Former U.S. surgeon general C. Everett Koop said once that "drugs don't work in patients who don't take them".

Studies show that approximately 40% to 60% of patients do not take medications as prescribed. These patients put themselves at the risk for serious negative health outcomes.

One reason why patients do not adhere to medication regimens is the cost of the medications. Health insurance plans that require high deductibles can reduce medication adherence because they put additional financial burdens on patients.

A new study compared medication adherence in patients that have a typical health insurance plan with those who have a “Consumer-Driven Health Plan” (CDHP), which have a higher deductible (around $3000-$4000). In a typical CDHP, the patient has a personal care account where he/she receives an annual allocation of money. The money can be used only to pay for medical services in a specific year, and unused funds can be rolled over to the next year. If the account runs out of money before the end of the year, the patients is financially responsible for the services until a deductible is met. After the deductible is met, the patient is partially financially responsible for the services until an annual out-of pocket maximum is met.

When it comes to paying for prescriptions, CDHPs are very different from traditional health insurance (managed care) plans. Patients who have CDHPs pay the full amount for which the insurer has contracted with the pharmacy until they have satisfied the deductible. Once the deductible is satisfied, they are responsible for a copayment. In traditional plans, patients are only responsible for copayments regardless of whether the deductible is satisfied.

The study used two years of medication claims data from 80 employers, and compared patients enrolled in CDHPs with those enrolled in a traditional plan for eight types of medications: asthma, cardiac, diabetes, epilepsy, hypertension, cholesterol, rheumatoid arthritis, and thyroid. The findings showed that CDHP patients were less likely to refill cardiac and cholesterol drugs but were equally likely to continue their prescriptions for the other six conditions. CDHP patients took slightly longer to resume their first prescriptions after they enrolled in the CDHP plan and they had poorer compliance for asthma, cardiac, and cholesterol medications. Moreover,CDHP patients also terminated their continuous drug supply 21 days earlier for epilepsy drugs and 27 days earlier for cholesterol drugs.

Overall, the study suggests that when patients have to pay more for their medications, they become less adherent for a few classes of medication. It warned that “the greatest concern is poor compliance with cholesterol medications. Adherence was consistently and significantly lower for CDHP patients taking medication for hypercholesterolemia by all measures.”