Intima-media thickness in treated and untreated patients with and without familial hypercholesterolemia: A systematic review and meta-analysis.

Familial hypercholesterolemia (FH) is a common genetic disorder of lipoprotein metabolism leading to premature atherosclerosis. From early onset, status and progression of atherosclerosis of the large peripheral arterial walls can be quantified by ultrasound intima-media thickness (IMT) measurements. Here we describe differences in IMT in treated and untreated FH patients versus unaffected controls over a broad age range. We conducted a systematic literature search using MEDLINE, EMBASE and Trials.gov up to April 2020 for studies addressing IMT in FH patients and controls. Our search yielded 558 articles of which 42 (6,143 participants) were included. Meta-analysis showed a mean (95%CI) difference between FH patients vs controls of 0.11 (95%CI 0.06-0.15) mm in carotid IMT (p<0.001), and 0.47 (0.19-0.74) mm in femoral IMT (p <0.001). We found a smaller mean (95%CI) difference in carotid IMT in treated FH patients vs controls: 0.05 (0.03-0.08) mm (p <0.001), than in untreated FH patients vs controls 0.12 (0.03-0.21) mm (p=0.009). When plotted against age, the mean (95%CI) difference in carotid IMT between FH patients vs controls increases with 0.0018 (-0.0007-0.0042) mm/year. This increase was smaller in treated vs untreated FH patients, when compared to controls (0.0023 (0.0021 to 0.0025) mm/year vs 0.0104 (0.0100-0.0108) mm/year, respectively). Our findings suggest that more robust earlier treatment initiation and achieving treatment targets could be beneficial to reduce cardiovascular risk in patients with FH.