VALUE OF PERFECT IMPLEMENTATION: INCREASING ADHERENCE TO CHOLESTEROL LOWERING THERAPIES

Purpose:

Cardiovascular disease (CVD) is the leading cause of death in most countries, and elevated cholesterol levels are among the top risk factors for disease. Treatment with statins was a major breakthrough 30 years ago, and PCSK9 inhibitors may represent a new breakthrough.. The high cost of PCSK9 inhibitors, however, reduces patient access to the drug, and other strategies to prevent CVD are needed. Most statins have lost their patent and are now available at low prices which makes treatment cost-effective in large patient groups. However, adherence to statin treatment is low with adherence rates below 50% less than two years after initiation of therapy.

Our objective was to explore the value of implementing strategies to improve adherence to treatment with cholesterol lowering drugs.

Methods:

We used a previously developed Markov model for CVD in Norway (NorCaD). Based on more than 300 parameter values, the model is comprehensive with 11 different health states including angina and congestive heart failure. The incidence of CVD events is based on Norwegian registries, and data on current adherence is based on data from the Norwegian Prescription Registry.

Based on Monte Carlo simulations, we estimated cost-effectiveness of statin treatment and expected value of perfect implementation (EVPIM), which illustrates the maximum that can be achieved through implementation initiatives. We also calculated the expected value of specific implementation (EVSIM), which illustrates what can be achieved through reaching specific levels of implementation.

Results:

Statins versus no therapy represent a dominant strategy (increase health and decrease cost) for everyone with somewhat elevated risk of CVD aged 40 and above. The discounted incremental  effectiveness ranged  between 0.2 and 0.4 years in different age/risk groups, while lifetime costs were reduced by $5000 to $12000 for statin treatment compared to no medical treatment.

The expected value of perfect implementation of statins (100% lifelong adherence), is $16 billion in a Norwegian population of only 5.2 million. For each percent increase in adherence that can be reached with an implementation initiative, the Norwegian health care system should be willing to pay $329 million, given the currently recommended cost-effectiveness threshold (approximately $80,000 per life year).

Conclusion:

Statin treatment is very cost-effective, but limited by low adherence. Interventions that can increase adherence could be exceedingly costly and still be cost-effective.