ContextProton pump inhibitors (PPIs) may interfere with calcium absorption through induction of hypochlorhydria but they also may reduce bone resorption through inhibition of osteoclastic vacuolar proton pumps.ObjectiveTo determine the association between PPI therapy and risk of hip fracture.Design, Setting, and PatientsA nested case-control study was conducted using the General Practice Research Database (1987-2003), which contains information on patients in the United Kingdom. The study cohort consisted of users of PPI therapy and nonusers of acid suppression drugs who were older than 50 years. Cases included all patients with an incident hip fracture. Controls were selected using incidence density sampling, matched for sex, index date, year of birth, and both calendar period and duration of up-to-standard follow-up before the index date. For comparison purposes, a similar nested case-control analysis for histamine 2 receptor antagonists was performed.Main Outcome MeasureThe risk of hip fractures associated with PPI use.ResultsThere were 13 556 hip fracture cases and 135 386 controls. The adjusted odds ratio (AOR) for hip fracture associated with more than 1 year of PPI therapy was 1.44 (95% confidence interval [CI], 1.30-1.59). The risk of hip fracture was significantly increased among patients prescribed long-term high-dose PPIs (AOR, 2.65; 95% CI, 1.80-3.90; P<.001). The strength of the association increased with increasing duration of PPI therapy (AOR for 1 year, 1.22 [95% CI, 1.15-1.30]; 2 years, 1.41 [95% CI, 1.28-1.56]; 3 years, 1.54 [95% CI, 1.37-1.73]; and 4 years, 1.59 [95% CI, 1.39-1.80]; P<.001 for all comparisons).ConclusionLong-term PPI therapy, particularly at high doses, is associated with an increased risk of hip fracture.

/pdf/long-term-proton-pump-inhibitor-therapy-and-risk-of-hip-57d6d3occr.pdf

Long-term proton pump inhibitor therapy and risk of hip fracture.

Background: The use of proton pump inhibitors has been associated with an increased risk of hip fracture. We sought to further explore the relation between duration of exposure to proton pump inhibitors and osteoporosis-related fractures. Methods: We used administrative claims data to identify patients with a fracture of the hip, vertebra or wrist between April 1996 and March 2004. Cases were each matched with 3 controls based on age, sex and comorbidities. We calculated adjusted odds ratios (OR) for the risk of hip fracture and all osteoporosis-related fractures for durations of proton pump inhibitor exposure ranging from 1 or more years to more than 7 years. Results: We matched 15 792 cases of osteoporosis-related fractures with 47 289 controls. We did not detect a significant association between the overall risk of an osteoportic fracture and the use of proton pump inhibitors for durations of 6 years or less. However, exposure of 7 or more years was associated with increased risk of an osteoporosisrelated fracture (adjusted OR 1.92, 95% confidence interval [CI] 1.16‐3.18, p = 0.011). We also found an increased risk of hip fracture after 5 or more years of exposure (adjusted OR 1.62, 95% CI 1.02‐2.58, p = 0.04), with even higher risk after 7 or more years exposure (adjusted OR 4.55, 95% CI 1.68‐12.29, p = 0.002). Interpretation: Use of proton pump inhibitors for 7 or more years is associated with a significantly increased risk of an osteoporosis-related fracture. There is an increased risk of hip fracture after 5 or more years exposure. Further study is required to determine the clinical importance of this finding and to determine the value of osteoprotective medications for patients with long-term use of proton pump inhibitors.

/pdf/use-of-proton-pump-inhibitors-and-risk-of-osteoporosis-ev5945deui.pdf

Use of proton pump inhibitors and risk of osteoporosis-related fractures

http://www.drmichaellevin.org/cell2002.pdf

Asymmetries in H+/K+-ATPase and cell membrane potentials comprise a very early step in left-right patterning

Background: Resistance to antitumor agents is a major cause of treatment failure in patients with cancer. Some mechanisms of tumor resistance to cytotoxic drugs may involve increased acidification of extracellular compartments. We investigated whether proton pump inhibitors (PPIs), currently used in the anti-acid treatment of peptic disease, could inhibit the acidification of the tumor microenvironment and increase the sensitivity of tumor cells to cytotoxic agents. Methods: We pretreated cell lines derived from human melanomas, adenocarcinomas, and lymphomas with the PPIs omeprazole, esomeprazole, or pantoprazole and tested their response to cytotoxic drugs in cell death assays. We also evaluated extracellular and intracellular pH and vacuolar-H + -ATPase (V-H + -ATPase) expression, distribution, and activity in PPI-pretreated cells by using western blot analyses, immunocytochemistry, laser scanning confocal analysis, and bioluminescence assays. Finally, we evaluated human melanoma growth and cisplatin sensitivity with or without omeprazole pretreatment in xenografted SCID/SCID mice. Results: PPI pretreatment sensitized tumor cell lines to the effects of cisplatin, 5-fluorouracil, and vinblastine, with an IC 50 value reduction up to 2 logs. PPI pretreatment was associated with the inhibition of V-H + -ATPase activity and increases in both extracellular pH and the pH of lysosomal organelles. PPI pretreatment induced a marked increase in the cytoplasmic retention of the cytotoxic drugs, with clear targeting to the nucleus in the case of doxorubicin. In in vivo experiments, oral pretreatment with omeprazole was able to induce sensitivity of human solid tumors to cisplatin. Conclusion: Our results open new possibilities for the treatment of drug-resistant tumors through combination strategies based on the use of well-tolerated pH modulators such as PPIs.

/pdf/effect-of-proton-pump-inhibitor-pretreatment-on-resistance-1j0ls92c9u.pdf

Effect of Proton Pump Inhibitor Pretreatment on Resistance of Solid Tumors to Cytotoxic Drugs

We studied the effect of proton pump inhibitors, histamine H(2) receptor antagonists, and other types of antacid drugs on fracture risk. All cases were subjects with any fracture sustained during the year 2000 (n = 124,655). For each case, three controls (n = 373,962) matched on age and gender were randomly drawn from the background population. The primary exposure variables were use of proton pump inhibitors, histamine H(2) antagonists, and other antacid drugs. Adjustments were made for several confounders, including diagnosis of an ulcer, nonsteroidal anti-inflammatory drug use, use of histamine H(1) antagonists, stomach resection, previous fracture, and use of corticosteroids. The effect of dose was examined by stratifying for cumulated dose (defined daily dose). Use of proton pump inhibitors was associated with an increase in fracture risk for use within the last year [odds ratio (OR) = 1.18, 95% confidence interval (CI) 1.12-1.43 for overall fracture risk; OR = 1.45, 95% CI 1.28-1.65 for hip fractures; and OR = 1.60, 95% CI 1.25-2.04 for spine fractures). Histamine H(2) antagonists were associated with a decreased fracture risk if they had been used within the last year (OR = 0.88, 95% CI 0.82-0.95 for any fracture, OR = 0.69, 95% CI 0.57-0.84 for hip fractures). Other antacids were not associated with overall fracture risk but were associated with hip and spine fractures. Proton pump inhibitors appeared to be associated with a limited increase in fracture risk, in contrast to histamine H( 2 ) antagonists, which seemed to be associated with a small decrease in fracture risk. In all cases, the changes in risk estimates were small and the clinical significance was limited.

Proton pump inhibitors, histamine H2 receptor antagonists, and other antacid medications and the risk of fracture.

Omeprazole is an inhibitor of gastric H+, K+-ATPase. Although the major proton transport of osteoclast is mediated by a vacuolar-type H+-ATPase which is different from the gastric H+, K+-ATPase,in vitro studies have demonstrated that omeprazole inhibits bone resorption. In this study, the effect of omeprazole on bone resorption was evaluated in patients who had a history of gastric ulcer and were treated with maintenance doses of H2 blocker without any gastric complaints at the study time. H2 blocker administration was changed to omeprazole treatment in the study group and to no treatment in the control group. Urinary excretion of hydroxyproline and calcium decreased after omeprazole treatment in the study group. Serum intact PTH, alkaline phosphatase, osteocalcin, and tartrate-resistant acid phosphatase (TRAP) increased in this group. In the control group, there were not any changes in these parameters. The discrepancy between serum TRAP and urinary excretion of hydroxyproline and calcium in the study group was thought to be due to the suppression of bone resorption by omeprazole, which probably interfered the acidification at resorption lacunae and resulted in the inactivation of TRAP and other lysosomal enzymes. The results of our study suggest the possibility that the specific inhibitors of the osteoclastic proton pump (such as bafilomycins) will more effectively suppress bone resorption and be useful for the treatment of metabolic bone diseases with increased bone resorption.

Kaichiro Katano

Papers

Effect of omeprazole, an inhibitor of H+,K(+)-ATPase, on bone resorption in humans