Falling into the coverage gap: Part D drug costs and adherence for Medicare Advantage prescription drug plan beneficiaries with diabetes.
OBJECTIVE
To compare drug costs and adherence among Medicare beneficiaries with the standard Part D coverage gap versus supplemental gap coverage in 2006.


METHODS
Pharmacy data from Medicare Advantage Prescription Drug (MAPD) plans.


METHODS
Parallel analyses comparing beneficiaries aged 65+ with diabetes in an integrated MAPD with a gap versus no gap (n=28,780); and in a network-model MAPD with a gap versus generic-only coverage during the gap (n=14,984).


RESULTS
Drug spending was 3 percent (95 percent confidence interval [CI]: 1-4 percent) and 4 percent (CI: 1-6 percent) lower among beneficiaries with a gap versus full or generic-only gap coverage, respectively. Out-of-pocket expenditures were 189 percent higher (CI: 185-193 percent) and adherence to three chronic drug classes was lower among those with a gap versus no gap (e.g., odds ratio=0.83, CI: 0.79-0.88, for oral diabetes drugs). Annual out-of-pocket spending was 14 percent higher (CI: 10-17 percent) for beneficiaries with a gap versus generic-only gap coverage, but levels of adherence were similar.


CONCLUSIONS
Among Medicare beneficiaries with diabetes, having the Part D coverage gap resulted in lower total drug costs, but higher out-of-pocket spending and worse adherence compared with having no gap. Having generic-only coverage during the gap appeared to confer limited benefits compared with having no gap coverage.
Fung
Vicki
V
Division of Research, Kaiser Permanente Medical Care Program, 2000 Broadway, 3rd floor, Oakland, CA 94612, USA. Vicki.Fung@kp.org
Mangione
Carol M
CM
Huang
Jie
J
Turk
Norman
N
Quiter
Elaine S
ES
Schmittdiel
Julie A
JA
Hsu
John
J
D000368:Aged; D000369:Aged, 80 and over; D003920:Diabetes Mellitus / Q000188:drug therapy*; D005252:Fees, Pharmaceutical / Q000639:trends*; D005260:Female; D005382:Financing, Personal; D006801:Humans; D019458:Insurance Coverage / Q000191:economics / Q000331:legislation & jurisprudence* / Q000458:organization & administration; D017054:Insurance, Medigap / Q000191:economics; D008297:Male; D054524:Medicare Part D / Q000191:economics / Q000331:legislation & jurisprudence / Q000458:organization & administration*; D012051:Reimbursement Mechanisms / Q000191:economics / Q000331:legislation & jurisprudence / Q000458:organization & administration*; D014481:United States