Journalist Philip Moeller answers your questions about health, aging, and retirement. Phil is the author of the book, “Get What’s Yours for Medicare,” and co-author of “Get What’s Yours: The Revised Secrets to Maxing Out Your Social Security.” Send your questions to Phil.

The private insurers operating Medicare Part D drug plans may be putting profits ahead of patient interests, according to a report from the program’s watchdog.

The report, issued by the U.S Department of Health and Human Services’ Office of Inspector General, analyzed rejections of millions of prescription requests during 2017, the most recent year for which comprehensive information is available.

Insurers initially rejected as many as 3.5 percent of Medicare beneficiaries’ attempts to fill prescriptions, the analysis found. While this may appear to be a small rate, it amounted to a very large number — about 84 million rejections out of 2.4 billion Part D pharmacy transactions.

“Because Part D covers more than 45 million beneficiaries, even low rates of denied or delayed medically necessary drugs or reimbursement could contribute to physical or financial harm for many Medicare beneficiaries,” the report said.

Under the rules of Part D plans, insurers (called “plan sponsors” in the report) must pay a portion of the program drug expenses so they risk losing money if the beneficiary spends more on prescription drugs than expected. That can “create an incentive for sponsors to deny requests for prescription drug coverage in an attempt to increase their profits,” the report said.

Many of the insurer denials were inappropriate or made for reasons that could have been avoided, the OIG said. Part D plans have complex rules that Medicare users must follow, it explained, but insurers often do not do a good job in explaining them to plan members or the doctors who prescribe their medications.

These include prescriptions for drugs that are not on a plan’s formulary list of covered drugs, prior authorizations that insurers may require before approving prescriptions, “step therapy” rules that require some people use cheaper drugs before being approved for the more costly drugs they were prescribed, and quantity limits on the amount of drugs that may be filled in a single prescription.

When consumers appealed their rejected prescriptions, 73 percent of the denials were overturned, which means many patients could have avoided the hassle of having their coverage denied in the first place.

Part D rules require insurers to process prescription coverage requests within 24 to 72 hours of receiving them so that people can get needed medications as soon as possible. The OIG’s investigation found that this often was not enough time for insurers to collect all of the supporting information needed to make an informed decision.

In many cases, investigators concluded, insurers “may issue a denial and then process any subsequent information that it receives as part of an appeal of that denial.” This business practice, however, comes at the expense of people who need timely access to their prescribed medicines.

The clear message to people with Part D plans is that they should do more homework before trying to fill a prescription.

The agency also looked at the tools that insurers provided to consumers to help them comply with Part D rules. The inspector general’s office concluded that it was very hard for consumers to find Medicare’s own performance reports that tell consumers which insurers reject claims most often. This information could be helpful when consumers choose which Part D plan will insure their drug needs. The report did not identify insurers or Part D plans by name.

Although insurers may have been too quick to deny prescriptions, the clear message to people with Part D plans is that they should do more homework before trying to fill a prescription. This includes working with their doctor and insurer ahead of time to make sure a drug is included in their plan formulary and that they are compliant with other plan rules.

The Office of the Inspector General asked Medicare’s oversight agency, the Centers for Medicare & Medicaid Services (CMS), to require Part D insurers to take steps to reduce “avoidable” and “inappropriate” pharmacy rejections and coverage determinations, and to make it easier for consumers to find information about insurer performance programs.

CMS agreed with all requests, the report said. However, it noted that CMS ended two drug-plan oversight programs earlier this year that provided much of the performance data on which its report was based.

“CMS stated that it ended these oversight efforts because they were no longer needed and were burdensome for Part D sponsors,” the inspector general’s office said, adding that it believed that continued performance problems by Part D plans argues for continued oversight.