Table 2.
Unadjusted and adjusted associations between receipt of chemotherapy among elderly patients With early stage breast cancer, and the characteristics of their oncologists, and their own demographic and clinical characteristics* (N=42,544)
| Characteristics | N | % | Unadjusted Odds Ratios (95% CI) | Adjusted Odds Ratios (95% CI) |
|---|---|---|---|---|
| Received chemotherapy | 8714 | 20.0 | ||
| a. Oncologist characteristics | ||||
| Degree | ||||
| DO | 324 | 20.2 | Reference | Reference |
| MD | 8390 | 20.4 | 1.01(0.90–1.15) | 0.87 (0.65–1.16) |
| US-trained | ||||
| No | 2112 | 22.1 | Reference | Reference |
| Yes | 6602 | 20.0 | 0.88 (0.83–0.93)* | 0.83 (0.74–0.93)* |
| Date of graduation | ||||
| <1975 | 3722 | 18.9 | Reference | Reference |
| ≥1975 | 4992 | 21.9 | 1.20 (1.15–1.26)* | 1.12 (1.01–1.26)* |
| Type of practice | ||||
| Non-private | 1356 | 17.4 | Reference | Reference |
| Private | 7358 | 21.2 | 1.27 (1.19–1.36)* | 1.40 (1.23–1.60)* |
| # Patients in cohort | ||||
| 1–40 | 4681 | 21.3 | Reference | Reference |
| >40 | 4033 | 19.6 | 0.90 (0.86–0.94)* | 1.07 (0.93–1.23) |
| Gender | ||||
| Male | 7205 | 20.4 | Reference | Reference |
| Female | 1509 | 20.8 | 1.03 (0.96–1.09) | 0.99 (0.87–1.14) |
| b. Demographic characteristics | ||||
| Age at diagnosis | ||||
| 65–69 | 3261 | 34.4 | Reference | Reference |
| 70–74 | 3052 | 24.2 | 0.61 (0.58–0.65)* | 0.53 (0.49–0.57)* |
| 75–79 | 1762 | 16.2 | 0.37 (0.34–0.39)* | 0.27 (0.25–0.30)* |
| 80+ | 639 | 6.7 | 0.14 (0.12–0.15)* | 0.07 (0.06–0.08)* |
| Race | ||||
| White | 7693 | 20.1 | Reference | Reference |
| Black | 563 | 24.9 | 1.32 (1.19–1.45)* | 0.99 (0.86–1.15) |
| Hispanic | 109 | 22.1 | 1.13 (0.91–1.39) | 0.90 (0.69–1.18) |
| Other | 349 | 22.1 | 1.13 (0.99–1.27) | 1.01 (0.86–1.18) |
| Residence | ||||
| Non-metropolitan | 811 | 20.3 | Reference | Reference |
| Metropolitan | 7903 | 20.5 | 0.99 (0.91–1.07) | 0.93 (0.82–1.06) |
| Marital status | ||||
| Unmarried | 3903 | 17.8 | Reference | Reference |
| Married | 4580 | 23.7 | 1.43 (1.36–1.50)* | 1.17 (1.10–1.24)* |
| Socioeconomic status | ||||
| Lowest quartile | 2594 | 20.0 | Reference | Reference |
| 2nd quartile | 2120 | 20.4 | 1.03 (0.97–1.10) | 1.02 (0.93–1.12) |
| 3rd quartile | 1877 | 20.8 | 1.06 (0.99–1.13) | 1.07 (0.98–1.16) |
| 4th quartile | 2062 | 21.1 | 1.07 (1.01–1.16)* | 1.11 (1.01–1.22)* |
| c. Patient clinical characteristics | ||||
| Stage | ||||
| I | 1566 | 6.9 | Reference | Reference |
| II | 5899 | 34.2 | 6.96 (6.55–7.39)* | 8.43 (7.72–9.09)* |
| III | 1249 | 46.3 | 11.57 (10.6–12.7)* | 17.68 (15.19–19.74)* |
| Hormone receptor status | ||||
| Er+ and/or PR+ | 5089 | 16.6 | Reference | Reference |
| Er− and PR− | 2384 | 47.9 | 4.54 (4.26–4.83)* | 4.52 (4.13–4.93)* |
| Grade | ||||
| Well/moderately differentiated | 3615 | 15 | Reference | Reference |
| Poorly differentiated | 4112 | 33.4 | 2.83 (2.69–2.99)* | 1.78 (1.67–1.90)* |
| Unknown | 987 | 15.8 | 1.06 (0.98–1.15) | 1.05 (0.94–1.16) |
| Comorbidity score | ||||
| 0 | 5627 | 21.8 | Reference | Reference |
| 1 | 2134 | 19.9 | 0.88 (0.84–0.94)* | 0.89 (0.83–0.95)* |
| >1 | 953 | 15.8 | 0.67 (0.62–0.72)* | 0.60 (0.55–0.66)* |
*
P-value <0.001
DO=Doctor of Osteopathic Medicine; ER=estrogen receptor; PR=progesterone receptor.
Odds Ratios based on univariate logistic regression.