The effects of proton pump inhibition on patient-reported severity of dyspepsia when receiving dual anti-platelet therapy with clopidogrel and low-dose aspirin: analysis from the Clopidogrel and the Optimization of Gastrointestinal Events Trial

The Future of Aspirin Therapy in Cardiovascular Disease

Much has been written about the demise of aspirin (ASA) but reports of its death are premature. The drug remains one of the most widely prescribed by physicians worldwide. It is cheap, familiar, and effective for a variety of uses, including in patients with acute or prior myocardial infarction, ischemic stroke, peripheral artery disease, and percutaneous or surgical revascularization procedures, as well as for use for pain and fever relief. Beyond physician prescription or recommendation, over the counter use of ASA is common, including for primary cardiovascular prevention, though this decision really should involve a discussion of risks and benefits with a physician. ASA is an essential member of the duo that makes up dual antiplatelet therapy (a P2Y₁₂ inhibitor plus ASA) and also dual pathway inhibition (vascular dose rivaroxaban plus ASA), and data for both approaches are growing. Furthermore, research is ongoing as to the optimal dosing frequency (once vs twice daily), potentially safer gastrointestinal delivery, and possibly more effective formulations in terms of platelet inhibition. One goal of ASA research is to try to reduce bleeding complications that are a risk with all anti-thrombotic therapies. Although its exact roles will continue to evolve, the future for ASA remains bright.

Aspirin Use in Secondary Cardiovascular Protection and the Development of Aspirin-Associated Erosions and Ulcers

Aspirin for secondary cardiovascular disease prevention is well established, but treatment discontinuation, often because of gastrointestinal mucosal injury or symptoms, can lead to increased risk for cardiovascular events. Proton pump inhibitor therapy is recommended for aspirin-treated patients at gastrointestinal risk. PA32540 [enteric-coated aspirin (EC-ASA) 325 mg + immediate-release omeprazole 40 mg] was compared with EC-ASA 325 mg alone once daily for 6 months in 2 duplicate, randomized double-blind trials in gastrointestinal-risk patients taking aspirin for ≥3 months for secondary prevention. In this post hoc analysis, we determined the prevalence of endoscopic upper gastrointestinal ulcers at screening and whether baseline endoscopic gastric erosions impacted subsequent ulcer development. At the screening endoscopy, 6% of subjects had upper gastrointestinal ulcers (not eligible for randomization) and 40% had gastric erosions. Conditional logistic regression modeling showed that baseline gastric erosions are significantly associated with endoscopic gastric ulcer development (OR = 2.12, 95% confidence interval, 1.26-3.57). In subjects with baseline gastric erosion, 4.2% of PA32540-treated versus 13.0% of EC-ASA-treated subjects (P = 0.001) subsequently developed endoscopic gastric ulcers. These data suggest that gastric injury predisposes to gastric ulcer development when taking EC-ASA, and exposure to immediate-release omeprazole in the presence of aspirin therapy significantly reduces the likelihood of progressing to gastric ulcers.

Pharmacogenomics of proton pump inhibitors

At present, proton pump inhibitors (PPIs), as a class of strong antacid agents, are widely used in the clinical treatment of gastrointestinal diseases. PPIs achieved a strong effect of acid suppression with high specificity and long duration. However, the issue of PPI abuse exists worldwide because of the lack of relevant knowledge. Due to tremendous inter-individual differences in uptake, the clinical application of PPIs appears to be limited. Therefore, rational use of PPIs in daily clinical practice is an important research topic. In addition, PPIs were found with many side effects. CYP2C19, as one of the most important enzymes in cytochrome P450 enzyme family, is responsible for the metabolism of over 10% of drugs. The bioavailability and metabolism of PPIs are mainly affected by drug-metabolizing enzymes CYP2C19 and CYP3A4, which are located in the liver. By suppressing cytochrome P450 isoenzyme, PPIs may affect the metabolism of multiple drugs, thus leading to unwanted side effects in case of combined medication. What's more, the individual difference in PPI administration is derived from distinct molecular mechanisms mediated by CYP3A4 and/or CYP2C19. Non-genetic factors, such as combined medication and food pyramid, also impact on the effectiveness of PPIs. Gene mutations can also alter the enzymatic activity of CY2C19, thereby resulting in different blood concentrations of drugs metabolized by CYP2C19. In conclusion, PPIs have the advantages of safety and effectiveness; however, the problem of drug resistance still exists, which indicates their selective application in clinical practice. In this paper, we review the advances in pharmacogenomics of PPIs, with an aim to provide reference to individualized clinical medication.

Optimal Duration of Dual Antiplatelet Therapy After Percutaneous Coronary Intervention

Dual antiplatelet therapy (DAPT) is an essential component of treatment in patients with coronary artery disease treated with percutaneous coronary intervention (PCI). Recommendations for duration of DAPT after PCI should consider patient-specific risk, clinical presentation, stent characteristics, and procedural factors. Prolonged DAPT results in a reduction of stent thrombosis (ST) and myocardial infarction (MI) at the cost of increased bleeding. Studies of shorter-duration DAPT demonstrate similar mortality, MI, ST, and less bleeding when compared with longer DAPT duration. We review current evidence for strategies of prolonged DAPT and abbreviated DAPT following PCI.

Comparative evaluation of methods approximating drug prescription durations in claims data: modeling, simulation, and application to real data

PURPOSE

The purpose of this study was to compare the predictive accuracy of different methods suggested for approximation of drug prescription durations in claims data.

METHODS

We expanded a well-established modeling and simulation framework to compare approximated drug prescription durations with 'true' (i.e., simulated) durations. Real claims data of persons aged ≥65 years insured by the German nationwide 'Statutory Health Insurance Fund' AOK between 2010 and 2012 provided empiric input parameters that were completed with missing information on actual dosing patterns from an observational cohort. The distinct approximation methods were based on crude measures (one tablet a day), population-averaged measures (defined daily doses), or individually-derived measures (longitudinal coverage approximation of the applied dose, COV). As a proof-of-principle, we assessed the methods' performance to predict the well-characterized bleeding risks of anticoagulant, antiplatelet, and/or non-steroidal anti-inflammatory drugs.

RESULTS

When applied to modeling and simulation data sets, the closest, least biased, and thus most accurate approximation was observed using the COV approximation. In a real-data example, rather similar results to an external reference were obtained for all methods. However, some of the differences between methods were meaningful, and the most reasonable and consistent results were obtained with the COV approach.

CONCLUSION

Based on theoretically most accurate approximations and practically reasonable estimates, the individual COV approach was preferable over the population-averaged defined daily dose technique, although the latter might be justified in certain situations. Advantages of the COV approach are expected to be even bigger for drug therapies with particularly large dosing heterogeneity. Copyright © 2016 John Wiley & Sons, Ltd.

Efficacy and Safety of Proton-Pump Inhibitors in High-Risk Cardiovascular Subsets of the COGENT Trial

BACKGROUND

Proton-pump inhibitors (PPIs) have been demonstrated to reduce rates of gastrointestinal events in patients requiring dual antiplatelet therapy (DAPT). Data are limited regarding the efficacy and safety of PPIs in high-risk cardiovascular subsets after acute coronary syndrome or percutaneous coronary intervention.

METHODS

All patients enrolled in COGENT (Clopidogrel and the Optimization of Gastrointestinal Events Trial) were initiated on DAPT (with aspirin and clopidogrel) for various indications within the prior 21 days. These post hoc analyses of the COGENT trial evaluated the efficacy and safety of omeprazole compared with placebo in subsets of patients requiring DAPT for the 2 most frequent indications: 1) patients undergoing percutaneous coronary intervention (for any indication) within 14 days of randomization (n = 2676; 71.2%); and 2) patients presenting with acute coronary syndrome managed with or without percutaneous coronary intervention (n = 1573; 41.8%). Unadjusted Cox proportional hazards models were used to estimate effect sizes through final follow-up.

RESULTS

Median follow-up duration was 110 days (interquartile range 55-167). In percutaneous coronary intervention-treated patients, omeprazole significantly reduced rates of composite gastrointestinal events at 180 days (1.2% vs 2.7%; hazard ratio [HR] 0.43; 95% confidence interval [CI], 0.22-0.85; P = .02) without increasing composite cardiovascular events (5.4% vs 6.3%; HR 1.00; 95% CI, 0.67-1.50; P = 1.00). Similarly, omeprazole lowered risk of the primary gastrointestinal endpoint at 180 days in patients presenting with acute coronary syndrome (1.1% vs 2.7%; HR 0.37; 95% CI, 0.13-1.01; P = .05) without a significant excess in cardiovascular events (5.6% vs 4.5%; HR 1.40; 95% CI, 0.77-2.53; P = .27).

CONCLUSIONS

PPI therapy attenuates gastrointestinal bleeding risk without significant excess in major cardiovascular events in high-risk cardiovascular subsets, regardless of indication for DAPT. Future studies will be needed to clarify optimal gastroprotective strategies for higher-intensity and longer durations of DAPT.

Proton-Pump Inhibitors Reduce Gastrointestinal Events Regardless of Aspirin Dose in Patients Requiring Dual Antiplatelet Therapy

BACKGROUND

The COGENT (Clopidogrel and the Optimization of Gastrointestinal Events Trial) showed that proton-pump inhibitors (PPIs) safely reduced rates of gastrointestinal (GI) events in patients requiring dual antiplatelet therapy (DAPT). However, utilization of appropriate prophylactic PPI therapy remains suboptimal, especially with low-dose aspirin.

OBJECTIVES

The authors investigated the safety and efficacy of PPI therapy in patients receiving DAPT in low- and high-dose aspirin subsets.

METHODS

Randomized patients with available aspirin dosing information in COGENT (N = 3,752) were divided into "low-dose" (≤ 100 mg) and "high-dose" (>100 mg) aspirin groups. The primary GI and cardiovascular endpoints were composite upper GI events and major adverse cardiac events, respectively. All events were adjudicated by independent, blinded gastroenterologists and cardiologists.

RESULTS

Median duration of follow-up was 110 days. Low-dose aspirin users (n = 2,480; 66.1%) were more likely to be older, female, and have higher rates of peripheral artery disease, prior stroke, and hypertension, whereas high-dose aspirin users (n = 1,272; 33.9%) had higher rates of hyperlipidemia, smoking, a history of percutaneous coronary intervention, and were more than twice as likely to be enrolled from sites within the United States (80.4% vs. 39.8%). High-dose aspirin was associated with similar 180-day Kaplan-Meier estimates of adjudicated composite GI events (1.7% vs. 2.1%; adjusted hazard ratio: 0.88; 95% confidence interval: 0.46 to 1.66) and major adverse cardiac events (4.8% vs. 5.5%; adjusted hazard ratio: 0.73; 95% confidence interval: 0.48 to 1.11) compared with low-dose aspirin. Randomization to PPI therapy reduced 180-day Kaplan-Meier estimates of the primary GI endpoint in low-dose (1.2% vs. 3.1%) and high-dose aspirin subsets (0.9% vs. 2.6%; p for interaction = 0.80), and did not adversely affect the primary cardiovascular endpoint in either group.

CONCLUSIONS

Gastroprotection with PPI therapy should be utilized in appropriately selected patients with coronary artery disease requiring DAPT, even if the patients are on low-dose aspirin. (Clopidogrel and the Optimization of Gastrointestinal Events Trial [COGENT]; NCT00557921).

Functional dyspepsia

PURPOSE OF REVIEW

Structural causes are absent in more than 50% of patients with symptoms referred to the gastroduodenal region when routine diagnostic tests are applied. New knowledge holds the prospect that targeted therapy may more optimally manage subsets of these patients with functional dyspepsia.

RECENT FINDINGS

An understanding of gut-to-brain and brain-to-gut pathways in functional dyspepsia is expanding. Minimal mucosal inflammation with eosinophils (and in some cases mast cells) characterized by ultrastructural changes in the duodenum appears to be present in a substantial subgroup of functional dyspepsia patients as identified now by investigators globally. Although antibiotic therapy targeting Helicobacter pylori appears to be effective in a small proportion of functional dyspepsia patients, eradication therapy may be more effective in functional dyspepsia patients with microscopic duodenal inflammation, a potentially important finding needing to be confirmed. This may suggest that the effects of antibiotics for functional dyspepsia are not simply mediated by the eradication of gastric H. pylori, but have other antibacterial effects (e.g., on the duodenal microbiome). Abnormal visceral sensory function plays a key role not only in the manifestations of functional dyspepsia but also in peptic ulcer disease.

SUMMARY

The pathophysiologic concepts underlying functional dyspepsia and related treatment approaches are shifting from a focus on H. pylori, acid suppression or modulation of motility toward new models. New evidence suggests that minimal duodenal inflammation plays a role in symptom generation in at least a proportion of patients with otherwise unexplained symptoms. This is a paradigm shift and ultimately may change the treatment of many patients with functional gastrointestinal disorders.