Table 1.
Descriptive Statistics for Our Study Population
| Characteristic | Calendar Year | ||
|---|---|---|---|
| 2005 | 2008 | 2011 | |
| No. of eligible beneficiaries in the 20% sample | 5,016,615 | 4,733,462 | 4,850,533 |
| No. of outpatient surgical episodes | 6,565,430 | 6,889,023 | 7,341,625 |
| Average age at the time of surgery, in years (SD) | 70.6 (1.2) | 70.4 (1.2) | 70.2 (1.2) |
| % of patients undergoing surgery who were male (SE) | 44.5 (1.6) | 45.0 (1.5) | 45.5 (1.4) |
| % of patients undergoing surgery who were white (SE) | 86.9 (11.1) | 86.4 (11.3) | 85.6 (11.4) |
| Average Charlson score at the time of surgery (SD) | 2.5 (0.3) | 2.5 (0.3) | 2.5 (0.3) |
| Average per capita income, in 1,000 USD (SD) | 31.2 (6.1) | 36.7 (7.1) | 38.3 (6.8) |
| % of population living below federal poverty limit (SE) | 14.1 (4.4) | 14.0 (3.8) | 16.6 (4.0) |
| % of population with bachelor's degree (SE) | 27.2 (4.7) | 24.6 (6.2) | 25.2 (6.3) |
| No. of active MDs, per 10,000 population (SD) | 20.7 (7.7) | 21.7 (8.4) | 21.2 (8.3) |
No., number; SD, standard deviation; SE, standard error.