[50] Instead of demonstrating the continued benefit of statin use during the trial period, these long-term follow-up studies simply demonstrate the continuing advantage of the initial study period for the treatment group. A systematic review by De Vera et al. (2014) found one cohort study that suggested a significant reduction in MI with two years of continuous statin use versus non-continuous use.[51] As outlined above in Scope of this Clinical Practice Guideline, the CPG applies to patients aged 40 years or older. The Work Group noted that evidence is limited to this population, which is why risk calculators require a minimum age of 40 years old. The Work Group understands there are conditions to consider for primary prevention treatment at younger ages, such as severely elevated LDL-C levels that may suggest a familial hyperlipidemic condition. These cases are challenging because there is no direct evidence to guide providers. Thus, shared decision making about the uncertain benefit and risks is the only recommended strategy for patients younger than age 40 who are interested in lipid testing and management. Several observational points can inform this decision but are not sufficient for an evidence-based recommendation. Cardiovascular events and mortality are very low in the under 40 age group, and even observational studies of FH do not suggest treatment is necessary. For example, a French registry of HeFH showed that only 7% had a lifetime history of MI, stroke, or peripheral arterial disease (PAD), which increased to 17% when revascularization was included.[52] Including revascularization, 4% of the registry had a CV event before age 40.[52] A Spanish registry showed that of the 15% of HeFH patients with CV event history, only 1.3% were age 40 or under when they had their first event.