Appendix Table 2.

Associations Between Medicare Advantage Plan Characteristics and the Difference Between Observed and Reported Rates of High-Risk Medication Use in 2006 and 2007^*

Plan Characteristic	Persons, n	Mean Unadjusted Difference Between Reported and Calculated Rate (95% CI), percentage points	P Value for Difference	Relative Adjusted Difference Between Reported and Calculated Rate (95% CI), percentage points
Profit status			0.98
Nonprofit	53	−5.8 (−6.9 to −4.7)		Reference
For-profit	119	−5.8 (−6.6 to −5.0)		−0.2 (−1.5 to 1.1)
Time participating in Medicare			0.053
<5 y	46	−4.8 (−6.2 to −3.4)		Reference
5–10 y	48	−6.9 (−8.4 to −5.4)		−1.6 (−3.4 to 0.2)
>10 y	78	−5.7 (−6.3 to −5.0)		−1.2 (−2.9 to 0.6)
Beneficiaries			0.70
<4845	33	−6.3 (−7.9 to −4.8)		Reference
4845–16 295	44	−5.6 (−6.9 to −4.3)		0.9 (−1.1 to 2.8)
16 296–32 390	48	−6.0 (−7.4 to −4.7)		0.6 (−1.5 to 2.7)
>32 390	47	−5.3 (−6.4 to −4.3)		1.1 (−1.1 to 3.3)
Model type			0.88
Nonstaff/nongroup	143	−5.6 (−6.3 to −4.9)		Reference
Staff/group	23	−5.8 (−7.1 to −4.4)		0.2 (−1.6 to 2.0)
State Medicare Advantage market penetration			0.34
<10%	28	−5.9 (−5.8 to −4.9)		Reference
10–25%	94	−6.2 (−7.1 to −5.2)		−0.4 (−2.1 to 1.4)
>25%	50	−5.1 (−6.3 to −3.9)		−1.0 (−3.5 to 1.5)
Census region			0.031
Northeast	46	−6.1 (−7.2 to −5.1)		Reference
Midwest	42	−5.8 (−7.0 to −4.6)		0.3 (−1.5 to 2.1)
South	42	−6.4 (−8.0 to −4.8)		−0.5 (−2.4 to 1.3)
West	38	−5.3 (−6.3 to −4.3)		1.7 (−0.2 to 3.5)
Puerto Rico	4	0.5 (−12.5 to 13.6)		5.9 (1.6 to 10.2)

^*Results adjusted for data shown in the “Plan Characteristics” column. Values with a negative difference signify underreporting. Bold values signify significant data; α = 0.05.