Members showed no ill effect from the switch from two-tier to three-tier co-pay structure either. Much skepticism about the three-tier co-pay structure has resulted from concern that it would encourage medication noncompliance and lead to increased medical costs. To the contrary, according to Motheral, no significant differences in medical costs were seen between the two-tier and three-tier plans.
Across commonly used therapy classes, medication continuation among adults was similar in the one-year follow-up period for the two plans studied by Motheral and Fairman. Only one class of drugs, antihypertensives, showed a statistically significant but small difference in continuation rates.
Comparison of mean emergency room visits for the six months before and after implementation showed no difference between the plans either. Inpatient hospitalizations over the same period remained unchanged.
"We wanted to determine whether moving to a three-tier co-pay structure would trigger unintended consequences," said Motheral. "The data show that it did not, at least in the short run."
Motheral says how much a plan sponsor can expect to save with a three-tier co-pay structure varies. "The magnitude of savings will vary, depending on co-pay amounts at the time of the change, co-pay amounts assigned to each of the three tiers, market share of preferred drugs, and the approach to selection of tier-three drugs," she said. This study was supported in part by The Agency for Healthcare Research and Quality.
Synopses of other presentations from the Express Scripts 2000 Outcomes Conference