Statin primary prevention effect in FH quantified
medwireNews: A retrospective analysis suggests that statin therapy reduces the risk of a first coronary artery disease (CAD) event or death in patients with familial hypercholesterolaemia (FH) by around 44%.
The study, which is published in the Journal of the American College of Cardiology, took advantage of the FH screening programme in the Netherlands to identify 1559 patients with heterozygous FH who were at least 18 years old and had no pre-existing CAD.
Researcher John Kastelein (Academic Medical Center, Amsterdam) and colleagues say that in the absence of randomised trial data – caused by the inability to ethically randomise FH patients to placebo – their study offers a good estimate of the risk reduction conferred by statin treatment.
And Joshua Knowles (Stanford University, California, USA) writes in an accompanying editorial that “it is hard to imagine a larger study” in this patient population. He adds that the calculated benefit may even be an underestimate, “given the relatively modest use of high-intensity statins”.
Four percent of the patients taking statins received low-intensity treatment, while 61.9% received moderate-intensity treatment (most commonly simvastatin 40 mg) and 34.1% received high-intensity treatment (mostly atorvastatin 40 mg).
The researchers compared outcomes of 1041 patients on statin treatment at baseline or during follow-up with those of 518 patients who never used statins. Knowles says this high percentage (33.2%) of never users “is surprising given the Netherlands’ track record in the excellent care of FH patients.”
Patients who used statins were older than those who did not (49.4 vs 40.5 years) and had a higher average body mass index and levels of low-density lipoprotein cholesterol and triglycerides. The team therefore adjusted for these differences in an analysis that accounted for patients’ probability of receiving statin treatment.
After this adjustment, the CAD and mortality rates were 7.5 versus 11.9 per 1000 patient–years in patients who did and did not take a statin, respectively. And after accounting for changes in exposure to statins and other cardioprotective treatments over time, statin use was associated with a significant 44% reduction in the risk of CAD and all-cause mortality.
Knowles calculates that this equates to a number needed to treat (NNT) of 222 patients for 1 year to prevent one death. He calls this “remarkable”, saying it “far outstrips” the NNT for primary prevention with statins in non-FH patients and even bests the NNT for secondary prevention.
“The evidence is now overwhelming that FH is highly morbid yet underappreciated, underdiagnosed, and undertreated”, he writes. “The terrible irony, strongly emphasized by this study, is that, if identified early enough and treated appropriately, the morbidity and mortality of FH can be markedly if not totally ameliorated.”
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