibrosis and Pancreatic Insufficiency: A Randomized Crossover Pilot Trial

BACKGROUND

Dietary fat malabsorption contributes to poor nutritional status in patients with cystic fibrosis (CF) and exocrine pancreatic insufficiency (EPI). Prescribing gastric acid-reducing agents such as proton-pump inhibitors (PPI) as an adjunct to pancreatic enzyme replacement therapy (PERT) to improve dietary fat absorption has been accepted in clinical practice despite limited evidence.

AIMS

This was a pilot randomized, double-blind, placebo-controlled crossover trial of subjects aged 12 and older with CF and EPI assessed on placebo and omeprazole to determine if PPI improved the efficacy of PERT as indicated by measures of dietary fat absorption.

METHODS

Fat malabsorption via stool coefficient of fat absorption (CFA) and malabsorption blood test (MBT), gastrointestinal pH (wireless motility capsule [WMC]), and quality of life (QOL) were assessed after 14 days on both placebo or PPI (omeprazole).

RESULTS

Total 19 subjects enrolled, 13 were randomized, and 9 provided paired results on placebo and PPI. The 3 subject results for CFA were as follows: 1 increased, 1 decreased, and 1 was within the reference range in both tests for fat absorption. For 9 MBT subjects, 7 decreased and 2 increased fat absorption. For the 4 WMC studies, no change in transit times, nor in pH profiles were noted. No differences were seen in the domains of the two QOL questionnaires comparing placebo and PPI.

CONCLUSIONS

These limited descriptive pilot study results in participants with CF and EPI on PERT evaluated by stool, blood, and QOL tests did not suggest improvement in fat absorption attributable to PPI.

Proton Pump Inhibitors and Oral-Gut Microbiota: From Mechanism to Clinical Significance

Proton pump inhibitors (PPIs) are some of the most commonly prescribed drugs worldwide, but there are increasing concerns about digestive complications linked to PPIs. Next-generation sequencing studies have suggested that PPIs can significantly affect the composition of the gut microbiota, which in turn may substantially contribute to the development of these complications. Recently, emerging evidence has suggested that the translocation of oral microbes into the gut may be the primary mechanism underlying the alterations in the gut microbiota induced by PPIs in the presence of gastric acid suppression and impaired oral-gut barrier function. Moreover, the significance of oral-gut microbial translocation in health and disease conditions has gained increasing recognition. Consequently, it is imperative to enhance our understanding of the functions of the oral-gut microbiota axis in digestive disorders associated with PPI therapies. This review aims to summarize current research findings and further elucidate the contribution of the oral-gut microbiota to the pathogenesis of PPI-related digestive diseases. We aim to provide a theoretical foundation for future therapeutic and preventive strategies targeting PPI-related digestive complications through modulation of the oral-gut microbiota.

Individualized prevention of proton pump inhibitor related adverse events by risk stratification

Proton pump inhibitors (PPIs) are commonly used for gastric acid-related disorders, but their safety profile and risk stratification for high-burden diseases need further investigation. Analyzing over 2 million participants from five prospective cohorts from the US, the UK, and China, we found that PPI use correlated with increased risk of 15 leading global diseases, such as ischemic heart disease, diabetes, respiratory infections, and chronic kidney disease. These associations showed dose-response relationships and consistency across different PPI types. PPI-related absolute risks increased with baseline risks, with approximately 82% of cases occurring in those at the upper 40% of the baseline predicted risk, and only 11.5% of cases occurring in individuals at the lower 50% of the baseline risk. While statistical association does not necessarily imply causation, its potential safety concerns suggest that personalized use of PPIs through risk stratification might guide appropriate decision-making for patients, clinicians, and the public.

Proton pump inhibitors and risk of gastrointestinal cancer: A meta‑analysis of cohort studies

Although proton pump inhibitors (PPIs) are widely used in the treatment of various acid-related disorders, observational studies have raised concern about an association between PPI use and the risk of gastrointestinal cancer. The present study aimed to investigate the association between them using a meta-analysis of cohort studies. PubMed and Excerpta Medica dataBASE were searched from inception to December 2022 to identify relevant cohort studies. The primary outcome was the risk of gastrointestinal cancer among PPI users, expressed as a pooled odds ratio (OR), relative risk (RR) or hazard ratio (HR) and its 95% CI based on a random-effects model. A total of 25 cohort studies from 23 articles were included in the final analysis. In the meta-analysis of all studies, an increased risk of gastrointestinal cancer following the use of PPIs was observed (OR/RR/HR, 2.09; 95% CI, 1.78-2.46). Subgroup analyses by type of cancer also revealed an association between PPI use and the risk of esophageal, gastric, liver and pancreatic cancer, whereas there was no association for colorectal cancer. The increased risk of gastrointestinal cancer was also observed in individuals who had used PPIs for <1 year (OR/RR/HR, 5.23; 95% CI, 2.96-9.24) as well as individuals who had used PPIs for up to 3 years. The present meta-analysis revealed that the use of PPIs was associated with an increased risk of gastrointestinal cancer.

Exposure to weak opioids and risk of gastrointestinal tract cancers: A series of nested case-control studies

AIMS

There is evidence gastrointestinal (GI) motility may play a role in the development of GI cancers. Weak opioids (codeine and dihydrocodeine) decrease GI motility, but their effect on GI cancer risk has not been assessed. We aim to assess the association between weak opioids and cancers of the GI tract.

METHODS

A series of nested case-control studies was conducted using Scottish general practice records from the Primary Care Clinical Informatics Unit Research database. Oesophageal (n = 2432), gastric (n = 1443) and colorectal cancer (n = 8750) cases, diagnosed between 1999 and 2011, were identified and matched with up to five controls. Weak opioid use was identified from prescribing records. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using conditional logistic regression, adjusting for relevant comorbidities and medication use.

RESULTS

There was no association between weak opioids and colorectal cancer (adjusted OR = 0.96, CI 0.90, 1.02, P = 0.15). There was an increased risk of oesophageal (adjusted OR = 1.16, CI 1.04, 1.29, P = 0.01) and gastric cancer (adjusted OR = 1.26, CI 1.10, 1.45, P = 0.001). The associations for oesophageal cancer, but not gastric cancer, were attenuated when weak opioid users were compared with users of another analgesic (adjusted OR = 1.03 CI 0.86, 1.22, P = 0.76 and adjusted OR = 1.29 CI 1.02, 1.64, P = 0.04 respectively).

CONCLUSIONS

In this large population-based study, there was no consistent evidence of an association between weak opioids and oesophageal or colorectal cancer risk, but a small increased risk of gastric cancer. Further investigation is required to determine whether this association is causal or reflects residual confounding or confounding by indication.

Confounded association between proton pump inhibitor use and risk of biliary tract cancer: Result from three cohorts

Recent epidemiological studies suggested that proton pump inhibitor (PPI) use was associated with an increased risk of biliary tract cancer (BTC), however, confounders were not adequately controlled. Our study aimed to evaluate PPI use and subsequent risk of BTC and its subtypes in three well-established cohorts. We conducted a pooled analysis of the subjects free of cancers in UK Biobank (n = 463 643), Nurses' Health Study (NHS, n = 80 235) and NHS II (n = 95 869). Propensity score weighted Cox models were used to estimate marginal HRs of PPIs use on BTC risk, accounting for potential confounders. We documented 284 BTC cases in UK Biobank (median follow-up: 7.6 years), and 91 cases in NHS and NHS II cohorts (median follow-up: 15.8 years). In UK biobank, PPI users had a 96% higher risk of BTC compared to nonusers in crude model (HR 1.96, 95% CI 1.44-2.66), but the effect was attenuated to null after adjusting for potential confounders (HR 0.95, 95% CI 0.60-1.49). PPI use was not associated with risk of BTC in the pooled analysis of three cohorts (HR 0.93, 95% CI 0.60-1.43). We also observed no associations between PPI use with risk of intrahepatic (HR 1.00, 95% CI 0.49-2.04), extrahepatic bile duct (HR 1.09, 95% CI 0.52-2.27) and gallbladder cancers (HR 0.66, 95% CI 0.26-1.66) in UK Biobank. In summary, regular use of PPIs was not associated with the risk of BTC and its subtypes.

Using proton pump inhibitors increases the risk of hepato-biliary-pancreatic cancer. A systematic review and meta-analysis

Background: More and more studies are focusing on the adverse effects and damage caused by PPI abuse, we carried out a systematic review and meta-analysis for assessing whether the proton pump inhibitor (PPI) leads to hepato-biliary-pancreatic cancer.

Methods: PubMed, EMBASE and Web of Science were searched until 1 July 2022, 25 studies (17 case-control and 8 cohort studies; 2741853 individuals) included in this study. Pooled Odd Ratios (ORs) were used for random effect models. Sensitivity analysis and dose-response analysis, subgroup analysis were all conducted.

Results: The aggregate OR of the meta-analysis was 1.69 (95% confidence interval (CI): 1.42–2.01, p = 0.01) and heterogeneity (I² = 98.9%, p < 0.001) was substantial. According to stratified subgroup analyses, the incidence of hepato-biliary-pancreatic cancer was associated, expect for study design, study quality and region. Risk of hepato-biliary-pancreatic cancer is highest when people is treated with normal doses of PPI. The risks decrease and become insignificant when the cumulative defined daily dose (cDDD) increases.

Conclusion: The use of PPI may be associated with an increased risk of hepato-biliary-pancreatic cancer. Hence, caution is needed when using PPIs among patients with a high risk of hepato-biliary-pancreatic cancer.

Association between Proton Pump Inhibitor Use and Risk of Hepatocellular Carcinoma: A Korean Nationally Representative Cohort Study

(1) Background: The association between proton pump inhibitor (PPI) use and hepatocellular carcinoma (HCC) has been controversial, especially in the general population. We aimed to determine the impact of PPI on HCC risk in participants without liver cirrhosis or chronic hepatitis virus infection. (2) Methods: We assessed 406,057 participants from the Korean National Health Insurance Service database who underwent health screening from 2003 to 2006. We evaluated exposure to PPI before the index date using a standardized daily defined dose (DDD) system. The association of proton pump inhibitor use with the risk of HCC was evaluated using multivariable-adjusted Cox proportional hazards regression. (3) Results: Compared with non-users, PPI use was not associated with the HCC risk in low (<30 DDDs; aHR, 1.07; 95% CI, 0.91−1.27), intermediate (30 ≤ PPI < 60 DDDs; aHR, 0.96; 95% CI, 0.73−1.26), and high (≥60 DDDs; aHR, 0.86; 95% CI, 0.63−1.17) PPI groups in the final adjustment model. In addition, risks of cirrhosis-associated HCC and non-cirrhosis-associated HCC were not significantly associated with PPI use. The results remained consistent after excluding events that occurred within 1, 2, and 3 years to exclude pre-existing conditions that may be associated with the development of HCC. We also found no PPI-associated increase in HCC risk among the selected population, such as those with obesity, older age, and chronic liver diseases. (4) Conclusions: PPI use may not be associated with HCC risk regardless of the amount. We call for future studies conducted in other regions to generalize our findings.

Oral antibiotic use and early-onset colorectal cancer: findings from a case-control study using a national clinical database

BACKGROUND

Antibiotic-induced gut dysbiosis has been associated with colorectal cancer (CRC) in older adults. This study will investigate whether an association exists between antibiotic usage and early-onset colorectal cancer (CRC), and also evaluate this in later-onset CRC for comparison.

METHODS

A case-control study was conducted using primary care data from 1999-2011. Analysis were conducted separately in early-onset CRC cases (diagnosed < 50 years) and later-onset cases (diagnosed ≥ 50 years). Conditional logistic regression was used to calculate odds ratios and 95% confidence intervals (CI) for the associations between antibiotic exposure and CRC by tumour location, adjusting for comorbidities.

RESULTS

Seven thousands nine hundred and three CRC cases (445 aged <50 years) and 30,418 controls were identified. Antibiotic consumption was associated with colon cancer in both age-groups, particularly in the early-onset CRC cohort (<50 years: adjusted Odds Ratio (ORadj) 1.49 (95% CI 1.07, 2.07), p = 0·018; ≥50 years (ORadj (95% CI) 1.09 (1.01, 1.18), p = 0·029). Antibiotics were not associated with rectal cancer (<50 years: ORadj (95% CI) 1.17 (0.75, 1.84), p = 0.493; ≥50 years: ORadj (95% CI) 1.07 (0.96, 1.19), p = 0.238).

CONCLUSION

Our findings suggest antibiotics may have a role in colon tumour formation across all age-groups.

The impact of proton pump inhibitors in liver diseases and the effects on the liver

In this systematic and comprehensive overview, we aimed to evaluate the impact of proton pump inhibitors (PPIs) on chronic liver diseases, especially on cirrhosis. A manual and comprehensive search of the PubMed database was conducted to obtain relevant literatures. PPIs altered the composition and function of the intestinal microflora and might lead to small intestinal bacterial overgrowth and bacterial translocation, which were associated with adverse effects in liver diseases. They might increase the risk of hepatic encephalopathy, spontaneous bacterial peritonitis, infections, and are related to an increased mortality in cirrhosis. PPIs might lead to an increased risk of hepatocellular carcinoma, although the mechanism is unknown, and the results are controversial. PPIs also had an impact on the direct-acting antiviral regimen in patients with chronic hepatitis C. They were associated with an increased risk of liver abscess and increased mortality. Additionally, PPIs might lead to metabolic risk events, such as liver steatosis and weight gain. PPIs are associated with several adverse outcomes in liver diseases. Cautious use of PPIs is recommended and clinicians should be aware of the indications for their use in patients with liver diseases.

Regular Use of Proton Pump Inhibitor and the Risk of Inflammatory Bowel Disease: Pooled Analysis of 3 Prospective Cohorts

BACKGROUND & AIMS

Proton pump inhibitors (PPIs) have a major impact on gut microbiome and immune function, which in turn, may increase the risk of inflammatory bowel disease (IBD). Our aim in this study was to evaluate PPI use and subsequent risk of IBD and subtypes (ie, Crohn's disease and ulcerative colitis).

METHODS

This was a pooled analysis of the Nurses' Health Study (NHS, n = 82,869), NHS II (n = 95,141), and UK Biobank (n = 469,397). We included participants with information on personal use of PPIs and free of IBD or cancer at baseline. We evaluated hazard ratios and 95% confidence intervals (CIs) with Cox regression adjusting for lifestyle factors, PPI indications, comorbidities, and other medications.

RESULTS

We documented 271 cases of IBD (median follow-up, 12 years) in the pooled NHS cohorts and 1419 cases (median follow-up, 8.1 years) in the UK Biobank. For both pooled NHS cohorts and UK Biobank, regular use of PPIs consistently showed a significantly positive association with IBD, Crohn's disease, and ulcerative colitis risk. Combined analyses of 3 cohorts showed that regular PPI users had an increased risk of IBD as compared with nonusers (hazard ratio, 1.42; 95% CI, 1.22-1.65; number needed to harm, 3770; 95% CI, 3668-4369). Direct comparison with H2 receptor antagonist, a less potent acid suppressor, showed that PPI use was also associated with higher IBD risk (hazard ratio, 1.38; 95% CI, 1.16-1.65).

CONCLUSIONS

Regular use of PPIs was associated with an increased risk of IBD and its subtypes. The findings should be interpreted with caution because the absolute risk was low and the clinical benefits of PPIs are substantial.

Ranitidine Use and Risk of Upper Gastrointestinal Cancers

BACKGROUND

The discovery that ranitidine is contaminated with N-nitrosodimethylamine, a suspected human carcinogen, raises the hypothesis of a gastrointestinal carcinogenic effect; however, evidence remains inconclusive.

METHODS

We used the nationwide Danish Prescription Registry to identify a cohort of incident ranitidine users and two active comparator cohorts comprising users of other histamine-2 receptor blockers (H2RB) and users of proton pump inhibitors (PPI). All Danish adults with a first prescription of ranitidine, other H2RBs, or PPIs in 1996 through 2008 were followed virtually completely through 2018 for incidence of esophageal, stomach, liver, and pancreatic cancers. We used Cox regression with propensity-score weighting to calculate hazard ratios and 10-year cumulative risk with 95% confidence intervals.

RESULTS

We ascertained 276 newly diagnosed esophageal, 342 stomach, 133 hepatocellular, and 517 pancreatic cancers among ranitidine users during follow-up (median 14 years). In comparison with use of other H2RBs or PPIs, we found no consistent evidence of increased HRs or excess 10-year cumulative risk of any upper gastrointestinal cancer following ranitidine use. We observed no association after restriction to subjects with at least 5 or 10 prescriptions or those with 10 prescriptions and at least 10 years of follow-up.

CONCLUSIONS

Our large prospective study using high-quality prescription and cancer incidence data, with two active comparator groups, provides no compelling evidence that ranitidine increases the risk of upper gastrointestinal cancers.

IMPACT

Our results, which do not support any carcinogenic effect on esophagus, stomach, liver or pancreas, should be reassuring for millions of concerned past users of ranitidine.

Comprehensive analysis of proton pump inhibitors and risk of digestive tract cancers

BACKGROUND

For the past two decades, dispute on whether proton pump inhibitor (PPI) leads to digestive tract cancer remains, and emerging studies in recent years still demonstrate inconsistent results, which continues to perpetuate concerns over the safety of PPI use. We performed a systematic review and meta-analysis, with comprehensive evaluation by Bradford Hill criteria of causation, to assess the effect of PPI use on digestive tract cancers.

METHODS

Medline, Embase and Web of Science databases were searched for observational studies published up to 15th January 2021. Pooled relative risks (RRs) were estimated via random effects models. Cumulative defined daily dose- and duration-risk relationships using restricted cubic spline and fractional polynomial models were investigated. Bradford Hill criteria were applied to evaluate causation. PROSPERO Registration: CRD42020211103.

RESULTS

Thirty-two publications containing 4,355,254 participants were included. PPI use is associated with an increased risk of overall digestive tract cancers (RR = 1.63, 95% confidence interval (CI) 1.33 to 2.00). PPI use is correlated with increased risks of gastric cancer (RR = 1.78, 95% CI 1.38 to 2.31), pancreatic cancer (RR = 1.72, 95% CI 1.05 to 2.82) and liver cancer (RR = 1.62, 95% CI 1.04 to 2.52), but not of esophageal cancer (RR = 2.06, 95% CI 0.65 to 6.57) and colorectal cancer (RR = 1.24, 95% CI 0.93 to 1.66). The association between PPI and digestive tract cancers is stronger in people with minimal exposure. When cumulative defined daily dose or duration increases, the risks decline and become non-significant. Evaluation by Bradford Hill criteria indicates weak evidence of causation.

CONCLUSIONS

A causal relationship between PPI use and digestive tract cancers is not supported by the evidence in the current review. Concerns over carcinogenic side-effects of PPI might be unfounded.

Neoplasm Reports in Food and Drug Administration Adverse Event Reporting System Following Angiotensin Receptor Blocker Recalls

BACKGROUND

A worldwide voluntary recall of valsartan in July 2018 due to the potential carcinogen N-nitrosodimethylamine received extensive media and public attention. This was followed by more Food and Drug Administration (FDA) recalls regarding other contaminated ARB (angiotensin receptor blocker) products. Our study investigated the association between the FDA recalls and ARB neoplasm adverse events (AEs) reported to the FDA adverse event reporting system.

METHODS

In this cross-sectional study, data were retrospectively collected from the FDA adverse event reporting system database from January 2015 to December 2019. Reporting odds ratios (RORs) were estimated to detect signals of association between ARBs (valsartan, irbesartan, and losartan) and reported neoplasm AEs using negative (amoxicillin and sertraline) and positive (omeprazole and ranitidine) control exposures. The χ² was used to compare categorical variables.

RESULTS

A total of 2 181 524 AEs, including 10 461 nonmetastatic neoplasm AEs were analyzed. Monthly RORs (95% CI) of valsartan-associated neoplasms versus controls (ROR*: valsartan/negative exposures; ROR†: valsartan/omeprazole; and ROR‡: valsartan/ranitidine) showed the highest signals after the recall date in July 2018 (7.64 [4.78-12.19]*; 4.77 [3.36-6.79]†; 4.13 [2.50-6.84]‡) and August 2018 (7.87 [5.19-11.94]*; 5.65 [4.12-7.75]†; and 7.20 [4.46-11.63]‡). In contrast, the highest cancer signals for the irbesartan and losartan recalls detected in March 2019 (4.80*; 4.06†; and 3.38‡) and April 2019 (3.63*; 3.69†; and 2.52‡) respectively, were lower. One-year postrecall reported neoplasm AEs were ≈2-fold higher for valsartan than irbesartan (OR, 1.77 [95% CI, 1.47-2.13], P<0.0001) and losartan (OR, 2.07 [95% CI, 1.85-2.32], P<0.0001). Although all ARBs had the same nitrosamine contamination, we found 1-year postrecall versus prerecall cancer signals for valsartan were 3-fold higher versus control exposures, while the changes in RORs for irbesartan and losartan were only 20-30% higher.

CONCLUSIONS

Significantly more postrecall neoplasms were reported for valsartan, with higher valsartan-associated cancer signals compared with irbesartan and losartan, although they all contained the same carcinogenic contaminant. Extensive media coverage of the FDA valsartan recall may have alarmed patients and generated these abrupt, biologically infeasible cancer signals.

Exposure to Ranitidine and Risk of Bladder Cancer: A Nested Case-Control Study

INTRODUCTION

Ranitidine has been shown to contain the carcinogen N-nitrosodimethylamine and increase urinary N-nitrosodimethylamine in humans. We investigated whether ranitidine use is associated with increased bladder cancer risk.

METHODS

A nested case-control study was conducted within the Primary Care Clinical Informatics Unit Research database which contains general practice records from Scotland. Bladder cancer cases, diagnosed between 1999 and 2011, were identified and matched with up to 5 controls (based on age, sex, general practice, and date of registration). Ranitidine, other histamine-2 receptor agonists, and proton pump inhibitors were identified from prescribing records. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using conditional logistic regression after adjusting for comorbidities and smoking.

RESULTS

There were 3,260 cases and 14,037 controls. There was evidence of an increased risk of bladder cancer in ranitidine users, compared with nonusers (fully adjusted OR = 1.22; 95% CI 1.06-1.40), which was more marked with use for over 3 years of ranitidine (fully adjusted OR = 1.43; 95% CI 1.05-1.94). By contrast, there was little evidence of any association between proton pump inhibitor use and bladder cancer risk based on any use (fully adjusted OR = 0.98; 95% CI 0.88-1.11) or over 3 years of use (fully adjusted OR = 0.98; 95% CI 0.80-1.20).

DISCUSSION

In this large population-based study, the use of ranitidine particularly long-term use was associated with an increased risk of bladder cancer. Further studies are necessary to attempt to replicate this finding in other settings.

Effect of Oral Ranitidine on Urinary Excretion of N-Nitrosodimethylamine (NDMA): A Randomized Clinical Trial

IMPORTANCE

In 2019, the US Food and Drug Administration (FDA) received a citizen petition indicating that ranitidine contained the probable human carcinogen N-nitrosodimethylamine (NDMA). In addition, the petitioner proposed that ranitidine could convert to NDMA in humans; however, this was primarily based on a small clinical study that detected an increase in urinary excretion of NDMA after oral ranitidine consumption.

OBJECTIVE

To evaluate the 24-hour urinary excretion of NDMA after oral administration of ranitidine compared with placebo.

DESIGN, SETTING, AND PARTICIPANTS

Randomized, double-blind, placebo-controlled, crossover clinical trial at a clinical pharmacology unit (West Bend, Wisconsin) conducted in 18 healthy participants. The study began in June 2020, and the end of participant follow-up was July 1, 2020.

INTERVENTIONS

Participants were randomized to 1 of 4 treatment sequences and over 4 periods received ranitidine (300 mg) and placebo (randomized order) with a noncured-meats diet and then a cured-meats diet. The cured-meats diet was designed to have higher nitrites, nitrates (nitrate-reducing bacteria can convert nitrates to nitrites), and NDMA.

MAIN OUTCOME AND MEASURE

Twenty-four-hour urinary excretion of NDMA.

RESULTS

Among 18 randomized participants (median age, 33.0 [interquartile range {IQR}, 28.3 to 42.8] years; 9 women [50%]; 7 White [39%], 11 African American [61%]; and 3 Hispanic or Latino ethnicity [17%]), 17 (94%) completed the trial. The median 24-hour NDMA urinary excretion values for ranitidine and placebo were 0.6 ng (IQR, 0 to 29.7) and 10.5 ng (IQR, 0 to 17.8), respectively, with a noncured-meats diet and 11.9 ng (IQR, 5.6 to 48.6) and 23.4 ng (IQR, 8.6 to 36.7), respectively, with a cured-meats diet. There was no statistically significant difference between ranitidine and placebo in 24-hour urinary excretion of NDMA with a noncured-meats diet (median of the paired differences, 0 [IQR, -6.9 to 0] ng; P = .54) or a cured-meats diet (median of the paired differences, -1.1 [IQR, -9.1 to 11.5] ng; P = .71). No drug-related serious adverse events were reported.

CONCLUSIONS AND RELEVANCE

In this trial that included 18 healthy participants, oral ranitidine (300 mg), compared with placebo, did not significantly increase 24-hour urinary excretion of NDMA when participants consumed noncured-meats or cured-meats diets. The findings do not support that ranitidine is converted to NDMA in a general, healthy population.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04397445.

Drugs in Focus: Proton Pump Inhibitors

Proton pump inhibitors (PPIs) are amongst the most commonly prescribed drugs in infants and children with the last decades witnessing a dramatic rise in their utilization. Although PPIs are clearly effective when used appropriately and have been regarded as safe drugs, there is growing evidence regarding their potential adverse effects. Although, largely based on adult data it is clear that many of these are also relevant to pediatrics. PPI use potentially affects gastrointestinal microbiota composition and function, decreases defence against pathogens resulting in increased risk for infections, interferes with absorption of minerals and vitamins leading to specific deficiencies and increased risk for bone fractures as well as interferes with protein digestion resulting in increased risk of sensitization to allergens and development of allergic diseases and eosinophilic esophagitis. An association with gastric, liver and pancreatic cancer has also been inferred from adult data but is tenuous and causation is not proven. Overall, evidence for these adverse events is patchy and not always compelling. Overall, the use of PPIs, for selected indications with a good evidence base, has significant potential benefit but carries more caution in infants and children. Pediatricians should be aware of the concerns regarding the potential adverse events associated with their use.

The effect of medications associated with drug-induced pancreatitis on pancreatic cancer risk: A nested case-control study of routine Scottish data

BACKGROUND

Inflammation plays a role in pancreatic cancer. Many medications cause pancreatic inflammation, with some leading to a diagnosis of drug-induced pancreatitis (DIP), but few studies have examined these medications and pancreatic cancer risk. We therefore investigated the associations between pancreatic cancer risk and commonly-prescribed medicines for which there is strongest evidence of DIP.

METHODS

A nested case-control study was undertaken using the Primary Care Clinical Informatics Unit Research database containing general practice (GP) records from Scotland. Pancreatic cancer cases, diagnosed between 1999 and 2011, were identified and matched with up to five controls (based on age, gender, GP practice and date of registration). Medicines in the highest category of evidence for DIP, based on a recent systematic review, and used by more than 2 % of controls were identified. Odds ratios (OR) and 95 % confidence intervals (CI) for associations with pancreatic cancer were calculated using conditional logistic regression after adjusting for comorbidities.

RESULTS

There were 1,069 cases and 4,729 controls. Thirteen medicines in the highest category of evidence for DIP were investigated. There was little evidence of an association between any of these medications and pancreatic cancer risk apart from metronidazole (adjusted OR 1.69, 95 % CI 1.18, 2.41) and ranitidine (adjusted OR 1.37, 95 %CI 1.10, 1.70). However, no definitive exposure-response relationships between these medicines and cancer risk were observed.

CONCLUSIONS

There is little evidence that commonly-prescribed medicines associated with inflammation of the pancreas are also associated with pancreatic cancer. These findings should provide reassurance to patients and prescribing clinicians.

Low-dose PPI to prevent bleeding after ESD: A multicenter randomized controlled study

BACKGROUND

Although proton pump inhibitors (PPIs) are widely used in the prevention of gastric bleeding caused by endoscopic submucosal dissection (ESD), there is no consensus on the optimal regimen for these patients. Therefore, we aim to investigate whether intermittent use of low-dose PPI is sufficient to prevent post-ESD bleeding.

METHODS

This multicenter, non-inferiority, randomized controlled trial was conducted at 9 hospitals in China. Consecutive eligible patients with a diagnosis of gastric mucosal lesions after ESD treatment were randomly assigned (1:1) to receive either intermittent low-dose or continuous high-dose PPIs treatment. After three days, all patients administered orally esomeprazole 40 mg once a day for 8 weeks. The primary endpoint was post-ESD bleeding within 7 days. Analysis was done according to the intention-to-treat principle with the non-inferiority margin (Δ) of 5%.

RESULTS

526 consecutive patients were assessed for eligibility from 30 September 2017 to 30 July 2019, of whom 414 were randomly assigned to low-dose (n = 209) or high-dose (n = 205) esomeprazole treatment group without dropouts within7 days. The total post-ESD bleeding is occurred in 13 (6.2 %, 95 % CI 3.3-9.6) of 209 within 7 days in the intermittent low-dose group, and 12 (5.9 %, 95 % CI 2.9-9.3) of 205 in the continuous high-dose group. The absolute risk reduction (ARR) was 0.4 % (-4.2, 4.9). One month after ESD, There are 44 patients (21.1 %, 95 % CI 15.8, 26.8) and 39 patients (19.0 % 95 % CI 13.7, 24.4) in scar stage respectively in low-dose group and high-dose group (P = 0.875).The hospital costs in the low-dose PPI group was lower than high -dose group (P = 0.005).

CONCLUSION

The intermittent use of low-dose PPIs is sufficient to prevent post-ESD bleeding. It might be applied in clinical practice to prevent post-ESD bleeding and reduce the costs related to PPIs.

A systematic assessment of the association between frequently prescribed medicines and the risk of common cancers: a series of nested case-control studies

BACKGROUND

Studies systematically screening medications have successfully identified prescription medicines associated with cancer risk. However, adjustment for confounding factors in these studies has been limited. We therefore investigated the association between frequently prescribed medicines and the risk of common cancers adjusting for a range of confounders.

METHODS

A series of nested case-control studies were undertaken using the Primary Care Clinical Informatics Unit Research (PCCIUR) database containing general practice (GP) records from Scotland. Cancer cases at 22 cancer sites, diagnosed between 1999 and 2011, were identified from GP records and matched with up to five controls (based on age, gender, GP practice and date of registration). Odds ratios (OR) and 95% confidence intervals (CI) comparing any versus no prescriptions for each of the most commonly prescribed medicines, identified from prescription records, were calculated using conditional logistic regression, adjusting for comorbidities. Additional analyses adjusted for smoking use. An association was considered a signal based upon the magnitude of its adjusted OR, p-value and evidence of an exposure-response relationship. Supplementary analyses were undertaken comparing 6 or more prescriptions versus less than 6 for each medicine.

RESULTS

Overall, 62,109 cases and 276,580 controls were included in the analyses and a total of 5622 medication-cancer associations were studied across the 22 cancer sites. After adjusting for comorbidities 2060 medicine-cancer associations for any prescription had adjusted ORs greater than 1.25 (or less than 0.8), 214 had a corresponding p-value less than or equal to 0.01 and 118 had evidence of an exposure-dose relationship hence meeting the criteria for a signal. Seventy-seven signals were identified after additionally adjusting for smoking. Based upon an exposure of 6 or more prescriptions, there were 118 signals after adjusting for comorbidities and 82 after additionally adjusting for smoking.

CONCLUSIONS

In this study a number of novel associations between medicine and cancer were identified which require further clinical and epidemiological investigation. The majority of medicines were not associated with an altered cancer risk and many identified signals reflected known associations between medicine and cancer.

Adverse Effects Associated with Proton Pump Inhibitor Use

Proton pump inhibitors (PPIs) marked a before and after in the management of gastric acid-related disorders since their introduction to the market in 1989. Due to a novel, highly effective mechanism of action blocking the last converging step of gastric acid secretion by parietal cells and very few and mostly tolerable side effects, these drugs quickly displaced other pharmacological compounds such as H2 antagonists as the first treatment choice for peptic ulcer disease, gastroesophageal ulcers, Zollinger-Ellison syndrome, nonsteroidal anti-inflammatory drug-associated ulcers, and eradication of Helicobacter pylori, leading to an exponential increase in their prescription up to now. However, widespread PPI use has led to emerging evidence of long-term adverse effects not described previously, including increased risk of kidney, liver, and cardiovascular disease, dementia, enteroendocrine tumors of the gastrointestinal tract, susceptibility to respiratory and gastrointestinal infections, and impaired absorption of nutrients. Although the evidence published thus far has not established strong correlations, it has been relevant enough to raise new questions about PPIs' safety profile and reconsideration of their clinical indications. Hence, the aim of this review is to evaluate the association between PPI use and the risk of serious adverse effects given increasing concerns about the overuse of PPIs in the general population.

The Association between Ranitidine Use and Gastrointestinal Cancers

N-nitrosodimethylamine (NDMA) is a carcinogen in experimental animals. It has been classified a probable human carcinogen and has been found in ranitidine. This study sought to evaluate the association between ranitidine use and cancer of the gastrointestinal system. Events reported to the FDA Adverse Events Reporting System that were associated with the use of proton pump inhibitors (PPIs) and H2 antagonists were selected. Proportionate reporting ratios (PRRs) and associated 95% confidence intervals (CIs) were calculated to compare the proportion of all reported adverse events that were for gastrointestinal system cancers among adverse event reports for ranitidine to adverse event reports for other H2 antagonists. The proportion of adverse events for any gastrointestinal system cancer relative to all other events was elevated for ranitidine compared to PPIs and other H2 antagonists (PRR 3.66, 95% CI 3.19-4.20). Elevated and significant PRRs were observed for pharyngeal (PRR 9.24), esophageal (PRR 3.56), stomach (PRR 1.48), colorectal (PRR 16.31), liver (PRR 2.64), and pancreatic (PRR 2.18) cancers. The PRRs for anal (PRR 4.62) and gallbladder (PRR 4.62) cancer were also elevated though not statistically significant. In conjunction with a large body of epidemiologic and human and animal basic science research, the study results support the hypothesis that NDMA-contaminated ranitidine increases the risk of cancer and supports the withdrawal of these medications from the market.

Use of Acid-Suppressant Medications After Diagnosis Increases Mortality in a Subset of Gastrointestinal Cancer Patients

BACKGROUND

Acid-suppressant medications, including proton pump inhibitors (PPIs) and H₂ receptor antagonists (H₂RAs), are frequently prescribed and have been linked to increased risk of some gastrointestinal cancers.

AIMS

We examined whether post-diagnosis use of PPIs/H₂RAs is associated with the risk of mortality in gastrointestinal cancer patients.

METHODS

We used data from patients with esophageal cancer, gastric cancer, or hepatocellular carcinomas (HCCs) in the national VA Central Cancer Registry diagnosed between 2002 and 2016. We identified PPI/H₂RA prescriptions that were filled before and after cancer diagnosis and used time-dependent Cox regression models to calculate adjusted hazard ratios (HRs) and 95% CIs for mortality risk. We used a time-varying exposure to avoid immortal-time bias and a 3-month lag to reduce reverse causation. A sensitivity analysis was conducted varying the lag duration between the date of cancer diagnosis and the start of follow-up.

RESULTS

PPIs were used by the majority (54% post-diagnosis use) of patients. We found no association between post-diagnosis PPI use and cancer-specific mortality in esophageal adenocarcinoma (HR 0.93; 95% CI 0.84-1.02), esophageal squamous cell carcinoma (HR 0.99; 95% CI 0.87-1.12), or gastric cardia cancer (HR 1.04; 95% CI 0.89-1.22) patients. Post-diagnosis PPI use was, however, associated with the increased risk of cancer-specific mortality for patients with gastric non-cardia cancer (HR 1.50; 95% CI 1.29-1.74) and HCC (HR 1.31; 95% CI 1.23-1.40). The results were similar for associations with post-diagnosis use of H₂RAs. There was no association with pre-diagnosis PPI/H₂RA use.

CONCLUSION

Post-diagnosis PPI/H₂RA use was associated with the increased mortality in gastric non-cardia cancer and HCC patients.

The deleterious association between proton pump inhibitors and prostate cancer-specific mortality - a population-based cohort study

BACKGROUND

Proton pump inhibitors (PPIs) are commonly prescribed medications that have been shown to have contradicting effects on cancer. We aimed to investigate the effect of pantoprazole and other PPIs on prostate cancer (PCa) specific mortality (PCSM), use of androgen deprivation therapy (ADT), and PCa diagnosis using a large Canadian population-based cohort.

METHODS

We identified 21,512 men aged ≥ 66, with a history of a single negative prostate biopsy and no previous use of any of the analyzed medications between 1994 and 2016. Multivariable Cox regression models with time-dependent covariates were used to assess the associations of PPIs with PCa outcomes. All models included other medications with a putative chemopreventative effect on PCa-outcomes, and were adjusted for age, rurality, comorbidity, and study inclusion year.

RESULTS

Over a mean follow-up of 8.06 years (SD 5.44 years), 10,999 patients (51.1%) used a PPI, 5187 patients (24.1%) had PCa, 2043 patients (9.5%) were treated with ADT, and 805 patients (3.7%) died from PCa. For every 6 months of cumulative use, pantoprazole was associated with a 3.0% (95% CI 0.3-6.0%) increased rate of ADT use, while any use of other PPIs was associated with a 39.0% (95% CI 18.0-64.0%) increased risk of PCSM. No association was found with PCa diagnosis.

CONCLUSIONS

Upon validation of the potentially negative association of PPIs with PCa, PPI use may need to be reassessed in PCa patients.

The association between acid-suppressive agent use and the risk of cancer: a systematic review and meta-analysis

BACKGROUND

Acid-suppressive agents (ASAs) may be associated with cancer; previous studies reported that the risk of cancer with acid suppressants has differed depending on the site of cancer. Here, we conducted a systematic review and meta-analysis of the association between ASA use and the type of cancer risk.

METHODS

MEDLINE, EMBASE, and Cochrane library databases were searched for publications up to the end of September 2019 for MeSH terms and text words related to cancer and ASAs. Studies on the association between ASAs and cancer risk, which included a control group and reported the relative risk of cancer, were included. The inverse-variance random effect model was used to estimate the pooled relative risk (RR) and 95% confidence interval (CI), and subgroup analysis for type of acid suppressants, drug uptake duration, and cumulative doses was performed. Heterogeneity was assessed using the I² test and Q statistic.

RESULTS

Thirty-nine cohort and case-control studies were included. ASA use was found to be significantly associated with a 46% higher risk of gastric cancer (RR, 1.46; 95% CI, 1.18-1.80) and a 53% higher risk of liver cancer (RR, 1.53; 95% CI, 1.31-1.78) compared with nonuse; however, there was no significant association for esophageal, colorectal, pancreatic, lung, breast, prostate, and kidney cancer; melanoma; and lymphoma.

CONCLUSIONS

ASAs were significantly associated with an increased risk of gastric and liver cancer; therefore, special attention of ASA use considering the potential risk of gastric and liver cancer is needed.

Proton Pump Inhibitor Use and Risk of Gastric, Colorectal, Liver, and Pancreatic Cancers in a Community-Based Population

INTRODUCTION

Proton pump inhibitors (PPIs) are commonly used for gastrointestinal disorders; given they increase the systemic levels of gastrin, a trophic hormone, there is a concern about their carcinogenicity. This study evaluated the association between PPI use and gastrointestinal cancers.

METHODS

We performed a nested case-control study in a large, community-based integrated healthcare setting. Cases were adults with gastric (n = 1,233), colorectal (n = 18,595), liver (n = 2,329), or pancreatic cancers (n = 567). Each case was matched with up to 10 controls by age, sex, race/ethnicity, medical facility, and enrollment duration. The primary exposure was defined as ≥2-year cumulative PPI supply. Data were obtained from pharmacy, cancer registry, and electronic medical record databases. Associations were evaluated using conditional logistic regression and adjusted for multiple confounders. We also evaluated the cancer risks separately by PPI dose, duration of use, and dose and duration.

RESULTS

PPI use of ≥2-years was not associated with the risks of gastric (odds ratio [OR]: 1.07, 95% confidence interval [CI]: 0.81-1.42), colorectal (OR: 1.05, 95% CI: 0.99-1.12), liver (OR: 1.14, 95% CI: 0.91-1.43), or pancreatic cancers (OR: 1.22, 95% CI: 0.89-1.67), compared to non-users. In exploratory analyses, elevated cancer risks were primarily restricted to those with ≥10 years of PPI use, but no consistent associations were found for increasing PPI dose and/or duration of use.

DISCUSSION

PPI use of ≥2 years was not associated with increased risks of gastrointestinal cancers. The cancer risks associated with PPI use of ≥10 years requires further study.

Association Between Acid-Suppressive Agents’ Use and Risk of Hepatocellular Carcinoma

Background:

Acid-suppressive agents (ASAs), which are mostly used in patients with upper gastrointestinal diseases (UGIDs), may influence the risk of hepatocellular carcinoma (HCC).

Methods:

A population-based retrospective cohort study was conducted. Patients with UGID who used ASAs and those who did not receive ASAs were identified. Patients without UGIDs were randomly selected and matched (comparison group). All groups were followed up for 6 years. A Cox proportional hazard model was used to estimate the risk of HCC among the different groups.

Results:

Patients with UGID who used ASAs had a significantly elevated HCC risk (adjusted hazard ratio [HR] 1.53; 95% confidence interval [CI], 1.32-1.76] compared to those who did not use ASAs. Patients with UGID who used more than 540 defined daily doses of ASAs had a significantly higher risk of HCC (adjusted HR 2.04; 95% CI, 1.62-2.58). Moreover, the dose effect on HCC risk exhibited a significant increasing trend ( P < .01). Furthermore, patients with UGID who did not use ASAs had a significantly elevated HCC risk (adjusted HR 1.94; 95% CI, 1.59-2.36) compared to the comparison group.

Conclusion:

The use of ASAs increased the risk of HCC in patients with UGIDs, and the effect of ASAs was dose dependent. In addition, UGIDs alone increased the risk of HCC.

Proton pump inhibitors and risk of liver cancer and mortality in patients with chronic liver disease: a systematic review and meta-analysis

BACKGROUND

Epidemiological studies investigating the use of proton pump inhibitors (PPI) on the risk of liver cancer and/or mortality among persons with chronic liver disease (CLD) have reported conflicting results. We conducted a systematic review and meta-analysis to determine the impact of PPI use on liver cancer and/or death among patients with CLD.

METHODS

The core databases including MEDLINE, EMBASE, and Cochrane library were searched through January 2020. We included studies, evaluating the association between PPIs and liver cancer or mortality among patients with CLD including randomized controlled, nonrandomized controlled, and observational studies. We used inverse-variance random-effects models to estimate the pooled relative risk (RR) and 95% confidence interval (CI) for liver cancer or mortality.

RESULTS

Eleven studies including 173,894 patients were selected. In three studies, individuals with CLD who used PPIs had a 67% greater risk of developing hepatocellular carcinoma (HCC) compared to nonusers (RR, 1.67; 95% CI, 1.12-2.50; I² = 92%). Combining data from the eight studies relating PPI to overall mortality, we observed a 57% increased risk of mortality in PPI users with CLD compared to CLD nonusers (RR: 1.57; 95% CI, 1.24-1.99; I² = 69%).

CONCLUSION

PPI use was associated with an increased risk of HCC and mortality in patients with CLD suggesting that PPI prescriptions in patients with CLD should be considered carefully.

Statin use and risk of liver cancer: Evidence from two population-based studies

Epidemiological studies of statin use and liver cancer risk have produced conflicting results. We examined the association between statin use and risk of primary liver cancer in two large independent study populations taking account of important covariates and main indications of statins such as high cholesterol and chronic liver disease. We performed a nested case-control study within the Scottish Primary Care Clinical Informatics Unit (PCCIU) database. Five controls were matched to cases with primary liver cancer and we used conditional logistic regression to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for associations with statin use. We also conducted a prospective cohort study within the UK Biobank using self-reported statin use and cancer-registry recorded primary liver cancer outcomes. Cox regression was used to calculate hazard ratios (HRs) and 95% CIs. In the PCCIU case-control analysis, 434 liver cancer cases were matched to 2,103 controls. In the UK Biobank cohort, 182 out of 475,768 participants developed incident liver cancer. Statin use was associated with 39% lower risk of liver cancer in the PCCIU (adjusted OR 0.61, 95% CI 0.43-0.87). When we examined specific subtypes of liver cancer in the UK Biobank, statin use was associated with lower risk of hepatocellular carcinoma (HCC; adjusted HR, 0.48; 95% CI, 0.24-0.94) but not intrahepatic bile duct carcinoma (IBDC; adjusted HR, 1.09; 95% CI, 0.45-2.64). In conclusion, we found a consistent inverse relationship between statin use and risk of primary liver cancer which was only seen for HCC but not IBDC.

[Proton pump inhibitors and cancers: A hazardous association?]

Proton pump inhibitors, a major progress in gastro-enterology, are globally among the most widely prescribed drugs. But, due to their strong gastric acid inhibition, they can be responsible for side effects, particularly in cancer patients. They are involved in renal function impairment, bone fractures, digestive bacterial overgrowth, particularlyclostridium difficile infections, anemia and hypomagnesemia. Long term use can increase the risks of gastric, pancreatic and liver cancers. They decrease absorption of weak bases drugs, particularly tyrosine kinase inhibitors and capecitabine and are responsible for a poorer prognosis if taken concomitantly with erlotinib, gefitinib and pazopanib. Modification of cyclin dependent kinases is also possible as well as decrease of efficacy of immune check point inhibitors (microbiome modifications). Absoption and efficacy of capecitabine seem also poorer with negative prognosis effect on treatment of gastric and colon cancer. Their long term use, particularly in cancer patients, should probably be avoided.

Proton pump inhibitors: placing putative adverse effects in proper perspective

PURPOSE OF REVIEW

This review summarizes the past year's literature, both clinical and basic science, regarding potential adverse effects of proton pump inhibitors (PPIs).

RECENT FINDINGS

PPIs are amongst the most widely prescribed and over-prescribed medications worldwide. Although generally considered well tolerated, epidemiologic studies that mine large databases have reported a panoply of putative adverse effects associated with PPIs. It should be emphasized that the quality of the evidence underlying most of these associations is very low and the studies, by design, cannot ascribe cause and effect. These associations continue to be sensationalized in the media and misinterpreted by providers and patients. The unintended consequences are that patients who require PPIs, such as those taking dual antiplatelet agents, are not being prescribed or taking these necessary medications. In addition, physicians are spending an inordinate amount of additional time placing these findings into proper perspective for their patients and reassuring them upon initiating PPI treatment as well as at every follow-up visit.

SUMMARY

Most of the recent publicized putative serious adverse effects attributed to PPIs rely on observational data and have not been confirmed in prospective randomized trials. Nevertheless, PPIs should be prescribed for valid indications and when prescribed long-term, they should be used at the lowest effective dose and the need for their use periodically reassessed.

Adverse Effects of Proton Pump Inhibitors-Evidence and Plausibility

Proton pump inhibitors (PPIs) have been increasingly used over the last decades and there are concerns about overuse and the numerous reported side-effects. It is uncertain whether associations between PPI use and potential side effects are causal. However, important evidence from experimental and mechanistic studies that could support a causal relationship may have been underestimated by epidemiologists and meta-analysists. In the current manuscript we review the combined epidemiological and mechanistic evidence of the adverse effects of PPI use.

Use of proton pump inhibitors and the risk of hepatocellular carcinoma: A systematic review and meta-analysis

BACKGROUND

Worldwide, proton pump inhibitors (PPIs) are commonly used for the treatment of peptic ulcer and gastro-esophageal reflux disease. Recently, concern has arisen over the potential association between PPIs and hepatocellular carcinoma (HCC). The aim of the current study was to evaluate the influence of PPI use on the risk of HCC, through a systematic review and meta-analysis.

METHODS

A review of all English-language literature was conducted, using the subject search terms: "hepatocellular carcinoma", "liver cancer", "hepatic tumor", and "proton pump inhibitor" in the major medical databases. A meta-analysis of the qualifying publications was then performed.

RESULTS

A total of five studies, which had shown that PPIs were associated with HCC (crude risk ratio [RR] = 2.27, 95% confidence interval [CI]: 1.44-3.57; p < 0.01) when an unadjusted RR were adopted, were eligible for meta-analysis. It was observed that the cumulative dose of PPIs may increase the risk of HCC in a linear model (p < 0.01). However, when using data that were adjusted by comorbidities and concurrent medications, the association between PPIs and HCC became insignificant (adjusted RR = 1.62, 95% CI: 0.89-2.93; p = 0.11) and this result was consistent in the sensitivity analysis.

CONCLUSION

The current meta-analysis has shown that PPI use does not significantly increase the risk of HCC after adjusting for confounding factors. However, further studies are warranted to verify the association between PPIs and HCC in special populations, such as viral or alcoholic liver diseases.