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

Proton pump inhibitors have no measurable effect on calcium and bone metabolism in healthy young males: a prospective matched controlled study

OBJECTIVES

Proton pump inhibitors (PPIs) are associated with an increased risk of bone fractures. This study sought to evaluate the effect of PPIs on biochemical markers of calcium and bone metabolism.

METHODS

Prospective matched controlled study involving healthy adult males (age 18-50years) suffering from frequent heartburn. Patients received standard-dose PPI for 12weeks and were matched by age with healthy controls. Blood studies were taken at 0, 1 and 3months for biochemical markers of mineral and bone metabolism. Two-way (time and PPI treatment) repeated measures analysis of variance (RM-ANOVA) and multiple linear regression were used for analysis.

RESULTS

A total of 58 participants (29 per group) completed the study. Mean age of participants was 33.2±7.5years. Baseline characteristics and biomarkers were similar for both groups except for higher BMI (28.6 vs. 25.6kg/m(2), p=0.008) and serum C-terminal cross linked telopeptides of type I collagen [CrossLaps, (300 vs. 228pg/ml, p=0.028)] in the PPI group. There was no difference in parathormone (PTH), ionized calcium, vitamin D, osteocalcin and CrossLaps between the PPI and control subjects (all non-significant; 2-way RM-ANOVA). Multiple linear regression modeling showed no effect of PPIs on any of the studied calcium or bone metabolism biomarkers.

CONCLUSION

PPI intake for 12weeks has no measurable effect on calcium or bone metabolism in healthy young males.

Gastric acid, calcium absorption, and their impact on bone health

Calcium balance is essential for a multitude of physiological processes, ranging from cell signaling to maintenance of bone health. Adequate intestinal absorption of calcium is a major factor for maintaining systemic calcium homeostasis. Recent observations indicate that a reduction of gastric acidity may impair effective calcium uptake through the intestine. This article reviews the physiology of gastric acid secretion, intestinal calcium absorption, and their respective neuroendocrine regulation and explores the physiological basis of a potential link between these individual systems.

The relationship between proton pump inhibitor use and longitudinal change in bone mineral density: a population-based study [corrected] from the Canadian Multicentre Osteoporosis Study (CaMos)

OBJECTIVES

Proton pump inhibitor (PPI) use has been identified as a risk factor for hip and vertebral fractures. Evidence supporting a relationship between PPI use and osteoporosis remains scant. Demonstrating that PPIs are associated with accelerated bone mineral density (BMD) loss would provide supportive evidence for a mechanism through which PPIs could increase fracture risk.

METHODS

We used the Canadian Multicentre Osteoporosis Study data set, which enrolled a population-based sample of Canadians who underwent BMD testing of the femoral neck, total hip, and lumbar spine (L1-L4) at baseline, and then again at 5 and 10 years. Participants also reported drug use and exposure to risk factors for osteoporosis and fracture. Multivariate linear regression was used to determine the independent association of PPI exposure and baseline BMD, and on change in BMD at 5 and 10 years.

RESULTS

In all, 8,340 subjects were included in the baseline analysis, with 4,512 (55%) undergoing year 10 BMD testing. After adjusting for potential confounders, PPI use was associated with significantly lower baseline BMD at the femoral neck and total hip. PPI use was not associated with a significant acceleration in covariate-adjusted BMD loss at any measurement site after 5 and 10 years of follow-up.

CONCLUSIONS

PPI users had lower BMD at baseline than PPI non-users, but PPI use over 10 years did not appear to be associated with accelerated BMD loss. The reasons for discordant findings between PPI use at baseline and during follow-up require further study.

Prescribing proton pump inhibitors: is it time to pause and rethink?

Proton pump inhibitors (PPIs) are among the most widely used agents in the world. The prevalence of reflux disease is increasing, as is the incidence of oesophageal adenocarcinoma, a complication that is strongly correlated with chronic reflux disease. Although these agents are generally safe, a number of potential side effects have been described and a careful assessment of the risks and benefits of PPI therapy is required in all patients being prescribed long-term therapy. Overutilization of PPIs is a problem in clinical practice and needs further attention. PPI use has been associated with osteoporosis and bone fracture, hypomagnesaemia, the development of gastric polyps, enteric infections, interstitial nephritis and pneumonia. Patients on long-term therapy should be periodically evaluated for the indications for continued therapy. Despite widespread publicity in the lay press, and regulatory guidance regarding a number of associations, the evidence for serious side effects is poor and the risk of confounding remains a real possibility for many associations. Patients are more concerned about the absolute risk of developing a complication than a relative risk. The absolute risk of all the complications attributed to PPIs is low and patients who need long-term PPI therapy need a clear discussion of the available data on the risk of therapy and also a discussion of the risk of continued reflux.

Drug-induced alterations in Mg2+ homoeostasis

Magnesium (Mg2+) balance is tightly regulated by the concerted actions of the intestine, bone and kidneys. This balance can be disturbed by a broad variety of drugs. Diuretics, modulators of the EGFR (epidermal growth factor receptor), proton pump inhibitors, antimicrobials, calcineurin inhibitors and cytostatics may all cause hypomagnesaemia, potentially leading to tetany, seizures and cardiac arrhythmias. Conversely, high doses of Mg2+ salts, frequently administered as an antacid or a laxative, may lead to hypermagnesaemia causing various cardiovascular and neuromuscular abnormalities. A better understanding of the molecular mechanisms underlying the adverse effects of these medications on Mg2+ balance will indicate ways of prevention and treatment of these adverse effects and could potentially provide more insight into Mg2+ homoeostasis.

The risks of PPI therapy

PPIs have become one of the most commonly used medications worldwide, as they are the treatment of choice for several acid-related gastrointestinal disorders. However, concerns have been raised about PPI therapy, including the risk of pneumonia, bone fractures and enteric infections, and a possible interaction with clopidogrel that could increase the risk of cardiovascular events. Observational studies have shown very modest associations between PPI therapy and these risks, although the association between PPI treatment and the risk of enteric infections seems to be stronger than the association with other risk factors. However, given the inherent limitations of observational studies, these associations could be attributable to bias and/or confounding factors. In addition, evidence from randomized, controlled trials does not support a clinically significant effect of PPI therapy on the risk of cardiovascular events in patients taking clopidogrel or the risk of pneumonia. Nevertheless, it is impossible to exclude the possibility that some of these associations might be causal or indeed that PPI therapy has an as yet unknown long-term adverse effect. As with any therapy, therefore, it is advisable to prescribe PPIs only to patients for whom these drugs have been proven beneficial.

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.

Use of proton pump inhibitors and risk of hip fracture in relation to dietary and lifestyle factors: a prospective cohort study

OBJECTIVE

To examine the association between chronic use of proton pump inhibitors (PPIs) and risk of hip fracture.

DESIGN

Prospective cohort study.

SETTING

Nurses' Health Study, which originally recruited from the 11 most populous states in the US.

PARTICIPANTS

79,899 postmenopausal women enrolled in the Nurses' Health Study who provided data on the use of PPIs and other risk factors biennially since 2000 and were followed up to 1 June 2008.

MAIN OUTCOME MEASURE

Incident hip fracture

RESULTS

During 565,786 person years of follow-up, we documented 893 incident hip fractures. The absolute risk of hip fracture among regular users of PPIs was 2.02 events per 1000 person years, compared with 1.51 events per 1000 person years among non-users. Compared with non-users, the risk of hip fracture among women who regularly used PPIs for at least two years was 35% higher (age adjusted hazard ratio 1.35 (95% confidence interval 1.13 to 1.62)), with longer use associated with increasing risk (P(trend)<0.01). Adjustment for risk factors, including body mass index, physical activity, and intake of calcium did not materially alter this association (hazard ratio 1.36 (1.13 to 1.63)). These associations were also not changed after accounting for reasons for PPI use. The relation between PPI use and fracture differed by smoking history (P(interaction)=0.03). Among current and former smokers, PPI use was associated with greater than 50% increase in risk of fracture, with a multivariate hazard ratio for fracture of 1.51 (1.20 to 1.91). In contrast, among women who never smoked there was no association (multivariate hazard ratio 1.06 (0.77 to 1.46)). In a meta-analysis of these results with 10 prior studies, the pooled odds ratio of hip fracture associated with PPI use was 1.30 (1.25 to 1.36).

CONCLUSION

Chronic use of PPIs is associated with increased risk of hip fracture, particularly among women with a history of smoking.

Proton pump inhibitors and risk of fractures: a meta-analysis of 11 international studies

BACKGROUND

Concerns have been raised about the risk of fractures with acid-suppressive medications, such as proton pump inhibitors and histamine(2)-receptor antagonists.

METHODS

This meta-analysis evaluated the association between proton pump inhibitor or histamine(2)-receptor antagonist use and fractures. We performed a systematic search of published literature (1970 to October 10, 2010) in MEDLINE, EMBASE, and other sources. Ten publications reporting 11 studies were considered eligible for analysis.

RESULTS

All studies were observational case-control or cohort studies and primarily evaluated older adults. The summary effect estimate for risk of hip fracture increased modestly among individuals taking proton pump inhibitors (relative risk [RR] 1.30, 95% confidence interval [CI], 1.19-1.43). There also was an increase in spine (RR 1.56, 95% CI, 1.31-1.85) and any-site fractures (RR 1.16, 95% CI, 1.04-1.30) among proton pump inhibitor users. These findings were similar in both men and women and after stratification by duration of use. In contrast, histamine(2)-receptor antagonist use was not significantly associated with increased risk of hip fracture (RR 1.12, 95% CI, 0.97-1.30).

CONCLUSION

In this meta-analysis of observational studies, proton pump inhibitors modestly increased the risk of hip, spine, and any-site fractures, whereas histamine(2)-receptor antagonists were not associated with fracture risk. The possibility of residual confounding cannot be excluded. Further skeletal evaluation should be considered for patients who are taking proton pump inhibitors and also at risk for osteoporotic fracture.

The relationship among proton pump inhibitors, bone disease and fracture

INTRODUCTION

There is growing concern about a possible association between the use of proton pump inhibitors (PPIs) and the development of fragility fractures, most notably hip and vertebral fractures. As PPIs are widely used in clinical practice, this association is of paramount clinical importance.

AREAS COVERED

The authors review the published papers analyzing the relationship between PPI use and the occurrence of fragility fractures. The authors also explore the data supporting possible mechanisms through which PPIs may increase the risk of fracture, including the effects of PPIs on calcium homeostasis, bone mineral density and direct effects of PPIs on bone metabolism.

EXPERT OPINION

Overall, though multiple observational studies have demonstrated an association between PPIs and fragility fractures, the lack of a proven mechanism through which PPIs increase the risk of fracture suggests that this association may not be causal. At this time, the authors do not recommend discontinuing PPIs in patients with a history of fracture or those at increased risk of fracture. However, clinicians should still endeavor to avoid using PPIs in situations where benefits are minimal or clinical indications are lacking.

[Chronic use of proton pump inhibitors: is the risk of osteoporosis and fractures real?]

Proton pump inhibitors (PPI) are one of the most widely used groups of drugs and their potential toxicity is periodically reviewed, emphasizing aspects originally considered secondary. The present review analyzes the physiological and pharmacological bases and the scarce clinical evidence for a potential association between the continued administration of PPI and the development of osteoporosis and bone fractures. Both disorders are clearly related to calcium homeostasis and are highly important in elderly patients due to their poor general prognosis and disabling consequences.

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.