The 2003 Canadian recommendations for dyslipidemia management: revisions are needed

The 2006 Canadian dyslipidemia guidelines will prevent more deaths while treating fewer people--but should they be further modified?

BACKGROUND

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.

OBJECTIVE

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.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

The relationship between physician supply, cardiovascular health service use and cardiac disease burden in Ontario: supply-need mismatch

BACKGROUND

While health service use appears to be positively correlated with resource availability, no study has explored the interactions among health service supply, cardiovascular disease burden and health service use. The objective of the present study was to examine the relationship among cardiovascular evaluation and management intensity, physician supply and cardiovascular disease burden in the Canadian population.

METHODS

The present cross-sectional, population-based study consisted of adult residents in Ontario in 2001. Cardiac evaluation and management intensity, the main outcome measure, was measured at the individual level, and consisted of receiving one or more of the following services: noninvasive cardiac testing, coronary angiography and statin use (the latter among individuals 65 years of age and older). Mortality was the secondary outcome measure. Cardiovascular disease burden, and cardiologist and primary care physician supply were measured at the regional (ie, county) level. Analyses were adjusted for age and sex using Poisson regression, accounting for regional clustering.

RESULTS

Regional per capita cardiologist supply varied more than twofold across regions, but was inversely related to the regional cardiovascular disease burden (r=-0.34, P=0.01). Primary care physician supply was relatively evenly distributed across regions. Residents in areas with more cardiologists were more likely to receive some form of cardiac intervention (RR=1.074, 95% CI 1.066 to 1.082 per additional cardiologist per 100,000). Those in areas with more primary care physicians were also more likely to receive noninvasive cardiac testing (RR=1.056, 95% CI 1.051 to 1.061 per six additional primary care physicians per 100,000). However, the intensity of provision of cardiac health services was unrelated to regional cardiovascular disease burden and was not associated with improved survival.

CONCLUSIONS

The mismatch between physician supply and cardiac disease burden may explain why cardiovascular health service use is neither concordant with the cardiovascular disease burden nor associated with mortality in the population. These results underscore the importance of physician service maldistribution and supply-sensitive care on the appropriateness of cardiac health service use.

Clinical and public health assessment of benefits and risks of statins in primary prevention of coronary events: resolved and unresolved issues

Peer-reviewed, evidence-based recommendations for statin use in primary prevention of cardiovascular events are limited. A narrative review of published randomized controlled trials and meta-analyses was conducted to critically appraise the benefits and risks of statins in primary prevention. Statins effectively reduce plasma concentrations of low-density lipoprotein cholesterol, and reduce the risk of cardiovascular events and death. The greatest benefits are observed in high-risk subjects, such as patients with diabetes or hypertension. Serious cardiovascular events should not be included among serious adverse events because they are efficacy outcomes and are dependent on the baseline risk of patients. Rates of specific serious adverse events, such as cancer and rhabdomyolysis, seem to be similar between the statin and control arms of the clinical trials examined. Thus, the benefits of statins in primary prevention outweigh the risks, particularly among high-risk patients. However, the benefit-risk ratio would likely be optimized through interventions designed to increase persistence and adherence in a real-life setting.

Statin use in Canadians: trends, determinants and persistence

BACKGROUND

Regular statin use is an important tool in chronic disease management, lowering cholesterol levels and reducing risk of cardiovascular disease (CVD). The objectives of this study are to describe statin use in Canada by comorbidity and lifestyle risk factors, and determine persistence in statin use.

METHODS

The longitudinal National Population Health Survey, 1994-2002, is a random sample of the 1994 Canadian population and five interviews were conducted at two-year intervals. A total of 8,198 respondents, aged 20 in 1994, completed all five interviews. Information collected included demographic variables, medication use, CVD lifestyle risk factors, CVD, diabetes and hypertension.

RESULTS

Age-adjusted rates of statin use increased from 1.6% to 7.8% over the period 1994-2002. Statin use was higher with increasing age, diabetes, BMI, physician visits, and insurance for prescription medication. Although persons with CVD were more likely to take statins than those without, by 2002 still only 32.7% of heart patients were taking statins. Statin use did not increase linearly with increasing numbers of CVD risk factors or comorbidities. Of the 441 persons reporting statin use in 2000, 74.6% were still taking them in 2002. People who completed their high school education were more likely to continue taking statins than those who did not complete high school.

CONCLUSION

While statin use increased over time, was associated with CVD and diabetes, and to a lesser extent with increased BMI, a substantive underuse in high-risk patients remains. Helping high-risk people to increase statin use continues to be a priority for health care professionals.

Canadian Cardiovascular Society position statement--recommendations for the diagnosis and treatment of dyslipidemia and prevention of cardiovascular disease

Since the last publication of the recommendations for the management and treatment of dyslipidemia, new clinical trial data have emerged that support a more vigorous approach to lipid lowering in specific patient groups. The decision was made to update the lipid guidelines in collaboration with the Canadian Cardiovascular Society. A systematic electronic search of medical literature for original research consisting of blinded, randomized controlled trials was performed. Meta-analyses of studies of the efficacy and safety of lipid-lowering therapies, and of the predictive value of established and emerging risk factors were also reviewed. All recommendations are evidence-based, and have been reviewed in detail by primary and secondary review panels. Major changes include a lower low-density lipoprotein cholesterol (LDL-C) treatment target (lower than 2.0 mmol/L) for high-risk patients, a slightly higher intervention point for the initiation of drug therapy in most low-risk individuals (LDL-C of 5.0 mmol/L or a total cholesterol to high-density lipoprotein cholesterol ratio of 6.0) and recommendations regarding additional investigations of potential use in the further evaluation of coronary artery disease risk in subjects in the moderate-risk category.