Increased use of acid-suppressing drugs before the occurrence of ischemic events: a potential source of confounding in recent observational studies

Proton pump inhibitors and myocardial infarction: an application of active comparators in a self-controlled case series

BACKGROUND

Previous studies investigating potential cardiovascular adverse events of acid-suppressing drugs are susceptible to protopathic bias and confounding. We aimed to investigate the association between short-term risk of myocardial infarction (MI) and proton pump inhibitors (PPIs) using a self-controlled case series (SCCS) with an active comparator.

METHODS

We conducted a SCCS using a population-wide database from Hong Kong from 2003-2014. Adult with ≥1 outpatient oral PPI prescription or H2 receptor antagonist (H2RA) and MI during the observation period were included. We used both simple ratio and effect modifier approaches to SCCS with active comparators to obtain comparator adjusted estimates.

RESULTS

A total of 2802 and 1889 people with MI who had exposure to PPIs and H2RA were included respectively. We observed a higher risk of MI during days 1-14 following the start of PPI prescription (Incidence rate ratio (IRR): 2.30, 95% confidence interval (CI): 1.76-3.00) versus baseline. Similarly, we observed a higher risk of MI during days 1-14 following the start of H2RA prescription (IRR: 2.46, 95%CI: 1.92-3.16) versus baseline. In the novel SCCS analyses, comparator adjusted estimates were 0.93 (95%CI: 0.57-1.30) and 0.83 (95%CI: 0.58-1.20) during days 1-14 in simple ratio and effect modifier approach, respectively.

CONCLUSIONS

We observed no difference in risk of MI associated with PPIs compared with baseline using H2RA as the active comparator. The elevated risk of MI associated with PPIs is likely due to protopathic bias. More studies are required to explore the feasibility of using active comparators in SCCS to address protopathic bias in addition to confounding.

Proton Pump Inhibitors and Risk of Cardiovascular Disease: A Self-Controlled Case Series Study

INTRODUCTION

We investigated cardiovascular risk due to proton pump inhibitor (PPI) treatment using a self-controlled case series (SCCS) study design, a type of case-only design and an approach to overcome between-person confounding in which individuals act as their own control.

METHODS

We conducted an SCCS study using the National Health Insurance Service-Health Screening cohort in Korea (2002-2015). The cohort included 303,404 adult participants without prior cardiovascular events, who were followed up until December 2015. The primary outcome was a composite of stroke or myocardial infarction. The SCCS method estimated the age-adjusted incidence rate ratio between periods with and without exposure to PPI among patients with primary outcomes. As sensitivity analysis, conventional multivariable Cox proportional regression analyses were performed, which treated the exposure to PPI and H2 blocker during follow-up as time-dependent variables.

RESULTS

In the SCCS design, 10,952 (3.6%) patients with primary outcomes were included. There was no association between PPI exposure and primary outcome (incidence rate ratio 0.98, 95% confidence interval [CI] 0.89-1.09). In the time-dependent Cox regression analyses, both PPI (adjusted hazard ratio 1.36, 95% CI 1.24-1.49) and H2 blocker (adjusted hazard ratio 1.46, 95% CI 1.38-1.55) were associated with an increased risk of the primary outcome.

DISCUSSION

Negative findings in the SCCS design suggest that association between increased cardiovascular risk and PPI, frequently reported in prior observational studies, is likely due to residual confounding related to conditions with PPI treatment, rather than a true relationship.

Association of Proton Pump Inhibitors With Higher Risk of Cardiovascular Disease and Heart Failure

OBJECTIVE

To examine associations of cumulative exposure to proton pump inhibitors (PPIs) with total cardiovascular disease (CVD; composed of stroke, coronary heart disease, and heart failure [HF]) and HF alone in a cohort study of White and African American participants of the Atherosclerosis Risk in Communities (ARIC) study.

METHODS

Use of PPIs was assessed by pill bottle inspection at visit 1 (January 1, 1987 to 1989) and up to 10 additional times before baseline (visit 5; 2011 to 2013). We calculated cumulative exposure to PPIs as days of use from visit 1 to baseline. Participants (n=4346 free of total CVD at visit 5; mean age, 75 years) were observed for incident total CVD and HF events through December 31, 2016. We used Cox regression to measure associations of PPIs with total CVD and HF.

RESULTS

After adjustment for potential confounding variables, participants with a cumulative exposure to PPIs of more than 5.1 years had a 2.02-fold higher risk of total CVD (95% CI, 1.50 to 2.72) and a 2.21-fold higher risk of HF (95% CI, 1.51 to 3.23) than nonusers.

CONCLUSION

Long-term PPI use was associated with twice the risk of total CVD and HF compared with nonusers. Our findings are in concordance with other research and suggest another reason to be cautious of PPI overuse.

Systematic review with meta-analysis: risk of adverse cardiovascular events with proton pump inhibitors independent of clopidogrel

BACKGROUND

Clopidogrel's anti-platelet effects may be attenuated by a pharmacokinetic interaction with co-prescribed proton pump inhibitors, which inhibit oxidative pathways that convert clopidogrel into its active metabolites. Despite this, the impact of PPIs on cardiovascular risk in the absence of clopidogrel is not well defined.

AIM

To report on a systematic review and meta-analysis of the association between PPIs and cardiovascular risk, independent of clopidogrel.

METHODS

The databases of MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Scopus, Web of Science, and ClinicalTrials.gov were systematically searched in October 2017. The primary outcome was association between PPI monotherapy and any adverse cardiovascular event. The secondary outcome was association between proton pump inhibitor monotherapy and acute myocardial infarction. Studies were excluded if they reported or did not adjust for concomitant anti-platelet therapy or involved participants aged less than 18 years.

RESULTS

A total of 22 studies were included in the systematic review. Data from 16 studies were included in the meta-analysis (involving 447 408 participants). Of these, eight were randomised controlled trials, seven were observational studies and one was a retrospective analysis of a randomised controlled trial. An increased risk of any adverse cardiovascular event with PPI monotherapy was observed using pooled data from observational studies (risk ratio 1.25, 95% CI 1.11-1.42, I² 81%, P < 0.001), but not from randomised controlled trials (risk ratio 0.89, 95% CI 0.34-2.33, I² 0%, P = 0.85).

CONCLUSION

There is no clear evidence of an association between PPI monotherapy and increased cardiovascular risk.

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

BACKGROUND AND AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Use of clopidogrel and proton pump inhibitors after a serious acute coronary event: Risk of coronary events and peptic ulcer bleeding

Some pharmacokinetic studies have reported that proton pump inhibitors (PPIs) reduce the activity of clopidogrel, but the results of studies assessing clinical outcomes in patients receiving both drugs are inconsistent. We have therefore carried out a population-based cohort study with nested case–control analysis, in order to evaluate changes in the risk of cardiovascular and peptic ulcer bleeding (PUB) events associated with PPI use in patients receiving clopidogrel. A total of 42,542 patients aged 50–84 years in 2000–2007 who survived an acute coronary event were identified in two UK-based primary care databases (The Health Improvement Network and the General Practice Research Database). Individuals were followed up to identify incident cases of non-fatal myocardial infarction/coronary death (n = 2,546) and PUB (n = 194). Controls were frequency matched to cases by age, sex and calendar year. Compared with PPI non-use, current continuous PPI use was not associated with a significant change in risk of non-fatal myocardial infarction/coronary death among current continuous users of clopidogrel monotherapy (relative risk [RR], 1.06; 95% confidence interval [95% CI], 0.47 to 2.36) or dual antiplatelet therapy (DAT; RR, 0.80; 95% CI, 0.47 to 1.37) who initiated their antiplatelet therapy shortly after their coronary event. Among patients prescribed DAT at the start date, the RR of PUB events associated with current PPI use initiated at the start date was 0.66 (95% CI, 0.27 to 1.60).

Use of proton pump inhibitors and the risk of coronary events in new users of low-dose acetylsalicylic acid in UK primary care

This study evaluated the risk of cardiovascular events associated with the use of proton pump inhibitors (PPIs) in new users of acetylsalicylic acid (ASA) for the secondary prevention of cardiovascular events. Two cohorts of patients aged 50–84 years were identified from UK primary care databases: individuals with a first prescription for ASA (75−300 mg/day) for secondary prevention of cardiovascular events (n = 39,513; CVD cohort) or with a record of hospitalisation for an acute coronary event (n = 42,542; ACS cohort) in 2000–2007. Cases of nonfatal myocardial infarction (MI) and coronary death were identified: 1,222 in the CVD cohort and 604 among new users of ASA in the ACS cohort. A nested case–control analysis estimated the relative risk (RR) of non-fatal MI or coronary death associated with use vs non-use of PPI therapy. Current continuous use of PPI therapy was not associated with a significant increase in RR overall: in the CVD cohort (RR = 1.14 [95% confidence interval = 0.91−1.43]); in the ACS cohort (0.88 [0.66−1.18]); or among current continuous users of ASA as antiplatelet monotherapy (CVD cohort: 1.15 [0.80−1.66]; ACS cohort: 0.73 [0.43−1.23]; pooled analysis of both cohorts: 0.96 [0.62−1.48]). In conclusion, among first-time users of ASA for the secondary prevention of cardiovascular events, PPI use was not shown to be associated with an increased risk of non-fatal MI or coronary death.

How May Proton Pump Inhibitors Impair Cardiovascular Health?

Proton pump inhibitors (PPIs) are among the most widely used drugs worldwide. They are used to treat a number of gastroesophageal disorders and are usually prescribed as a long-term medication or even taken without a prescription. There are a number of clinical studies that associate PPI use with an increased cardiovascular risk. In this article, we review the clinical evidence for adverse cardiovascular effects of PPIs, and we discuss possible biological mechanisms by which PPIs can impair cardiovascular health.

Safety of Concomitant Metformin and Proton Pump Inhibitor Use: A Population Retrospective Cohort Study

PURPOSE

The purpose of this study was to investigate the effect of concomitant use on important clinical outcomes.

METHODS

In this retrospective cohort study, a cohort of new metformin users was identified between 2004 and 2010 and followed up until termination of insurance coverage, December 31, 2010, or the outcomes were reached. The primary outcome was a composite of time to all-cause mortality or hospitalization; our secondary outcome was time to cardiovascular hospitalization. Exposures to metformin, a proton pump inhibitor (PPI), and/or a histamine2 receptor antagonist (H2RA) were compared with a Cox proportional hazards model after adjustment.

FINDINGS

Relative to metformin-only users, metformin and PPI users were at increased risk of the primary outcome (adjusted hazard ratio [HR] = 1.55; 95% CI, 1.46-1.64); metformin and H2RA users also had an elevated risk (adjusted HR = 1.29; 95% CI, 0.97-1.70). Similar patterns were seen with cardiovascular-specific hospitalization. Compared with no drug use, metformin users had an increased risk of the primary outcome, but risk was substantially elevated when patients were taking PPIs or H2RAs, alone or in combination with metformin.

IMPLICATIONS

Concomitant use of metformin and a PPI or metformin and an H2RA were associated with an increased risk of death or hospitalization. This finding suggests that the harm observed may not be due to a specific drug interaction but uncontrolled confounding secondary to an increased risk in those patients using a PPI or H2RA.

Proton pump inhibitor use before percutaneous endoscopic gastrostomy is associated with adverse outcomes

BACKGROUND/AIMS

Knowledge of the risk factors associated with adverse outcomes after percutaneous endoscopic gastrostomy (PEG) may be helpful for developing PEG recommendations. The purpose of this study was to identify the clinical risk factors associated with adverse clinical outcomes after PEG, especially regarding the use of proton pump inhibitors (PPIs).

METHODS

We retrospectively reviewed the data from PEG patients at seven university hospitals between June 2006 and January 2012. All patients were followed up through February 2012 after PEG, and the clinical risk factors for adverse clinical outcomes after PEG were analyzed.

RESULTS

Data from 1,021 PEG patients were analyzed. PPI users were more frequently included in the complication group than the noncomplication group (p=0.040). PEG-related complications (p=0.040) and mortality (p=0.003) were more frequent in the PPI group than in the control group. In the subgroup analysis of complicated PEG cases, infectious complications were more frequently found in the PPI group than in the control group (35.8% vs 27.8%). After adjustment for multiple possible confounding factors, PPI users (odds ratio, 1.531; 95% confidence interval, 1.017 to 2.305) and diabetic patients had increased mortality after PEG.

CONCLUSIONS

PPI use may be associated with adverse outcomes in patients with PEG; however, further prospective studies investigating this issue are warranted.

Risk of uncomplicated peptic ulcer disease in a cohort of new users of low-dose acetylsalicylic acid for secondary prevention of cardiovascular events

BACKGROUND

The aim of this study was to analyse the risk of uncomplicated peptic ulcer disease (PUD) in a cohort of new users of low-dose acetylsalicylic acid (ASA) for secondary prevention of cardiovascular events in a UK primary care setting.

METHODS

New users of low-dose ASA for secondary prevention of cardiovascular events, aged 50-84 years in 2000-2007, were identified from The Health Improvement Network. Among those 38,975 individuals, 309 patients were considered to be incident cases of uncomplicated PUD. Incidence of uncomplicated PUD was calculated and a nested case-control analysis adjusted for potential confounding factors was performed to calculate the odds ratios (ORs) for the association of potential risk factors with uncomplicated PUD.

RESULTS

The crude incidence of uncomplicated PUD was 1.41 per 1000 person-years (95% confidence interval [CI], 1.26-1.58). Individuals with a history of PUD were more likely to develop uncomplicated PUD than those without such a history (hazard ratio [HR], 2.22, 95% CI, 1.60-3.09). In nested case-control analyses, the risk of uncomplicated PUD was associated with current use of non-steroidal anti-inflammatory drugs, oral steroids or acid suppressants. Other risk factors for developing uncomplicated PUD included smoking, stress, depression, anaemia and social deprivation.

CONCLUSION

Our results indicate that several risk factors significantly increase the risk of development of uncomplicated PUD in new users of low-dose ASA. Therefore, physicians should monitor ASA users for gastrointestinal symptoms and signs of ulcer, particularly if they have additional risk factors.

Impact of proton pump inhibitor therapy on the efficacy of clopidogrel in the CAPRIE and CREDO trials

BACKGROUND

Proton pump inhibitors (PPIs) may interfere with the metabolic activation of clopidogrel via inhibition of cytochrome P450 2C19, but the clinical implications remain unclear.

METHODS AND RESULTS

The impact of PPI use on the 1-year primary end point (ischemic stroke, myocardial infarction [MI], or vascular death) in the Clopidogrel versus Aspirin in Patients at Risk of Ischemic Events (CAPRIE) trial and the 28-day (all-cause death, MI, or urgent target vessel revascularization) and 1-year (all-cause death, MI, or stroke) primary end points in the Clopidogrel for Reduction of Events During Observation (CREDO) trial were examined. Clopidogrel appeared to elevate risk for the primary end point in CAPRIE among PPI users (estimated hazard ratio [EHR] 2.66, 95% CI 0.94 to 7.50) while lowering it for non-PPI users (EHR 0.90, 95% CI 0.83 to 0.99, interaction P=0.047). Moreover, PPI use was associated with worse outcomes in patients receiving clopidogrel (EHR 2.39, 95% CI 1.74 to 3.28) but not aspirin (EHR 1.04, 95% CI 0.70 to 1.57, interaction P=0.001). Clopidogrel did not significantly alter risk for the 1-year primary end point in CREDO among PPI users (EHR 0.82, 95% CI 0.48 to 1.40) while lowering it for non-PPI users (EHR 0.71, 95% CI 0.52 to 0.98, interaction P=0.682). Also, PPI use was associated with worse outcomes in both patients receiving clopidogrel (EHR 1.67, 95% CI 1.06 to 2.64) and those receiving placebo (EHR 1.56, 95% CI 1.06 to 2.30, interaction P=0.811).

CONCLUSIONS

In CREDO, the efficacy of clopidogrel was not significantly affected by PPI use. However, in CAPRIE, clopidogrel was beneficial to non-PPI users while apparently harmful to PPI users. Whether this negative interaction is clinically important for patients receiving clopidogrel without aspirin needs further study.

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.

No consistent evidence of differential cardiovascular risk amongst proton-pump inhibitors when used with clopidogrel: meta-analysis

BACKGROUND

Data from pharmacokinetic and pharmacodynamic studies indicate that the adverse clopidogrel-proton pump inhibitor (PPI) interaction may vary between PPIs, with pantoprazole considered relatively less problematic. We aimed to evaluate systematically whether individual PPIs differ in their risk for cardiovascular events when concomitantly administered with clopidogrel.

METHODS

We searched MEDLINE, EMBASE and Cochrane Trials Register up to December 2011 for randomized and non-randomized studies that reported adverse cardiovascular events with exposure to specific PPIs in patients receiving clopidogrel. We performed random effects meta-analysis, and assessed heterogeneity using the I(2) statistic.

RESULTS

A total of 23 studies with 222,311 participants were included. Meta-analysis of major adverse cardiovascular events was mostly limited by moderate-substantial heterogeneity. Pooled estimates of cardiovascular risk were significantly elevated for individual PPIs such as omeprazole, esomeprazole, lansoprazole, and pantoprazole when used with clopidogrel. However, meta-analysis of adverse cardiovascular risk in seven observational studies reporting on PPI therapy alone (without concomitant clopidogrel) also found an elevated odds ratio of 1.28 (95% CI 1.14-1.44) compared with no clopidogrel/no PPI exposure. Meta-analysis of two randomized controlled trials did not show significant adverse cardiovascular effect from omeprazole or esomeprazole.

CONCLUSIONS

The absence of consistent evidence on differential cardiovascular risk amongst PPIs (particularly regarding safety of pantoprazole) is in direct opposition to the platelet function and pharmacokinetic data. Our findings of increased cardiovascular risk with PPIs in the absence of clopidogrel suggest that confounding and bias are strong possibilities. The clinical validity or relevance of the hypothesized PPI-clopidogrel interaction remains questionable.