What is the actual epidemiology of familial hypercholesterolemia in Italy? Evidence from a National Primary Care Database

Background There are some inconsistencies on prevalence estimates of familial hypercholesterolemia (FH) in general population across Europe due to variable application of its diagnostic criteria. We aimed to investigate the FH epidemiology in Italy applying the Dutch Lipid Clinical Network (DLCN) score, and two alternative diagnostic algorithms to a primary care database. Methods We performed a retrospective population-based study using the Health Search IMS Health Longitudinal Patient Database (HSD) and including active (alive and currently registered with their general practitioners (GPs)) patients on December 31, 2014. Cases of FH were identified by applying DLCN score. Two further algorithms, based on either ICD9CM coding for FH or some clinical items adopted by the DLCN, were tested towards DLCN itself as gold standard. Results We estimated a prevalence of 0.01% for "definite" and 0.18% for "definite" plus "probable" cases as per the DLCN. Algorithms 1 and 2 reported a FH prevalence of 0.9 and 0.13%, respectively. Both algorithms resulted in consistent specificity (1: 99.10%; 2: 99.9%) towards DLCN, but Algorithm 2 considerably better identified true positive (sensitivity=85.90%) than Algorithm 1 (sensitivity=10.10%). Conclusion The application of DLCN or valid diagnostic alternatives in the Italian primary care setting provides estimates of FH prevalence consistent with those reported in other screening studies in Caucasian population. These diagnostic criteria should be therefore fostered among GPs. In the perspective of FH new therapeutic options, the epidemiological picture of FH is even more relevant to foresee the costs and to plan affordable reimbursement programs in Italy.