Anywhere from 15% to 28% of seniors might stop taking life-saving drugs when they reach the so-called “doughnut hole” in multi-tiered Medicare drug plans or other spending limits, a new study finds.

Many seniors stop taking medications for such chronic illnesses as diabetes and high blood pressure even before their plan’s coverage runs out, according to the RAND Corporation study featured in the September-October issue of the journal Health Affairs.

“Prescription use falls significantly as patients reach their benefit caps,” said Geoffrey Joyce, the study’s lead author and a senior economist at RAND, a nonprofit research organization. “Most of the drugs we studied help prevent long-term complications of chronic disease so there are likely to be adverse health consequences for seniors who hit their caps.”

Most of the drugs studied were used to prevent long-term complications of chronic illnesses, researchers note. The study also suggested that adverse health consequences are a likely outcome of seniors who reach their spending limits. In the long run, the situation could result in increased hospitalizations among seniors who stop taking their needed medications, say researchers.