Out-of-pocket drug costs and medication access vary widely among Medicare prescription drug plans, according to a Kaiser Family Foundation study.

Investigators examined 35 drug plans offered by 14 organizations. The plans, on average, covered 81% of the 152 drugs seniors use most often. Overall, percents ranged from 64% to 97%.

Out-of-pocket costs also covered a wide range. For example, out-of-pocket costs for the arthritis drug Fosmax ranged from $15 to $100. For the arthritis drug Enbrel, the range was even wider: $20 to $1,276. Plans also varied in their use of quantity limits, prior-authorization requirements and step-therapy provisions.