ATLANTA — Patients with epilepsy who were treated with valproate had a markedly lower risk of acute MI than the general Danish population in a large case-control study.
This is a particularly intriguing observation in light of a recent report that a diagnosis of epilepsy was associated with nearly a fivefold increased risk of MI during longitudinal follow-up after adjustment for age, gender, and education (Brain 2009;132:2798–804).
The implication of the Danish study is that valproate is an especially attractive antiepileptic therapy, particularly in patients with high levels of the standard cardiovascular risk factors, according to Dr. Jonas B. Olesen of Gentofte University Hospital, Copenhagen.
At the annual scientific session of the American College of Cardiology, Dr. Olesen reported on 9,273 patients with epilepsy who started taking valproate during 1997–2006. Each subject was matched by age and gender with 10 controls.
In a Cox proportional-hazards analysis, valproate-treated epileptic patients had a 20% lower relative risk of MI during follow-up than did controls, but a 46% increased risk of all-cause mortality.
However, upon more extensive adjustment for prior stroke or MI, Charlson Comorbidity Index score, concomitant medications, and socioeconomic status, both groups had similar risk of all-cause mortality. Moreover, this adjustment for background comorbidity and other potential confounders also had the effect of magnifying the apparent impact of valproate on MI risk reduction.
Dr. Olesen indicated that he has no relevant financial relationships.