Table 1.
Patient demographics and other baseline characteristics, by type of treatment
| Demographic variable | IFN therapy (n = 1525) | Non-IFN therapy (n = 16,550) | P value |
|---|---|---|---|
| Agea (years)* | |||
| Mean ± SD | 58 ± 12.0 | 57 ± 15.1 | 0.128 |
| Minimum-maximum | 18–88 | 18–100 | |
| Genderb | |||
| Male | 898 (58.9%) | 9004 (54.4%) | 0.034 |
| Female | 627 (41.1%) | 7546 (45.6%) | |
| Employmentb status* | |||
| Active full time | 455 (29.8%) | 4759 (28.8%) | <0.0001 |
| Active part time or seasonal | 10 (0.6%) | 86 (0.5%) | |
| Early retiree | 137 (9.0%) | 1225 (7.4%) | |
| Medicare eligible retiree | 165 (10.8%) | 2990 (18.1%) | |
| Retiree (status unknown) | 42 (2.8%) | 782 (4.7%) | |
| COBRA continuee | 30 (2.0%) | 79 (0.5%) | |
| Long-term disability | 7 (0.5%) | 47 (0.3%) | |
| Surviving spouse/dependent | 6 (0.4%) | 273 (1.6%) | |
| Other/unknown | 671 (44.0%) | 6309 (38.1%) | |
| Missing** | 2 (0.1%) | 0 | |
| Claim typeb | |||
| Medicare supplemental | 187 (12.0%) | 1973 (11.9%) | 0.700 |
| Commercial | 1338 (88.0%) | 14568 (88.0%) | |
| Missing** | 0 | 9 (0.1%) | |
| Industryb | |||
| Oil and gas extraction, mining | 9 (0.6%) | 130 (0.8%) | 0.021 |
| Manufacturing, durable | 244 (16.0%) | 3230 (19.5%) | |
| Manufacturing, nondurable | 72 (4.7%) | 870 (5.3%) | |
| Transportation, communications, utilities | 134 (8.8%) | 1885 (11.4%) | |
| Retail trade | 41 (2.7%) | 281 (1.7%) | |
| Finance, insurance, real | 69 (4.5%) | 885 (5.4%) | |
| Services | 89 (5.8%) | 878 (5.2%) | |
| Missing** | 867 (56.9%) | 8391 (50.7%) | |
Notes:
a
t-test used to compare means in the IFN and non-IFN therapy groups;
b
Chi-square tests used to compare proportions in the IFN and non-IFN therapy groups;
*
age and employment status were calculated based on time of the surgery claim;
**
missing data was included to calculate the Chi-square tests.
Abbreviations: COBRA, Consolidated Omnibus Budget Reconciliation Act; IFN, interferon alfa-2b; n, number of patients; SD, standard deviation.