Rapid Acting Insulin Use and Persistence among Elderly Type 2 Diabetes Patients Adding RAI to Oral Antidiabetes Drug Regimens

Table 3

Adjusted odds ratios and 95% confidence intervals from logistic regressions of multiple versus single rapid acting insulin prescriptions during 12-month follow-up among elderly (≥65 years) Medicare beneficiaries with type 2 diabetes mellitus who added rapid acting insulin to their oral antidiabetic drug. Humana Medicare Advantage Prescription Drug Plan database 2007–2012.

	AOR	95% CI	value
Number of OADs
1 OAD	0.72	[0.58, 0.91]	<0.01
2 OADs	0.92	[0.73, 1.16]
≥3 OADs
Demographic characteristics
Gender
Female	1.11	[0.96, 1.29]
Male
Race
White
African American	0.98	[0.80, 1.22]
Others	0.92	[0.64, 1.32]
Missing	1.64	[0.99, 2.72]
Age in years
65–69 years
70–74 years	0.83	[0.70, 1.00]	<0.05
75–79 years	0.71	[0.58, 0.87]	<0.001
80+ years	0.96	[0.76, 1.21]
Region
Midwest	1.05	[0.80, 1.36]
South	0.68	[0.53, 0.88]	<0.01
Northeast/west/others
Health insurance characteristics
Type of plan
PFFS
HMO	1.01	[0.84, 1.22]
PPO/others	0.98	[0.82, 1.18]
Baseline clinical characteristics
Any hypoglycemia
Yes	0.82	[0.66, 1.01]
No
aDCSI score
0	0.82	[0.66, 1.02]	<0.01
1-2	0.88	[0.73, 1.07]
3-4	0.82	[0.66, 1.02]
5–13
A1C
<8%
8-9%	1.48	[1.05, 2.07]	<0.05
>9%	1.94	[1.42, 2.65]	<0.001
Not available	1.21	[0.99, 1.47]
Baseline healthcare utilization
Any inpatient visit
Yes	0.54	[0.44, 0.65]	<0.001
No
Any ER visit
Yes	0.90	[0.75, 1.07]
No
Special conditions for the elderly
Polypharmacy
Yes (>14)	0.88	[0.72, 1.09]
No (≤14)
Cognitive impairment
Yes	1.51	[1.23, 1.85]	<0.001
No
Depression
Yes	1.23	[1.00, 1.51]	<0.05
No
Fall
Yes	0.88	[0.65, 1.18]
No
Urinary incontinence
Yes	1.08	[0.76, 1.52]
No
One-year follow-up basal insulin use
Basal insulin
Yes	2.30	[1.99, 2.66]	<0.001
No
One-year follow-up RAI out-of-pocket cost per RAI prescription
Average OOP cost per RAI prescription
0.0–<6.3
6.3–<36	0.55	[0.45, 0.67]	<0.001
36–<56	0.53	[0.43, 0.65]	<0.001
≥56	1.10	[0.89, 1.38]

Note: based on 3,734 elderly Medicare beneficiaries aged 65 years and above with type 2 diabetes mellitus, who were continuously enrolled in the Humana Medicare prescription drug plans for 18 months between 2007 and 2011 and added rapid acting insulin to their oral antidiabetic drugs regimen. The reference group for the dependent variable is having more than one RAI prescription during the one-year follow-up period.
A1C: glycated hemoglobin; aDCSI: adapted-Diabetes Complications Severity Index; AOR: adjusted odds ratio; CI: confidence interval; ER: emergency room; HMO: health maintenance organization; OAD: oral antidiabetic drug; PFFS: private fee-for-service; PPO: preferred provider organization; RAI: rapid acting insulin.