Premature Discontinuation of Dual Antiplatelet Therapy After Coronary Stenting in Veterans: Characteristics and Long-Term Outcomes.

Background Premature discontinuation of dual antiplatelet therapy (DAPT) after percutaneous coronary intervention is related to higher short-term risks of adverse outcomes. Whether these risks persist in the long-term is uncertain. Methods and Results We assessed all patients having percutaneous coronary intervention with coronary second- or first-generation drug-eluting stents in the Veterans Affairs healthcare system between 2006 and 2012 who were free of major ischemic or bleeding events in the first 12 months. The characteristics of patients who stopped DAPT prematurely (1-9 months duration), compared with >9 to 12 months, or extended duration (>12 months) were assessed by odds ratios (ORs) from multivariable logistic models. The risk of adverse clinical outcomes over a mean 5.1 years in patients who stopped DAPT prematurely was assessed by hazard ratios (HRs) and 95% CIs from Cox regression models. A total of 14 239 had second-generation drug-eluting stents, and 8583 had first-generation drug-eluting stents. Premature discontinuation of DAPT was more likely in Black patients (OR, 1.54; 95% CI, 1.40-1.68), patients with greater frailty (OR, 1.04; 95% CI, 1.03-1.05), and patients with higher low-density lipoprotein cholesterol, and less likely in patients on statins (OR, 0.87; 95% CI, 0.80-0.95). Patients who stopped DAPT prematurely had higher long-term risks of death (second-generation drug-eluting stents: HR, 1.35; 95% CI, 1.19-1.56), myocardial infarction (second-generation drug-eluting stents: HR, 1.46; 95% CI, 1.22-1.74), and repeated coronary revascularization (second-generation drug-eluting stents: HR, 1.24; 95% CI, 1.08-1.41). Conclusions Patients who stop DAPT prematurely have features that reflect greater frailty, poorer medication use, and other social factors. They continue to have higher risks of major adverse outcomes over the long-term and may require more intensive surveillance many years after percutaneous coronary intervention.

Design and conduct of a provider survey to determine a clinically persuasive effect size in planning VA Cooperative Study #590 (Li+).

BACKGROUND: The estimation of an effect size is an important step in designing an adequately powered, feasible clinical trial intended to change clinical practice. During the planning phase of VA Cooperative Study #590, "Double-Blind Placebo-Controlled Study of Lithium for Preventing Repeated Suicidal Self-Directed Violence in Patients with Depression or Bipolar Disorder (Li+)," it was not clear what effect size would be considered large enough to influence prescribing behavior among practicing clinicians. METHODS: We conducted an online survey of VA psychiatrists to assess their interest in the study question, their clinical experience with lithium, and their opinion about what suicide reduction rate would change their prescribing habits. The 9-item survey was hosted on SurveyMonkey© and VA psychiatrists were individually emailed an invitation to complete an anonymous online survey. Three email waves were sent over three weeks. RESULTS: Overall, 862 of 2713 VA psychiatrists (response rate = 31.8%) responded to the anonymous survey. 74% of the respondents would refer a patient to the proposed trial, 9% would not, and 17% were unsure. Presented with suicide reduction rates in 10% increments ranging from 10 to 100%, 61% of respondents indicated that they would use lithium if suicide attempts were reduced by at least 40%; 83% would use lithium if it reduced attempts by at least 50%. CONCLUSIONS: Even with the limitations of response bias and the reliability of responses on future prescribing behavior, a survey of potential users of a clinical trial's results offers a convenient, empirical method for determining and justifying clinically relevant effect sizes.