Background and aims: Proprotein convertase subtilisin/kexin 9 monoclonal antibodies (PCSK9 mAbs) reduce low-density lipoprotein (LDL-c) with a favourable safety profile. Available data from PCSK9 antibody trials suggest LDL-c reduction is lower in women compared to men. Data in real-world setting is scarce. The aim of this study was to assess sex differences in efficacy and safety of PCSK9 antibodies in clinical care. Methods: All patients starting with evolocumab or alirocumab in our lipid clinic were included in a prospective registry. We collected clinical information, including baseline and follow-up mean LDL-C levels after initiation of PCSK9 mAbs treatment. In addition, side effects and PCSK9 mAbs discontinuation were recorded. Results: We analysed 436 patients (209 women), mean age 58 ± 11 years. Women had higher baseline LDL-c levels compared to men (4.7 ± 1.6 mmol/L vs 4.1 ± 1.4 mmol/L, p < 0.01). PCSK9 mAbs resulted in less relative LDL-c reduction in women compared to men (50% vs 61% p<0.01), but equal absolute LDL-c reduction (respectively 2.3 ± 1.3 mmol/L vs 2.5 ± 1.1 mmol/L, p = 0.087). Women less often reached LDL-c target levels than men (50% vs 72%). No sex differences were observed in reporting of side effects (women 32% vs men 27% p = 0.26) or PCSK9 mAbs discontinuation (women 13% vs men 10%, p = 0.46). Conclusions: In clinical practice, PCSK9 mAbs are less effective in reducing LDL-c levels in women compared to men and equally safe, implying the importance of sex differences in PCSK9 metabolism.</p
