Benefit of Combination Ezetimibe/Simvastatin Among High-Risk Populations: Lessons from the IMPROVE-IT Trial.

PURPOSE OF REVIEW: The Improved Reduction of Outcomes: Vytorin Efficacy International Trial (IMPROVE-IT) demonstrated the clinical benefit of the combination of ezetimibe-simvastatin compared to placebo-simvastatin following acute coronary syndrome (ACS). This review highlights key findings from this study with particular attention to the practice-changing impact on guidelines for low-density lipoprotein cholesterol (LDL-C) reduction after ACS, especially among high-risk populations. RECENT FINDINGS: Consistent reductions in LDL-C have been reported with newer lipid-lowering therapies (proprotein convertase subtilisin/kexin type 9 inhibitors, cholesterol ester transfer proteins, bempedoic acid) in combination with statin in high-risk subgroups. Since high-risk subgroups remain a focus of guidelines, exploration of high-risk subgroups can help define the optimal use of new therapies. Ezetimibe reduced the LDL-C by 16.7 mg/dL compared to placebo at 1 year, resulting in a significant reduction in the primary composite endpoint (absolute risk difference 2.0%; relative risk difference 6.4%, hazard ratio, 0.936; 95% confidence interval, 0.89 to 0.99; P = 0.016). The benefits achieved with ezetimibe in both LDL-C reduction and the primary clinical composite across 10 pre-specified high-risk subgroups, including the elderly; women; patients with diabetes, prior coronary artery bypass graft, history of stroke, polyvascular disease, low baseline LDL-C, renal dysfunction, prior heart failure, and an elevated TIMI risk score for secondary prevention, were similar or greater than in the corresponding non-high-risk subgroups. Safety events were similar between ezetimibe and placebo across the high-risk subgroups. These data support the addition of ezetimibe to statin therapy in high-risk patients who require additional therapy to lower the LDL-C post-ACS.

Association of Serial High-Sensitivity Cardiac Troponin T With Subsequent Cardiovascular Events in Patients Stabilized After Acute Coronary Syndrome: A Secondary Analysis From IMPROVE-IT.

Importance: Studies have demonstrated an association between single measures of high-sensitivity troponin (hsTn) and future cardiovascular events in patients with chronic coronary syndromes. However, limited data exist regarding the association between changes in serial values of hsTn and subsequent cardiovascular events in this patient population. Objective: To evaluate the association between changes in high-sensitivity troponin T (hsTnT) and subsequent cardiovascular events in patients stabilized after acute coronary syndrome (ACS). Design, Setting, and Participants: This is a secondary analysis from the Improved Reduction of Outcomes: Vytorin Efficacy International Trial (IMPROVE-IT), a randomized clinical trial of ezetimibe vs placebo on a background of simvastatin in 18 144 patients hospitalized for an ACS across 1147 sites in 39 countries. The current biomarker substudy includes the 6035 participants consenting to the biomarker substudy with available hsTnT at months 1 and 4. Data were collected from October 26, 2005, through July 8, 2010, with the database locked October 21, 2014. Data were analyzed from February 28, 2021, through August 14, 2022. Main Outcomes and Measures: The outcomes of interest were cardiovascular death, myocardial infarction (MI), stroke, or hospitalization for heart failure (HHF). Associations of absolute and relative changes in hsTnT between month 1 and month 4 as a function of the starting month 1 hsTnT and the composite outcome were examined using landmark analyses. Results: Of 6035 patients in this analysis (median [IQR] age, 64 [57-71]), 1486 (24.6%) were female; 361 (6.0%) were Asian; 121 were (2.0%) Black; 252 (4.2%) were Spanish descent; 4959 were (82.2%) White; and 342 (5.7%) reported another race (consolidated owing to small numbers), declined to respond, or were not asked to report race owing to regulatory prohibitions. Most patients (4114 [68.2%]) had stable hsTnT values (change <3 ng/L), with 1158 (19.2%) and 763 (12.6%) having changes of 3 to less than 7 ng/L and 7 ng/L or more, respectively. After adjustment for clinical risk factors and stratification by the starting month 1 hsTnT level, an absolute increase in hsTnT of 7 ng/L or more was associated with a more than 3-fold greater risk of the composite outcome (adjusted hazard ratio [aHR], 3.33; 95% CI, 1.99-5.57; P < .001), whereas decreases of 7 ng/L or more were associated with similar to lower risk (aHR, 0.51; 95% CI, 0.26-1.03; P = .06) compared with stable values. There was a stepwise association moving from larger absolute decreases (aHR, 0.51; 95% CI, 0.26-1.03) to larger absolute increases (aHR, 3.33; 95% CI, 1.99-5.57) in hsTnT with future risk of the composite outcome (P trend <.001). A similar association was observed when analyzed on the basis of relative percent and continuous change. Conclusions and Relevance: Among stable patients post-ACS, changes in hsTnT were associated with a gradient of risk of subsequent cardiovascular events across the range of starting hsTnT values. Serial assessment of hsTnT may refine risk stratification with the potential to guide therapy decisions in this patient population. Trial Registration: ClinicalTrials.gov Identifier: NCT00202878.

Cardiovascular Events and Long-Term Risk of Sudden Death Among Stabilized Patients After Acute Coronary Syndrome: Insights From IMPROVE-IT.

Background Unlike patients with low ejection fraction after an acute coronary syndrome (ACS), little is known about the long-term incidence and influence of cardiovascular events before sudden death among stabilized patients after ACS. Methods and Results A total of 18 144 patients stabilized within 10 days after ACS in IMPROVE-IT (Improved Reduction of Outcomes: Vytorin Efficacy International Trial) were studied. Cumulative incidence rates (IRs) and IRs per 100 patient-years of sudden death were calculated. Using Cox proportional hazards, the association of ≥1 additional postrandomization cardiovascular events (myocardial infarction, stroke, and hospitalization for unstable angina or heart failure) with sudden death was examined. Early (≤1 year after ACS) and late sudden deaths (>1 year) were compared. Of 2446 total deaths, 402 (16%) were sudden. The median time to sudden death was 2.7 years, with 109 early and 293 late sudden deaths. The cumulative IR was 2.47% (95% CI, 2.23%-2.73%) at 7 years of follow-up. The risk of sudden death following a postrandomization cardiovascular event (150/402 [37%] sudden deaths; median 1.4 years) was greater (IR/100 patient-years, 1.45 [95% CI, 1.23-1.69]) than the risk with no postrandomization cardiovascular event (IR/100 patient-years, 0.27 [95% CI, 0.24-0.30]). Postrandomization myocardial infarction (hazard ratio [HR], 3.64 [95% CI, 2.85-4.66]) and heart failure (HR, 4.55 [95% CI, 3.33-6.22]) significantly increased future risk of sudden death. Conclusions Patients stabilized within 10 days of an ACS remain at long-term risk of sudden death with the greatest risk in those with an additional cardiovascular event. These results refine the long-term risk and risk effectors of sudden death, which may help clinicians identify opportunities to improve care. Registration: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00202878.

Similar major cardiovascular outcomes between pure statin and ezetimibe-statin in comparable intensity for type 2 diabetes with extremely atherosclerotic risks.

Atorvastatin 40 mg (ATOR 40) and ezetimibe 10 mg/simvastatin 20 mg (EZ-SIM 20) have similar reductions of low-density lipoprotein cholesterol (LDL-C) but cardiovascular (CV) outcomes between these two therapies are unclear. Our real-world cohort study is to test the hypothesis of pleiotropic effects of purely higher dose statin on CV outcomes beyond similar reductions of LDL-C, especially for extremely CV risk patients. Between January 1, 2007 and December 31, 2013, a total of 3,372 patients with type 2 diabetes mellitus (T2DM) admitted due to acute coronary syndrome (ACS) or acute ischemic stroke (AIS) were selected as the study cohort from the Taiwan National Health Insurance Research Database. Clinical outcomes were evaluated by ATOR 40 group (n = 1686) matched with EZ-SIM 20 group (n = 1686). Primary composite outcome includes CV death, non-fatal myocardial infarction, and non-fatal stroke. Secondary composite outcome includes hospitalization for unstable angina (HUA), percutaneous coronary intervention (PCI), and coronary artery bypass grafting (CABG). With a mean follow-up of 2.4 years, no significant difference of primary composite outcome was observed between ATOR 40 and EZ-SIM 20 groups (subdistribution hazard ratio [SHR], 1.09; 95% confidence interval [CI], 0.95-1.25). Nevertheless, ATOR 40 group had lower risks of HUA (SHR, 0.50; 95% CI, 0.35-0.72), PCI (SHR, 0.82; 95% CI, 0.69-0.97) and CABG (SHR, 0.62; 95% CI, 0.40-0.97) than EZ-SIM 20 group. For T2DM patients after ACS or AIS, ATOR 40 and EZ-SIM 20 had similar major CV outcomes, which still supported the main driver for CV risk reductions is LDL-C lowering.

Statin/ezetimibe combination therapy vs statin monotherapy for carotid atherosclerotic plaque inflammation.

ABSTRACT: It remains uncertain whether statin/ezetimibe combination therapy serves as a useful and equivalent alternative to statin monotherapy for reducing atherosclerotic plaque inflammation. The aim of the present study was to compare the effects of statin/ezetimibe combination therapy and statin monotherapy on carotid atherosclerotic plaque inflammation using 18F-fluorodeoxyglucose (18FDG) positron emission tomography (PET)/computed tomography (CT) imaging. Data were pooled from 2 clinical trials that used serial 18FDG PET/CT examination to investigate the effects of cholesterol-lowering therapy on carotid atherosclerotic plaque inflammation. The primary outcome was the percent change in the target-to-background ratio (TBR) of the index vessel in the most diseased segment (MDS) at 6-month follow-up. Baseline characteristics were largely similar between the 2 groups. At the 6-month follow-up, the MDS TBR of the index vessel significantly decreased in both groups. The percent change in the MDS TBR of the index vessel (primary outcome) did not differ significantly between the 2 groups (-8.41 ±â€Š15.9% vs -8.08 ±â€Š17.0%, respectively, P = .936). Likewise, the percent change in the whole vessel TBR of the index vessel did not differ significantly between the 2 groups. There were significant decreases in total and LDL cholesterol levels in both groups at follow-up (P < .001). There were no significant correlations between the percent changes in MDS TBR of the index vessel, changes in the lipid, and high-sensitive C-reactive protein levels. The reduction in carotid atherosclerotic plaque inflammation by statin/ezetimibe combination therapy was equivalent to that by the statin monotherapy.

Aortic valvular stenosis: Novel therapeutic strategies.

BACKGROUND: Aortic stenosis (AS) prevalence is estimated to reach 4.5 million cases worldwide by the year 2030. AS is a progressive disease without a pharmacological treatment. In the current review, we aimed to investigate novel therapeutic approaches for non-surgical AS treatment, at least in patients with mild-to-moderate AS. MATERIALS AND METHODS: The most recent and relevant papers concerned with novel molecular pathways that have potential as therapeutic targets in AS were selected from searches of PubMed and Web of Science up to February 2021. RESULTS: Growing evidence indicates that therapies using proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, simvastatin/ezetimibe combination, cholesteryl ester transfer protein inhibitors or antisense oligonucleotides targeting apolipoprotein(a) reduce the risk of AS progression. It has been shown that enhanced valvular lipid oxidation may drive AS development by leading to the activation of valvular interstitial cells (VICs), the most abundant valvular cells having a major contribution to valve calcification. Since VICs are able to release pro-inflammatory cytokines, clotting factors and proteins involved in calcification, strategies targeting these cell activations seem promising as therapeutic interventions. Recently, non-vitamin K antagonist oral anticoagulants (NOACs) have been shown to inhibit activation of VICs. CONCLUSION: Several novel molecular pathways of AS development have been identified over the past few years. Therapies using PCSK9 inhibitors, simvastatin/ezetimibe combination, lipoprotein(a)-lowering therapy are highly promising candidates as therapeutics in the prevention of mild AS progression, while preclinical studies show that NOACs may inhibit valvular inflammation and coagulation activation and slower the rate of AS progression.

Frequency and Impact of Hyponatremia on All-Cause Mortality in Patients With Aortic Stenosis.

Asymptomatic aortic stenosis (AS) is a frequent condition that may cause hyponatremia due to neurohumoral activation. We examined if hyponatremia heralds poor prognosis in patients with asymptomatic AS, and whether AS in itself is associated with increased risk of hyponatremia. The study question was investigated in 1,677 individuals that had and annual plasma sodium measurements in the SEAS (Simvastatin and Ezetimibe in AS) trial; 1,873 asymptomatic patients with mild-moderate AS (maximal transaortic velocity 2.5 to 4.0 m/s) randomized to simvastatin/ezetimibe combination versus placebo. All-cause mortality was the primary endpoint and incident hyponatremia (P-Na+ <137 mmol/L) a secondary outcome. At baseline, 4% (n = 67) had hyponatremia. After a median follow-up of 4.3 (interquartile range 4.1 to 4.6) years, 140 (9%) of those with initial normonatremia had developed hyponatremia, and 174 (10%) had died. In multiple regression Cox models, both baseline hyponatremia (hazard ratio [HR] 2.1, [95% confidence interval 1.1 to 3.8]) and incident hyponatremia (HR 1.9, [95% confidence interval 1.0 to 3.4], both p ≤ .03) was associated with higher all-cause mortality as compared with normonatremia. This association persisted after adjustment for diuretics as a time-varying covariate. Higher N-terminal pro b-type natriuretic peptide levels and lower sodium levels at baseline was associated with higher risk of incident hyponatremia. Conversely, assignment to simvastatin/ezetimibe protected against incident hyponatremia. In conclusion, both prevalent and incident hyponatremia associate with increased mortality in patients with AS. The prevalence of hyponatremia is around 4% and the incidence about 2% per year, which is comparable to that of older adults without AS.

Cholesterol induced heart valve inflammation and injury: efficacy of cholesterol lowering treatment.

BACKGROUND: Heart valves often undergo a degenerative process leading to mechanical dysfunction that requires valve replacement. This process has been compared with atherosclerosis because of shared pathology and risk factors. In this study, we aimed to elucidate the role of inflammation triggered by cholesterol infiltration and cholesterol crystals formation causing mechanical and biochemical injury in heart valves. METHODS: Human and atherosclerotic rabbit heart valves were evaluated. New Zealand White male rabbits were fed an enriched cholesterol diet alone or with simvastatin and ezetimibe simultaneous or after 6 months of initiating cholesterol diet. Inflammation was measured using C-reactive protein (CRP) and RAM 11 of tissue macrophage content. Cholesterol crystal presence and content in valves was evaluated using scanning electron microscopy. RESULTS: Cholesterol diet alone induced cholesterol infiltration of valves with associated increased inflammation. Tissue cholesterol, CRP levels and RAM 11 were significantly lower in simvastatin and ezetimibe rabbit groups compared with cholesterol diet alone. However, the treatment was effective only when initiated with a cholesterol diet but not after lipid infiltration in valves. Aortic valve cholesterol content was significantly greater than all other cardiac valves. Extensive amounts of cholesterol crystals were noted in rabbit valves on cholesterol diet and in diseased human valves. CONCLUSIONS: Prevention of valve infiltration with cholesterol and reduced inflammation by simvastatin and ezetimibe was effective only when given during the initiation of high cholesterol diet but was not effective when given following infiltration of cholesterol into the valve matrix.

Apolipoprotein B, Triglyceride-Rich Lipoproteins, and Risk of Cardiovascular Events in Persons with CKD.

BACKGROUND AND OBJECTIVES: Triglyceride-rich lipoproteins may contribute to the high cardiovascular risk of patients with CKD. This study evaluated associations of apo-B and markers of triglyceride-rich lipoproteins with cardiovascular events in people with CKD. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Analyses were conducted in 9270 participants with CKD in the Study of Heart and Renal Protection (SHARP): 6245 not on dialysis (mean eGFR 26.5 ml/min per 1.73 m2), and 3025 on dialysis when recruited. Cox regression methods were used to evaluate associations of lipids with incident atherosclerotic and nonatherosclerotic vascular events, adjusting for demographics and clinical characteristics. Hazard ratios (HRs) were calculated per 1 SD higher level for apo-B, HDL cholesterol, LDL cholesterol, triglyceride-rich lipoprotein cholesterol (i.e., total cholesterol minus LDL cholesterol minus HDL cholesterol), non-HDL cholesterol, log triglyceride, and log ratio of triglyceride to HDL cholesterol. RESULTS: During a median follow-up of 4.9 years (interquartile range, 4.0-5.5 years), 1406 participants experienced at least one atherosclerotic vascular event. In multivariable adjusted models, positive associations with atherosclerotic vascular events were observed for apo-B (HR per 1 SD, 1.19; 95% confidence interval, 1.12 to 1.27), triglycerides (1.06; 1.00 to 1.13), the ratio of triglyceride to HDL cholesterol (1.10; 1.03 to 1.18), and triglyceride-rich lipoprotein cholesterol (1.14; 1.05 to 1.25). By contrast, inverse associations with nonatherosclerotic vascular events were observed for each of these lipid markers: apo-B (HR per 1 SD, 0.92; 0.85 to 0.98), triglycerides (0.86; 0.81 to 0.92), the ratio of triglyceride to HDL cholesterol (0.88; 0.82 to 0.94), and triglyceride-rich lipoprotein cholesterol (0.85; 0.77 to 0.94). CONCLUSIONS: Higher apo-B, triglycerides, ratio of triglyceride to HDL cholesterol, and triglyceride-rich lipoprotein cholesterol concentrations were associated with increased risk of atherosclerotic vascular events in CKD. Reducing triglyceride-rich lipoproteins using novel therapeutic agents could potentially lower the risk of atherosclerotic cardiovascular disease risk in the CKD population.

Effects of ezetimibe/simvastatin 10/10 mg versus Rosuvastatin 10 mg on carotid atherosclerotic plaque inflammation.

BACKGROUND: Using 18F-fluorodeoxyglucose (18FDG) positron emission tomography-computed tomography (PET/CT) imaging, we examined the effects of ezetimibe/simvastatin 10/10 mg versus rosuvastatin 10 mg on carotid atherosclerotic plaque inflammation. Whether the combination therapy of ezetimibe with low-dose statin is as effective as potent statin monotherapy in attenuating carotid atherosclerotic plaque inflammation remains unclear. METHODS: In this 2-by-2 factorial trial, 50 patients with 18FDG uptake (target-to-background ratio [TBR] ≥1.6) in the carotid artery and acute coronary syndrome were randomized to receive either simvastatin/ezetimibe 10/10 mg or rosuvastatin 10 mg. 18FDG PET/CT examinations were performed at baseline and at 6 months. The percent change in the TBR of the index vessel at the most diseased segment (MDS) was the primary endpoint. RESULTS: Baseline characteristics of the two groups were largely similar. At 6-month follow-up, the MDS TBR of the index vessel and aorta significantly decreased in ezetimibe/simvastatin group and tended to decrease in rosuvastatin group. However, the percent change in the MDS TBR of the index vessel was similar between the 2 groups (- 10.22 ± 17.49% vs. -5.84 ± 15.78%, respectively, p = 0.357), as was the percent change in the whole vessel TBR of the index vessel. Likewise, the changes in the MDS TBR or whole vessel TBR of the aorta were similar in both groups. Total cholesterol and low-density lipoprotein cholesterol levels improved to a similar degree in both groups. CONCLUSION: Treatment with ezetimibe/simvastatin versus rosuvastatin resulted in a similar improvement of carotid atherosclerotic plaque inflammation, suggesting their equivalent anti-inflammatory effects. TRIAL REGISTRATION: The trial is registered at ClinicalTrials.gov : NCT02378064, 3-4-2015. /IRB No. 2015-0194.

Effect of Simvastatin-Ezetimibe Compared With Simvastatin Monotherapy After Acute Coronary Syndrome Among Patients 75 Years or Older: A Secondary Analysis of a Randomized Clinical Trial.

Importance: Limited evidence is available regarding the benefit and hazard of higher-intensity treatment to lower lipid levels among patients 75 years or older. As a result, guideline recommendations differ for this age group compared with younger patients. Objective: To determine the effect on outcomes and risks of combination ezetimibe and simvastatin compared with simvastatin monotherapy to lower lipid levels among patients 75 years or older with stabilized acute coronary syndrome (ACS). Design, Setting, Participants: In this prespecified secondary analysis of the global, multicenter, prospective clinical randomized Improved Reduction of Outcomes: Vytorin Efficacy International Trial (IMPROVE-IT), outcomes and risks were compared by age among patients 50 years or older after a hospitalization for ACS. Data were collected from October 26, 2005, through July 8, 2010, with the database locked October 21, 2014. Data were analyzed May 29, 2015, through March 13, 2018, using Kaplan-Meier curves and Cox proportional hazards models. Interventions: Double-blind randomized assignment to combined simvastatin and ezetimibe or simvastatin and placebo with follow-up for a median of 6 years (interquartile range, 4.3-7.1 years). Main Outcomes and Measures: The primary composite end point consisted of death due to cardiovascular disease, myocardial infarction (MI), stroke, unstable angina requiring hospitalization, and coronary revascularization after 30 days. Individual adverse ischemic and safety end points and lipid variables were also analyzed. Results: Of 18 144 patients enrolled (13 728 men [75.7%]; mean [SD] age, 64.1 [9.8] years), 5173 (28.5%) were 65 to 74 years old, and 2798 (15.4%) were 75 years or older at randomization. Treatment with simvastatin-ezetimibe resulted in lower rates of the primary end point than simvastatin-placebo, including 0.9% for patients younger than 65 years (HR, 0.97; 95% CI, 0.90-1.05) and 0.8% for patients 65 to 74 years of age (hazard ratio [HR], 0.96; 95% CI, 0.87-1.06), with the greatest absolute risk reduction of 8.7% for patients 75 years or older (HR, 0.80; 95% CI, 0.70-0.90) (P = .02 for interaction). The rate of adverse events did not increase with simvastatin-ezetimibe vs simvastatin-placebo among younger or older patients. Conclusions and Relevance: In IMPROVE-IT, patients hospitalized for ACS derived benefit from higher-intensity therapy to lower lipid levels with simvastatin-ezetimibe compared with simvastatin monotherapy, with the greatest absolute risk reduction among patients 75 years or older. Addition of ezetimibe to simvastatin was not associated with any significant increase in safety issues among older patients. These results may have implications for guideline recommendations regarding lowering of lipid levels in the elderly. Trial Registration: ClinicalTrials.gov identifier: NCT00202878.

Patient Phenotypes, Cardiovascular Risk, and Ezetimibe Treatment in Patients After Acute Coronary Syndromes (from IMPROVE-IT).

Risk prediction following acute coronary syndrome (ACS) remains challenging. Data-driven machine-learning algorithms can potentially identify patients at high risk of clinical events. The Improved Reduction of Outcomes: Vytorin Efficacy International Trial randomized 18,144 post-ACS patients to ezetimibe + simvastatin or placebo + simvastatin. We performed hierarchical cluster analysis to identify patients at high risk of adverse events. Associations between clusters and outcomes were assessed using Cox proportional hazards models. The primary outcome was cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, unstable angina hospitalization, or coronary revascularization ≥30 days after randomization. We evaluated ezetimibe's impact on outcomes across clusters and the ability of the cluster analysis to discriminate for outcomes compared with the Global Registry of Acute Coronary Events (GRACE) score. Five clusters were identified. In cluster 1 (n = 13,252), most patients experienced a non-STEMI (54.8%). Cluster 2 patients (n = 2,719) had the highest incidence of unstable angina (n = 83.3%). Cluster 3 patients (n = 782) all identified as Spanish descent, whereas cluster 4 patients (n = 803) were primarily from South America (56.2%). In cluster 5 (n = 587), all patients had ST elevation. Cluster analysis identified patients at high risk of adverse outcomes (log-rank p <0.0001); Cluster 2 (vs 1) patients had the highest risk of outcomes (hazards ratio 1.33, 95% confidence interval 1.24 to 1.43). Compared with GRACE risk, cluster analysis did not provide superior outcome discrimination. A consistent ezetimibe treatment effect was identified across clusters (interaction p = 0.882). In conclusion, cluster analysis identified significant difference in risk of outcomes across cluster groups. Data-driven strategies to identify patients who may differentially benefit from therapies and for risk stratification require further evaluation.

Medication Discontinuation in the IMPROVE-IT Trial.

BACKGROUND: Although cholesterol-lowering medications can reduce the risk of recurrent cardiovascular events, premature discontinuation limits effectiveness. Discontinuation rates have not been systematically reported for lipid-lowering trials. METHODS AND RESULTS: We evaluated medication discontinuation in IMPROVE-IT (Improved Reduction of Outcomes: Vytorin Efficacy International Trial), which evaluated placebo+simvastatin versus ezetimibe+simvastatin in patients hospitalized with the acute coronary syndrome and followed longitudinally postdischarge. Reasons for discontinuation were evaluated from randomization through study end (median 71.9 [interquartile range 51.8-85.8] months). Kaplan-Meier (KM) discontinuation rates were evaluated at 30 days, 1 year, and through year 7, and compared by treatment arm and region, with Cox proportional hazards modeling used to evaluate predictors of discontinuation. Overall, 46.7% of subjects discontinued study medication (KM rate by study end 50.9% [95% CI, 50.1%-51.7%]). The risk of discontinuation was highest early in the trial but decreased with increasing time, with a terminal KM rate per 100 person-years of 8.4 (8.2-8.6) from years 1 to 7. Discontinuation was higher in the placebo+simvastatin versus ezetimibe+simvastatin arm (KM rate 52.0% versus 49.8%, P=0.049) and was highest in the United States (7-year KM rate 57.4%). In multivariable modeling, smoking, prior revascularization, hypertension, unstable angina, female sex, nonwhite race, and US location were associated with higher discontinuation rates. CONCLUSIONS: Although discontinuation was highest early and stabilized to 8% per year, because of prolonged follow-up, most discontinuation occurred after year 1. Adding ezetimibe to statin therapy did not increase discontinuation risk. Geographic differences and patient-level factors should be considered in trial design and analysis. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov . Unique identifier: NCT00202878.