Hypochlorhydria from short-term omeprazole treatment does not inhibit intestinal absorption of calcium, phosphorus, magnesium or zinc from food in humans

Recent safety concerns with proton pump inhibitors

There have been recent concerns about the safety of proton pump inhibitors (PPIs). We focus here on 3 specific concerns-the possible interaction between PPIs and clopidogrel, the postulated link between PPI use and fractures, and the possibility that long-term PPI use might lead to hypomagnesemia. There is evidence for an in vitro interaction between clopidogrel and at least some PPIs. The Food and Drug Administration (FDA) has warned against the use of certain PPIs by patients on clopidogrel. However, a randomized controlled trial that compared clopidogrel alone with the combination of clopidogrel and omeprazole found no increase in adverse cardiovascular outcomes and a reduction in the rate of adverse gastrointestinal outcomes attributable to omeprazole. PPI use may be a weak risk factor for certain fractures, but the quality of evidence is relatively poor and there is a strong possibility of confounding. The mechanism whereby PPI use might increase fracture risk is unknown. Currently, no additional measures concerning calcium supplementation or bone mineral density monitoring are recommended for patients on a PPI. The FDA has suggested monitoring serum magnesium levels in patients on PPI therapy. The mechanism and frequency of PPI-induced hypomagnesemia are unclear. PPI treatment should not be withheld from patients who genuinely require it, but the PPI should be taken in the lowest effective dose and only for as long as clinically indicated. The same is, of course, true for all medicines. The benefits of PPI therapy greatly outweigh the risks.

[Adverse effects of proton pump inhibitors: should we worry about long-term exposure?]

Long-term treatment with proton pump inhibitors (PPI) is becoming more prevalent. Although they are well tolerated in the short term, serious concerns about long-term use have arisen. Recent data suggest that the latter is associated with an increased risk for osteoporotic fracture (especially vertebral), Clostridium difficile infection and rebound acid hypersecretion after treatment discontinuation. Acute interstitial nephritis is rare but may progress to chronic renal failure. An increased risk of community-acquired pneumonia has not been established in the general population and seems limited to the most vulnerable patients. Consistent data are still missing to correctly assess the risk of iron deficiency, vitamin B12 deficiency or hypomagnesaemia and the risk of digestive malignant diseases, despite the pathophysiological basis that exists concerning gastric malignancy. Many drug interactions can occur on long-term treatment, including some that imply the cytochrome P450 enzymes. Finally, the risk-benefit balance for a chronic PPI use in children seems unfavorable in most cases.

Long-term acid inhibition: benefits and harms

Proton pump inhibitors (PPIs) are the drugs of choice in the therapy of acid-related disorders. PPIs are as a class remarkably safe. Serious adverse events such as acute interstitial nephritis are extremely rare. Some reports in recent years have placed some concern on the long-term use of PPIs. Long-term therapy with PPIs can cause hypochlorhydria, hypergastrinemia and has interactions on hepatic cytochrome P450 enzymes which might increase the risk of infectious complications, nutritional deficiencies and drug-drug interactions. The vast majority of data came from retrospective case-control or cohort studies which are prone to confounders. At the moment we cannot conclude that long-term PPI use causes anemia, osteoporosis and bone fractures, increases the risk for pulmonary or enteric infections, has an effect on GUT mucosa, polyp or tumor formation, or that PPI use increases the risk of cardiovascular events in patients on PPIs and clopidogrel. We need prospective randomized trials to be able to definitely answer the questions raised in epidemiologic studies. Maintenance therapy with PPIs should be started only if strict indications for that therapy are fulfilled.

Proton pump inhibitors therapy and risk of hip fracture: a systematic review and meta-analysis

BACKGROUND AND AIMS

Previous studies have reported inconsistent findings that proton pump inhibitors (PPIs) therapy might increase the risk of hip fracture. We investigated the association between PPIs therapy and hip fracture by a systematic review and meta-analysis.

METHODS

We systematically searched PubMed, EMBASE, and the Cochrane Library. We included studies assessing the effects of PPIs on hip fracture. Data from the studies about odds ratio and 95% confidence interval were gathered and summarized.

RESULTS

Seven studies met the inclusion criteria. PPIs therapy was associated with a statistically significant increase of hip fracture risk (pooled odds ratio=1.24; 95% confidence interval: 1.15-1.34; P<0.00001) under a random model. Meanwhile, we found that the effect of PPIs on hip fracture differs in different duration groups.

CONCLUSION

These results indicate that PPIs therapy might have the potential risk of hip fracture. Different effects on hip fracture in the subgroup analysis do not support a causal relationship between PPIs and hip fracture. Whether the risk exists warrants further investigation.

Meta-analysis: risk of fractures with acid-suppressing medication

AIMS

Recent studies have suggested an increased risk of fractures with proton pump inhibitors (PPIs) and histamine-2 receptor antagonists (H2RAs). We planned to perform a meta-analysis of fractures in patients taking PPIs and H2RAs.

METHODS

We searched MEDLINE and EMBASE in September 2010 for observational studies reporting on the risk of fractures with acid-suppressing medication (PPIs and H2RA). We also checked the references lists of included studies and regulatory authority websites for additional data. We performed random effects meta-analysis of odds ratios (OR) according to fracture type and conducted subgroup analyses by duration of exposure. Heterogeneity was assessed using the I(2) statistic.

RESULTS

Our review included 12 studies covering 1,521,062 patients. Pooled analysis of PPI use showed significant risk for spine fractures (4 studies, OR 1.50, 95% CI 1.32-1.72, p<0.001, I(2)=0%) but this was not significant for H2RA (3 studies, OR 1.05, 95% CI 0.92-1.19, p=0.50, I(2)=0%). Similarly for hip fractures, there was a significant risk of fractures with PPIs (10 studies, OR 1.23, 95% CI 1.11-1.36, p<0.001, I(2)=72%), but not for H2RAs (9 studies, OR 1.12, 95% CI 0.99-1.27, p=0.06, I(2)=75%), respectively). Analysis of fractures overall (based on all 12 studies covering a mixture of fracture types) yielded an OR of 1.20 (95% CI 1.11-1.30, p<0.001, I(2)=78%) for PPIs, and OR of 1.08 (95% CI 1.00-1.18, p=0.06, I(2)=82%) for H2RA. However, aside from the risk of spine fractures, all the other analyses were limited by substantial heterogeneity. One study that reported on a direct comparison between acid-suppressing medications found an increased risk with PPIs vs. H2RA for hip fractures, OR 1.34 (95% CI 1.14-1.38).

CONCLUSION

There is some evidence for a modest association between PPI use and risk of fractures, which was not seen with H2RA exposure. The association is most consistent for spine fractures, while there is substantial heterogeneity in the magnitude of risk for other fractures. Clinicians who are concerned about patients with high fracture risk may wish to consider the option of H2RAs instead of PPIs.

Adverse effects of long-term proton pump inhibitor therapy

Proton pump inhibitors have an excellent safety profile and have become one of the most commonly prescribed class of drugs in primary and specialty care. Long-term, sometimes lifetime, use is becoming increasingly common, often without appropriate indications. This paper is a detailed review of the current evidence on this important topic, focusing on the potential adverse effects of long-term proton pump inhibitor use that have generated the greatest concern: B12 deficiency; iron deficiency; hypomagnesemia; increased susceptibility to pneumonia, enteric infections, and fractures; hypergastrinemia and cancer; drug interactions; and birth defects. We explain the pathophysiological mechanisms that may underlie each of these relationships, review the existing evidence, and discuss implications for clinical management. The benefits of proton pump inhibitor use outweigh its risks in most patients. Elderly, malnourished, immune-compromised, chronically ill, and osteoporotic patients theoretically could be at increased risk from long-term therapy.

Omeprazole decreases magnesium transport across Caco-2 monolayers

AIM

To elucidate the effect and underlying mechanisms of omeprazole action on Mg(2+) transport across the intestinal epithelium.

METHODS

Caco-2 monolayers were cultured in various dose omeprazole-containing media for 14 or 21 d before being inserted into a modified Ussing chamber apparatus to investigate the bi-directional Mg(2+) transport and electrical parameters. Paracellular permeability of the monolayer was also observed by the dilution potential technique and a cation permeability study. An Arrhenius plot was performed to elucidate the activation energy of passive Mg(2+) transport across the Caco-2 monolayers.

RESULTS

Both apical to basolateral and basolateral to apical passive Mg(2+) fluxes of omeprazole-treated epithelium were decreased in a dose- and time-dependent manner. Omeprazole also decreased the paracellular cation selectivity and changed the paracellular selective permeability profile of Caco-2 epithelium to Li(+), Na(+), K(+), Rb(+), and Cs(+) from series VII to series VI of the Eisenman sequence. The Arrhenius plot revealed the higher activation energy for passive Mg(2+) transport in omeprazole-treated epithelium than that of control epithelium, indicating that omeprazole affected the paracellular channel of Caco-2 epithelium in such a way that Mg(2+) movement was impeded.

CONCLUSION

Omeprazole decreased paracellular cation permeability and increased the activation energy for passive Mg(2+) transport of Caco-2 monolayers that led to the suppression of passive Mg(2+) absorption.

Association of long-term proton pump inhibitor therapy with bone fractures and effects on absorption of calcium, vitamin B12, iron, and magnesium

Proton pump inhibitors (PPI) are one of the most widely used classes of drugs. PPIs have a very favorable safety profile, and it is unusual for a patient to stop them because of side effects. However, with increasing numbers of patients chronically taking PPIs for gastroesophageal reflux disease and other common, persistent conditions, the long-term potential adverse effects are receiving increasing attention. An insufficiently studied area receiving much attention is the long-term effect of chronic acid suppression on the absorption of vitamins and nutrients. This increased attention results from the reported potential adverse effect of chronic PPI treatment leading to an increased occurrence of bone fractures. Interest in this area has led to examination of the effects of PPIs on calcium absorption/metabolism and numerous cohort, case-control, and prospective studies of their ability to affect bone density and cause bone fractures. In this article, these studies are systematically examined, as are studies of the effects of chronic PPI use on absorption of VB(12), iron, and magnesium. Studies in each area have led to differing conclusions, but when examined systematically, consistent results of several studies support the conclusion that long-term adverse effects on these processes can have important clinical implications.

Proton pump inhibitors and severe hypomagnesaemia

PURPOSE OF REVIEW

Hypomagnesaemia has recently been recognized as a rare, but severe, complication of proton pump inhibitor (PPI) use. We reviewed all the cases published to date in peer-reviewed journals to summarize what is known of the epidemiology, risk factors, cause and treatment.

RECENT FINDINGS

Hypomagnesaemia has been described with all substituted pyridylmethylsulphonyl benzimidazadole derivatives and is a class effect, recurring with substitution of one PPI for another. A long duration of use and high rates of adherence are probably risk factors, but the prevalence is unknown. The diagnosis is often missed, despite the severe symptomatology. Renal magnesium handling is normal, so implicating impairment of net intestinal absorption as the proximate cause. It is not known whether this is the consequence of defective absorption of magnesium through the active or passive transport processes, or increased losses.

SUMMARY

PPI-associated hypomagnesaemia is a rare, but potentially life-threatening, side-effect that has emerged only in the era of mass use of these agents. The cause of hypomagnesaemia remains poorly understood, but it responds rapidly to withdrawal of the PPI.

Use of proton pump inhibitors and risk of hip/femur fracture: a population-based case-control study

Previous studies evaluated the association between proton pump inhibitor (PPI) use and subsequent fracture risk, but they showed ambiguous results. Therefore, the objective was to evaluate this association in a different study population. Our findings show that there is probably no causal relationship between PPI use and hip fracture risk.

INTRODUCTION

Previous studies evaluated the association between PPI use and subsequent fracture risk, but they showed ambiguous results. To further test these conflicting results, the objective of this study was to evaluate the association between the use of PPIs and the risk of hip/femur fracture in a different study population.

METHODS

A case-control study was conducted using data from the Dutch PHARMO record linkage system. The study population included 6,763 cases aged 18 years and older with a first hip/femur fracture during enrollment and 26,341 age-, gender- and region-matched controls.

RESULTS

Current users of PPIs had an increased risk of hip/femur fracture yielding an adjusted odds ratio (AOR) of 1.20 (95% CI 1.04-1.40). Fracture risk attenuated with increasing durations of use, resulting in AORs of 1.26 (95% CI 0.94-1.68) in the first 3 months, 1.31 (95% CI 0.97-1.75) between 3 and 12 months, 1.18 (95% CI 0.92-1.52) between 13 and 36 months and 1.09 (95% CI 0.81-1.47) for use longer than 36 months.

CONCLUSION

Our findings show that there is probably no causal relationship between PPI use and hip fracture risk. The observed association may be the result of unmeasured distortions: although current use of PPIs was associated with a 1.2-fold increased risk of hip/femur fracture, the positive association was attenuated with longer durations of continuous use. Our findings do not support that discontinuation of PPIs decreases risk of hip fracture in elderly patients.

Proton pump inhibitors and fracture risk: true effect or residual confounding?

Fracture is a major contributor to human morbidity and mortality, especially in the elderly. It has been discussed in the literature that conditions associated with decreased stomach acidity may lead to a decrease in intestinal calcium absorption and, consequently, to an increased fracture risk. In recent years, several observational studies reported a slightly increased fracture risk in association with the use of proton pump inhibitors (PPIs) and/or histamine H(2) receptor antagonists. It was the objective of this review to critically assess the available evidence linking PPI use to an increased fracture risk. A MEDLINE and EMBASE search from 1960 to June 2010 was performed to identify the relevant articles using predefined search terms. Because (i) there is no proven mechanism, (ii) the reported magnitude of the risk elevation associated with the use of PPIs was only weak, and (iii) the likelihood of residual confounding despite adjustment for known co-morbidities and drug use cannot be ruled out, we conclude that the currently available literature does not support the notion that the use of PPIs is causally related to a materially increased fracture risk in humans.

Do proton pump inhibitors decrease calcium absorption?

Proton pump inhibitors (PPIs) increase osteoporotic fracture risk presumably via hypochlorhydria and consequent reduced fractional calcium absorption (FCA). Existing studies provide conflicting information regarding the direct effects of PPIs on FCA. We evaluated the effect of PPI therapy on FCA. We recruited women at least 5 years past menopause who were not taking acid suppressants. Participants underwent three 24-hour inpatient FCA studies using the dual stable isotope method. Two FCA studies were performed 1 month apart to establish baseline calcium absorption. The third study occurred after taking omeprazole (40 mg/day) for 30 days. Each participant consumed the same foods during all FCA studies; study meals replicated subjects' dietary habits based on 7-day diet diaries. Twenty-one postmenopausal women ages 58 ± 7 years (mean ± SD) completed all study visits. Seventeen women were white, and 2 each were black and Hispanic. FCA (mean ± SD) was 20% ± 10% at visit 1, 18% ± 10% at visit 2, and 23% ± 10% following 30 ± 3 days of daily omeprazole (p = .07, ANOVA). Multiple linear regression revealed that age, gastric pH, serum omeprazole levels, adherence to omeprazole, and 25-hydroxyvitamin D levels were unrelated to changes in FCA between study visits 2 and 3. The 1,25-dihydroxyvitamin D(3) level at visit 2 was the only variable (p = .049) associated with the change in FCA between visits 2 and 3. PPI-associated hypochlorhydria does not decrease FCA following 30 days of continuous use. Future studies should focus on identifying mechanisms by which PPIs increase the risk of osteoporotic fracture.

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.

Inhibiting gastric acid production does not affect intestinal calcium absorption in young, healthy individuals: a randomized, crossover, controlled clinical trial

Proton pump inhibitors (PPIs) are the most potent gastric acid suppressing drugs available, and their use is widespread. An emerging concern about chronic PPI therapy is whether these drugs impair intestinal calcium absorption, resulting in a negative calcium balance and thereby potentially causing bone loss. The objective of this study was to evaluate the acute effect of the PPI esomeprazole or placebo on intestinal calcium absorption in healthy adults. Twelve young adults participated in a placebo-controlled, double-blind, crossover study. There were two 3-week interventions that included a 14-day adjustment period (designed to stabilize calcium homeostasis) followed by 6 days of a diet containing 800 mg of calcium and 2.1 g/kg of protein (intervention). During the last 3 days of the adjustment period and throughout the intervention period, subjects consumed esomeprazole or placebo. Half the subjects underwent 24-hour continuous gastric acid pH monitoring. Intestinal calcium absorption was measured using dual-stable calcium isotopes at the end of each intervention. Treatment with esomprazole significantly increased gastric pH (mean pH on PPI 5.38 +/- 0.13, mean pH on placebo 2.70 +/- 0.44, p = .005). Neither calcium absorption (PPI 34.2% +/- 2.4%, placebo 31.5% +/- 2.1%, p = .24) nor urinary calcium (PPI 321 +/- 38 mg/34 hours, placebo 355 +/- 37 mg/34 hours, p = .07) differed between the PPI and placebo groups. It is concluded that short-term gastric acid suppression by PPIs does not attenuate intestinal calcium absorption in healthy young adults.

High-Calcium Milk Prevents Overweight and Obesity among Postmenopausal Women

Background

The Sixth National Nutrition Survey 2003 revealed that the highest prevalence of overweight and obesity among Filipino female adults (30.8%) was found in the age group from 40 to 59 years. Obesity is associated with a number of chronic diseases, including cardiovascular disease, hypertension, and diabetes. Low calcium intake has been identified as a potential contributing factor to overweight and obesity.

Objective

To assess the effect of a high-calcium, fortified, low-fat milk drink with added vitamin D versus a low-calcium placebo drink on anthropometric measurements of postmenopausal women.

Methods

Women who were at least 5 years postmenopausal were invited to participate in the study. Potential participants underwent three stages of screening: initial interview, dual-energy x-ray absorptiometry, and blood testing for biochemical screening. Anthropometric indices were measured at baseline and the end of the study. Sixty women were qualified to participate in the study. The women were randomly assigned to two groups, one of which received 400 ml of the high-calcium milk daily for 16 weeks while the other received the placebo drink.

Results

No significant increases were observed in the anthropometric indices of the subjects receiving the high-calcium fortified milk at the end of the study. However, there were significant increases in the weight ( p = .008), body mass index ( p = .007), and waist ( p = .018) and hip ( p = .003) circumferences of the subjects receiving the placebo drink.

Conclusions

A change in dietary calcium intake may be a useful measure as part of an overall approach to prevent the occurrence of overweight and obesity among postmenopausal women.

Proton pump inhibitors and histamine-2 receptor antagonists are associated with hip fractures among at-risk patients

BACKGROUND & AIMS

Drugs that inhibit gastric acid might increase the risk of hip fracture. However, little long-term exposure data exist and no large studies have been conducted in the United States.

METHODS

We conducted a case-control study using data from an integrated health services organization. We evaluated 33,752 patients with incident diagnoses of hip/femur fractures (cases), 130,471 matched members without fractures (controls), prescription data for use of proton pump inhibitors (PPIs) or histamine-2 receptor antagonists (H2RAs) (up to 10 years' cumulative duration), and confounders.

RESULTS

Patients with hip fractures were more likely than controls to have previously received a > or =2-year supply of PPIs (odds ratio [OR], 1.30; 95% confidence interval [CI], 1.21-1.39) or H2RAs (OR, 1.18; 95% CI, 1.08-1.29). The risk was reduced after discontinuation of medication (OR of 1.30 [95% CI, 1.21-1.41] for current PPI users vs OR of 1.09 [95% CI, 0.64-1.85] for patients who received their last prescription 2-2.9 years ago). Higher dosages (but not increasing cumulative durations) were associated with increased risk (eg, > or =1.5 pills/day: OR, 1.41 [95% CI, 1.21-1.64]; <0.74 pills/day: OR, 1.12 [95% CI, 0.94-1.33]). Excess fracture risk for PPI use was only present among persons with at least one other fracture risk factor.

CONCLUSIONS

Use of drugs that inhibit gastric acid is associated with an increased risk of hip fracture; however, this association was only found among persons with at least one other risk factor for hip fracture. Acid inhibition might therefore be associated with fracture risk in persons already at risk for osteoporosis, although other confounding cannot be excluded.

Proton pump inhibitor use, hip fracture, and change in bone mineral density in postmenopausal women: results from the Women's Health Initiative

BACKGROUND

Proton pump inhibitor (PPI) medications have been inconsistently shown to be associated with osteoporotic fractures. We examined the association of PPI use with bone outcomes (fracture, bone mineral density [BMD]).

METHODS

This prospective analysis included 161 806 postmenopausal women 50 to 79 years old, without history of hip fracture, enrolled in the Women's Health Initiative (WHI) Observational Study and Clinical Trials with a mean (SD) follow-up of 7.8 (1.6) years. Analyses were conducted for 130 487 women with complete information. Medication information was taken directly from drug containers during in-person interviews (baseline, year 3). The main outcome measures were self-reported fractures (hip [adjudicated], clinical spine, forearm or wrist, and total fractures) and for a subsample (3 densitometry sites), 3-year change in BMD.

RESULTS

During 1 005 126 person-years of follow-up, 1500 hip fractures, 4881 forearm or wrist fractures, 2315 clinical spine fractures, and 21 247 total fractures occurred. The multivariate-adjusted hazard ratios for current PPI use were 1.00 (95% confidence interval [CI], 0.71-1.40) for hip fracture, 1.47 (95% CI, 1.18-1.82) for clinical spine fracture, 1.26 (95% CI, 1.05-1.51) for forearm or wrist fracture, and 1.25 (95% CI, 1.15-1.36) for total fractures. The BMD measurements did not vary between PPI users and nonusers at baseline. Use of PPIs was associated with only a marginal effect on 3-year BMD change at the hip (P = .05) but not at other sites.

CONCLUSION

Use of PPIs was not associated with hip fractures but was modestly associated with clinical spine, forearm or wrist, and total fractures.

Safety of proton pump inhibitors: current evidence for osteoporosis and interaction with antiplatelet agents

Proton pump inhibitors (PPIs) are commonly used in millions of patients. Despite the widespread usage and favorable safety profile, much attention has focused recently on potential adverse events associated with use. One area of particular concern is the reported potential adverse effects on bone density, causing possible osteoporosis and related bone fractures. The low magnitude of the association (OR < 2), lack of experimental evidence documenting a mechanism, and inability to assess potential confounding factors limit statements regarding causality. The other area of particular concern has been the combined use with antiplatelet agents, in particular with clopidogrel. Several retrospective studies suggested an adverse cardiovascular outcome if clopidogrel was combined with PPIs. The theoretic concern was raised to a possible interference with the bioactivation of the prodrug via competitive interference for both drugs at the cytochrome P450 pathway. Although ex vitro studies suggested a possible effect and several retrospective analyses were supportive of an adverse clinical outcome, the more recent prospective controlled trial data do not support an adverse cardiovascular outcome. This report reviews the scientific hypothesis, biologic plausibility, and the most recent clinical trial data for both areas of controversy.

Optimizing bone health in older adults: the importance of dietary protein

Age-related bone loss is progressive and can lead to osteoporosis. While it is accepted that both dietary calcium and vitamin D are important and beneficial for skeletal health, the impact of dietary protein on calcium metabolism and bone balance remains controversial. Contrary to the hypothesis that increasing dietary protein contributes to bone loss, research supports the notion that protein may play a pivotal role in maintenance of bone health by several mechanisms; for example, increasing dietary protein increases IGF-1, calcium absorption, muscle strength and mass, all of which could potentially benefit the skeleton. A moderate increase in dietary protein recommendations for the aging population (above the recommended dietary allowance of 0.8 g/kg) may be beneficial to bone health, while still falling within the safe and acceptable range for protein intake (as defined by the dietary reference intakes).

Hypomagnesaemia due to proton-pump inhibitor therapy: a clinical case series

BACKGROUND

Reports since 2006 have identified proton-pump inhibitor (PPI) therapy as a cause of hypomagnesaemia, in a total of 13 cases.

AIMS

To summarize the clinical course of 10 patients (one male, nine female) identified with severe hypomagnesaemia, all of whom were on PPI therapy. A case report illustrates the experience of a severely affected patient.

METHODS

Clinical and biochemical review. Severe hypomagnesaemia was defined as 0.54 mmol/l or less, >4 SD below the mean.

RESULTS

Patients were 68.8 +/- 8.6 years old when they presented with severe hypomagnesaemia, having been on PPI therapy for a mean of 8.3 +/- 3.5 years. Eight patients were on diuretics at initial presentation. There was significant morbidity as eight patients remained on PPI therapy after presentation for a mean of 2.75 +/- 1.54 years. There were 18 emergency hospital admissions with severe hypomagnesaemia. Oral and parenteral magnesium supplements were relatively ineffective at correcting the problem, but stopping PPI therapy lead to prompt resolution of the hypomagnesaemia (within 2 weeks in five carefully monitored patients), with symptomatic benefit. Hypomagnesaemia recurred if PPI therapy was re-introduced because of troublesome dyspepsia. However, pantoprazole, the least potent PPI, largely relieved dyspepsia and hypomagnesaemia did not inevitably develop when combined with oral magnesium supplements.

CONCLUSION

These cases confirm that long-term PPI therapy can cause severe, symptomatic hypomagnesaemia, which resolves when PPI therapy is withdrawn. The serum magnesium should be checked annually in patients on long-term PPI therapy, or if they feel unwell.

Safety of the long-term use of proton pump inhibitors

The proton pump inhibitors (PPIs) as a class are remarkably safe and effective for persons with peptic ulcer disorders. Serious adverse events are extremely rare for PPIs, with case reports of interstitial nephritis with omeprazole, hepatitis with omeprazole and lansoprazole, and disputed visual disturbances with pantoprazole and omeprazole. PPI use is associated with the development of fundic gland polyps (FGP); stopping PPIs is associated with regression of FGP. In the absence of Helicobacter pylori infection, the long-term use of PPIs has not been convincingly proven to cause or be associated with the progression of pre-existing chronic gastritis or gastric atrophy or intestinal metaplasia. Mild/modest hypergastrinemia is a physiological response to the reduction in gastric acid secretion due to any cause. The long-term use of PPIs has not been convincingly proven to cause enterochromaffin-like cell hyperplasia or carcinoid tumors. PPIs increase the risk of community acquired pneumonia, but not of hospital acquired (nosocomial) pneumonia. There is no data to support particular care in prescribing PPI therapy due to concerns about risk of hip fracture with the long-term use of PPIs. Long-term use of PPIs does not lead to vitamin B12 deficiencies, except possibly in the elderly, or in persons with Zollinger-Ellison Syndrome who are on high doses of PPI for prolonged periods of time. There is no convincingly proven data that PPIs increase the risk of Clostridium difficile-associated diarrhea in persons in the community. The discontinuation of PPIs may result in rebound symptoms requiring further and even continuous PPI use for suppression of symptoms. As with all medications, the key is to use PPIs only when clearly indicated, and to reassess continued use so that long-term therapy is used judiciously. Thus, in summary, the PPIs are a safe class of medications to use long-term in persons in whom there is a clear need for the maintenance of extensive acid inhibition.

Adverse effects of proton pump inhibitors

Proton pump inhibitors (PPI) are very effective drugs used largely in acid related disorders. During the last years concern have been raised regarding their overutilisation in benign condition, such as gastroesophageal reflux disease. The debate focussed also on the risk of adverse events related to long term use of PPI. Apart of the case of Helicobacter Pylori (H. Pylori) positive patients, in whose long term acid suppression lead to the development of corpus predominant atrophic gastritis, precursor of cancer; the other assumed adverse events, have never been demonstrated in prospective studies. The attention should move towards the appropriate prescription of PPI, rather than the fear adverse effects of PPI. In fact, in clinical practise, PPI are often prescribed in patients without a specific acid related disease and continued long term based on their safety profile. This review focus on the main adverse events related to long term PPI use.

Hip fracture risk in patients with a diagnosis of pernicious anemia

BACKGROUND & AIMS

Pernicious anemia (PA) is characterized by vitamin B-12 deficiency and achlorhydria, both of which have a detrimental effect on bone strength. The principle aim of this study was to determine the risk of hip fracture in patients with PA.

METHODS

This is a retrospective cohort study using the General Practice Research Database (GPRD) from the United Kingdom. GPRD data from May 1987 until April 2002 were utilized to identify patients between 40 and 90 years of age at the time of GPRD enrollment. The exposed group contained patients with a diagnosis of PA being treated with vitamin B-12 therapy. We matched each patient having a diagnosis of PA with 4 randomly selected non-PA patients with respect to age (+/-1 year) and sex. Cox regression analysis was used to determine the hazard ratio (HR) for hip fracture associated with PA.

RESULTS

Nine thousand five hundred six patients with a diagnosis of PA receiving vitamin B-12 injection therapy were identified and compared to 38,024 controls. Patients with PA had a greater risk of hip fracture than the controls (HR = 1.74; 95% CI: 1.45-2.08). The increase in hip fracture risk was even more pronounced among those patients newly diagnosed with PA during GPRD follow-up (HR = 2.63; 95% CI: 2.03-3.41).

CONCLUSIONS

Patients with a diagnosis of PA have an elevated risk of hip fracture. The increased hip fracture risk was persistent even years after vitamin B-12 therapy. Chronic achlorhydria could be the mechanism contributing to the persistently elevated hip fracture risk.

Proton Pump Inhibitor Suppression of Calcium Absorption Presenting as Respiratory Distress in a Patient with Bilateral Laryngeal Paralysis and Hypocalcemia

We report an unusual case of hypocalcemia and respiratory distress related to acid-suppressive therapy. The patient was a 50-year-old woman with bilateral laryngeal paralysis and hypoparythyroidism resulting from a thyroidectomy performed more than 30 years previously. She required large doses of calcium supplementation to maintain a normal calcium level. Her airway had been marginally adequate. A few weeks prior to presentation, she began to experience increasing dyspnea. Examination was suggestive of laryngopharyngeal reflux, and she was started on a therapeutic trial of esomeprazole 40 mg twice daily. Three days later, she presented to the emergency room with airway distress. Laboratory studies indicated that the patient had hypocalcemia. The esomeprazole was discontinued, and she was treated with intravenous calcium; her symptoms resolved. We attribute the airway distress to tetany in synkinetically reinnervated laryngeal adductor muscles. We recommend that acid-suppressive therapy should be used with caution in patients with hypoparathyroidism or hypocalcemia.

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.

Fracture risk in patients receiving acid-suppressant medication alone and in combination with bisphosphonates

SUMMARY

Previous studies have found an association between acid suppressants and fracture risk. We assessed fracture risk in patients taking concomitant acid suppressant and bisphosphonates. Positive associations were observed for any hip and vertebral fracture. The effect size was modest; however, the significance lies in the widespread prescribing of acid suppressants.

INTRODUCTION

Previous studies have found that acid-suppressive medication (ASM) is associated with an increased risk of fracture. Bisphosphonates can cause upper gastrointestinal problems, and patients may be prescribed ASM to minimise these effects.

METHODS

A retrospective cohort study using the GPRD was conducted in patients aged 40 years and older starting proton pump inhibitors (PPI, N = 234,144), H(2) receptor antagonists (H(2)RA, N = 166,798) or bisphosphonates (N = 67,309). Fracture risk in current versus past use of ASM and concomitant use of bisphosphonate plus ASM versus bisphosphonate alone was compared using time-dependent Cox regression.

RESULTS

In the 6 months before initiating bisphosphonate therapy, 20.1% of patients received a PPI and 7.5% an H(2)RA. Current PPI use was associated with an increased risk of any (adjusted relative rate (ARR) 1.15, 95% CI 1.10-1.20), hip (ARR 1.22, 95% CI 1.10-1.37), and vertebral fracture (ARR 1.40, 95% CI 1.11-1.78); and concomitant bisphosphonates and PPIs with an increased risk of any (ARR 1.08, 95% CI 1.01-1.16) and hip fracture (ARR 1.24, 95% CI 1.08-1.42).

CONCLUSIONS

ASM is associated with an increased risk of fracture when taken alone or in combination with bisphosphonates. Given the frequency of coprescription of ASM and bisphosphonates, this issue requires further investigation.

Proton pump inhibitors, osteoporosis, and osteoporosis-related fractures

Proton pump inhibitors (PPIs) are among the most commonly prescribed medications today with an excellent short-term safety profile. Recently, a number of studies from a variety of data sources have reported an association between PPI use and hip fractures. However, there is not yet any direct evidence of a causal link between PPI use and the development of hip fracture. In the following paper, we will review the recent studies which have described this association between PPI use and hip fracture, and discuss the evidence supporting the likelihood of this association being causal, using data from previous work on the effects of surgical and pharmacological inhibition of gastric acid secretion on calcium absorption and bone mineral density. We will conclude by summarizing the current state of evidence on the relationship between gastric acid inhibition and the risk of fracture, and suggest management strategies for patients who require the long-term use of gastric acid inhibiting medications who also may be at risk for metabolic bone disease and fracture.

Proton pump inhibitors: actions and reactions

Proton pump inhibitors are the second most commonly prescribed drug class in the United States. The increased utilization of PPIs parallels the rising incidence of reflux disease. Owing to their clinical efficacy and relative lack of tachyphylaxis, PPIs have largely displaced H-2 receptor antagonists in the treatment of acid peptic disorders. The elevation of intragastric pH and subsequent alterations of gastric physiology induced by PPIs may yield undesired effects within the upper GI tract. The ubiquity of the various types of H(+), K(+)-ATPase could also contribute to non-gastric effects. PPIs may influence physiology in other ways, such as inducing transepithelial leak.

Proton pump inhibitors and bone fractures?

The objective of this study was to critically assess studies regarding proton pump inhibitors (PPIs) and fractures. A MEDLINE search was conducted to identify relevant articles. Three case-control studies assessed fractures and PPI use. A study of all subjects with fracture in Denmark in 2000 revealed adjusted OR=1.18 (1.12-1.43) for PPI use within the last year (hip fracture OR=1.45,1.28-1.65); no dose-response relationship was identified. A study of hip fractures in UK patients > or =50 years found adjusted OR=1.44 (1.30-1.59) for >1 year of PPIs; duration and average daily dose were significantly associated with fracture risk: adjusted OR for >1.75 times average daily dose for >1 year was 2.65 (1.80-3.90). A study of vertebral, wrist, and hip fractures in Manitoba patients > or =50 years found adjusted OR=0.99 (0.90-1.11) for > or =1 year of continuous PPI; association became significant > or =7 years (OR=1.92, 1.16-3.18). Consistency of some positive results in all studies, the dose and/or duration response in two studies, the possibility that acid inhibition may decrease calcium absorption, and association with histamine(2)-receptor antagonists in some studies support a causal association. The low magnitude of the association (ORs<2), lack of dose-response in one study, lack of association with histamine(2)-receptor antagonists in one study, lack of experimental evidence documenting a mechanism, and inability to assess potential confounding factors limit statements regarding causality. As with all medications, PPIs should be used for appropriate indications and not in higher doses or longer durations than necessary to achieve the desired outcomes.

The effect of proton pump-inhibiting drugs on mineral metabolism

Two recent studies have reported increased hip fracture rates with long-term proton pump inhibitor (PPI) use raising concerns about adverse effects of this class of drugs on mineral metabolism. One plausible mechanism by which PPIs could affect calcium economy and skeletal homeostasis is by impairing intestinal calcium absorption. In the long term, this could potentially lead to a negative whole body calcium balance, resulting in higher rates of bone loss and a greater risk of fragility fractures.

Gastrointestinal side effects of prescription medications in the older adult

Gastrointestinal (GI) symptoms resulting from either prescription medications or over-the-counter drugs are frequently encountered in geriatric practice but often mistaken for symptoms of an organic disease leading to multiple diagnostic studies. The morbidity, mortality, and medical costs associated with drug toxicity, even when restricted to the GI tract, are probably underestimated. The consequences of drug toxicity are quite variable and range from a symptom of mild discomfort (eg, drug-induced diarrhea) at one end of the spectrum, to fatal GI hemorrhage or perforation. Better awareness of the possibility of drug-induced GI tract pathology by primary care physicians improves the recognition of these adverse effects, and ultimately, improves patient care. This review focuses on the most common and well-described drug-related side effects of the GI tract.

Increase in vertebral fracture risk in postmenopausal women using omeprazole

Proton pump inhibitors are taken by millions of patients for prevention and treatment of gastroesophageal diseases. Case-control studies have suggested that use of omeprazole is associated with an increased risk of hip fractures. The aim of this prospective study was to assess the risk of vertebral fractures in postmenopausal women using omeprazole. We studied 1,211 postmenopausal women enrolled in the Osteoporosis and Ultrasound Study from the general population. Information on omeprazole and other risk factors for fractures including prevalent fractures and bone mineral density was obtained at baseline. Vertebral fractures were assessed on X-rays obtained at baseline and at the end of the 6-year follow-up and analyzed centrally. At baseline, 5% of this population was using omeprazole. Age-adjusted rates for vertebral fractures were 1.89 and 0.60 for 100 person-years for omeprazole users and nonusers, respectively (P = 0.009). In the multivariate analysis, omeprazole use was a significant and independent predictor of vertebral fractures (RR = 3.50, 95% CI 1.14-8.44). The other predictors were age higher than 65 years (RR = 2.34, 95% CI 1.02-5.34), prevalent vertebral fractures (RR = 3.62, 95% CI 1.63-8.08), and lumbar spine T score </= -2.5 (RR = 2.38, 95% CI 1.03-5.49). Omeprazole use is associated with an increased risk of vertebral fractures in postmenopausal women. Further studies are required to determine the mechanism of the association between the underlying gastric disease, omeprazole use, and risk of osteoporotic fractures.

Hip fracture and proton pump inhibitor therapy: balancing the evidence for benefit and harm

Gastroenterology is full of examples of drugs being enthusiastically promoted only to be withdrawn or prescription curtailed once the harms of the medication are realized. Cox-2 inhibitors, alosetron, and tegaserod are all recent examples of this phenomenon. The problem is that potential harms of drugs are being highlighted in the medical literature all the time and it can be difficult to determine whether these represent a genuine risk to our patients or are just spurious epidemiological associations. The association between proton pump inhibitor therapy and hip fracture is a good illustration of this dilemma. We use this example to highlight an approach that can be taken to critically evaluate the evidence for harms of medication.

Severe hypomagnesaemia in long-term users of proton-pump inhibitors

OBJECTIVE

To explore the mechanism underlying severe hypomagnesaemia in long-term users of proton-pump inhibitors (PPIs).

PATIENTS

Two cases of severe hypomagnesaemia in adult long-term users of the PPI omeprazole, presenting with hypocalcaemic seizures.

MEASUREMENTS

We studied renal magnesium handling during an incremental intravenous magnesium infusion, and assessed total body magnesium status by the 24-h retention of the parenteral load. We also observed the effects of oral magnesium supplements whilst continuing the PPI, and the effect of withdrawal of the PPI.

RESULTS

Both patients were severely magnesium-depleted and had avid renal magnesium retention, implicating a failure of intestinal magnesium absorption. There was no evidence of generalized malabsorption. The hypomagnesaemia could be partially corrected by high dose oral magnesium supplementation, and resolved on withdrawal of PPIs.

CONCLUSIONS

PPI use can inhibit active magnesium transport in the intestine, though it is not clear if this is an idiosyncratic effect. Long-term PPI users who are highly adherent to treatment can eventually deplete total body magnesium stores and present with severe complications of hypomagnesaemia.

Omeprazole and refractory hypomagnesaemia

Omeprazole may cause hypomagnesaemia, along withhypocalcaemia and hypokalaemia

Proton pump-inhibiting drugs, calcium homeostasis, and bone health

Proton pump inhibitors (PPIs) are commonly used drugs, several of which are available without a prescription. Two recent studies have demonstrated increased hip fracture rates associated with PPI use. Theoretically, PPIs could impair intestinal calcium absorption resulting in increased rates of bone loss and a greater risk of fragility fracture.

Management of gastroesophageal reflux disease

Gastroesophageal reflux disease is the most common and expensive digestive disease with complex and multi-factorial pathophysiologic mechanisms. Transient inappropriate relaxation of the lower esophageal sphincter is the predominant mechanism in the majority of patients with mild to moderate disease. Hiatal hernias and a reduced lower esophageal sphincter pressure have a significant role in patients with moderate to severe disease. Typical manifestations of gastroesophageal reflux disease include heartburn, regurgitation, and dysphagia. Atypical symptoms, such as noncardiac chest pain, pulmonary manifestations of asthma, cough, aspiration pneumonia, or ENT manifestations of globus and laryngitis, can be seen in patients with or without typical symptoms of gastroesophageal reflux disease. Endoscopy and ambulatory pH tests are best to evaluate the anatomic and physiologic impact ofgastroesophageal reflux disease. Complications of chronic gastroesophageal reflux disease include peptic strictures and Barrett metaplasia. Barrett esophagus is a major risk factor for esophageal adenocarcinoma, and upper endoscopy with surveillance biopsies is recommended for patients with Barrett esophagus. Medical therapy with anti-secretory agents (H2 blockers and proton pump inhibitors) is effective for most patients with gastroesophageal reflux disease. Surgical fundoplications and endoscopic treatment modalities are mechanical treatment options for patients with gastroesophageal reflux disease.

Gastric juice: a barrier against infectious diseases

All vertebrates produce gastric acid. Its main function is inactivation of ingested microorganisms. The majority of microbiological pathogens ingested never reaches the intestine because of the gastric barrier. Although gastric hypochlorhydria is fairly common due to atrophic gastritis, gastric surgery or use of inhibitors of gastric acid secretion, the resulting susceptibility to infection has not been studied extensively. Drug-induced blockade of acid secretion leads to gastrointestinal bacterial overgrowth; the clinical significance of this is still controversial. Gastric acidity is known to protect against non-typhoid salmonellosis and cholera and it is suspected that it protects against several parasitic diseases as giardiasis and strongyloides. There is a lack of studies focusing on the impact of the gastric acidic barrier on viral infections. Concerning prion infections only a single study has been performed, demonstrating a possible role of gastric acidity in the protection against foodborne prion disease in mice. The combination of malnutrition and hypochlorhydria may contribute to the high prevalence of gastrointestinal infections in developing countries. Further studies are needed to evaluate the clinical consequences of impaired gastric acidity with respect to susceptibility to infections.

The effect of pharmacologically altered gastric pH on cadmium absorption from the diet and its accumulation in murine tissues

Solubility of Cd in Cd-amended mouse chow in water was reduced by increased pH; even less Cd was solubilized by simulated digestion in vitro, where increased gastric phase pH decreased solubility, an effect that persisted following intestinal digestion at pH 5.5. These data suggested that increasing gastric pH in vivo pharmacologically would reduce Cd accumulation in target organs of mice treated with omeprazole (a proton-pump inhibitor) or cimetidine (a H2-receptor antagonist). This expectation was mostly not realized. Gastric pH in animals receiving Cd-amended diet was increased by omeprazole, but not cimetidine, relative to animals receiving no drugs, and Cd-amended diet. Tissue concentrations of Cd were similar among the three groups receiving Cd-amended diet, for liver, kidney and testes. Small intestine Cd concentration was lower for omeprazole-treated animals than for those receiving neither drug and Cd-amended diet, suggesting that omeprazole decreased Cd absorption by this organ. This effect may have been compensated for by increased uptake of complexed Cd by the large intestine, as accumulation in the liver, kidney and testes was not reduced. In vitro determinations of bioaccessible Cd in food may not predict in vivo bioaccumulation in all target organs.

Magnesium bioavailability from mineral water. A study in adult men

OBJECTIVE

To assess magnesium enteral absorption from a magnesium-rich mineral water.

DESIGN

Experimental study.

SETTING

Department of Nuclear Medicine, Brugmann Hospital, Brussels, Belgium.

SUBJECTS

Ten healthy male volunteers in the age range 25-42 y.

INTERVENTION

Each subject completed two sessions in a random order. At one session, they received an oral load of 300 ml of water (containing 1.2 mmol Mg), traced with (28)Mg, and at the other session they received an intravenous injection of (28)Mg, in order to take into account the metabolism of endogenous magnesium. The dietary consumption was further noted on a weekly diary.

RESULTS

The mean bioavailability was 59.1% (s.d.+/-13.6). Magnesium absorption and age were significantly inversely correlated (r=-0.68, P=0.035).

CONCLUSION

Magnesium-rich mineral water is a reliable source of magnesium. Our observation of decreased magnesium absorption with age deserves further investigations.

SPONSORSHIP

The study was sponsored by SEV, Bourg la Reine, France.

Changes in gastric mucosa and luminal environment during acid-suppressive therapy: a review in depth

Acid-suppressive therapy and subsequent changes in gastric mucosa and luminal environment rank highly amongst the investigated issues in gastroenterology over the past two to three decades. Herewith, we present an overview of these intragastric changes, particularly during long-term administration of acid-suppresive medication and concurrent infection with Helicobacter pylori. Current evidence indicates that: i) Long-term acid suppression facilitates the development of fundic ECL cell hyperplasia, especially in the presence of Helicobacter pylori. No neoplastic changes directly attributable to acid suppression have so far been demonstrated in humans. ii) Acid-suppressive therapy increases the risk of enteric infections. iii) Acid-suppressive therapy does not alter fat and mineral bioavailability, but may decrease the absorption of protein-bound vitamin B12. iv) Acid suppression invariably results in intragastric overgrowth of non-Helicobacter pylori bacterial species. The concurrent infection with Helicobacter pylori may promote this bacterial overgrowth and the intragastric formation of N-nitrosamines. v) Acid-suppressive therapy alters the natural course of Helicobacter pylori gastritis, transforming the antral-predominant pattern into a body-predominant pattern, which in turn may progress to body gland atrophy. The pathophysiology of this phenomenon is currently under investigation. vi) In view of the potential adverse effects of acid suppression in the presence of Helicobacter pylori, the screen-and-treat strategy is advocated for Helicobacter pylori in subjects considered for long-term treatment.

Alteration in digestion and absorption of nutrients during profound acid suppression

Gastric acid suppression therapy has for many years been the cornerstone of the treatment of peptic disease. The availability of more potent inhibitors of gastric acid secretion and the increasing demand for maintenance therapy has renewed interest in the potential side-effects of profound and/or long-lasting therapy. This chapter focuses on the potential interference of gastric acid suppression therapy with the process of the digestion and absorption of nutrients. The theoretical mechanisms by which hypochlorhydria resulting from gastric acid suppression therapy may hamper digestion and absorption are multiple and well documented. Clinical studies evaluating the effect of gastric acid suppression therapy on the assimilation of nutrients are, on the other hand, scarce and have, moreover, yielded conflicting results. The reason for the latter may be related, at least in part, to elements of study design. Data indicating overt malabsorption or clear deficiencies in patients on long-term gastric acid suppression therapy are currently lacking. Nevertheless, it seems prudent, while awaiting the results of additional long-term studies, regularly to monitor these patients, especially those with increased nutrient demand, poor intake or suboptimal stores.

Review article: potential gastrointestinal effects of long-term acid suppression with proton pump inhibitors

This review examines the evidence for the development of adverse effects due to prolonged gastric acid suppression with proton pump inhibitors. Potential areas of concern regarding long-term proton pump inhibitor use have included: carcinoid formation; development of gastric adenocarcinoma (especially in patients with Helicobacter pylori infection); bacterial overgrowth; enteric infections; and malabsorption of fat, minerals, and vitamins. Prolonged proton pump inhibitor use may lead to enterochromaffin-like cell hyperplasia, but has not been demonstrated to increase the risk of carcinoid formation. Long-term proton pump inhibitor treatment has not been documented to hasten the development or the progression of atrophic gastritis to intestinal metaplasia and gastric cancer, although long-term studies are required to allow definitive conclusions. At present, we do not recommend that patients be tested routinely for H. pylori infection when using proton pump inhibitors for prolonged periods. Gastric bacterial overgrowth does increase with acid suppression, but important clinical sequelae, such a higher rate of gastric adenocarcinoma, have not been seen. The risk of enteric infection may increase with acid suppression, although this does not seem to be a common clinical problem with prolonged proton pump inhibitor use. The absorption of fats and minerals does not appear to be significantly impaired with chronic acid suppression. However, vitamin B12 concentration may be decreased when gastric acid is markedly suppressed for prolonged periods (e.g. Zolllinger-Ellison syndrome), and vitamin B12 levels should probably be assessed in patients taking high-dose proton pump inhibitors for many years. Thus, current evidence suggests that prolonged gastric acid suppression with proton pump inhibitors rarely, if ever, produces adverse events. Nevertheless, continued follow-up of patients taking proton pump inhibitors for extended periods will provide greater experience regarding the potential gastrointestinal adverse effects of long-term acid suppression.

The aging gut. Nutritional issues

With improvements in health care, living standards, and socioeconomic status, more adults are living to old age. As the population ages, it is increasingly important to understand the factors that affect the nutritional status and thus the health status of older adults. Many factors contribute to inadequate nutrition, including health status, financial capacities, mobility, exercise, and physiologic needs. This article considered only the potential changes in nutritional needs because of alterations in the gastrointestinal tract owing to aging. One of the most remarkable changes with aging is the frequent development of atrophic gastritis and the inability to secrete gastric acid. This process affects approximately a third of older adults in the United States and only recently was recognized to be due to infection by H. pylori in the majority of cases. The lack of gastric acid in atrophic gastritis may lead to small intestinal bacterial overgrowth and influences the absorption of a variety of micronutrients, including iron, folate, calcium, vitamin K, and vitamin B12. Lactose maldigestion is a frequent condition in older adults and is extremely common worldwide. The intolerance of dairy products leads to avoidance of these foods and likely contributes to the development of osteopenia. Overall, the small intestine and pancreas undergo astonishingly few clinically significant changes with aging. The relative preservation of overall gastrointestinal function with aging is likely due to the large reserve capacity of this multiorgan system. Further research is needed to define the precise nutritional needs for older adults because simple extrapolation of values from younger adults is now recognized to be insufficient. In addition, it is no longer acceptable to define adequate nutriture in terms of amounts of vitamins needed to maintain serum levels of a nutrient. Further RDAs must consider the functional implications of adequate nutrition. Nutrients in the elderly will be measured as to whether they result in improvements in markers of chronic disease such as homocysteine or, most importantly, in the prevention of chronic disease such as osteoporosis and cardiovascular disease.