Home  About us  Contact
 

Hoc Subgroup Analysis (hoc + subgroup_analysis)

Distribution by Scientific Domains
Medical Sciences83%

Kinds of Hoc Subgroup Analysis

  • post hoc subgroup analysis
    		•

    Selected Abstracts

    Flaws in the U.S. Food and Drug Administration's Rationale for Supporting the Development and Approval of BiDil as a Treatment for Heart Failure Only in Black Patients

    THE JOURNAL OF LAW, MEDICINE & ETHICS, Issue 3 2008
    George T. H. Ellison
    The U.S. Food and Drug Administration's (FDA) rationale for supporting the development and approval of BiDil (a combination of hydralazine hydrochloride and isosorbide dinitrate; H-I) for heart failure specifically in black patients was based on under-powered, post hoc subgroup analyses of two relatively old trials (V-HeFT I and II), which were further complicated by substantial covariate imbalances between racial groups. Indeed, the only statistically significant difference observed between black and white patients was found without any adjustment for potential confounders in samples that were unlikely to have been adequately randomized. Meanwhile, because the accepted baseline therapy for heart failure has substantially improved since these trials took place, their results cannot be combined with data from the more recent trial (A-HeFT) amongst black patients alone. There is therefore little scientific evidence to support the approval of BiDil only for use in black patients, and the FDA's rationale fails to consider the ethical consequences of recognizing racial categories as valid markers of innate biological difference, and permitting the development of group-specific therapies that are subject to commercial incentives rather than scientific evidence or therapeutic imperatives. This paper reviews the limitations in the scientific evidence used to support the approval of BiDil only for use in black patients; calls for further analysis of the V-HeFT I and II data which might clarify whether responses to H-I vary by race; and evaluates the consequences of commercial incentives to develop racialized medicines. We recommend that the FDA revise the procedures they use to examine applications for race-based therapies to ensure that these are based on robust scientific claims and do not undermine the aims of the 1992 Revitalization Act. [source]

    Publication bias perpetuates use of ineffective drugs in stroke

    INTERNATIONAL JOURNAL OF STROKE, Issue 3 2009
    K. Prasad
    Drugs approved and used for treatment of stroke vary from country to country. This is, at least, partly because of variation in the standards of evidence that is required for approval of drugs across countries. For example, some countries, usually low and middle income ones, approve a drug on the basis of a small positive study or post hoc subgroup analysis in a overall negative study, while others, usually high income countries, require confirmatory or replication studies before approving the same drug. Needless to say that such confirmatory or replication studies need to be published and adequately disseminated as soon as possible so that approval decisions can be revised in the light of additional evidence. However, this does not always happen. The new evidence often remains hidden in the form of nonpublication or abbreviated publication. Sometimes, it is published but with undue delay. What is worrisome is that these problems occur more often when the new evidence does not favor the new drugs than when it favors them, a manifestation of what is called ,publication bias.' This bias is well documented in the stroke research literature (1, 2). [source]

    Efficacy and Safety of a Once-Yearly Intravenous Zoledronic Acid 5 mg for Fracture Prevention in Elderly Postmenopausal Women with Osteoporosis Aged 75 and Older

    JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 2 2010
    Steven Boonen MD
    OBJECTIVES: To determine the efficacy of once-yearly intravenous zoledronic acid (ZOL) 5 mg in reducing risk of clinical vertebral, nonvertebral, and any clinical fractures in elderly osteoporotic postmenopausal women. DESIGN: A post hoc subgroup analysis of pooled data from the Health Outcome and Reduced Incidence with Zoledronic Acid One Yearly (HORIZON) Pivotal Fracture Trial and the HORIZON Recurrent Fracture Trial. SETTING: Multicenter, randomized, double-blind, placebo-controlled trials. PARTICIPANTS: Postmenopausal women (aged ,75) with documented osteoporosis (T -score ,,2.5 at femoral neck or ,1 prevalent vertebral or hip fracture) or a recent hip fracture. INTERVENTION: Patients were randomized to receive an intravenous infusion of ZOL 5 mg (n=1,961) or placebo (n=1,926) at baseline and 12 and 24 months. MEASUREMENTS: Primary endpoints were incidence of clinical vertebral and nonvertebral and any clinical fracture after treatment. RESULTS: At 3 years, incidence of any clinical, clinical vertebral, and nonvertebral fracture were significantly lower in the ZOL group than in the placebo group (10.8% vs 16.6%, 1.1% vs 3.7%, and 9.9% vs 13.7%, respectively) (hazard ratio (HR)=0.65, 95% confidence interval (CI)=0.54,0.78, P<.001; HR=0.34, 95% CI=0.21,0.55, P<.001; and HR=0.73, 95% CI=0.60,0.90, P=.002, respectively). The incidence of hip fracture was lower with ZOL but did not reach statistical significance. The incidence rate of postdose adverse events were higher with ZOL, although the rate of serious adverse events and deaths was comparable between the two groups. CONCLUSION: Once-yearly intravenous ZOL 5 mg was associated with a significant reduction in the risk of new clinical fractures (vertebral and nonvertebral) in elderly postmenopausal women with osteroporosis. [source]

    Latest news and product developments

    PRESCRIBER, Issue 10 2008
    Article first published online: 3 JUN 200
    Glitazones more than double fracture risk An analysis of the UK General Practice Research Database has found that both glitazones increase the risk of fracture more than two-fold (Arch Intern Med 2008;168:820-5). Compared with nonusers, the odds ratio for fracture (mostly hip and wrist) was 2.59 for pioglitazone and 2.38 for rosiglitazone. The risk increased with dose but was unrelated to age and sex. Reduce antipsychotics in dementia patients Antipsychotics should be prescribed for patients with dementia only as a last resort at times of severe distress or critical need, the All-Party Parliamentary Group on Dementia has concluded. Its inquiry (available at www.alzheimers.org.uk) found that antipsychotics are being prescribed for patients with mild behavioural symptoms and for prolonged periods despite the limited benefits they offer and the risk of serious adverse effects such as stroke. Contributory factors include lack of training for staff, inadequate leadership and exclusion of family and friends from decisions about treatment. High-dose atorvastatin in chronic kidney disease High-dose atorvastatin (Lipitor) reduces cardiovascular events in patients with chronic kidney disease (CKD) more than a low dose , despite similar reductions in LDL-C (J Am Coll Cardiol 2008;51:1448-54). A post hoc subgroup analysis of the Treating-to-New-Targets study involving 10 001 patients with CHD, with or without CKD, found that atorvastatin 10 and 80mg per day reduced LDLC and triglycerides to similar levels; there was no change in HDL-C. After a median follow-up of five years, the incidence of cardiovascular events in patients with CKD was 9.3 per cent at 80mg per day and 13.4 per cent at 10mg per day (number needed to treat to prevent one event, NNT, 24). In patients with no CKD, the corresponding figures were 7.9 vs 9.2 per cent (NNT 74). There was no difference in all-cause mortality; adverse events were more frequent at the higher dose. COX-2 NSAIDs not more cost-effective An economic analysis of COX-2 selective NSAIDs has concluded that they are not more cost effective than older agents plus a proton pump inhibitor (PPI) in the treatment of osteoarthritis and rheumatoid arthritis (Health Technology Assessment 2008;12:No. 11). The analysis concluded that selective and nonselective NSAIDs were similarly effective but selective agents were associated with a lower risk of upper GI events and a higher risk of cardiovascular events. However, the available evidence includes only low numbers of events and further studies are needed. Compared with ibuprofen or diclofenac plus a PPI, the COX-2 selective NSAIDs look ,generally unattractive from a cost effectiveness point of view', even in high-risk patients with a history of peptic ulcer. There were insufficient data to allow a reliable comparison within the COX-2s. Naftidrofuryl helps intermittent claudication Naftidrofuryl increases pain-free walking distance (PFWD) in patients with intermittent claudication, a new Cochrane review has shown (Cochrane Database of Systematic Reviews 2008, Issue 2. Art. No.: CD001368. DOI: 10.1002/ 14651858.CD001368.pub3; also see page 49 in this issue). The meta-analysis of six trials involving a total of 1083 patients found that, compared with placebo, naftidrofuryl increased PFWD by over a third with a proportion successfully treated of 20 per cent (NNT 4.5). Coversyl Arginine To clarify any confusion following our recent news item (Perindopril brand switch, 19 April issue, page 12), Servier has asked us to reiterate that the new formulations Coversyl Arginine 2.5, 5 and 10mg are equivalent to 2, 4 and 8mg of the discontinued Coversyl formulation. Coversyl Arginine contains perindopril arginine, a salt that offers greater stability and a longer shelf-life. Prescriptions for the Coversyl brand of perindopril must in future be written as Coversyl Arginine in its revised strengths. Coversyl Plus has also been replaced by Coversyl Arginine Plus and the same revised dosages apply. Generic formulations of perindopril remain unaffected. Copyright © 2008 Wiley Interface Ltd [source]

    Efficacy of Phosphodiesterase Type 5 Inhibitor Treatment in Men with Erectile Dysfunction and Dyslipidemia: A Post Hoc Analysis of the Vardenafil Statin Study

    THE JOURNAL OF SEXUAL MEDICINE, Issue 5 2010
    Martin M. Miner MD
    ABSTRACT Introduction., Dyslipidemia occurs often in subjects with erectile dysfunction (ED), but there is little information about how this condition affects ED treatment responses. Aim., To determine whether low-density lipoprotein cholesterol (LDL-C) levels, total cholesterol (TC)/high-density lipoprotein cholesterol (HDL-C) ratio; or the presence of metabolic syndrome influenced efficacy of vardenafil in men with ED and dyslipidemia. Methods., Post hoc subgroup analysis of a 12-week study of the influence of lipid levels and presence of metabolic syndrome on the efficacy of vardenafil as measured by International Index of Erectile Function-Erectile Function (IIEF-EF) domain score, responses to Sexual Encounter Profile (SEP) SEP2 and SEP3 questions, duration of erection leading to successful intercourse, and erection duration regardless of the answer to SEP3. Lipid values were obtained at study start, after patients had received at least 3 months of therapy with a statin. Main Outcome Measures., Outcomes in subjects with LDL-C <100, ,100 to <130, or ,130 mg/dL [<2.59, ,2.59 to <3.36, or ,3.36 mmol/L]; TC/HDL-C ratio <3.5 vs. ,3.5, and presence or absence of metabolic syndrome. Results., Vardenafil improved all endpoints evaluated compared with placebo in all subgroups, however, nominally significant treatment by subgroup interaction terms did not follow a distinct pattern. Increasing LDL-C (P = 0.033), but not TC/HDL-C ratio or metabolic syndrome, was associated with an increase in treatment response measured by the IIEF-EF domain score. Responses to SEP3 were nominally influenced by LDL-C levels (P = 0.019), but were not significantly influenced by TC/HDL-C ratio, or the metabolic syndrome. Only higher TC/HDL-C ratios (,3.5) were associated with larger treatment differences in duration of erection leading to successful intercourse (P = 0.028). Conclusions., Vardenafil was effective in men with dyslipidemia regardless of LDL-C levels, TC/HDL-C ratio, and/or presence of metabolic syndrome. Despite the known presence of ED and dyslipidemia, other cardiovascular risk factors were apparently not aggressively managed. Miner MM, Barnes A, and Janning S. Efficacy of phosphodiesterase type 5 inhibitor treatment in men with erectile dysfunction and dyslipidemia: A post hoc analysis of the vardenafil statin study. J Sex Med 2010;7:1937,1947. [source]

    Safety and Efficacy of Bivalirudin in High-risk Patients Admitted Through the Emergency Department

    ACADEMIC EMERGENCY MEDICINE, Issue 8 2009
    Chadwick D. Miller MD
    Abstract Objectives:, The objective was to assess the safety and efficacy of bivalirudin monotherapy in patients with high-risk acute coronary syndrome (ACS) presenting to the emergency department (ED). Methods:, Data from the Acute Catheterization and Urgent Intervention Triage StrategY (ACUITY) trial were used to conduct a post hoc subgroup analysis of high-risk ACS patients (cardiac biomarker elevation or ST-segment deviation) who initially presented to the ED. The ACUITY trial randomized patients to receive heparin (unfractionated [UFH] or enoxaparin) plus glycoprotein IIb/IIIa inhibition (GPI), bivalirudin plus GPI, or bivalirudin monotherapy. Endpoints included composite ischemia, major bleeding (not coronary artery bypass graft (CABG) related), and net clinical outcome (major bleeding plus composite ischemia). Results:, Of 13,819 participants in the ACUITY trial, 6,441 presented initially to the ED, met high-risk criteria, and were included in the primary analysis. Bivalirudin alone when compared to heparin plus GPI, after adjusting for covariates, was associated with an improvement in net clinical outcome (12.3% vs. 14.3%, adjusted odds ratio [OR] = 0.81, 95% confidence interval [CI] = 0.66 to 0.99), similar composite ischemia (9.3% vs. 9.1%, adjusted OR = 0.98, 95% CI = 0.77 to 1.24), and less major bleeding (4.0% vs. 6.8%, adjusted OR = 0.57, 95% CI = 0.42 to 0.75). Bivalirudin plus GPI when compared to heparin plus GPI had similar net clinical outcome (13.8% vs. 14.3%, adjusted OR = 0.91, 95% CI = 0.75 to 1.11), composite ischemia (8.8% vs. 9.1%, adjusted OR = 0.87, 95% CI = 0.69 to 1.11), and major bleeding (6.8% vs. 6.8%, adjusted OR = 1.01, 95% CI = 0.79 to 1.30). Conclusions: Bivalirudin monotherapy decreases major bleeding while providing similar protection from ischemic events compared to heparin plus GPI in patients with high-risk ACS admitted through the ED. [source]