Today through Dec. 31 is an important time for many senior citizens, and the reason has nothing to do with the fast-approaching holiday season.

Every year from Nov. 15 to the end of the year, seniors who have coverage for prescription drugs through Medicare Part D or ConnPACE, the state's supplemental assistance plan for low- and moderate-income seniors and the disabled, have a chance to choose a different offering from the menu of private plans available through the government programs. Letters from Medicare and Conn-PACE reminding seniors of the open enrollment period have been arriving in their mailboxes, and program officials are urging people to read them carefully and act.

"Sometimes folks let it go," said Carol Maloof, acting regional administrator for the New England office of the Centers for Medicare and Medicaid Services, in an interview at The Day last week. "Prescription drug and health plans change each year as to each beneficiary's individual coverage needs, so we are encouraging all people with Medicare ... to review their coverage options."

For most of the approximately 36,000 New London County seniors with prescription coverage, these six weeks are mainly a time to determine whether their current plans are still the best ones, given changes in prescription needs - each plan covers a different array of drugs - premiums and co-pay amounts charged by each plan, and each senior's personal finances. Taking no action means a senior continues under the same plan, even if it may no longer be the best option.

For two groups of seniors, the six-week review-and-switch time is especially critical this year. Failure to choose a new plan would leave them without prescription drug coverage in the new year.

"There is a sense of urgency" for these groups, said Roseanne Pawelec, spokeswoman for the New England Medicare office.

One group is the 5,300 Connecticut residents with Medicare Advantage plans that include prescription coverage that are being discontinued in 2010. These are private insurance plans some seniors purchase to essentially act as the agent for their Medicare benefits. Those effected should have received letters notifying them of the cancellations and their implications, Pawelec said.

"If you don't understand the changes, call one of the Choices counselors or ask a family member," she said. "Don't be afraid to ask for help."

The Choices program provides trained counselors to assist seniors with Medicare Part D and other programs. Locally, they are available at Senior Resources - Agency on Aging in Norwich. Many town senior citizens centers also have assistance available.

The other group that especially needs to act this enrollment period are seniors with ConnPACE. Statewide, there are about 33,000 seniors with ConnPACE, which is available to those with incomes of up to $25,100 for a single person or $33,800 for a couple. Before this year's budget crisis brought cuts to scores of state programs including ConnPACE, ConnPACE served as wrap-around coverage for about 1,400 seniors with Medicare Part D plans. ConnPACE would cover the cost of any prescription not covered by their plan.

That benefit is ending. Any appeals seeking to overturn coverage denials must be made by the senior's doctor to Medicare, not the state.

In addition, the annual enrollment fee for all ConnPACE recipients is increasing from $30 to $45.

The other major change affects ConnPACE recipients who had their Medicare Advantage or Part D premiums paid for by ConnPACE. Now the state will provide premium assistance for only 12 selected private plans, meaning anyone with any of the three dozen other offerings will have to switch or pay the premium costs themselves.

About 5,000 ConnPACE recipients are already enrolled in one of the 12 plans, said David Dearborn, spokesman for the state Department of Social Services.

But another 18,500 are in unapproved Part D plans and will have to switch or lose the assistance, he said.

An additional 8,000 ConnPACE recipients are now in Medicare Advantage plans and, if they stay in, will have to pay the premiums out-of-pocket, unless they change to one of the 12 selected plans. The social services department runs ConnPACE.

Dearborn said the estimated savings to the state from the ConnPACE changes is about $2.75 million over the next two years. The entire program will cost Connecticut about $17 million over the two-year budget cycle.

As seniors learn of the changes and how they will be affected, said Maloof and Pawelec of the New England Medicare office, they should also be wary of pitches from companies trying to get people to switch to their particular Part D plan.

"Particularly during this open-enrollment period," Pawelec said, "people do prey on seniors. Don't ever give out your Medicare number, which is your Social Security number, on the phone."

"Folks can't make cold calls" to seniors to sell them on new plans, added Maloof. "If that happens, you should hang up the phone. And they can't show up at your door."

Nationally, the Centers for Medicare and Medicaid have stepped up oversight of plan marketing activities, according to an agency news release.Anyone who sees suspicious marketing practices should report it by calling Medicare's hot line at: (800) 633-4227.

j.benson@theday.com