Risk of adverse outcomes in Taiwan associated with concomitant use of clopidogrel and proton pump inhibitors in patients who received percutaneous coronary intervention

Pharmacokinetic Interactions Between Tegoprazan and the Combination of Clarithromycin, Amoxicillin and Bismuth in Healthy Chinese Subjects: An Open-Label, Single-Center, Multiple-Dosage, Self-Controlled, Phase I Trial

BACKGROUND

Tegoprazan is a potassium-competitive acid blocker that inhibits gastric acid and which may be used for eradicating Helicobacter pylori. This study focuses on the pharmacokinetic interaction and safety between tegoprazan and the combination of clarithromycin, amoxicillin and bismuth in healthy Chinese subjects.

METHODS

An open-label, three-period, single-center, multiple-dosage, single-sequence, phase I trial was conducted in 22 healthy subjects. In period 1, the subjects took tegoprazan 50 mg twice daily for 7 days, and in period 2 they were administered clarithromycin 500 mg, amoxicillin 1000 mg and bismuth potassium citrate 600 mg twice daily for 7 days (days 14-20). Tegoprazan, clarithromycin, amoxicillin and bismuth potassium citrate were then administered in combination for 7 days (days 21-27) in period 3. Blood samples were collected up to 12 h after the last dose of each period. Safety assessments were performed in each period.

RESULTS

The geometric mean ratios (GMRs) [90% confidence interval (CI)] of maximum plasma concentration at steady state (Cmax,ss) and area under the plasma concentration-time curve over the dosing interval (AUCτ) at steady state were 195.93% (175.52-218.71%) and 287.54% (263.28-314.04%) for tegoprazan and 423.23% (382.57-468.22%) and 385.61% (354.62-419.30%) for tegoprazan metabolite M1, respectively. The GMRs (90% CI) of Cmax,ss and AUCτ were 83.69% (77.44-90.45%) and 110.30% (102.74-118.41%) for clarithromycin, 126.25% (114.73-138.93%) and 146.94% (135.33-159.55%) for 14-hydroxyclarithromycin, 75.89% (69.73-82.60%) and 94.34% (87.94-101.20%) for amoxicillin, and 158.43% (125.43-200.11%) and 183.63% (156.42-215.58%) for bismuth, respectively. All reported adverse events were mild. The frequency of adverse events during the coadministration stage was not higher than that during the single- or triple-drug administration stages.

CONCLUSION

The plasma exposure of tegoprazan, M1, 14-hydroxyclarithromycin and bismuth was increased after the coadministration of tegoprazan, clarithromycin, amoxicillin and bismuth. The coadministration exhibited favorable safety and tolerability.

CLINICAL TRIALS REGISTRATION

CTR20230643.

Efficacy and safety of vonoprazan-based dual therapy and esomeprazole-based dual therapy in eradicating primary Helicobacter pylori infection: A propensity score matching analysis

BACKGROUND

According to the Maastricht VI/Florence consensus report, potassium-competitive acid blockers (P-CAB) may improve Helicobacter pylori eradication treatment.

MATERIALS AND METHODS

A total of 213 H. pylori treatment-naive patients aged between 18 and 70 years were treated with two regimens. The two regimens are VDT: 20 mg vonoprazan twice a day and 1 g amoxicillin three times daily and EDT: 20 mg esomeprazole four times a day and 750 mg amoxicillin four times daily. 13 C-urea breath tests were used to evaluate eradication rate 4-6 weeks after treatment. Based on propensity score matching (PSM), this retrospective study analyzed the eradication rates, adverse events (AEs), compliance, and antibiotic resistance rates in VDT and EDT groups.

RESULTS

On intention-to-treat (ITT) analysis, the eradication rate in VDT group (89.0%; 95% CI 81.7-96.3) was non-inferior to that in EDT group (87.7%; 95% CI 80.1-95.3; p = 0.796). The corresponding per-protocol (PP) eradication rates were 94.1% (95% CI 88.4-99.8) and 92.8% (95% CI 86.7-98.9; p = 1.000), respectively. There were no significant between-group differences with respect to compliance or incidence of AEs.

CONCLUSIONS

The efficacy and safety of 14-day VDT and EDT were comparable. Therefore, 14-day VDT or EDT may be recommended for the first-line treatment of H. pylori infection.

2018 update of expert consensus statement on antiplatelet therapy in East Asian patients with ACS or undergoing PCI

East Asians are the most populous race in the world and their health status is an important global issue. Compared with Caucasian populations, East Asian patients have a different benefit/risk ratio when using antithrombotic treatment. Despite this observation, treatment strategies in East Asian patients are mostly based on the American and European guidelines. Despite a lower platelet inhibitory response to clopidogrel, East Asian patients show a similar or even a lower rate of ischemic event occurrence and higher bleeding risk compared with Caucasian patients. For potent P2Y₁₂ inhibitors (ticagrelor and prasugrel), East Asian patients have shown less favorable net clinical benefits compared with Caucasian patients, which may be related to differences in pharmacokinetic/pharmacodynamic profiles and therapeutic zone of antiplatelet effect. This updated consensus mainly focuses on state-of-the-art and current controversies in the East Asian population. In addition, when East Asian patients are administered potent P2Y₁₂ receptor inhibitors, the strategies and ongoing trials to overcome the related hurdles are discussed.

Proton-Pump Inhibitor Use and the Risk of First-Time Ischemic Stroke in the General Population: A Nationwide Population-Based Study

OBJECTIVES

An increased risk of adverse cardiovascular events was reported for concomitant use of proton-pump inhibitors (PPIs) in patients taking antiplatelet agents. The present study aimed at determining whether PPI use alone could be associated with first-time ischemic stroke.

METHODS

This was a retrospective nationwide study using database from Taiwan National Health Insurance and involved subjects aged ≥20 years. In propensity score-matched analysis, patients with current PPI use were compared with propensity score-matched PPI non-use controls at a 1:1 ratio. Patients with prior stroke or hospitalization before the index date were excluded. The primary outcome measure was hospitalization with a primary diagnosis of ischemic stroke during 120-day follow-up. A parallel analysis adopting a nested case-control design was carried out. Patients hospitalized for a first-time ischemic stroke were identified and were compared with matched controls using conditional logistic regression analyses focusing on PPI use before the index date.

RESULTS

The propensity score-matched analysis included 198,148 PPI treatment courses and control periods without PPI use. PPI use was associated with a higher risk of hospitalization due to ischemic stroke with a hazard ratio of 1.36 (95% confidence interval (CI) 1.14-1.620, P=0.001). Based on subgroup analysis, patients aged <60 years were more susceptible (P=0.043 for interaction), whereas gender, history myocardial infarction, diabetes mellitus, hypertension, use of antiplatelet agents of non-steroidal anti-inflammatory drugs, or type of PPIs had no effect on the risk. In the nested case-control analysis, 15,378 patients hospitalized owing to ischemic stroke were identified and were compared with 15,378 matched controls. An association between PPI use and increased cerebrovascular risks was identified, and the adjusted odds ratios for PPI use were 1.77 (95% CI 1.45-2.18, P<0.001) within 30 days, 1.65 (95% CI 1.31-2.08, P<0.001) between 31 and 90 days, and 1.28 (95% CI 1.03-1.59, P=0.025) between 91 and 180 days before the onset of first-time ischemic stroke.

CONCLUSIONS

PPI use is associated with an increased risk of first-time ischemic stroke in the general population, and the risk is independent of antiplatelet agents. However, caution should be exercised when considering its clinical relevance as the magnitude of association was modest and a cause-and-effect relationship remained to be established.

Risk factors of adverse health outcomes after hospital discharge modifiable by clinical pharmacist interventions: a review with a systematic approach

The present review assessed the evidence on risk factors for the occurrence of adverse health outcomes after discharge (i.e. unplanned readmission or adverse drug event after discharge) that are potentially modifiable by clinical pharmacist interventions. The findings were compared with patient characteristics reported in guidelines that supposedly indicate a high risk of drug-related problems. First, guidelines and risk assessment tools were searched for patient characteristics indicating a high risk of drug-related problems. Second, a systematic PubMed search was conducted to identify risk factors significantly associated with adverse health outcomes after discharge that are potentially modifiable by a clinical pharmacist intervention. After the PubMed search, 37 studies were included, reporting 16 risk factors. Only seven of 34 patient characteristics mentioned in pertinent guidelines corresponded to one of these risk factors. Diabetes mellitus (n = 11), chronic obstructive lung disease (n = 9), obesity (n = 7), smoking (n = 5) and polypharmacy (n = 5) were the risk factors reported most frequently in the studies. Additionally, single studies also found associations of adverse health outcomes with different drug classes {e.g. warfarin [hazard ratio 1.50; odds ratio (OR) 3.52], furosemide [OR 2.25] or high beta-blocker starting doses [OR 3.10]}. Although several modifiable risk factors were found, many patient characteristics supposedly indicating a high risk of drug-related problems were not part of the assessed risk factors in the context of an increased risk of adverse health outcomes after discharge. Therefore, an obligatory set of modifiable patient characteristics should be created and implemented in future studies investigating the risk for adverse health outcomes after discharge.

East Asian perspective on the interaction between proton pump inhibitors and clopidogrel

Both proton pump inhibitors (PPIs) and clopidogrel are widely prescribed in the Asia-Pacific population. PPIs are the mainstay therapeutic agents for prophylaxis against aspirin gastropathy and for acid-related disorders including gastroesophageal reflux disease. They are also co-prescribed with oral anticoagulant agents and with dual-antiplatelet therapy for the treatment and prevention of gastrointestinal bleeding. Clopidogrel belongs to the drug class of thienopyridines and is currently the most widely prescribed oral anticoagulant agent either alone or in combination with aspirin. Platelet inhibition by clopidogrel is prone to significant inter-individual variability and is believed to be affected by several factors such as genetics and drug-drug interactions. Since it was first reported in 2009, the potential for drug-drug interactions between PPIs and clopidogrel has remained headline news, and its significance in clinical practice is the subject of an ongoing debate. For East Asian patients in particular, the clinical relevance of the interaction between PPIs and clopidogrel remains unclear because of conflicting data, as well as underrepresentation of East Asian subjects in landmark trials. Increased CYP2C19 genetic polymorphisms in individuals from Asia-Pacific countries only fuel the confusion. Recent studies in East Asian cohorts suggests that the potential of PPIs to attenuate the efficacy of clopidogrel could be minimized by the use of newer PPIs with weaker affinity for the CYP2C19 isoenzyme, namely, pantoprazole, dexlansoprazole, and rabeprazole. This review aims to help clinicians choose the most appropriate PPI for co-prescription with clopidogrel in patients from Asia-Pacific countries.

Patient-centered Outcomes with Concomitant Use of Proton Pump Inhibitors and Other Drugs

PURPOSE

We performed a systematic review of patient-centered outcomes after the concomitant use of proton pump inhibitors (PPIs) and other drugs.

METHODS

We searched 4 databases in July 2016 to find studies that reported mortality and morbidity after the concomitant use of PPIs and other drugs. We conducted direct meta-analyses using a random-effects model and graded the quality of evidence according to the Grading of Recommendations Assessment, Development and Evaluation working group approach.

FINDINGS

We included data from 17 systematic reviews and meta-analyses, 16 randomized controlled trials, and 16 observational studies that examined the concomitant use of PPIs with medications from 10 drug classes. Low-quality evidence suggests that the use of PPIs is associated with greater morbidity when administered with antiplatelet drugs, bisphosphonates, antibiotics, anticoagulants, metformin, mycophenolate mofetil, or nelfinavir. Concomitant PPIs reduce drug-induced gastrointestinal bleeding and are associated with greater docetaxel and cisplatin response rates in patients with metastatic breast cancer. For demonstrated statistically significant relative risks and benefits from concomitant PPIs, the magnitudes of the effects are small, with <100 attributable events per 1000 patients treated, and the effects are inconsistent among specific drugs. Among individual PPIs, the concomitant use of pantoprazole or esomeprazole, but not omeprazole or lansoprazole, is associated with an increased risk for all-cause mortality, nonfatal myocardial infarction, or stroke. Clopidogrel is associated with a greater risk for myocardial infarction compared with prasugrel. Conflicting results between randomized controlled trials and observational studies and high risk for bias in the body of evidence lessened our confidence in the results.

IMPLICATIONS

Available evidence suggests a greater risk for adverse patient outcomes after the concomitant use of PPIs and medications from 9 drug classes and warns against inappropriate drug combinations.

Effects of omeprazole or pantoprazole on platelet function in non-ST-segment elevation acute coronary syndrome patients receiving clopidogrel

BACKGROUND

This study evaluated the effect of omeprazole or pantoprazole on platelet reactivity in non-ST-segment elevation acute coronary syndrome (NSTE-ACS) patients receiving clopidogrel.

METHODS

Consecutive patients with NSTE-ACS (n = 620) from general hospital of Shenyang Military Command were randomized to the omeprazole or pantoprazole (20 mg/d) group (1:1), and received routine dual antiplatelet treatment. Patients' reversion rate of adenosine diphosphate-induced platelet aggregation (ADP-PA) was assessed at baseline, 12 to 24 h after administration of medication, and after 72 h of percutaneous coronary intervention (PCI). The primary endpoint of the study was platelet reactivity assessed with ADP-PA at 30 days after PCI. Adverse events (AEs) were recorded for 30-day and 180-day follow-up periods.

RESULTS

There were no significant differences between both the groups in platelet response to clopidogrel at 12-24 h after drug administration (54.09% ± 18.90% vs 51.62% ± 19.85%, P = 0.12), 72 h after PCI (52.15% ± 19.45% vs 49.66% ± 20.05%, P = 0.18), and 30 days after PCI (50.44% ± 14.54% vs 48.52% ± 15.08%, P = 0.17). The rate of AEs did not differ significantly between groups during the 30-day (15.2% vs 14.8%, P = 0.91) and 180-day (16.5% vs 14.5%, P = 0.50) follow-up periods after PCI.

CONCLUSIONS

The addition of omeprazole or pantoprazole to clopidogrel did not restrict the effect of platelet aggregation by reducing the conversion of clopidogrel. Compared with clopidogrel alone, pantoprazole-clopidogrel and omeprazole-clopidogrel combinations did not increase the incidence of adverse clinical events during 30-day and 180-day follow-up periods after PCI.

TRIAL REGISTRATION

The study is registered in the National Institutes of Health website with identifier NCT01735227. Registered 14 November 2012.

Effects of Clopidogrel and Proton Pump Inhibitors on Cardiovascular Events in Patients with Type 2 Diabetes Mellitus after Drug-Eluting Stent Implantation: A Nationwide Cohort Study

Objective

To investigate whether there is an increased risk of cardiac events in diabetic patients with a combined therapy of clopidogrel (CLO) and proton pump inhibitors (PPIs) after drug-eluting stent (DES) deployment.

Methods

By using National Health Insurance Research Database, all patients who received CLO with or without PPI therapy within 90 days after undergoing DES (limus-eluting or paclitaxel-eluting stents) deployment were enrolled. Endpoints were acute coronary syndrome (ACS) and readmission for revascularization (percutaneous coronary intervention or coronary artery bypass graft surgery) after 3, 6, and 12 months.

Results

A total of 6,603 diabetic patients received LESs (5,933 in the CLO subgroup and 670 in the CLO plus PPIs subgroup), and 3,202 patients received PESs (2,923 in the CLO subgroup and 279 in the CLO plus PPIs subgroup). The patients who received CLO plus PPIs were at higher risk of ACS than those receiving CLO within 1 year after DES deployment (LESs: 6-month hazard ratio [HR] = 1.63, and 1-year HR = 1.37; PESs: 3-month HR = 1.72). Patients with a history of ACS who received CLO plus PPIs were at higher risk of ACS after LES implantation (HR = 1.55) than those in the CLO group.

Conclusion

In “real-world” diabetic patients with LES deployment, the combination of PPIs and CLO is associated with higher rates of ACS after 6 months and 1 year. Even after correction for confounding factors, concomitant PPI use remained an independent predictor of cardiac events, emphasizing the clinical importance of this drug—drug interaction.

Impact of esomeprazole on platelet reactivity and clinical outcome according to CYP2C19 genotype in coronary heart disease patients during dual antiplatelet therapy

OBJECTIVES

The aim of this study was to investigate the effect of CYP2C19 polymorphism and co-therapy with esomeprazole on the antiplatelet efficacy of clopidogrel.

BACKGROUND

The antiplatelet efficacy of clopidogrel depends on CYP2C19 polymorphism or the co-administration of some kind of proton pump inhibitor (PPI).

METHODS

CYP2C19 genotype and the residual platelet reactivity (RPR) were measured in 361 coronary heart disease patients (male, mean age 69yrs), and the risk of cardiovascular events over a 3-month follow-up was assessed to evaluate the impact of co-administration of esomeprazole during dual antiplatelet therapy with aspirin and clopidogrel.

RESULTS

The values of RPR did not differ between esomeprazole and non-esomeprazole groups (4389 ± 1112 versus 4079 ± 1355 AU·min, P=0.103). RPR value was higher in intermediate metabolizers (IM) than in extensive metabolizers (EM) (4089 ± 1252 versus 3697 ± 1215 AU·min P=0.012) and, similarly, higher in poor metabolizers (PM) than in IM (4884 ± 1027 versus 4089 ± 1252 AU·min, P<0.001). There were no differences in RPR between esomeprazole and non-esomeprazole groups according to CYP2C19 genotype (EM, 3954 ± 1192 versus 3645 ± 1220 AU·min, P=0.361; IM, 4401 ± 1063 versus 4051 ± 1271 AU·min, P=0.293; PM, 4917 ± 669 versus 4876 ± 1099 AU·min, P=0.907, respectively). There was also no difference in clinical outcomes between esomeprazole and non-esomeprazole groups in the three-month follow-up (0% versus 0.92%, P=0.487).

CONCLUSIONS

These results suggest that concomitant use of esomeprazole with clopidogrel is not associated with reduced antiplatelet efficacy of clopidogrel or increased risk of cardiovascular events, irrespective of CYP2C19 genotype.

Prognosis of concomitant users of clopidogrel and proton-pump inhibitors in a high-risk population for upper gastrointestinal bleeding

Background

It is unclear whether concomitant use of clopidogrel and proton-pump inhibitors (PPIs) increases the risk of recurrence of cardiovascular disease or death in patients at high risk of upper gastrointestinal (GI) bleeding.

Methods

Based on the Swedish Patient Register, a cohort of cardiovascular disease (including acute myocardial infarction, stroke and angina, from 2006 to 2008) was selected from a population with any diagnosis of upper GI bleeding. Data on drug prescription was retrieved from the Prescribed Drug Register. Patients entered into the cohort after their first discharge for cardiovascular disease and were followed up to death, recurrence of cardiovascular disease, or 90 days. A Cox regression model was conducted and hazard ratios (HRs) with 95% confidence intervals (CIs) were estimated to evaluate the risks among users of different drug prescriptions.

Results

Patients who were current users of only PPIs (HR 2.02, 95% CI 1.19-3.44), only clopidogrel (HR 1.14, 95% CI 0.53-2.45) and nonusers of both (HR 2.36, 95% CI 1.39-4.00) were at a higher risk of death compared with patients with a concomitant use. Results were similar among 1779 patients who had any history of upper GI bleeding (HR 2.05, 95% CI 1.18-3.54; HR 1.25, 95% CI 0.57-2.72; HR 2.30, 95% CI 1.33-3.98, respectively).

Conclusion

Among patients at high risk of upper GI bleeding, those with a concomitant use of PPIs and clopidogrel were at a decreased risk of mortality, and possibly also a decreased risk of recurrence of cardiovascular disease.

Increased risk for developing major adverse cardiovascular events in stented Chinese patients treated with dual antiplatelet therapy after concomitant use of the proton pump inhibitor

BACKGROUND

Some clinical studies have demonstrated that the proton pump inhibitor (PPI) could decrease clopidogrel platelet response and increase major adverse cardiovascular events (MACE) in white or black subjects. However, that remains to be determined in Chinese patients. In this study, we sought to determine whether there could be an increased risk for developing MACE after concomitant use of dual antiplatelet therapy (DAT) and a PPI in Chinese patients treated with percutaneous coronary intervention (PCI) and stenting.

METHODS

This study was a 5-year, single-center, retrospective cohort analysis of eligible patients (n = 6188) who received DAT and a PPI concomitantly (defined as PPI users) before discharge and/or 12-month follow-up after discharge as compared with those who received DAT alone (also defined as non-PPI users, n = 1465). The incidence of recurrent MACE, such as myocardial infarction (MI), definite stent thromboses (ST), or cardiovascular death, was compared between the PPI users and non-users.

RESULTS

PPI users had a significantly higher incidence of the MACE than non-users (13.9% vs. 10.6%; adjusted HR: 1.33; 95% CI: 1.12 - 1.57, P = 0.007). Stratified analysis revealed that concurrent use of DAT and a PPI was associated with a significantly increased risk for developing ST compared with DAT alone (1% vs. 0.4%; adjusted HR: 2.66, 95% CI: 1.16 - 5.87, P = 0.012). However, there were no significant differences in the risk of MI, cardiovascular death and other adverse events, regardless of combination of clopidogrel and a PPI.

CONCLUSIONS

The study further suggests that concomitant use of DAT and a PPI may be associated with an increased risk for developing MACE, in particular definite ST, in Chinese PCI patients after discharge as compared with use of DAT alone.

Japanese postmarketing surveillance of clopidogrel for patients with non-ST-segment-elevation acute coronary syndrome indicated for percutaneous coronary intervention (J-PLACE NSTE-ACS)

Clopidogrel in combination with aspirin has been a standard therapy for patients who have undergone percutaneous coronary intervention. The present study was conducted as a postmarketing surveillance, for the purpose of assessing the safety and efficacy of clopidogrel in real clinical practice in patients with non-ST-segment-elevation acute coronary syndrome (NSTE-ACS). Subjects were registered between March 2008 and December 2010, and as a result, patients not only with NSTE-ACS but also other types of ischemic heart diseases were enrolled. Data on off-label subjects were used only in safety evaluation. After excluding patients with inappropriate clinical report forms, 3,673 patients with non-ST-segment-elevation myocardial infarction, unstable angina, STEMI, stable angina, or old myocardial infarction were observed for safety evaluation. Efficacy was assessed in 2,562 of the 3,673 patients with NSTE-ACS. Aspirin was concomitantly prescribed to 3,615/3,673 (98.6 %) of the safety group, and 2,374/3,673 (64.6 %) received a loading dose of clopidogrel. During a maximum follow-up period of 12 months, 397 (10.8 %) of the 3,673 patients experienced adverse drug reactions (ADRs), of whom 145 (4.0 %) had serious conditions, as classified by the investigators. The most frequently observed ADRs were hepatobiliary and gastrointestinal disorders. Bleeding adverse events were observed in 138 patients (3.8 %) and 80 cases (2.2 %) were considered as serious. The 1-year cumulative incidence of major adverse cardiovascular events and major adverse cardiac and cerebrovascular events in the patients with NSTE-ACS were estimated to be 11.6 and 12.2 %, respectively. Serious AEs that substantially affect the safety profile of clopidogrel were not confirmed.

Antiplatelet therapy and proton pump inhibition: cause for concern?

PURPOSE OF REVIEW

To review the current evidence on the clinical significance of the drug-drug interactions between the available antiplatelet agents and proton pump inhibitors (PPIs).

RECENT FINDINGS

Gastrointestinal bleeding is associated with higher rates of morbidity and mortality following a myocardial infarction. PPIs are commonly used to prevent gastrointestinal bleeding. PPIs can attenuate metabolism of clopidogrel to its active metabolite by inhibiting various hepatic CYP450 enzymes, mainly CYP2C19. Concomitant use of a PPI with clopidogrel reduces clopidogrel active metabolite generation and subsequent platelet inhibition. In observational studies, the clinical significance of this drug-drug interaction is mixed. Evidence from the only randomized trial studying the clinical implications of the PPI-clopidogrel interaction did not demonstrate any difference in cardiovascular outcomes but did show a reduction in gastrointestinal bleeding with use of a PPI.

SUMMARY

The drug-drug interaction between antiplatelet agents and PPIs at the enzymatic level does not seem to result in worse clinical outcomes. The risk of gastrointestinal bleeding with antiplatelet therapy is substantial. Clinicians should use PPIs in selected high-risk patients to prevent gastrointestinal bleeding.

Increased risk of gastrointestinal malignancy in patients with diabetes mellitus and correlations with anti-diabetes drugs: a nationwide population-based study in Taiwan

OBJECTIVE

Although the major cause of morbidity and mortality in patients with diabetes mellitus (DM) is cardiovascular disease, DM is also associated with certain site-specific cancers. However, whether DM is associated with an increased risk of cancer of the digestive tract remains undetermined. A nationwide, population-based database in Taiwan was analyzed to explore the relationship between DM and cancer of the digestive organs.

METHODS

From 2000 to 2007, a study cohort consisting of 39,515 patients with newly diagnosed diabetes without a previous diagnosis of gastrointestinal (GI) cancer was identified from the National Health Insurance Research Database in Taiwan. A control cohort of 79,030 age- and sex-matched non-diabetic subjects was selected to compare the occurrence of GI malignancies between the two groups. The association between the incidence of GI cancers and the use of glucose-lowering therapies was also investigated.

RESULTS

During the 7-year follow-up period, GI cancers developed in 929 diabetic patients (2.35%) and 1,126 subjects (1.42%) in the comparison cohort. DM was associated with a 2.75-fold (95% confidence interval (CI), 2.51-3.02) higher risk of developing GI malignancy. Among GI cancers, the incidences of stomach (adjusted hazard ratio (HR), 1.49; 95% CI, 1.16-1.92), liver (adjusted HR, 2.65; 95% CI, 2.29-3.07), colon (adjusted HR, 1.58; 95% CI, 1.28-1.94) and pancreatic cancers (adjusted HR, 4.35; 95% CI, 2.93-6.47) were significantly increased in the patients with DM. An analysis of the effects of various glucose-lowering therapies in the diabetic patients revealed the use of α-glucosidase inhibitors to be associated with a lower risk of hepatic cancer (adjusted HR, 0.62; 95% CI, 0.4-0.94). Thiazolidinedione (TZD) treatment was associated with lower stomach (adjusted HR, 0.11; 95% CI, 0.02-0.82) and hepatic cancer risks (adjusted HR, 0.46; 95% CI, 0.29-0.73), while sulfonylurea use was associated with a lower colon cancer risk (adjusted HR, 0.74; 95% CI, 0.51-1.09) and a higher pancreatic cancer risk (adjusted HR, 2.36; 95% CI, 1.21-4.61).

CONCLUSION

Patients with DM have an increased risk of GI malignancy that may be affected by the use of different categories of glucose-lowering therapies.

Genetic polymorphisms and drug interactions leading to clopidogrel resistance: why the Asian population requires special attention

Ischemic heart disease and stroke are the two leading causes of death worldwide. Antiplatelet therapy plays the most significant role in the management of these cardiovascular and cerebrovascular occlusive events to prevent recurrent ischemic attack. Clopidogrel, an antiplatelet drug, is widely prescribed either alone or in combination with aspirin as dual antiplatelet therapy for the prevention of vascular occlusive events. The antiplatelet response to clopidogrel varies widely. Hyporesponders and nonresponders are likely to have adverse cardiovascular events during follow-up. Some drugs, such as proton pump inhibitors (omeprazole), calcium channel blockers, selective serotonin reuptake inhibitors (nefazadone), coumarin derivatives (phenprocoumon), benzodiazepines, sulfonylurea, erythromycin, and itraconazole, decrease the antiplatelet effect of clopidogrel when administered concomitantly. Decreased response to clopidogrel is common among Asians due to genetic polymorphisms associated with clopidogrel resistance, and it is nearly 70% in some of the Asian communities. It is necessary to study Asian populations, because there are a large number of Asians throughout the world due to increased migration. Current guidelines do not make genetic testing or platelet response testing mandatory prior to clopidogrel prescription. Therefore, it is important for clinicians treating Asian patients to keep in mind the interindividual variability in response to clopidogrel when prescribing the drug.

Gastroesophageal reflux disease and atrial fibrillation: a nationwide population-based study

OBJECTIVES

Precise mechanisms of atrial fibrillation (AF) are uncertain, but their association with esophageal disorders has been recently proposed. The association between gastroesophageal reflux disease (GERD), the most common gastroesophageal disorder, and AF remains undetermined. We therefore aimed to investigate the association between GERD and later development of AF.

METHODS AND RESULTS

Patients with GERD were identified from the 1,000,000-person cohort dataset sampled from the Taiwan National Health Insurance database. The study cohort comprised 29,688 newly diagnosed adult GERD patients; 29,597 randomly selected age-, gender-, comobidity-matched subjects comprised the comparison cohort. Cox proportional hazard regressions were performed as a means of comparing the AF-free survival rate for the two cohorts. During a maximum three years of follow-up, a total of 351 patients experienced AF, including 184 (0.62%) patients in the GERD cohort and 167 (0.56%) in the control group. The log-rank test showed that patients with GERD had significantly higher incidence of AF than those without GERD (p = 0.024). After Cox proportional hazard regression model analysis, GERD was independently associated with the increased risk of AF (hazard ratio, 1.31; 95% confidence interval, 1.06-1.61, p = 0.013).

CONCLUSION

GERD was independently associated with an increased risk of future AF in a nationwide population-based cohort.

Effect of the clopidogrel-proton pump inhibitor drug interaction on adverse cardiovascular events in patients with acute coronary syndrome

STUDY OBJECTIVE

To examine the effect of the drug interaction between clopidogrel and proton pump inhibitors (PPIs) on the risk of an adverse cardiovascular event.

DESIGN

Population-based, retrospective cohort study.

DATA SOURCE

IMS LifeLink Health Plan administrative claims database.

PATIENTS

A total of 10,101 patients aged 18 years or older with a diagnosis of acute coronary syndrome (ACS) made during a hospitalization or emergency department visit between 2001 and 2008 and who had their first clopidogrel prescription within 90 days after their ACS diagnosis were included in the study. Patients were stratified according to concurrent use (clopidogrel plus PPI group) or no use (clopidogrel alone group) of the following PPIs: esomeprazole, lansoprazole, omeprazole, pantoprazole, or rabeprazole.

MEASUREMENTS AND MAIN RESULTS

Data were collected on baseline patient demographic and clinical characteristics. Patients were followed from their first clopidogrel prescription until they experienced an adverse cardiovascular event, defined as inpatient hospitalization or emergency department visits for myocardial infarction, percutaneous coronary intervention, or intermediate coronary syndrome; were disenrolled; discontinued clopidogrel; or reached the end of the study period. Using a propensity scoring method, the clopidogrel plus PPI group was matched in a 1:1 ratio with the clopidogrel alone group. Exposure to overlapping clopidogrel-PPI prescriptions was modeled as a time-dependent covariate. The Cox hazards regression model was used to estimate the risk of an adverse cardiovascular event in the clopidogrel plus PPI group versus the clopidogrel alone group. Propensity score matching resulted in 2674 patient pairs. In the propensity score-matched sample, the mean age was 61.30 years, with a mean follow-up of 268 days, and 70.04% were male. Concurrent use of clopidogrel with a PPI was associated with a significantly increased risk of a cardiovascular adverse event (hazard ratio 1.438, 95% confidence interval 1.237-1.671) compared with clopidogrel alone.

CONCLUSION

Concurrent use of clopidogrel plus a PPI was associated with a significant increase in risk of an adverse cardiovascular event in patients with ACS. Large randomized studies are needed to confirm this finding. Until then, clinicians should prescribe the concurrent use of these two drugs cautiously.

Effect of the clopidogrel-proton pump inhibitor drug interaction on adverse cardiovascular events in patients with acute coronary syndrome

STUDY OBJECTIVE

To examine the effect of the drug interaction between clopidogrel and proton pump inhibitors (PPIs) on the risk of an adverse cardiovascular event.

DESIGN

Population-based, retrospective cohort study.

DATA SOURCE

IMS LifeLink Health Plan administrative claims database.

PATIENTS

A total of 10,101 patients aged 18 years or older with a diagnosis of acute coronary syndrome (ACS) made during a hospitalization or emergency department visit between 2001 and 2008 and who had their first clopidogrel prescription within 90 days after their ACS diagnosis were included in the study. Patients were stratified according to concurrent use (clopidogrel plus PPI group) or no use (clopidogrel alone group) of the following PPIs: esomeprazole, lansoprazole, omeprazole, pantoprazole, or rabeprazole.

MEASUREMENTS AND MAIN RESULTS

Data were collected on baseline patient demographic and clinical characteristics. Patients were followed from their first clopidogrel prescription until they experienced an adverse cardiovascular event, defined as inpatient hospitalization or emergency department visits for myocardial infarction, percutaneous coronary intervention, or intermediate coronary syndrome; were disenrolled; discontinued clopidogrel; or reached the end of the study period. Using a propensity scoring method, the clopidogrel plus PPI group was matched in a 1:1 ratio with the clopidogrel alone group. Exposure to overlapping clopidogrel-PPI prescriptions was modeled as a time-dependent covariate. The Cox hazards regression model was used to estimate the risk of an adverse cardiovascular event in the clopidogrel plus PPI group versus the clopidogrel alone group. Propensity score matching resulted in 2674 patient pairs. In the propensity score-matched sample, the mean age was 61.30 years, with a mean follow-up of 268 days, and 70.04% were male. Concurrent use of clopidogrel with a PPI was associated with a significantly increased risk of a cardiovascular adverse event (hazard ratio 1.438, 95% confidence interval 1.237-1.671) compared with clopidogrel alone.

CONCLUSION

Concurrent use of clopidogrel plus a PPI was associated with a significant increase in risk of an adverse cardiovascular event in patients with ACS. Large randomized studies are needed to confirm this finding. Until then, clinicians should prescribe the concurrent use of these two drugs cautiously.

The association of tooth scaling and decreased cardiovascular disease: a nationwide population-based study

OBJECTIVE

Poor oral hygiene has been associated with an increased risk for cardiovascular disease. However, the association between preventive dentistry and cardiovascular risk reduction has remained undetermined. The aim of this study is to investigate the association between tooth scaling and the risk of cardiovascular events by using a nationwide, population-based study and a prospective cohort design.

METHODS

Our analyses were conducted using information from a random sample of 1 million persons enrolled in the nationally representative Taiwan National Health Insurance Research Database. Exposed individuals consisted of all subjects who were aged ≥ 50 years and who received at least 1 tooth scaling in 2000. The comparison group of non-exposed persons consisted of persons who did not undergo tooth scaling and were matched to exposed individuals using propensity score matching by the time of enrollment, age, gender, history of coronary artery disease, diabetes, hypertension, and hyperlipidemia.

RESULTS

During an average follow-up period of 7 years, 10,887 subjects who had ever received tooth scaling (exposed group) and 10,989 age-, gender-, and comorbidity-matched subjects who had not received tooth scaling (non-exposed group) were enrolled. The exposed group had a lower incidence of acute myocardial infarction (1.6% vs 2.2%, P<.001), stroke (8.9% vs 10%, P=.03), and total cardiovascular events (10% vs 11.6%, P<.001) when compared with the non-exposed group. After multivariate analysis, tooth scaling was an independent factor associated with less risk of developing future myocardial infarction (hazard ratio [HR], 0.69; 95% confidence interval [CI], 0.57-0.85), stroke (HR, 0.85; 95% CI, 0.78-0.93), and total cardiovascular events (HR, 0.84; 95% CI, 0.77-0.91). Furthermore, when compared with the non-exposed group, increasing frequency of tooth scaling correlated with a higher risk reduction of acute myocardial infarction, stroke, and total cardiovascular events (P for trend<.001).

CONCLUSION

Tooth scaling was associated with a decreased risk for future cardiovascular events.

Clopidogrel and proton pump inhibitors - where do we stand in 2012?

Clopidogrel in association with aspirine is considered state of the art of medical treatment for acute coronary syndrome by reducing the risk of new ischemic events. Concomitant treatment with proton pump inhibitors in order to prevent gastrointestinal side effects is recommended by clinical guidelines. Clopidogrel needs metabolic activation predominantly by the hepatic cytochrome P450 isoenzyme Cytochrome 2C19 (CYP2C19) and proton pump inhibitors (PPIs) are extensively metabolized by the CYP2C19 isoenzyme as well. Several pharmacodynamic studies investigating a potential clopidogrel-PPI interaction found a significant decrease of the clopidogrel platelet antiaggregation effect for omeprazole, but not for pantoprazole. Initial clinical cohort studies in 2009 reported an increased risk for adverse cardiovascular events, when under clopidogrel and PPI treatment at the same time. These observations led the United States Food and Drug Administration and the European Medecines Agency to discourage the combination of clopidogrel and PPI (especially omeprazole) in the same year. In contrast, more recent retrospective cohort studies including propensity score matching and the only existing randomized trial have not shown any difference concerning adverse cardiovascular events when concomitantly on clopidogrel and PPI or only on clopidogrel. Three meta-analyses report an inverse correlation between clopidogrel-PPI interaction and study quality, with high and moderate quality studies not reporting any association, rising concern about unmeasured confounders biasing the low quality studies. Thus, no definite evidence exists for an effect on mortality. Because PPI induced risk reduction clearly overweighs the possible adverse cardiovascular risk in patients with high risk of gastrointestinal bleeding, combination of clopidogrel with the less CYP2C19 inhibiting pantoprazole should be recommended.

Comparison of early outcomes after primary stenting in Japanese patients with acute myocardial infarction between clopidogrel and ticlopidine in concomitant use with proton-pump inhibitor

BACKGROUND

Recent studies have reported that concomitant use of clopidogrel with proton-pump inhibitors (PPIs) might decrease antiplatelet effects and increase the risk of adverse outcomes after coronary stenting. However, little is known about the difference between clopidogrel and ticlopidine in concomitant use with PPIs, especially within the Asian population.

METHODS

We retrospectively analyzed 302 consecutive patients (248 males, mean age 66 ± 12 years) undergoing primary stenting for acute myocardial infarction from July 2006 to June 2010. PPIs were administered to 92% (278/302) of the patients. The patients were divided into two groups on the basis of clopidogrel (clopidogrel group, n=187) or ticlopidine (ticlopidine group, n=91) with PPI. Their characteristics, medications, and 30-day clinical outcomes were examined.

RESULTS

There were no significant differences in 30-day major adverse cardiac events (cardiac death, non-fatal myocardial infarction, and definite stent thrombosis), bleeding events, and stroke between the two groups. The discontinuation of clopidogrel due to side effects was significantly less frequent than that of ticlopidine (1.1% vs 7.7%, p=0.003, respectively).

CONCLUSION

Our findings suggest that concomitant use of clopidogrel with PPIs might be safer than ticlopidine with PPIs in patients undergoing primary stenting for acute myocardial infarction.

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.

Association of proton pump inhibitor use on cardiovascular outcomes with clopidogrel and ticagrelor: insights from the platelet inhibition and patient outcomes trial

BACKGROUND

The clinical significance of the interaction between clopidogrel and proton pump inhibitors (PPIs) remains unclear.

METHODS AND RESULTS

We examined the relationship between PPI use and 1-year cardiovascular events (cardiovascular death, myocardial infarction, or stroke) in patients with acute coronary syndrome randomized to clopidogrel or ticagrelor in a prespecified, nonrandomized subgroup analysis of the Platelet Inhibition and Patient Outcomes (PLATO) trial. The primary end point rates were higher for individuals on a PPI (n=6539) compared with those not on a PPI (n=12 060) at randomization in both the clopidogrel (13.0% versus 10.9%; adjusted hazard ratio [HR], 1.20; 95% confidence interval [CI], 1.04-1.38) and ticagrelor (11.0% versus 9.2%; HR, 1.24; 95% CI, 1.07-1.45) groups. Patients on non-PPI gastrointestinal drugs had similar primary end point rates compared with those on a PPI (PPI versus non-PPI gastrointestinal treatment: clopidogrel, HR, 0.98; 95% CI, 0.79-1.23; ticagrelor, HR, 0.89; 95% CI, 0.73-1.10). In contrast, patients on no gastric therapy had a significantly lower primary end point rate (PPI versus no gastrointestinal treatment: clopidogrel, HR, 1.29; 95% CI, 1.12-1.49; ticagrelor, HR, 1.30; 95% CI, 1.14-1.49).

CONCLUSIONS

The use of a PPI was independently associated with a higher rate of cardiovascular events in patients with acute coronary syndrome receiving clopidogrel. However, a similar association was observed between cardiovascular events and PPI use during ticagrelor treatment and with other non-PPI gastrointestinal treatment. Therefore, in the PLATO trial, the association between PPI use and adverse events may be due to confounding, with PPI use more of a marker for, than a cause of, higher rates of cardiovascular events.

CLINICAL TRIAL REGISTRATION

http://www.clinicaltrials.gov. Unique identifier: NCT00391872.

Increased risk of ischemic stroke in patients with systemic lupus erythematosus: a nationwide population-based study

BACKGROUND

Systemic lupus erythematosus (SLE) has been reported to be associated with an increased risk of cardiovascular disease. However, most studies have been criticized for either a small sample size or the lack of a prospective control. Our study investigated the relationship of SLE and the subsequent development of ischemic stroke using a nationwide, population-based database in an Asian population.

METHODS

From 2000 to 2007, we identified a study cohort consisting of a total of 11,637 newly diagnosed SLE patients using the National Health Insurance Research Database in Taiwan. A control cohort of 58,185 subjects without SLE, matched for age, gender, and comorbidities were selected for comparison to observe the occurrence of ischemic stroke in these two groups.

RESULTS

During a follow-up period of up to 7 years, ischemic stroke developed in 258 (2.22%) of the patients with SLE and in 873 (1.5%) of patients in the comparison cohort. Kaplan-Meier analysis also revealed a tendency of SLE patients toward ischemic stroke development (log rank test, p = 0.001). After Cox model adjustment for patients' demographic characteristics and selected comorbidities, patients with SLE were found to have a 1.67-fold (95% CI, 1.45 to 1.91) higher risk of developing ischemic stroke.

CONCLUSION

Patients with SLE have an increased risk of stroke.

Clinical outcomes following coronary stenting in Japanese patients treated with and without proton pump inhibitor

BACKGROUND

The aim of this study was to examine the effect of proton-pump inhibitor (PPI) on clinical outcomes in Japanese patients who undergo coronary stent implantation.

METHODS AND RESULTS

A total of 1,270 patients (males 915, 69 years) were enrolled and dual antiplatelet therapy of aspirin and a thienopyridine derivative was prescribed (clopidogrel 630, ticlopidine 640). Patients were divided into 2 groups treated with or without PPI. PPI was administered in 331 cases (26%), and non-PPI in 939 (74%). There were no significant differences in cardiovascular death (PPI vs. non-PPI: 5 vs. 11 cases), nonfatal myocardial infarction (3 vs. 5), and stroke (3 vs. 16) between PPI and non-PPI groups, but the ratio of gastrointestinal events had a higher tendency in non-PPI group compared with PPI group (1 vs. 17, P=0.08). In subgroup analysis of patients taking clopidogrel, or patients with acute coronary syndrome, there was no significant difference in the ratio of cardiovascular events (7 vs. 16, 6 vs. 17, NS). The non-PPI group had a tendency of an increased risk of gastrointestinal events compared with the PPI group (0 vs. 9, P=0.06; 1 vs. 7, P=0.14).

CONCLUSIONS

In contrast to the negative drug interaction of PPI reported elsewhere, in the present study the intake of PPI was not associated with an increased risk for adverse clinical outcomes in patients treated with stents.

The interaction between proton pump inhibitors and clopidogrel and upper gastrointestinal bleeding

There is increasing concern regarding a possible adverse interaction between proton pump inhibitors (PPIs) and clopidogrel that could lead to reduced cardiovascular protection by clopidogrel. We performed a literature search for relevant original studies and systematic reviews. PPIs likely affect the antiplatelet activity of clopidogrel as measured in vitro, and this may be a class effect. We conclude that the pharmacodynamic effect has not been translated into any clinically meaningful adverse effect. PPI cotherapy reduces the incidence of recurrent peptic ulcer and of upper gastrointestinal bleeding among patients on clopidogrel.

Clinical evidence of interaction between clopidogrel and proton pump inhibitors

Clopidogrel is approved for reduction of atherothrombotic events in patients with cardiovascular (CV) and cerebrovascular disease. Dual antiplatelet therapy with aspirin and clopidogrel decreases the risk of major adverse cardiac events after acute coronary syndrome or percutaneous coronary intervention, compared with aspirin alone. Due to concern about gastrointestinal bleeding in patients who are receiving clopidogrel and aspirin therapy, current guidelines recommend combined use of a proton pump inhibitor (PPI) to decrease the risk of bleeding. Data from previous pharmacological studies have shown that PPIs, which are extensively metabolized by the cytochrome system, may decrease the ADP-induced platelet aggregation of clopidogrel. Results from retrospective cohort studies have shown a higher incidence of major CV events in patients receiving both clopidogrel and PPIs than in those without PPIs. However, other retrospective analyses of randomized clinical trials have not shown that the concomitant PPI administration is associated with increased CV events among clopidogrel users. These controversial results suggest that large specific studies are needed. This article reviews the metabolism of clopidogrel and PPIs, existing clinical data regarding the interaction between clopidogrel and PPIs, and tries to provide recommendations for health care professionals.

Clopidogrel-drug interactions

Multidrug therapy increases the risk for drug-drug interactions. Clopidogrel, a prodrug, requires hepatic cytochrome P450 (CYP) metabolic activation to produce the active metabolite that inhibits the platelet P2Y₁₂ adenosine diphosphate (ADP) receptor, decreasing platelet activation and aggregation processes. Atorvastatin, omeprazole, and several other drugs have been shown in pharmacodynamic studies to competitively inhibit CYP activation of clopidogrel, reducing clopidogrel responsiveness. Conversely, other agents increase clopidogrel responsiveness by inducing CYP activity. The clinical implications of these pharmacodynamic interactions have raised concern because many of these drugs are coadministered to patients with coronary artery disease. There are multiple challenges in proving that a pharmacodynamic drug-drug interaction is clinically significant. To date, there is no consistent evidence that clopidogrel-drug interactions impact adverse cardiovascular events. Statins and proton pump inhibitors have been shown to decrease adverse clinical event rates and should not be withheld from patients with appropriate indications for therapy because of concern about potential clopidogrel-drug interactions. Clinicians concerned about clopidogrel-drug interactions have the option of prescribing either an alternative platelet P2Y₁₂ receptor inhibitor without known drug interactions, or statin and gastro-protective agents that do not interfere with clopidogrel metabolism.

Statin use in patients with asthma: a nationwide population-based study

BACKGROUND

Statins have pleiotropic effects, with potential clinical applications beyond their lipid-lowering effect. We hypothesized that statins could inhibit airway inflammation. The aim of our study was to determine whether statin use may reduce hospitalization in patients with asthma.

MATERIALS AND METHODS

 We conducted a nationwide population-based study to investigate the possible influence of statin use on patients with asthma using the Taiwan National Health Insurance Database.

RESULTS

 A total of 3965 patients with asthma (mean age 60·69 ± 0·39 years, male 41·3%) who received statins after asthma diagnosis were identified from the 1 000 000 sampling cohort data set between January 2000 and December 2007. Another 7843 patients with asthma who were matched for age, gender and medication for asthma treatment but did not use statin were enrolled as the control group. The patients with statin use had more hypertension (P < 0·001), diabetes mellitus (P < 0·001), coronary artery disease (P < 0·001), dysrhythmia (P = 0·001) and chronic kidney disease (P < 0·001) than patients without statin use. Till the end of 2007, there were 974 patients who were hospitalized because of asthma. After multivariate analysis, only increasing age (hazard ratio, 1·02; 95% confidence interval, 1·02-1·03, P < 0·001) and statin use (hazard ratio, 0·82; 95% confidence interval, 0·71-0·95, P = 0·006) were independently associated with the decreased risk of hospitalization for asthma.

CONCLUSIONS

Statin use is associated with reduced hospitalization for asthma attack in patients with asthma, suggesting possible applications of statin in patients with asthma.

Angiotensin II receptor blockers and risk of cancer in patients with systemic hypertension

Recently, concerns have been raised that angiotensin II receptor blockers (ARBs) may be associated with an increased risk for cancer development. However, the relation between ARBs and cancer is still unclear. Therefore, a nationwide population-based study was conducted to investigate the possible influence of ARBs on the occurrence of new cancers in patients with hypertension by using the Taiwan National Health Insurance database. A total of 109,002 patients with newly diagnosed hypertension were identified from a cohort database of 1 million individuals from January 1, 1998, to December 31, 2006. Among them, 40,124 (36.8%) had received ARBs for hypertension. The end point was the development of any type of cancer before the end of 2007. During an average of 5.7 ± 2.6 years of follow-up, a total of 9,067 cases of new cancer occurrence were observed. The log-rank test showed that the occurrence rate of newly diagnosed cancers in the subjects receiving ARBs was significantly lower than those receiving treatment without ARBs (ARBs vs controls 3,082 vs 5,985, p <0.001). After adjusting for age, gender, co-morbidities, and medications for hypertension control, ARB use was found to be independently associated with a decreased risk for cancer occurrence (hazard ratio 0.66, 95% confidence interval 0.63 to 0.68, p <0.001). In conclusion, long-term use of ARBs is associated with a lower incidence of cancer occurrence, thereby suggesting that ARBs may prevent cancer development.

The potential interaction between clopidogrel and proton pump inhibitors: a systematic review

BACKGROUND

Recently, several publications have investigated a possible drug interaction between clopidogrel and proton pump inhibitors (PPIs), and regulatory agencies have issued warnings despite discordant study results. In an attempt to clarify the situation, we performed a systematic review with a critical analysis of study methodologies to determine whether varying study quality (that is, bias) could explain the discordant results.

METHODS

A systematic review of all studies reporting clinical outcomes was performed using an electronic literature search of the MEDLINE and EMBASE databases, abstracts from the major cardiology conferences and a hand-search of bibliographies from identified articles. Each study was evaluated for its risk of bias according to a prespecified quality measure scale.

RESULTS

A total of 18 studies were identified. Ten of 13 studies judged to be of low scientific quality reported a statistically positive interaction between clopidogrel and the general class of PPIs, and each concluded this was likely a clinically meaningful effect. None of the five studies judged to be of moderate or high quality reported a statistically significant association. Multiple sources of heterogeneity (that is, different populations, outcomes assessed, drug exposure methods and study quality) prevented a formal quantitative analysis of all studies. An increased risk of bias was observed in the positive studies, resulting in an inverse correlation between study quality and a reported statistically positive interaction (10/13 versus 0/5; P = p = 0.007). There was also no clinical evidence for a positive interaction according to specific PPIs.

CONCLUSION

The observed association between clopidogrel and PPIs is found uniquely in studies judged to be of low quality and with an increased risk of bias. High-quality evidence supporting a clinically significant clopidogrel/PPI interaction is presently lacking.