Research
Primary prevention with lipid lowering drugs and long term risk of vascular events in older people: population based cohort study
(Published 19 May 2015)
BMJ 2015;350:h2335

Objective
To determine the association between use of lipid lowering drugs (statin or fibrate) in older people with no known history of vascular events and long term risk of coronary heart disease and stroke

Design Ongoing prospective population based cohort study recruited in 1999-2000, with five face-to-face examinations.

Setting Random sample of community dwelling population aged 65 years and over, living in three French cities (Bordeaux, Dijon, Montpellier).

Participants 7484 men and women (63%) with mean age 73.9 years and no known history of vascular events at entry. Mean follow-up was 9.1 years.

Main outcome measures;
Adjusted hazard ratios of coronary heart disease and stroke in baseline lipid lowering drug users compared with non-users, calculated using multivariable Cox proportional hazard models adjusted for numerous potential confounding factors.
Hazard ratios were estimated for use of any lipid lowering drug and for statin and fibrate separately.

Results
Lipid lowering drug users were at decreased risk of stroke compared with non-users (hazard ratio 0.66, 95% confidence interval 0.49 to 0.90); hazard ratios for stroke were similar for statin (0.68, 0.45 to1.01) and fibrate (0.66, 0.44 to 0.98).
No association was found between lipid lowering drug use and coronary heart disease (hazard ratio 1.12, 0.90 to 1.40).
Analyses stratified by age, sex, body mass index, hypertension, systolic blood pressure, triglyceride concentrations, and propensity score did not show any effect modification by these variables, either for stroke or for coronary heart disease.

Conclusion
In a population based cohort of older people with no history of vascular events, use of statins or fibrates was associated with a 30% decrease in the incidence of stroke.

COMMENTARY;
In high income countries, a growing proportion of vascular events occur in the oldest people.
According to the French national mortality statistics for 2010, people aged 85 years and over accounted for 43% of deaths from coronary heart disease and 49% of deaths from stroke. In contrast, participants in most randomised controlled trials testing cardiovascular drugs are predominantly under the age of 70 years.
Therefore, the benefit of these drugs in the oldest people remains uncertain.
Randomised trials support the use of hydroxymethyl glutaryl coenzyme A reductase inhibitors (statins) for reducing the incidence of major cardiovascular and cerebrovascular events in people with a history of cardiovascular disease, including those aged 65 years and over.
However, evidence of the benefit of statin treatment for primary prevention is limited, especially in older people.
Regarding fibrates, the other main class of lipid lowering drugs, very few trials support their efficacy for the primary prevention of cardiovascular events.

What is already known on this topic
Randomised controlled trials have established the efficacy of lipid lowering drugs for secondary and primary prevention of cardiovascular events (coronary heart disease, stroke, or both) in the population aged 50 to 70 years
In clinical trial participants, the effect of lipid lowering drugs is greater for coronary heart disease than for stroke events and risk reduction is greater for statins than for fibrates
New guidelines do not support lipid lowering treatment in people aged over 75 years without clinical atherosclerotic disease, but lipid lowering drugs are largely used for primary prevention in the older age groups

What this study adds
Use of lipid lowering drugs was associated with a 30% lower risk of stroke (compared with non-users) during a mean follow-up of 9 years in a large population based cohort (mean age 74 years) without known history of vascular disease

Reduction in risk of stroke was similar in statin users and fibrate users
If replicated, the study results suggest that lipid lowering drugs might be considered for the prevention of stroke in older populations

G Mohan.