The audit of Humana is one of about 90 "corrective action plans" that the Centers for Medicare and Medicaid Services recently made public on its Web site. CMS issues such plans when a provider fails to comply with program rules, but the agency rarely makes the details so public.

Dozens of insurers were the subject of two years' worth of corrective action plans placed on the Web site. But Humana, headquartered in Louisville, Ky., merited particular attention. That's important because 4.6 million Medicare beneficiaries use Humana insurance plans. The company's products are popular in many rural counties.

In one audit, dated July 30, officials wrote that the company was having difficulty keeping up with all the complaints it was getting so that it could investigate each of them, as it had committed to doing.

Medicare officials also said many of the beneficiaries' complaints indicated that Humana's agents gave them incorrect information.

"Thus, CMS questions the effectiveness of the training of these agents and the oversight that Humana has over these agents in the field," the audit states.

Records also indicated that the company takes scant disciplinary action against agents who generate large numbers of policy cancellations. One agent's file showed 50 cancellations or disenrollments, but no disciplinary action was taken.

Often, agents don't even respond to the company's request for details about a particular beneficiaries' enrollment, the audit said.

Humana provides prescription drug coverage for 3.5 million Medicare beneficiaries. The federal government subsidizes that coverage through payments to the insurers. Another 1.1 million people get more comprehensive health coverage through a program called Medicare Advantage.

Many complaints about the new Medicare drug benefit have come from beneficiaries who believed they were signing up for coverage of medicine. Instead, they were signed up for the much more comprehensive health coverage. Federal officials got so many complaints about that practice that seven of the largest insurers, including Humana, agreed at one point to quit marketing certain plans to beneficiaries.

CMS announced recently that the marketing ban would be lifted for all seven companies because they had met the agency's guidance for participation. The plans agreed to the following steps:

--All brokers and agents selling products must pass a written exam to demonstrate an understanding of Medicare policies and the products being marketed.

--Plans must telephone beneficiaries requesting enrollment in certain plans to confirm they understand the product.

--The insurers also have to list sales events sponsored by the plan's brokers so that CMS can attend the events and monitor their sales pitches.

Heidi Margulis, senior vice president of government relations at Humana, said several issues cited in the audits were addressed by the company. She said that CMS's approval of Humana to renew its marketing of Medicare Advantage products showed the company was in compliance with CMS requirements.

"It's CMS's opinion that we are in compliance," Margulis said. "They are the people who lifted the moratorium."

Margulis said the company has reduced the number of insurance agencies it contracts with to sell its products and increased its oversight staff to ensure that the sales process is appropriately monitored.

"We market to a very vulnerable population, and we understand the trust that governments have placed in us in providing health care coverage for this population," Margulis said.

Kerry Weems, CMS's acting administrator, agreed to make the audits public as part of an effort to make the work of Medicare's contractors more transparent. Next month, his agency will issue report cards for all plans offering the new Medicare drug benefit or more comprehensive health coverage through Medicare Advantage.