Randomized trials have shown marked reductions in low-density lipoprotein cholesterol (LDL-C), a risk factor for cardiovascular disease (CVD), when evolocumab is administered. We hypothesized that evolocumab added to standard of care (SOC) vs SOC alone is cost-effective in the treatment of patients with heterozygous familial hypercholesterolemia (HeFH) or atherosclerotic CVD (ASCVD) with or without statin intolerance and LDL-C >100 mg/dL. Using a Markov cohort state transition model, primary and recurrent CVD event rates were predicted considering population-specific trial-based mean risk factors and calibrated against observed rates in the real world. The LDL-C-lowering effect from population-specific phase 3 randomized studies for evolocumab was used together with estimated LDL-C-lowering effect on CVD event rates per 38.67-mg/dL LDL-C lowering from a statin-trial meta-analysis. Costs and utilities were included from published sources. Evolocumab treatment was associated with both increased cost and improved quality-adjusted life-years (QALY): HeFH (incremental cost: US$153 289, incremental QALY: 2.02, incremental cost-effectiveness ratio: US$75 863/QALY); ASCVD (US$158 307, 1.12, US$141 699/QALY); and ASCVD with statin intolerance (US$136 903, 1.36, US$100 309/QALY). Evolocumab met both the American College of Cardiology/American Heart Association (ACC/AHA) and World Health Organization (WHO) thresholds in each population evaluated. Sensitivity and scenario analyses confirmed that model results were robust to changes in model parameters. Among patients with HeFH and ASCVD with or without statin intolerance, evolocumab added to SOC may provide a cost-effective treatment option for lowering LDL-C using ACC/AHA intermediate/high value and WHO cost-effectiveness thresholds. More definitive information on the clinical and economic value of evolocumab will be available from the forthcoming CVD outcomes study.

Background

The value of lipoprotein(a) (Lp[a]) for predicting cardiovascular disease (CVD) across low-density lipoprotein cholesterol (LDL-C) is uncertain.

Hypothesis

In older high-risk adults, higher LDL and Lp(a) combined would be associated with higher CVD risk and more healthcare costs.

Methods

We included 3251 high-risk subjects (prior CVD, diabetes, or 10-year Framingham CVD risk >20%) age ≥65 years from the Cardiovascular Health Study and examined the relation of Lp(a) tertiles with incident CVD, coronary heart disease (CHD), and all-cause mortality within LDL-C strata (spanning <70 mg/dL to ≥160 mg/dL). We also examined 1-year all-cause and CVD healthcare costs from Medicare claims.

Results

Over a 22.5-year follow-up, higher Lp(a) levels predicted CVD and total mortality (both standardized hazard ratio [HR]: 1.06, P < 0.01), whereas higher LDL-C levels predicted higher CHD (standardized HR: 1.09, P < 0.01) but lower total mortality (standardized HR: 0.94, P < 0.001). Adjusted HRs in the highest (vs lowest) tertile of Lp(a) level were 1.95 (P = 0.06) for CVD events and 2.68 (P = 0.03) for CHD events when LDL-C was <70 mg/dL. One-year all-cause healthcare costs were increased for Lp(a) ($771 per SD of 56 µg/mL [P = 0.03], $1976 for Lp(a) 25-64 µg/mL vs <25 µg/mL [P = 0.02], and $1648 for Lp(a) ≥65 µg/mL vs <25 µg/mL [P = 0.054]) but not LDL-C.

Conclusions

In older high-risk adults, increased Lp(a) levels were associated with higher CVD risk, especially in those with LDL-C <70 mg/dL, and with higher healthcare costs.

Robust associations between lipoprotein(a) [Lp(a)] and CVD outcomes among general populations have been published in previous studies. However, associations in high risk primary prevention and secondary prevention populations are less well defined. In order to investigate this further, a systematic review was performed including prospective studies, which assessed the relationship between Lp(a) and CVD outcomes using multivariable analyses. Additional information was gathered on Lp(a) assays, multivariable modelling and population characteristics. Literature searches from inception up to December 2015 retrieved 2850 records. From these 60 studies were included. Across 39 primary prevention studies in the general population (hazard ratios ranged from 1.16 to 2.97) and seven high risk primary prevention studies (hazard ratios ranged from 1.01 to 3.7), there was evidence of a statistically significant relationship between increased Lp(a) and an increased risk of future CVD. Results in 14 studies of secondary prevention populations were also suggestive of a modest statistically significant relationship (hazard ratios ranged from 0.75 to 3.7).Therefore current evidence would suggest that increased Lp(a) levels are associated with modest increases in the risk of future CVD events in both general and higher risk populations. However, further studies are required to confirm these findings.