This analysis of Part D plans shows that at least 1 ARB was present on the formularies of all plans in 2006. Seniors who paid fully out-of-pocket for their ARBs before Part D would have lower per-prescription cost-sharing on average if they were to join a PDP, although premiums and lack of gap coverage may erase these gains. The average senior with private insurance before Part D will experience an increase in cost-sharing for their ARBs.
The most commonly used ARBs, valsartan and losartan, are also the most common on formularies nationwide. Whereas this concordance will limit the number of seniors who must experience therapeutic substitution to maintain ARB coverage, some seniors will have to switch ARBs when they join a PDP. Our results were similar to a Kaiser Family Foundation report that included analysis of 14 national formularies using the http://www.Medicare.gov/
website, although that study included information on only the lowest-premium plans.3
Whereas therapeutic substitution is often difficult for patients, it may be less of an issue with ARBs, which are generally equivalent in their antihypertensive effect.15
This therapeutic switching may be more clinically significant for medications like antidepressants or statins under Part D, which deserve further research.
The average prescription cost-sharing under Part D for each of the ARBs ranges from $28 to $47. A prior study limited to 15 national PDPs that excluded plans that only offered coinsurance, rather than copays, found a mean copay for valsartan of $33.16
Our study adds to this work by examining all the ARBs for every plan across the country and puts these findings in the context of current spending through MEPS. These copays represent an increase compared to what seniors who have private insurance, including retiree benefits, currently pay for their ARBs. Average copays are more than twice as high for the Part D plans compared to current coverage. Whereas beneficiaries with retiree prescription coverage may opt out of Part D, if employers were to drop or cut retiree drug benefits, more seniors on ARBs would be subjected to higher cost-sharing in Part D plans. In a report on retiree health benefits last year from the Kaiser Family Foundation and Hewitt Associates, 80% of employers surveyed said they were likely to increase premium contributions for retiree coverage in 2007.11
In addition, 36% said they were likely to increase drug copays or coinsurance.
Conversely, seniors who currently pay for their ARBs out-of-pocket will experience lower cost-sharing for a month’s supply of medication on average, although they will have the added expense of a monthly premium. It is important to note that these cost-sharing amounts under Part D are before reaching the ‘donut hole’ where seniors will likely be paying the full cost of their ARBs. Recent work showed that only 1 or 2 PDPs in most regions offered brand-name gap coverage in 2006 and their premiums averaged $61/month compared to $37/month for average plans nationwide.16,17
Some regions had no options for brand-name gap coverage. This is important considering that approximately one-half of seniors who take ARBs will be affected by the ‘donut hole’ and there will be no generic ARBs until at least 2009 when the patent on losartan (Cozaar) expires. Therefore, average cost-sharing under Part D per prescription across the year will be significantly higher than what is noted in Table for individuals who reach the ‘donut hole’. Studies have repeatedly shown that increased out-of-pocket costs and drug benefit caps are associated with worsened medication adherence and potentially increased adverse events and emergency room visits.18–20