Is there a dark side to long-term proton pump inhibitor therapy? Am J Ther. 2008;15:536-542. [PMID: 19127138 DOI: 10.1097/mjt.0b013e31817149bf]

Use of proton pump inhibitors and risk of ischemic events in the general population

BACKGROUND AND AIMS

A potential increased risk of cardiovascular events has been suggested for proton pump inhibitors (PPIs), the most commonly prescribed drugs for the management of upper gastrointestinal disorders. We aimed to estimate the risk of hospitalization for cardio/cerebrovascular (CV) events in a cohort of incident PPI users.

METHODS

A nested case-control study was carried out using regional healthcare utilization databases. For each case (hospitalization for non-haemorrhagic CV event), up-to-five controls randomly selected from the cohort were matched by gender, age at cohort entry, and index date. Exposure was estimated as recency of therapy (current, recent and past users) and number of days covered. Adjusted conditional logistic regression was used to estimate the association between exposure and outcome.

RESULTS

Among new PPI users, we identified 17,832 cases and 89,160 controls (males 64.9%; mean age 58.9 years). Cases showed a significantly higher prevalence of use of drugs for diabetes, hypertension and hypercholesterolemia than controls. Risk of CV events was significantly higher for current (OR 1.61; 95%CI 1.55-1.68) and recent users (OR 1.15; 95%CI 1.06-1.26) compared to past users. Analogous results were found stratifying for cardiovascular (OR_current 1.71; 95%CI 1.63-1.81) and cerebrovascular events (OR_current 1.43; 95%CI 1.34-1.54). The increased risk was confirmed in subgroups by antithrombotic, statin use, or exposure duration. The same analysis for H2-antagonists use showed no significant results.

CONCLUSIONS

In primary care setting, PPI use was independently associated with increased risk of first-time cardiovascular event, consistent with the evidence that PPIs adversely impact vascular function, underlying the need to promote appropriate prescribing of these drugs.

Effective and safe proton pump inhibitor therapy in acid-related diseases - A position paper addressing benefits and potential harms of acid suppression

BACKGROUND

The introduction of proton pump inhibitors (PPIs) into clinical practice has revolutionized the management of acid-related diseases. Studies in primary care and emergency settings suggest that PPIs are frequently prescribed for inappropriate indications or for indications where their use offers little benefit. Inappropriate PPI use is a matter of great concern, especially in the elderly, who are often affected by multiple comorbidities and are taking multiple medications, and are thus at an increased risk of long-term PPI-related adverse outcomes as well as drug-to-drug interactions. Herein, we aim to review the current literature on PPI use and develop a position paper addressing the benefits and potential harms of acid suppression with the purpose of providing evidence-based guidelines on the appropriate use of these medications.

METHODS

The topics, identified by a Scientific Committee, were assigned to experts selected by three Italian Scientific Societies, who independently performed a systematic search of the relevant literature using Medline/PubMed, Embase, and the Cochrane databases. Search outputs were distilled, paying more attention to systematic reviews and meta-analyses (where available) representing the best evidence. The draft prepared on each topic was circulated amongst all the members of the Scientific Committee. Each expert then provided her/his input to the writing, suggesting changes and the inclusion of new material and/or additional relevant references. The global recommendations were then thoroughly discussed in a specific meeting, refined with regard to both content and wording, and approved to obtain a summary of current evidence.

RESULTS

Twenty-five years after their introduction into clinical practice, PPIs remain the mainstay of the treatment of acid-related diseases, where their use in gastroesophageal reflux disease, eosinophilic esophagitis, Helicobacter pylori infection, peptic ulcer disease and bleeding as well as, and Zollinger-Ellison syndrome is appropriate. Prevention of gastroduodenal mucosal lesions (and symptoms) in patients taking non-steroidal anti-inflammatory drugs (NSAIDs) or antiplatelet therapies and carrying gastrointestinal risk factors also represents an appropriate indication. On the contrary, steroid use does not need any gastroprotection, unless combined with NSAID therapy. In dyspeptic patients with persisting symptoms, despite successful H. pylori eradication, short-term PPI treatment could be attempted. Finally, addition of PPIs to pancreatic enzyme replacement therapy in patients with refractory steatorrhea may be worthwhile.

CONCLUSIONS

Overall, PPIs are irreplaceable drugs in the management of acid-related diseases. However, PPI treatment, as any kind of drug therapy, is not without risk of adverse effects. The overall benefits of therapy and improvement in quality of life significantly outweigh potential harms in most patients, but those without clear clinical indication are only exposed to the risks of PPI prescription. Adhering with evidence-based guidelines represents the only rational approach to effective and safe PPI therapy. Please see related Commentary: doi: 10.1186/s12916-016-0724-1 .

The Helicobacter Eradication Aspirin Trial (HEAT): A Large Simple Randomised Controlled Trial Using Novel Methodology in Primary Care

Background

Clinical trials measuring the effect of an intervention on clinical outcomes are more influential than those investigating surrogate measures but are costly. We developed methods to reduce costs substantially by using existing data in primary care systems, to ask whether Helicobacter pylori eradication would reduce the incidence of hospitalisation for ulcer bleeding in aspirin users.

Methods

The Helicobacter Eradication Aspirin Trial (HEAT) is a National Institute of Health Research-funded, double-blind placebo controlled randomised trial of the effects of H. pylori eradication on subsequent ulcer bleeding in infected individuals taking aspirin daily, conducted in practices across the whole of England, Wales and Northern Ireland. A bespoke web-based trial management system developed for the trial (and housed within the secure NHS Data Network) communicates directly with the HEAT Toolkit software downloaded at participating practices, which issues queries searching entry criteria (≥ 60 years, on chronic aspirin ≤ 325 mg daily, not on anti-ulcer therapy or non-steroidal anti-inflammatory drugs) for GP review of eligibility. Trial participation is invited using a highly secure automated online mail management system. Interested patients are seen once for consent and breath testing. Those with a positive test are randomised to eradication treatment (lansoprazole, clarithromycin, metronidazole) or placebo, with drug sent by post. Events are tracked by upload of accumulating information in the GP database, patient contact, review of National Hospital Episode Statistics and Office of National Statistics data.

Results

HEAT is the largest Clinical Research Network-supported drug trial, with 115,660 invitation letters sent from 850 practices, 22,922 volunteers, and 3038 H. pylori positive patients randomised to active or placebo treatment after 2.5 years of recruitment. 178 practices have performed their first follow-up data search to identify 21 potential endpoints to date.

Discussion

HEAT is important medically, because aspirin is so widely used, and methodologically, as a successful trial would show that large-scale studies of important clinical outcomes can be conducted at a fraction of the cost of those conducted by industry, which in turn will help to ensure that trials of primarily medical rather than commercial interest can be conducted successfully in the UK.

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HEAT, a large clinical trial investigating effects of H. pylori eradication on incidence of ulcer bleeding in aspirin users

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HEAT methodology allows large-scale trials of important clinical outcomes to be conducted at low cost affordable to the NHS

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As the largest CRN-supported drug study, HEAT has currently invited participation from over 115,000 patients countrywide

Systematic toxicity mechanism analysis of proton pump inhibitors: an in silico study

Proton pump inhibitors (PPIs) are extensively used for the treatment of gastric acid-related disorders. PPIs appear to be well tolerated and almost have no short-term side effects. However, the clinical adverse reactions of long-term PPI usage are increasingly reported in recent years. So far, there is no study that elucidates the side effect mechanisms of PPIs comprehensively and systematically. In this study, a well-defined small molecule perturbed microarray data set of 344 compounds and 1695 samples was analyzed. With this high-throughput data set, a new index (Identity, I) was designed to identify PPI-specific differentially expressed genes. Results indicated that (1) up-regulated genes, such as RETSAT, CYP1A1, CYP1A2, and UGT, enhanced vitamin A's metabolism processes in the cellular retinol metabolism pathway; and that (2) down-regulated genes, such as C1QA, C1QC, C4BPA, C4BPB, CFI, and SERPING1, enriched in the complement and coagulation cascades pathway. In addition, strong association was observed between these PPI-specific differentially expressed genes and the reported side effects of PPIs by the gene-disease association network analysis. One potential toxicity mechanism of PPIs as suggested from this systematic PPI-specific gene expression analysis is that PPIs are enriched in acidic organelles where they are activated and inhibit V-ATPases and acid hydrolases, and consequently block the pathways of antigen presentation, the synthesis and secretion of cytokines, and complement component proteins and coagulation factors. The strategies developed in this work could be extended to studies on other drugs.

Non-Specific Gastric Inflammation in Children is Associated with Proton Pump Inhibitor Treatment for More than 6 Weeks

BACKGROUND AND AIMS

Non-specific gastric inflammation (NSGI) is a commonly reported pathological finding. We investigated if it is associated with the use of proton pump inhibitors (PPIs) in children at a single tertiary center.

METHODS

We performed an IRB-approved chart review of all endoscopy and biopsy reports of patients who underwent esophagogastroduodenoscopy between July 2009 and July 2010 (n = 310). Demographic data, dose, duration of exposure to PPI, and biopsy results were collected and analyzed. All esophageal, gastric, and duodenal biopsies were independently reviewed by a pathologist. Patients with acute gastritis, moderate/severe chronic gastric inflammation, or Helicobacter pylori infection were excluded. The presence of NSGI was compared between patients exposed and not exposed to PPI as well as between patients with different doses and durations of PPI exposure to assess for potential associations.

RESULTS

A total of 193 patients were included: 88 (46%) had a history of PPI use and 48 (25%) were found to have NSGI. Compared to patients not exposed to PPI, the odds ratio of NSGI in patients exposed to PPIs was 2.81 (95% CI: 1.36-5.93). The odds ratio of NSGI in patients exposed to PPI for >3 months was 4.53 (95% CI: 1.69-11.97). Gender, ethnicity, and age were not associated with NSGI. No histological differences were found in the esophagus and duodenum between patients exposed and not exposed to PPI.

CONCLUSION

This study found that PPI exposure is associated with NSGI with a higher risk for those exposed for >3 months. As the clinical implications of NSGI are not known, judicious use of PPIs is needed. Prospective studies are required to confirm and to determine the etiologic factors (i.e., alteration of the gastric pH, serum gastrin) that may be related with the presence of NGSI.

Quality of life following laparoscopic Nissen fundoplication: Assessing short-term and long-term outcomes

AIM: To investigate the quality of life following laparoscopic Nissen fundoplication by assessing short-term and long-term outcomes.

METHODS: From 1992 to 2005, 249 patients underwent laparoscopic Nissen fundoplication. Short-term outcome data including symptom response, side effects of surgery, endoscopy, and patient’s perception of overall success were collected prospectively. Long-term outcomes were investigated retrospectively in patients with a median follow-up of 10 years by assessment of reflux symptoms, side effects of surgery, durability of antireflux surgery, need for additional treatment, patient’s perception of success, and quality of life. Antireflux surgery was considered a failure based on the following criteria: moderate to severe heartburn or regurgitation; moderate to severe dysphagia reported in combination with heartburn or regurgitation; regular proton pump inhibitor medication use; endoscopic evidence of erosive esophagitis Savary-Miller grade 1-4; pathological 24-h pH monitoring; or necessity to undergo an additional surgery. The main outcome measures were short- and long-term cure rates and quality of life, with patient satisfaction as a secondary outcome measure.

RESULTS: Conversion from laparoscopy to open surgery was necessary in 2.4% of patients. Mortality was zero and the 30-d morbidity was 7.6% (95%CI: 4.7%-11.7%). The median postoperative hospital stay was 2 d [interquartile range (IQR) 2-3 d]. Two hundred and forty-seven patients were interviewed for short-term analysis following endoscopy. Gastroesophageal reflux disease was cured in 98.4% (95%CI: 95.9%-99.6%) of patients three months after surgery. New-onset dysphagia was encountered postoperatively in 13 patients (6.7%); 95% reported that the outcome was better after antireflux surgery than with preoperative medical treatment. One hundred and thirty-nine patients with a median follow-up of 10.2 years (IQR 7.2-11.6 years) were available for a long-term evaluation. Cumulative long-term cure rates were 87.7% (81.0%-92.2%) at 5 years and 72.9% (64.0%-79.9%) at 10 years. Gastrointestinal symptom rating scores and RAND-36 quality of life scores of patients with treatment success were similar to those of the general population but significantly lower in those with failed antireflux surgery. Of the patients available for long-term follow-up, 83% rated their operation a success.

CONCLUSION: For the long-term, our results indicate decreasing effectiveness of laparoscopic antireflux surgery, although most of the patients seem to have an overall quality of life similar to that of the general population.

V-ATPase is a candidate therapeutic target for Ewing sarcoma

Suppression of oxidative phosphorylation combined with enhanced aerobic glycolysis and the resulting increased generation of protons are common features of several types of cancer. An efficient mechanism to escape cell death resulting from intracellular acidification is proton pump activation. In Ewing sarcoma (ES), although the tumor-associated chimeric gene EWS-FLI1 is known to induce the accumulation of hypoxia-induced transcription factor HIF-1α, derangements in metabolic pathways have been neglected so far as candidate pathogenetic mechanisms. In this paper, we observed that ES cells simultaneously activate mitochondrial respiration and high levels of glycolysis. Moreover, although the most effective detoxification mechanism of proton intracellular storage is lysosomal compartmentalization, ES cells show a poorly represented lysosomal compartment, but a high sensitivity to the anti-lysosomal agent bafilomycin A1, targeting the V-ATPase proton pump. We therefore investigated the role of V-ATPase in the acidification activity of ES cells. ES cells with the highest GAPDH and V-ATPase expression also showed the highest acidification rate. Moreover, the localization of V-ATPase was both on the vacuolar and the plasma membrane of all ES cell lines. The acidic extracellular pH that we reproduced in vitro promoted high invasion ability and clonogenic efficiency. Finally, targeting V-ATPase with siRNA and omeprazole treatments, we obtained a significant selective reduction of tumor cell number. In summary, glycolytic activity and activation of V-ATPase are crucial mechanisms of survival of ES cells and can be considered as promising selective targets for the treatment of this tumor.

Proton pump inhibitors for irritable infants

QUESTION

Crying is common in infants; however, caring for infants with inconsolable crying, previously also known as colic or reflux, is often extremely distressing for parents. Is there a benefit to using gastric acid suppression (eg, proton pump inhibitors [PPIs]) in these infants?

ANSWER

The use of PPIs in infants and children has increased in recent years. The efficacy of proton pump inhibitors has not been demonstrated in the treatment of irritability and excessive crying in otherwise healthy infants younger than 3 months of age. Conversely, while PPIs are generally well tolerated, there is some evidence to link the use of PPIs with increased susceptibility to acute gastroenteritis, community-acquired pneumonia, and disorders of nutrient absorption and utilization. Irrespective of treatment, crying and irritability in infancy generally improve with time. Proton pump inhibitors do not improve symptoms in the interim.

Use of Proton Pump Inhibitor and Risk of Colorectal Cancer: A Meta-analysis of Observational Studies

Background

Previous case-control studies have reported inconsistent findings regarding the association between proton pump inhibitor (PPI) use and colorectal cancer (CRC) risk. We investigated these associations using meta-analysis.

Methods

We searched MEDLINE (PubMed), EMBASE, and the Cochrane Library in April 2011. Two evaluators independently reviewed and selected articles, based on pre-determined selection criteria.

Results

Out of 737 articles meeting our initial criteria, 5 case-control studies, which involved 120,091 participants (9,514 cases and 110,577 controls), were included in the final analyses. The overall use of PPI (used vs. never or rarely used) was not significantly associated with the risk of CRC in a fixed-effects model meta-analysis of all 5 case-control studies (odds ratio [OR], 1.08; 95% confidence interval [CI], 0.96 to 1.20; I² = 3.5%). Also, in sensitivity meta-analysis by cumulative duration of PPI use, there was no association between PPI use of 1 year or longer and the risk of colorectal cancer in a fixed-effects meta-analysis (OR, 1.09; 95% CI, 0.98 to 1.22; I² = 0%).

Conclusion

Although hypergastrinemia could be an important factor in the pathogenesis of some colorectal cancers, our study suggests that this does not lead to significant clinical risk for most PPI users. Further prospective studies or randomized controlled trials related to PPI use and colorectal cancer risk are needed to investigate this association.

Systematic review: hypomagnesaemia induced by proton pump inhibition

BACKGROUND

Proton pump inhibitors (PPIs) are a mainstay therapy for all gastric acid-related diseases. Clinical concerns arise from a small but growing number of case reports presenting PPI-induced hypomagnesaemia (PPIH) as a consequence of long-term PPI use. Current opinion is that reduced intestinal magnesium absorption might be involved, but nothing is known on the molecular mechanism underlying PPIH.

AIM

To investigate whether or not PPIH is a true, long-term drug-class effect of all PPIs and to scrutinise a possible role of comorbidity in its aetiology. Therefore, the primary objective in particular was to investigate serum magnesium dynamics in trials drug withdrawal and re-challenge. The secondary objective was to profile the 'patient at risk'.

METHODS

We reviewed systematically all currently available case reports on the subject and performed a statistical analysis on extracted data.

RESULTS

Proton pump inhibitor-induced hypomagnesaemia PPIH is a drug-class effect and occurred after 5.5 years (median) of PPI use, onset was broad and ranged from 14 days to 13 years. Discontinuation of PPIs resulted in fast recovery from PPIH in 4 days and re-challenge led to reoccurrence within 4 days. Histamine-2-receptor antagonists were the preferable replacement therapy in PPIH and prevented reoccurrence of hypomagnesaemia. In PPIH no specific risk profile was identified that was linked to the hypomagnesaemia.

CONCLUSIONS

The cases of PPIH show severe symptoms of magnesium depletion and identification of its causation was only possible through withdrawal of the PPI. Clinical awareness of PPIH is key to avoid putting patients at risk.

Reflux and aerodigestive tract diseases

Gastroesophageal reflux disease can present with a wide variety of extraesophageal symptoms. In particular, the type of disease characterized predominately by laryngopharyngeal reflux may be difficult to diagnose because of the absence of regurgitation or heartburn. The available battery of diagnostic tools is often insufficient to confirm a diagnosis of reflux, so the diagnosis is often made by elimination. In many cases, treatment with proton pump inhibitors will relieve symptoms and respiratory complications, despite the persistence of non-acidic reflux. Such treatment is often employed to "confirm" the diagnosis, as measured by patient response. Many diseases have been related to this condition in the literature. The authors review knowledge about these manifestations and their relationship with refluxed gastric content. Physiopathology, symptoms and treatment are reviewed in order to clarify our understanding of laryngopharyngeal reflux diseases and related manifestations.

In vitro effect of pantoprazole on lower esophageal sphincter tone in rats

AIM: To investigate the in vitro effects of pantoprazole on rat lower esophageal sphincter (LES) tone.

METHODS: Rats weighing 250-300 g, provided by the Yeditepe University Experimental Research Center (YÜDETAM), were used throughout the study. They were anesthetized before decapitation. LES tissues whose mucosal lining were removed were placed in a standard 30-mL organ bath with a modified Krebs solution and continuously aerated with 95% oxygen-5% carbon dioxide gas mixture and kept at room temperature. The tissues were allowed to stabilize for 60 min. Subsequently, the contractile response to 10^-6 mol/L carbachol was obtained. Different concentrations of freshly prepared pantoprazole were added directly to the tissue bath to generate cumulative concentrations of 5 × 10^-6 mol/L, 5 × 10^-5 mol/L, and 1.5 × 10^-4 mol/L. Activities were recorded on an online computer via a 4-channel transducer data acquisition system using the software BSL PRO v 3.7, which also analyzed the data.

RESULTS: Pantoprazole at 5 × 10^-6 mol/L caused a small, but statistically insignificant, relaxation in the carbachol-contracted LES (2.23% vs 3.95%). The 5 × 10^-5 mol/L concentration, however, caused a significant relaxation of 10.47% compared with the control. 1.5 × 10^-4 mol/L concentration of pantoprazol caused a 19.89% relaxation in the carbachol contracted LES (P < 0.001).

CONCLUSION: This is the first study to demonstrate that pantoprazole has a relaxing effect in isolated LESs. These results might have significant clinical implications for the subset of patients using proton pump inhibitors who do not receive full symptomatic alleviation from gastroesophageal reflux disease.

Risk of fracture and pneumonia from acid suppressive drugs

A recently published systematic review and meta-analysis, incorporating all relevant studies on the association of acid suppressive medications and pneumonia identified up to August 2009, revealed that for every 200 patients, treated with acid suppressive medication, one will develop pneumonia. They showed the overall risk of pneumonia was higher among people using proton pump inhibitors (PPIs) [adjusted odds ratio (OR) = 1.27, 95% CI: 1.11-1.46, I² = 90.5%] and Histamine_-2 receptor antagonists (H₂RAs) (adjusted OR = 1.22, 95% CI: 1.09-1.36, I² = 0.0%). In the randomized controlled trials, use of H₂RAs was associated with an elevated risk of hospital-acquired pneumonia (relative risk 1.22, 95% CI: 1.01-1.48, I² = 30.6%). Another meta-analysis of 11 studies published between 1997 and 2011 found that PPIs, which reduce stomach acid production, were associated with increased risk of fracture. The pooled OR for fracture was 1.29 (95% CI: 1.18-1.41) with use of PPIs and 1.10 (95% CI: 0.99-1.23) with use of H₂RAs, when compared with non-use of the respective medications. Long-term use of PPIs increased the risk of any fracture (adjusted OR = 1.30, 95% CI: 1.15-1.48) and of hip fracture risk (adjusted OR = 1.34, 95% CI: 1.09-1.66), whereas long-term H₂RA use was not significantly associated with fracture risk. Clinicians should carefully consider when deciding to prescribe acid-suppressive drugs, especially for patients who are already at risk for pneumonia and fracture. Since it is unnecessary to achieve an achlorhydric state in order to resolve symptoms, we recommend using the only minimum effective dose of drug required to achieve the desired therapeutic goals.

Association between proton pump inhibitor use and anemia: a retrospective cohort study

BACKGROUND

Proton pump inhibitors (PPIs) are widely prescribed to treat gastrointestinal diseases. However, concerns have been raised regarding their long-term use. Gastric acid suppression may decrease iron absorption, and it remains uncertain whether iron-deficiency anemia may result from chronic PPI therapy.

AIMS

We aimed to explore the association between chronic PPI use and iron-deficiency anemia.

METHODS

We conducted a retrospective cohort study of adult patients in an academic outpatient setting who received PPI therapy for at least 1 year between January 1, 2004 and January 1, 2006. We compared the change in hematologic indices among patients receiving PPI therapy for at least 1 year with matched controls.

RESULTS

Of the 98 patients on chronic PPI therapy who met inclusion criteria, 35% had no documented indication for such therapy. At baseline, demographics and hematologic indices were similar between PPI-users and controls. Among patients on PPI therapy, all hematologic indices decreased from baseline, including hemoglobin (-0.19 g/dL, P=0.03), hematocrit (-0.63%, P=0.02), and mean corpuscular volume (-0.49 fL, P=0.05). PPI users had significant decreases in mean hemoglobin and hematocrit (P<0.01 for both) compared with matched controls. After adjustment for confounders, including rates of esophagogastroduodenoscopy, colonoscopy and remote cancer status, the odds ratio of decreasing hemoglobin by 1.0 g/dL while on chronic PPI therapy was 5.03 (95% CI, 1.71-14.78, P<0.01), while the odds ratio of decreasing hematocrit by 3% was 5.46 (95% CI, 1.67-17.85, P<0.01).

CONCLUSIONS

Among adult patients receiving chronic PPI therapy, there is a significant decrease in hematologic indices from baseline.

[Guidelines for the treatment of gastroesophageal reflux disease]

Gastroesophageal reflux disease (GERD) is defined as a condition that develops when the reflux of stomach contents causes troublesome symptoms and/or complications. In the last decade, GERD has been increasing in Korea. Seventeen consensus statements for the treatment of GERD were developed using the modified Delphi approach. Acid suppression treatments, such as proton pump inhibitors (PPIs), histmine-2 receptor antagonists and antacids are effective in the control of GERD-related symptoms. Among them, PPIs are the most effective medication. Standard dose PPI is recommended as the initial treatment of erosive esophagitis (for 8 weeks) and non-erosive reflux disease (at least for 4 weeks). Long-term continuous PPI or on-demand therapy is required for the majority of GERD patients after the initial treatment. Anti-reflux surgery can be considered in well selected patients. Prokinetic agents and mucosal protective drugs have limited roles. Twice daily PPI therapy can be tried to control extra-esophageal symptoms of GERD. For symptomatic patients with Barrett's esophagus, long-term treatment with PPI is required. Further studies are strongly needed to develop better treatment strategies for Korean patients with GERD.

Weakly acidic reflux

The advent of multichannel intraluminal impedance-pH (MII-pH) monitoring has generated interest in the role of weakly acidic reflux in persistent symptoms in patients with gastroesophageal reflux disease (GERD). Emerging evidence suggests that MII-pH may be superior to conventional pH testing under certain circumstances in the detection of reflux and expert opinions have been put forth advocating a central role for pH impedance monitoring in the detection of GERD. However the clinical relevance of an impedance-based diagnosis of reflux and its impact on clinically relevant outcomes is less clear. This review appraises the role of weakly acidic reflux in health and in GERD patients and the clinical utility of detecting weakly acidic reflux in the management of GERD.

Use of acid-suppressive drugs and risk of pneumonia: a systematic review and meta-analysis

BACKGROUND

Observational studies and randomized controlled trials have yielded inconsistent findings about the association between the use of acid-suppressive drugs and the risk of pneumonia. We performed a systematic review and meta-analysis to summarize this association.

METHODS

We searched three electronic databases (MEDLINE [PubMed], Embase and the Cochrane Library) from inception to Aug. 28, 2009. Two evaluators independently extracted data. Because of heterogeneity, we used random-effects meta-analysis to obtain pooled estimates of effect.

RESULTS

We identified 31 studies: five case-control studies, three cohort studies and 23 randomized controlled trials. A meta-analysis of the eight observational studies showed that the overall risk of pneumonia was higher among people using proton pump inhibitors (adjusted odds ratio [OR] 1.27, 95% confidence interval [CI] 1.11-1.46, I(2) 90.5%) and histamine(2) receptor antagonists (adjusted OR 1.22, 95% CI 1.09-1.36, I(2) 0.0%). In the randomized controlled trials, use of histamine(2) receptor antagonists was associated with an elevated risk of hospital-acquired pneumonia (relative risk 1.22, 95% CI 1.01-1.48, I(2) 30.6%).

INTERPRETATION

Use of a proton pump inhibitor or histamine(2) receptor antagonist may be associated with an increased risk of both community- and hospital-acquired pneumonia. Given these potential adverse effects, clinicians should use caution in prescribing acid-suppressive drugs for patients at risk.

Safety of proton pump inhibitor exposure

Proton pump (H(+)/K(+)-adenosine triphosphatase) inhibitors (PPIs) are widely used to treat patients with acid-related disorders because they are generally perceived to be safe and effective. However, as with any pharmacologic agent, they have the potential for side effects. Many studies have examined the side effects of long-term or short-term PPI exposure. We review the mechanism of action of PPIs, focusing on recently released products that might have greater risks of adverse effects than older products because of increased potency and/or duration of action. We summarize the data available on the putative adverse effects of PPI therapy and propose guidelines for clinicians who prescribe these agents to limit the potential for adverse outcomes in users of these effective therapeutic agents.

Editorial: just how "difficult" is it to withdraw PPI treatment?

Two recent studies-one of which is published in this edition of the American Journal of Gastroenterology-have reported that new dyspeptic or reflux symptoms may develop among previously asymptomatic individuals after withdrawal of a short course of a proton pump inhibitor (PPI). It has been suggested that this is attributable to rebound gastric acid hypersecretion, and that the same phenomenon explains why some patients become chronic PPI users and physicians experience "difficulty" in withdrawing PPI treatment from patients. Although we congratulate the authors of both studies for their controlled observations, we question the generalizability of these observations and hypotheses to the clinical domain. PPI treatment continues to be the optimal management strategy for most patients with gastroesophageal reflux disease and is indicated for chronic use as ulcer prophylaxis in nonsteroidal anti-inflammatory drug takers at high risk for bleeding. However, as with all drugs, PPIs should be dosed appropriately, and should be reserved for patients with conditions for which there is clear evidence of benefit from therapy.

Meta-analysis: proton pump inhibitor use and the risk of community-acquired pneumonia

BACKGROUND

Observational studies examining the association between proton pump inhibitor (PPI) use and risk of community-acquired pneumonia are conflicting.

AIM

To assess systematically the association between risk of community-acquired pneumonia and PPI use in adults.

METHODS

We searched MEDLINE, EMBASE and CINAHL databases between 1988 and January 2010. Two reviewers independently selected studies based on eligibility criteria and extracted data. Included studies evaluated adults (> or =18 years) who took PPIs as an out-patient. The primary outcome was community-acquired pneumonia. Only observational studies with a comparison arm were included.

RESULTS

Over 2600 citations were reviewed. Six studies were included. All were nested case-control studies. Meta-analysis found an increased risk of community-acquired pneumonia associated with PPI use [OR 1.36 (95% CI 1.12-1.65)]; significant heterogeneity remained (I(2) 92%, P < 0.001). In exploratory subgroup analysis, short duration of use was associated with an increased odds of community-acquired pneumonia [OR 1.92 (95% CI 1.40-2.63), I(2) 75%, P = 0.003], whereas chronic use was not [OR 1.11 (95% CI 0.90-1.38), I(2) 91%, P < 0.001], a significant interaction (P < 0.005).

CONCLUSIONS

Heterogeneity precluded interpretation of the summary statistic. Exploratory analysis revealed that duration of PPI use may impact the risk of community-acquired pneumonia, a finding that should be explored in future studies.

A case series of proton pump inhibitor-induced hypomagnesemia

Proton pump inhibitor (PPI)-induced hypomagnesemia has been recognized since 2006. Our aim was to further characterize the clinical consequences and possible mechanisms of this electrolyte disorder using 4 cases. Two men (aged 63 and 81 years) and 2 women (aged 73 and 62 years) had been using a PPI (esomeprazole, pantoprazole, omeprazole, and rabeprazole, 20-40 mg) for 1-13 years. They developed severe hypomagnesemia (magnesium, 0.30 +/- 0.28 mEq/L; reference, 1.40-2.10 mEq/L) with hypocalcemia (calcium, 6.4 +/- 1.8 mg/dL), relative hypoparathyroidism (parathyroid hormone, 43 +/- 6 pg/mL), and extremely low urinary calcium and magnesium excretion. One patient was admitted with postanoxic encephalopathy after a collapse likely caused by arrhythmia. The others had electrocardiogram abnormalities (prolonged QT interval, ST depression, and U waves). Concomitant hypokalemia (potassium, 2.8 +/- 0.1 mEq/L) was considered the trigger for these arrhythmias. Hypomagnesemia-induced kaliuresis (potassium excretion, 65 +/- 24 mEq/L) was identified as the cause of hypokalemia. This series of PPI-induced hypomagnesemia shows that this is a generic effect. It also indicates that hypomagnesemia may occur within 1 year of PPI therapy initiation and can have serious clinical consequences, likely triggered by the associated hypokalemia. A high index of suspicion is required in PPI users for unexplained hypomagnesemia, hypocalcemia, hypokalemia, or associated symptoms.