The main results derived from the present study are two. Firstly, this investigation demonstrated that in our region from central Catalonia, the constitution of an LU was necessary to respond to referrals from primary care for the study, treatment, and management of lipid disorders.
The other main finding was the poor degree of control, with only 22% of the sample achieving lipid targets despite treatment with high-intensity and high-dose statins (69% and 30%, respectively) and the presence of 51% of modifiable CV factors, in a high and very high CV risk cohort.
Regarding referral rate, lipid profile alterations are the main CV risk factor in our country and their prevalence rises to 49.3% in some series22. Unfortunately, adequate control is achieved in only one-fifth of patients23,24. This situation, partly explained by an inappropriate use of statins25,26 justifies the creation and actualitation of territorial LU.
Our study showed that referral for dyslipidemia from primary care is frequent, 6.2% of derivations (38 patient-years or a ratio of 33.9 x 100000 inhabitants), significantly lower than reported by other authors14,27, but enough to require a weekly monographic unit for outpatient lipid care, based on clinical management tools21. One possible explanation for this low referral rate could be related to the lack of awareness of the existence of the LU, so its promotion should be a priority in this new period, in line with the recommendations of the SEA1.
Concerning lipid control, our results are in the same direction of Froylan D MS study group28 who evaluated 1196 mexican patients with CAD (54 ± 8 median of age, 80.3% men and 2.4 median years of evolution of CAD) and the percentage of LDL under tight control, using American Association of Clinical Endocrinologists Guidelines29 that established lipid goal in below 55 mg/dL, raised the 11.4%. Among our group of 44 patients with FH and very high CV risk (59.5 ± 10.5 median of age, 61.9% men) with the same strict lipid control goal, only 6 patients (13.6% of this group and 5% of the entire sample) achieved such a lower concentration. Closer, in SpAnish Familial hypErcHolEsterolemiA cohoRT (SAFEHEART)30, 4132 patients with FH were evaluated (45.0 (34.0–56.0) median age, 45.5% men and a follow up of 5.1 ± 3.1 years) following the guidelines of European Atherosclerosis Society and American Heart Association from 201631 which established a target of LDL below 70 mg/dL for FH with very high CV risk, detected only 4 patients at inclusion and 13 at the follow up (1.1 and 4.7% of the sample) who reached this goal.
The ezetimibe-statin combination group achieved better results in terms of LDL and had a better percentage of LDL target achievement suggesting a greater reduction in CV risk32. Regarding other CV risk factors, a high prevalence of those modifiable in patients with DLCN ≥ 6 could be translate as a failure of one of the main functions of the LU1. Percentages of 31.5% smoking, 25% obesity and 22.8% hypertension are equivalent or worse than the overall prevalence in Spain22, although this is a population with an increased risk of CAD between 10 and 13-fold4.
A considerable proportion of patients with prediabetes, higher than reported in the general population22, was detected, in relation to the hyperglycemic effect of statins. The highest proportion was identified among those treated with rosuvastatin and those who used statins different than simvastatin or high doses of atorvastatin, unlike other authors33.
Focusing on the CV characterization of patients with FH, in our study we demonstrated a better association between Lp(a) concentrations and CVD than carotid plaques detection by CU. In the same direction we find different risk equations as the Familial Hypercholesterolemia-Risk-Score (FH-Risk-Score)34 or the SAFEHEART Registry (SAFEHEART-RE)35, among others36, which use lipoprotein concentrations but not ultrasound as a parameter to establish risk in this type of patient.
The cross-sectional design of the study, the application of the DLCN according to anamnesis or self-reference of the patients in reference to personal and family history, lack of information on waist circumference, CU or Lp(a) concentrations in some patients and the change in LDL targets over the years were potential limitations of our observational study. Another weakness could be related to the variability in the detection of atheromatous plaques due to the participation of different radiology specialists.
In summary, this study confirmed the need for an LU in our territory based on referral data from primary care, the reported degree of LDL control and the inappropriate proportion of modifiable CV risk factors. The creation and approval of the LU as well as the adoption of new control objectives and monitoring parameters could reduce the high CV risk of this group of patients in the future.