When clinical guidelines affect large numbers of individuals or substantial resources, it is important to understand their benefits, harms and costs from a population perspective. Many countries' dyslipidemia guidelines include these perspectives.
To compare the effectiveness and efficiency of the 2003 and 2006 Canadian dyslipidemia guidelines for statin treatment in reducing deaths from coronary artery disease (CAD) in the Canadian population.
The 2003 and 2006 Canadian dyslipidemia guidelines were applied to data from the Canadian Heart Health Survey (weighted sample of 12,300,000 people), which includes information on family history and physical measurements, including fasting lipid profiles. The number of people recommended for statin treatment, the potential number of CAD deaths avoided and the number needed to treat to avoid one CAD death with five years of statin therapy were determined for each guideline.
Compared with the 2003 guidelines, 1.4% fewer people (20 to 74 years of age) are recommended statin treatment, potentially preventing 7% more CAD deaths. The number needed to treat to prevent one CAD death over five years decreased from 172 (2003 guideline) to 147 (2006 guideline).
From a population perspective, the 2006 Canadian dyslipidemia recommendations are an improvement of earlier versions, preventing more CAD events and deaths with fewer statin prescriptions. Despite these improvements, the Canadian dyslipidemia recommendations should explicitly address issues of absolute benefit and cost-effectiveness in future revisions.
Cites: CMAJ. 2005 Apr 12;172(8):1027-3115824409
Cites: Heart. 2005 Dec;91 Suppl 5:v1-5216365341
Cites: BMJ. 2006 Mar 18;332(7542):659-6216543339
Cites: BMJ. 2006 Jun 17;332(7555):141916737980
Cites: Can J Cardiol. 2006 Sep;22(11):913-2716971976
Cites: Lancet. 2007 Jan 20;369(9557):168-917240267
Comment In: Can J Cardiol. 2008 Aug;24(8):62118697284
Purinergic signaling plays an important role in inflammation and vascular integrity, but little is known about purinergic mechanisms during the pathogenesis of atherosclerosis in humans.
The objective of this study is to study markers of purinergic signaling in a cohort of patients with peripheral artery disease.
Plasma ATP and ADP levels and serum nucleoside triphosphate diphosphohydrolase-1 (NTPDase1/CD39) and ecto-5'-nucleotidase/CD73 activities were measured in 226 patients with stable peripheral artery disease admitted for nonurgent invasive imaging and treatment. The major findings were that ATP, ADP, and CD73 values were higher in atherosclerotic patients than in controls without clinically evident peripheral artery disease (P
Logistic regression models are frequently used in cohort studies to determine the association between treatment and dichotomous outcomes in the presence of confounding variables. In a logistic regression model, the association between exposure and outcome is measured using the odds ratio (OR). The OR can be difficult to interpret and only approximates the relative risk (RR) in certain restrictive settings. Several authors have suggested that for dichotomous outcomes, RRs, RR reductions, absolute risk reductions, and the number needed to treat (NNT) are more clinically meaningful measures of treatment effect.
We describe a method for deriving clinically meaningful measures of treatment effect from a logistic regression model. This method involves determining the probability of the outcome if each subject in the cohort was treated and if each subject was untreated. These probabilities are then averaged across the study cohort to determine the average probability of the outcome in the population if all subjects were treated and if they were untreated.
Risk differences, RRs, and NNTs were derived using a logistic regression model.
Clinically meaningful measures of effect can be derived from a logistic regression model in a cohort study. These methods can also be used in randomized controlled trials when logistic regression is used to adjust for possible imbalance in prognostically important baseline covariates.
Therapy for management of acute myocardial infarction (AMI) varies according to patient, prescriber and geographical characteristics.
To describe the in-hospital use of reperfusion therapy for ST elevation MI (STEMI) and discharge use of acetylsalicylic acid, beta-blockers, angiotensin-converting enzyme inhibitors (ACEIs) and statins in patients presenting with either STEMI or non-STEMI in Canada from 1999 to 2002.
Four Canadian registries (FASTRAK II, Canadian Acute Coronary Syndromes, Enhanced Feedback for Effective Cardiac Treatment and Improving Cardiovascular Outcomes in Nova Scotia) were used to identify patients with AMI in Canada and to measure in-hospital reperfusion and medication use. Use rates were compared by age, sex, time period and geographical area, according to available data.
Use rates for reperfusion in STEMI patients ranged from 60% to 70%, primarily representing fibrinolytic therapy. A delay in presentation to hospital after symptom onset represented an impediment to timely therapy, which was particularly pronounced for women and elderly patients. Overall, less than 50% of patients met the door-to-needle target of less than 30 min. Medication use rates at discharge increased from 1999/2000 to 2000/2001 across the different data sources: acetylsalicylic acid, 83% to 88%; beta-blockers, 74% to 89%; ACEIs, 54% to 67%; statins, 41% to 53%; and calcium antagonists, 21% to 32%.
Canadian and provincial rates of use of evidence-based medications for the treatment of AMI have increased over time, although there remains room for improvement. A single, comprehensive data source would supply better insights into the management of AMI in Canada.
Population studies of statin adherence are generally restricted to one to two years of follow-up and do not analyze adherence to other drugs.
To report long-term adherence rates for statins, angiotensin-converting enzyme (ACE) inhibitors and beta-blockers in patients who recently experienced a first cardiovascular event.
Linked administrative databases in the province of Saskatchewan were used in this retrospective cohort study. Eligible patients received a new statin prescription within one year of their first cardiovascular event between 1994 and 2001. Adherence to statins, beta-blockers and ACE inhibitors was assessed from the first statin prescription to a subsequent cardiovascular event.
Of 1221 eligible patients, the proportion of patients adherent to statin medications dropped to 60.3% at one year and 48.8% at five years. The decline in the proportion of adherent patients was most notable during the first two years (100% to 53.7%). Several factors were associated with statin adherence, including age (P = 0.012), number of physician service days (P = 0.037), chronic disease score (P = 0.032), beta-blocker adherence (P
In familial hypercholesterolemia (FH) the level of LDL cholesterol is 2-3 times that of the normal population and leads to accelerated atherosclerosis. Improved care for risk factors has decreased cardiovascular mortality of these patients. We studied subclinical atherosclerotic changes with morphologic and functional aortic magnetic resonance imaging (MRI) in FH patients under the age of 50.39 DNA test-verified heterozygous FH-North Karelia patients, aged 6-48, 28 of them treated with statins, and 25 healthy controls, aged 12 to 50, underwent aortic MRI, carotid ultrasound (US), and risk-factor assessment. No differences in any of the morphologic or functional aortic parameters appeared between patients and controls. Age and gender were independent predictors of the majority of the morphologic and functional measures. Carotid intima-media thickness assessed by US was greater in patients (0.57 mm +/- 0.13 vs. 0.48 +/- 0.13 mm, p = 0.005) as was cholesterol-years score (243 +/- 122 vs. 137 +/- 74, p