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 | P 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.