Journal Club: Niacin in Patients with Low HDL Cholesterol Levels Receiving Intensive Statin Therapy by the AIM-HIGH Investigators

Transcription

1 Journal Club: Niacin in Patients with Low HDL Cholesterol Levels Receiving Intensive Statin Therapy by the AIM-HIGH Investigators Shaikha Al Naimi Doctor of Pharmacy Student College of Pharmacy Qatar University December 14, 2011 The Journal What is the name of the journal? New England Journal of Medicine What is the reputation of the journal? Free access? Impact factor? Medical journal cited more often than any other medical journal, with weekly publications Online, peer-reviewed, and requires subscription Biomedical and clinical research Impact factor: What was the submission date, publication date and the related time interval? Published: November 15, 2011 Submission: May-November

2 Authors Are the authors qualified? Were any authors involved with the study sponsors? Were conflicts of interest declared? Has the senior/coordinating author published other papers in this area? Physicians specialized in cardiology from USA and Canada Some are affiliated to universities Conflict of interest Principal investigator received fees from Abbott, some authors received fees from other companies Principal investigator (William Boden): Several articles in the field of cardiology Funding What was the source and nature of the study funding, if any? Was the study registered? Supported by National Heart, Lung, and Blood Institute and by an unrestricted grant from Abbott Laboratories. Abbott Laboratories donated the extended-release niacin, the matching placebo, and the ezetimibe; Merck donated the simvastatin 2

3 Article Title Is the title appropriate for the content? Is the title unbiased? Does the title adequately describe the trial? Good title: Clear Doesn t give away results But did not describe: Study design, Randomized Controlled Trial (RCT) Study drugs and circumstances (simvastatin, ezetimibe, in patiens with Cornary Heart Disease, CHD) Study duration Introduction Was the introduction structured? Structured and has a logical flow Described: Benefits of strict lipid management Benefits of niacin when added to statins, fibrates, or alone versus placebo Do they describe pertinent research? Described studies focusing on the effect of niacin in CHD patients 3

4 Introduction Rationale: why authors think this study important? No clear rationale, they do not state the gap in research that this study is addressing E.g. There was no study assessing the effect of niacin when added to intensive statin therapy in patients where strict control of lipds is desired Introduction Objective: what are they going to do in this study? Note: 1. They did not state death from cardiovascular disease as the outcome of interest 2. They don t address intensive statin therapy 4

5 Methods What was the general design of the study? Multicenter, double-blind RCT Randomization was performed with the use of a secure internet application Allocation concealment?? Disease definition: Patients with cardiovascular disease defined as documented CHD, PAD, and cerebrovascular or carotid disease, with dyslipidemia+low HDL Subjects provided informed consent The study was approved by ethics committee Methods What were the inclusion/exclusion criteria? Inclusion Males and females, age >= 45, with established vascular disease and dyslipidemia Exclusion Hospitalized 4 weeks before enrollment (ACS, CABG) Stroke (past 8 weeks before enrollment) Run-in period (4-8 weeks) Subjects received simvastatin 40 mg qd + niacin 500 mg qd titrated to 2g qd Subjects tolerating at least a daily niacin dose (1.5g) were randomized 5

6 Methods Treatment (independent variable) Intervention: simvastatin+ niacin (1.5g-2g qd) +/- ezetimibe (10mg qd) What determined the dose for niacin? Control: simvastatin+ placebo (niacin 50 mg) +/- ezetimibe (10mg qd) Why did placebo contain niacin? No information on ensuring the physical form of the niacin/placebo were identical Dose adjusted to maintain LDL mg/dl Adherence assessed by manual pill count Methods Outcome (dependent variable) Primary endpoint: Death from CHD, nonfatal MI, ischemic stroke, hospitalization (>23 hours) for an ACS, or coronary/cerebral revascularization Secondary endpoint composite: Death from CHD, nonfatal MI, ischemic stroke, or hospitalization for a high-risk ACS Tertiary endpoint include: Death from any cause 6

7 Statistics Level of significance Efficacy= Other outcomes=0.05 Calculated study power (85%) for events detected during 4.6 years No information on the calculated sample size to achieve this power analyzed as per intention to treat Subgroup analysis (age, gender, diabetes, metabolic syndrome, prior myocardial infarction, and use of statins at entry) Baseline table did not include: weight, smoking status, and p- value of difference 7

8 Population 4273 began the open-label niacin run-in period 3414 of those patients were randomized Intervention=1718, control=1696 Men=85.2%, white=92.2%, diabetes=33.9% (type 1 or type 2) Generalizability??? Lipid levels HDL increased by 25.0% in intervention group 9.8% in the control group (P<0.001) LDL decreased by 12.0% in the intervention group 5.5% in the control group 8

9 Adherence More subjects in the niacin group discontinued the study drug (p<0.001) Effect on blinding? More subjects in placebo received 80mg simvastatin (24.7% vs. 17.5%, P = 0.02) Study was d/c prematurely (18 months) for lack of efficacy and because more patients had ischemic stroke in the niacin group 9

10 How were the results presented? were complemented by tables However, no randomization figure was presented All patients were accounted for as per the intention to treat Almost all results were presented Not enough information was provided regarding subgroup analysis except for absence of statistical significance 10

11 Discussion Did the authors inappropriately introduce any new data in this section? No new data presented in the discussion Did the authors compare the results of the trial to the resultsof similar previous trials? Discussed previous trials were that assessed the efficacy of niacin Did the authors discuss the limitations of the trial? Limitations: generalizability, placebo, premature d/c Conclusion Were valid conclusions drawn? The conclusion was clear, concise, and based on objectives, and results Proposal for future studies? Benefit of niacin may be studied: Higher-risk cardiac patients Patients with LDL not intensively controlled by a statin 11

12 External Validity In the Coronary Drug Project, niacin 3 grams/day reduced mortality 11% over placebo Niacin can be an option for patients unable to use statins The efficacy of niacin on clinically relevant outcomes seems to be unremarkable in high risk patients already receiving intensive statin therapy Ischemic stroke?? 12

13 Thank you 13