Cost-effectiveness of treatments reducing coronary heart disease mortality in Ireland, 2000 to 2010

A systematic literature review of methods of incorporating mortality in cost-effectiveness analyses of lipid-lowering therapies

AIMS

Cost effectiveness analysis (CEA) is a useful tool for estimating the value of an intervention in relation to alternatives. In cardiovascular disease (CVD), CEA is especially important, given the high economic and clinical burden. One key driver of value is CVD mortality prevention. However, data used to inform CEA parameters can be limited, given the difficulty in demonstrating statistically significant mortality benefit in randomized clinical trials (RCTs), due in part to the frequency of fatal events and limited trial durations. This systematic review identifies and summarizes whether published CVD-related CEAs have incorporated mortality benefits, and the methodology among those that did.

MATERIALS AND METHODS

A systematic literature review was conducted of CEAs of lipid-lowering therapies published between 2000-2017. Health technology assessments (HTA) and full-length manuscripts were included, and sources of mortality data and methods of applying mortality benefits were extracted. Results were summarized as proportions of articles to articulate common practices in CEAs of CVD.

RESULTS

This review identified 100 studies for inclusion, comprising 93 full-length manuscripts and seven HTA reviews. Among these, 99% assumed a mortality benefit in the model. However, 87 of these studies that incorporated mortality differences did so despite the trials used to inform model parameters not demonstrating statistically significant differences in mortality. None of the 12 studies that used statistically significant findings from an individual RCT were based on active control studies. In a sub-group analysis considering the 60 CEAs that incorporated a direct mortality benefit, 48 (80%) did not have RCT evidence for statistically significant benefit in CVD mortality.

LIMITATIONS AND CONCLUSIONS

The finding that few CEA models included mortality inputs from individual RCTs of lipid-lowering therapy may be surprising, as one might expect that treatment efficacy should be based on robust clinical evidence. However, regulatory requirements in CVD-related RCTs often lead to insufficient sample sizes and observation periods for detecting a difference in CVD mortality, which results in the use of intermediate outcomes, composite end-points, or meta-analysis to extrapolate long-term mortality benefit in a lifetime CEA.

Health Benefits and Cost-Effectiveness of Asymptomatic Screening for Hypertension and High Cholesterol and Aspirin Counseling for Primary Prevention

PURPOSE

Our aim was to update estimates of the health and economic impact of clinical services recommended for the primary prevention of cardiovascular disease (CVD) for the comparative rankings of the National Commission on Prevention Priorities, and to explore differences in outcomes by sex and race/ethnicity.

METHODS

We used a single, integrated, microsimulation model to generate comparable results for 3 services recommended by the US Preventive Services Task Force: aspirin counseling for the primary prevention of CVD and colorectal cancer, screening and treatment for lipid disorders (usually high cholesterol), and screening and treatment for hypertension. Analyses compare lifetime outcomes from the societal perspective for a US-representative birth cohort of 100,000 persons with and without access to each clinical preventive service. Primary outcomes are health impact, measured by the net difference in lifetime quality-adjusted life years (QALYs), and cost-effectiveness, measured in incremental cost per QALY or cost savings per person in 2012 dollars. Results are also presented for population subgroups defined by sex and race/ethnicity.

RESULTS

Health impact is highest for hypertension screening and treatment (15,600 QALYs), but is closely followed by cholesterol screening and treatment (14,300 QALYs). Aspirin counseling has a lower health impact (2,200 QALYs) but is found to be cost saving ($31 saved per person). Cost-effectiveness for cholesterol and hypertension screening and treatment is $33,800 per QALY and $48,500 per QALY, respectively. Findings favor hypertension over cholesterol screening and treatment for women, and opportunities to reduce disease burden across all services are greatest for the non-Hispanic black population.

CONCLUSIONS

All 3 CVD preventive services continue to rank highly among other recommended preventive services for US adults, but individual priorities can be tailored in practice by taking a patient's demographic characteristics and clinical objectives into account.

Cost-effectiveness of statin therapy for vascular event prevention in adults with elevated C-reactive protein: implications of JUPITER

OBJECTIVES

High-sensitivity C-reactive protein (hs-CRP) has been explored for use in predicting cardiovascular risk. The recent Justification for the Use of Statins in Primary Prevention: An Intervention Trial Evaluating Rosuvastatin (JUPITER) study found that statin therapy reduced cardiovascular events in those with low-density lipoprotein (LDL) cholesterol levels below current treatment thresholds (≤130 mg/dL, 3.4 = mmol/L), but with elevated hs-CRP levels (≥2.0 mg/L). This study examines the cost-effectiveness of statin treatment for individuals with elevated hs-CRP but normal LDL cholesterol.

METHODS

A Markov decision-analytic model was conducted from the U.S. societal perspective. Data from JUPITER were used to estimate rates of myocardial infarction, angina and stroke. Statin costs were based on generic simvastatin 80 mg, equipotent to the rosuvastatin 20 mg dose used in JUPITER. Primary prevention was the focus and secondary prevention was not modeled explicitly. Quality-adjusted life-years (QALYs) were calculated using nationally representative preference-based utility weights. One-way sensitivity analyses and multivariate probabilistic sensitivity analysis were used to explore uncertainty in model parameters as well as estimate the likelihood of cost-effectiveness when all event rates, costs and utilities were drawn randomly from distributions reflecting uncertainty.

RESULTS

Statin therapy cost $10,889/QALY for vascular event prevention in this population. Results were sensitive to the cost of statin treatment. Based on 10,000 simulations, statin therapy was cost-effective in 99.5% of simulations, using a willingness-to-pay threshold of $20,000/QALY, and 100% of simulations using a threshold of $50,000/QALY.

CONCLUSIONS

Treatment with statins in patients with elevated hs-CRP but normal cholesterol appears to be cost-effective. Limitations of this study include the assumption that an equipotent dose of simvastatin resulted in the same risk reduction as rosuvastatin. Further, post-event states simulated the average experience of a patient. Continued statin use, subsequent events and/or heart failure were not explicitly modeled.