PHILADELPHIA - The American Diabetes Association, a leading patient health group, privately enlisted an Eli Lilly & Co. executive to chart its growth strategy and write its slogan.

The National Alliance on Mental Illness, an outspoken patient advocate, lobbies for treatment programs that also benefit its drug-company donors.

The National Gaucher Foundation, an advocate for people with a rare disease, gets nearly all its money from one drug maker, Genzyme Corp.

Although patients seldom know it, many patient groups and drug companies maintain close, multimillion-dollar relationships while disclosing limited or no details about the ties.

At a time when people are making more of their own health-care decisions, such coziness raises questions about the impartiality of groups that patients trust for unbiased information. It also poses a challenge for groups trying to hold patients’ trust and still raise money to serve them.

A Philadelphia Inquirer examination of a half-dozen groups, each a leading advocate for patients in a disease area, found that the groups rarely disclose such ties when commenting or lobbying about donors’ drugs. They also tend to be slower to publicize treatment problems than breakthroughs. And few openly questioned drug prices.

At the same time, the groups perform an important function by providing services unavailable elsewhere, such as patient education and help in obtaining medications or affording insurance.

They also try to police themselves. For example, each declares it does not endorse or reject products. All formally require that industry grants be "unrestricted," meaning that there are no strings attached. One of them, Children & Adults with Attention Deficit/Hyperactivity Disorder, or CHADD, formally caps pharmaceutical donations.

Combined, the six received at least $29 million from drug companies last year, according to tax returns and annual reports. The amount ranged from 2 percent to 7 percent of revenue at the Arthritis Foundation, to 89 percent to 91 percent at the much smaller National Gaucher Foundation.

Some health-care experts, although applauding the groups’ work, are calling for greater disclosure. And many patients expressed surprise at the ties.

"I don’t think that would make a difference as far as taking a drug," said Gloria Antonucci, 65, leader of a Montgomery County, Pa., pain-support group that relies on Arthritis Foundation advice. "But I think it would make me, maybe, 250 percent more skeptical about what the group is saying."