Assessing the Impact of Medication Adherence on Long-Term Cardiovascular Outcomes.

BACKGROUND: Although guideline-recommended therapies reduce major adverse cardiovascular events (MACE) in patients after myocardial infarction (MI) or those with atherosclerotic disease (ATH), adherence is poor. OBJECTIVES: The goal of this study was to determine the association between medication adherence levels and long-term MACE in these patients. METHODS: We queried the claims database of a large health insurer for patients hospitalized for MI or with ATH. The primary outcome measure was a composite of all-cause death, MI, stroke, or coronary revascularization. Using proportion of days covered for statins and angiotensin-converting enzyme inhibitors, patients were stratified as fully adherent (≥80%), partially adherent (≥40% to ≤79%), or nonadherent (<40%). Per-patient annual direct medical (ADM) costs were estimated by using unit costs from 2 national files. RESULTS: Data were analyzed for 4,015 post-MI patients and 12,976 patients with ATH. In the post-MI cohort, the fully adherent group had a significantly lower rate of MACE than the nonadherent (18.9% vs. 26.3%; hazard ratio [HR]: 0.73; p = 0.0004) and partially adherent (18.9% vs. 24.7%; HR: 0.81; p = 0.02) groups at 2 years. The fully adherent group had reduced per-patient ADM costs for MI hospitalizations of $369 and $440 compared with the partially adherent and nonadherent groups, respectively. In the ATH cohort, the fully adherent group had a significantly lower rate of MACE than the nonadherent (8.42% vs. 17.17%; HR: 0.56; p < 0.0001) and the partially adherent (8.42% vs. 12.18%; HR: 0.76; p < 0.0001) groups at 2 years. The fully adherent group had reduced per-patient ADM costs for MI hospitalizations of $371 and $907 compared with the partially adherent and nonadherent groups. CONCLUSIONS: Full adherence to guideline-recommended therapies was associated with a lower rate of MACE and cost savings, with a threshold effect at >80% adherence in the post-MI population; at least a 40% level of long-term adherence needs to be maintained to continue to accrue benefit. Novel approaches to improve adherence may significantly reduce cardiovascular events.

A polypill strategy to improve global secondary cardiovascular prevention: from concept to reality.

The prevention of cardiovascular disease (CVD) by using a polypill has gained increasing momentum as a strategy to contain progression of the disease. Since its initial conception just over a decade ago, only a handful of trials have been completed assessing the efficacy and safety of this innovative concept. The results of these trials have supported the viability of the polypill in CVD prevention and management, albeit with a few caveats, essentially related to the lack of evidence on the effect of the polypill to effectively reduce cardiovascular events. The polypill has the potential to control the global health epidemic of CVD by effectively reaching underdeveloped regions of the world, simplifying healthcare delivery, improving cost-effectiveness, increasing medication adherence, and supporting a comprehensive prescription of evidence-based cardioprotective drugs. Major trials underway will provide definitive evidence on the efficacy of the polypill in reducing cardiovascular events in a cost-effective manner. The results of these studies will determine whether a polypill strategy can quell the burgeoning public health challenge of CVD and will potentially provide the evidence to implement an effective, simple, and innovative solution to restrain the global CVD pandemic.

Role of thioredoxins in the response of Saccharomyces cerevisiae to oxidative stress induced by hydroperoxides.

Glutaredoxins and thioredoxins are highly conserved, small, heat-stable oxidoreductases. The yeast Saccharomyces cerevisiae contains two gene pairs encoding cytoplasmic glutaredoxins (GRX1, GRX2) and thioredoxins (TRX1, TRX2), and we have used multiple mutants to determine their roles in mediating resistance to oxidative stress caused by hydroperoxides. Our data indicate that TRX2 plays the predominant role, as mutants lacking TRX2 are hypersensitive, and mutants containing TRX2 are resistant to these oxidants. However, the requirement for TRX2 is only apparent during stationary phase growth, and we present three lines of evidence that the thioredoxin isoenzymes actually have redundant activities as antioxidants. First, the trx1 and trx2 mutants show wild-type resistance to hydroperoxide during exponential phase growth; secondly, overexpression of either TRX1 or TRX2 leads to increased resistance to hydroperoxides; and, thirdly, both Trx1 and Trx2 are equally able to act as cofactors for the thioredoxin peroxidase, Tsa1. The antioxidant activity of thioredoxins is required for both the survival of yeast cells as well as protection against oxidative stress during stationary phase growth, and correlates with an increase in the expression of both TRX1 and TRX2. We show that the requirement for thioredoxins during this growth phase is dependent on their activity as cofactors for the antioxidant enzyme Tsa1, and for regulation of the redox state and protein-bound levels of the low-molecular-weight antioxidant glutathione.

The yeast glutaredoxins are active as glutathione peroxidases.

The yeast Saccharomyces cerevisiae contains two glutaredoxins, encoded by GRX1 and GRX2, which are active as glutathione-dependent oxidoreductases. Our studies show that changes in the levels of glutaredoxins affect the resistance of yeast cells to oxidative stress induced by hydroperoxides. Elevating the gene dosage of GRX1 or GRX2 increases resistance to hydroperoxides including hydrogen peroxide, tert-butyl hydroperoxide and cumene hydroperoxide. The glutaredoxin-mediated resistance to hydroperoxides is dependent on the presence of an intact glutathione system, but does not require the activity of phospholipid hydroperoxide glutathione peroxidases (GPX1-3). Rather, the mechanism appears to be mediated via glutathione conjugation and removal from the cell because it is absent in strains lacking glutathione-S-transferases (GTT1, GTT2) or the GS-X pump (YCF1). We show that the yeast glutaredoxins can directly reduce hydroperoxides in a catalytic manner, using reducing power provided by NADPH, GSH, and glutathione reductase. With cumene hydroperoxide, high pressure liquid chromatography analysis confirmed the formation of the corresponding cumyl alcohol. We propose a model in which the glutathione peroxidase activity of glutaredoxins converts hydroperoxides to their corresponding alcohols; these can then be conjugated to GSH by glutathione-S-transferases and transported into the vacuole by Ycf1.