One pharmacy benefit manager (PBM) says the public exchange plan enrollees it serves are much sicker than enrollees in employer-sponsored health plans.

But the PBM, Prime Therapeutics Inc., has published one bit of data suggesting that the enrollees could be healthier than exchange plan enrollees at a competitor, Express Scripts Inc. (NYSE:ESRX).

The PBM, Prime Therapeutics, came up with its statistics by analyzing 13 million Patient Protection and Affordable Care Act (PPACA) exchange qualified health plan (QHP) claims it received in 2014, and 143 million commercial plan claims.

About 0.6 percent of the QHP enrollees took HIV drugs, compared with 0.016 percent of the employer plan enrollees. The QHP enrollees were 3.75 times more likely to be taking HIV drugs.

Express Scripts reported in October that the QHP enrollees it served were 4.5 times more likely to be taking HIV drugs.

Hepatitis C use statistics paint a different picture. Express Scripts said the QHP enrollees it served were twice as likely as commercial plan enrollees to be taking hepatitis C drugs. At Prime Therapeutics, QHP enrollees are about 2.5 times more likely to be taking hepatitis C drugs. The hepatitis C drug use ratio could have changed in the past year because of the introduction of major new medications, such as Harvoni.

But Express Scripts says the PPACA Medicaid expansion program has helped utilization rates for expensive specialty drugs at Medicaid plans.

When states used Medicaid expansion money to reach uninsured, low-income adults, they brought in enrollees who were healthy enough not to have qualified for health programs aimed at patients with serious problems.

Because of that shift, at Medicaid plans served by Express Scripts, the likelihood that enrollees ages 20 to 34 would be taking specialty drugs of any kind fell 8.7 percent in 2014.

The likelihood that enrollees ages 35 to 64 would be taking specialty drugs fell 9.9 percent.