Not a surprising finding but an important one nonetheless. Using data from the 2013–17 National Health Interview Survey (NHIS) a paper by Gaffney et al. (2020) finds:
Although people with VHA [Veterans Health Administration] coverage were older and in worse health and had lower incomes than those with other coverage, VHA patients had lower rates of cost-related medication nonadherence: 6.1 percent versus 10.9 percent for non-VHA patients, an adjusted 5.9-percentage-point difference. VHA coverage was associated with especially large reductions in nonadherence among people with chronic illnesses and with reduced racial/ethnic and socioeconomic disparities in nonadherence.
Cost-related medication adherence was defined as anyone who answered ‘yes’ to at least one of the the following NHIS questions:
- “needed…[a prescription drug], but didn’t get it because [they] couldn’t afford it”;
- “skipped medication doses to save money”;
- “took less medicine to save money”;
- “delayed filling a prescription to save money.
As you said this is not surprising, but I think the more important question is: were the additional healthcare costs and diminished quality of life of lower adherence greater than the lower out-of-pocket costs? This was a retrospective, short-term study. What if the individuals who chose lower adherence knew something that the researchers didn’t? We shouldn’t assume that every patient is clueless.
I guess what I am saying is that just because the sign of the relationship is what we expected it to be, we shouldn’t assume the magnitude is large enough to make a difference.