Improving statin treatment strategies to reduce LDL-cholesterol: factors associated with targets' attainment in subjects with and without type 2 diabetes

Abstract

Background: This cross-sectional study aimed to identify actionable factors to improve LDL-cholesterol target achievement and overcome underuse of lipid-lowering treatments in high- or very-high-cardiovascular risk patients.

Methods: We evaluated healthcare records of 934,332 subjects from North-Italy, including subjects with available lipid profile and being on statin treatments up to December 2018. A 6-month-period defined adherence with proportion-of-days-covered ≥ 80%. Treatment was classified as high-intensity-statin (HIS) + ezetimibe, HIS-alone, non-HIS (NHIS) + ezetimibe or NHIS alone.

Results: We included 27,374 subjects without and 10,459 with diabetes. Among these, 30% and 36% were on secondary prevention, respectively. Adherence was high (78-100%) and increased with treatment intensity and in secondary prevention. Treatment intensity increased in secondary prevention, but only 42% were on HIS. 2019-guidelines LDL-cholesterol targets were achieved in few patients and more often among those with diabetes (7.4% vs. 10.7%, p < 0.001). Patients in secondary prevention had mean LDL-cholesterol levels aligned slightly above 70 mg/dl (range between 68 and 73 mg/dl and between 73 and 85 mg/dl in patients with and without diabetes, respectively). Moreover, the differences in mean LDL-cholesterol levels observed across patients using treatments with well-stablished different LDL-lowering effect were null or much smaller than expected (HIS vs. NHIS from - 3 to - 11%, p < 0.001, HIS + ezetimibe vs. HIS-from - 4 to + 5% n.s.). These findings, given the observational design of the study, might suggest that a "treat to absolute LDL-cholesterol levels" approach (e.g., targeting LDLc of 70 mg/dl) was mainly used by physicians rather than an approach to also achieve the recommended 50% reduction in LDL-cholesterol levels. Our analyses suggested that female sex, younger age, higher HDL-c, and elevated triglycerides are those factors delaying prescription of statin treatments, both in patients with and without diabetes and in those on secondary prevention.

Conclusions: Among patients on statin treatment and high adherence, only a small proportion of patients achieved LDL-cholesterol targets. Late initiation of high-intensity treatments, particularly among those with misperceived low-risk (e.g., female subjects or those with high HDL-cholesterol), appears as pivotal factors needing to be modified to improve CVD prevention.

Keywords: Cardiovascular prevention; Ezetimibe; Gender; HDL; PCSK9; Statins.

Fig. 1

Proportion of patients (in %) on each single molecule and dosage according to presence or absence of diabetes and recorded cardiovascular events. Area under the blue area (i.e. statin alone) is 100%, sum of pink area (i.e., statin + ezetimibe) is 100%, in each of the four panel

Fig. 2

Patients with event achieving guidelines recommended targets. Error Bar represents 95% CI; § for p < 0.001 Diabetes vs. w/o Diabetes at < 55 mg/dl and * for p < 0.001 Diabetes vs. w/o Diabetes at < 70 mg/dl

Fig. 3

Factors associated with LDL-c levels < 70 mg/dl in patients without and with diabetes (model adjusted by age, sex, prior history of cardiovascular events, adherence, statin treatment intensity, HDL-c, triglycerides, eGFR)