Hawaii had the nation's largest percentage of Medicare beneficiaries falling into the so-called “;doughnut hole”; in Part D prescription drug coverage in 2007, leaving thousands of residents paying for all of their medicine, according to the AARP.

More than one-third—36 percent—of isle residents enrolled in the Medicare drug program hit the coverage gap.

“;That left about 33,000 beneficiaries on the hook for 100 percent of their drug costs, while still paying premiums,”; AARP said in a news release.

The state's high incidence of diabetes and renal failure are cited as major factors.

“;We have about three to five times the rate of diabetes, compared to the mainland,”; Mary Rydell, Pacific area representative for the Centers for Medicare and Medicaid Services, said in an interview.

Diabetes is a major cause of renal failure, and Medicare is the primary payer for renal services and diabetic supplies, she said.

But Medicare covers diabetes screening, she said, urging residents to be tested and “;take care of themselves before kidneys fail.”;

Nationally, 26 percent of Medicare drug plan enrollees, about 3.4 million people, hit the doughnut hole in 2007, according to a Kaiser Family Foundation report.

When patients and their drug plans have paid $2,700, they reach the doughnut hole, the point at which patients must cover 100 percent of their drug costs. People on dialysis reach that figure faster because they use a lot of drugs, Rydell said.

The hole closes after beneficiaries pay $4,350 out of pocket, when catastrophic coverage kicks in and they pay roughly 5 percent of drug costs, depending on their plan.

AARP Hawaii Associate Director Jackie Boland said the doughnut hole is expected to widen substantially in coming years.

The size of the coverage gap is updated annually based on growth in per capita drug spending by Part D beneficiaries, which is affected by changes in drug prices, drug use and mix of therapy.

The current coverage gap is $3,454. It will be $3,610 next year, and AARP projects it to be $6,000 by 2016.

“;There is growing evidence that many beneficiaries who reach the coverage gap forgo needed medications when faced with the full cost of their prescriptions—often leading to expensive hospitalization and adverse health outcomes,”; the AARP Policy Institute said this year.

AARP is asking Congress as part of a Health Action Now campaign to close the doughnut hole and lower prescription prices so no one has to cut back or stop using prescription drugs.

Rising drug prices are especially hard on women and people with lower incomes, AARP said.

“;Even before the current economic downturn,”; it said, “;one out of 10 residents surveyed said they delayed filling a prescription, took a smaller dose of medication or cut back on food or utilities to afford the cost of a prescription.”;

Hawaii has an older population with 193,333 Medicare beneficiaries last year, and many have chronic illnesses, with a considerably higher risk of reaching the doughnut hole, AARP said.