Table 1.
Baseline Characteristics of the Study Population.*
| Beneficiary | No. of Beneficiaries | Demographic Characteristics | Evaluative and Diagnostic Practices | Diagnoses | HCC Risk Score† | ||||
|---|---|---|---|---|---|---|---|---|---|
| Age | Female Sex | Black Race | Doctor Visits | Laboratory Tests | Imaging Services | ||||
| yr (95% CI) | % (95% CI) | no. (95% CI) | score (95% CI) | ||||||
| Resident of quintile 1, region with lowest intensity of practice | |||||||||
| Did not change HRR of residence | 600,490 | 75.5 (75.5–75.5) | 59.4 (59.3–59.5) | 1.5 (1.5–1.6) | 9.7 (9.7–9.7) | 7.3 (7.3–7.4) | 2.9 (2.9–2.9) | 0.51 (0.51–0.51) | 0.95 (0.94–0.95) |
| Moved within quintile 1 | 7,984 | 76.1 (76.0–76.3) | 64.3 (63.3–65.4) | 0.5 (0.3–0.6) | 10.8 (10.6–11.1) | 7.5 (7.3–7.7) | 3.1 (3.0–3.2) | 0.59 (0.57–0.61) | 1.03 (1.01–1.05) |
| Moved to higher-intensity region | 3,811 | 75.5 (75.3–75.7) | 64.0 (62.5–65.5) | 3.0 (2.4–3.5) | 10.8 (10.5–11.2) | 7.5 (7.1–7.8) | 3.1 (2.9–3.2) | 0.55 (0.53–0.58) | 0.97 (0.95–0.99) |
| Resident of quintile 2 | |||||||||
| Did not change HRR of residence | 583,865 | 75.4 (75.4–75.4) | 61.0 (60.8–61.1) | 6.3 (6.3–6.4) | 11.0 (10.9–11.0) | 8.5 (8.4–8.5) | 3.2 (3.2–3.2) | 0.59 (0.59–0.59) | 0.99 (0.99–0.99) |
| Moved to lower-intensity region | 1,589 | 76.1 (75.8–76.4) | 67.1 (64.8–69.4) | 2.1 (1.4–2.9) | 12.4 (11.8–13.1) | 8.6 (8.1–9.2) | 3.5 (3.3–3.7) | 0.64 (0.60–0.69) | 1.05 (1.01–1.09) |
| Moved within quintile 2 | 2,302 | 76.3 (76.0–76.6) | 67.0 (65.1–69.0) | 4.0 (3.2–4.8) | 12.4 (11.8–12.9) | 8.3 (7.8–8.8) | 3.6 (3.4–3.8) | 0.68 (0.65–0.72) | 1.08 (1.04–1.11) |
| Moved to higher-intensity region | 3,206 | 75.7 (75.5–75.9) | 67.1 (65.5–68.8) | 7.3 (6.4–8.2) | 11.9 (11.4–12.3) | 8.5 (8.1–8.9) | 3.4 (3.2–3.5) | 0.60 (0.57–0.63) | 1.00 (0.98–1.03) |
| Resident of quintile 3 | |||||||||
| Did not change HRR of residence | 593,265 | 75.3 (75.3–75.3) | 61.5 (61.4–61.7) | 8.0 (8.0–8.1) | 11.5 (11.5–11.5) | 9.0 (9.0–9.0) | 3.4 (3.3–3.4) | 0.61 (0.61–0.61) | 1.00 (1.00–1.01) |
| Moved to lower-intensity region | 2,205 | 76.0 (75.7–76.2) | 67.9 (65.9–69.8) | 4.5 (3.7–5.4) | 12.5 (11.9–13.1) | 8.8 (8.3–9.3) | 3.5 (3.3–3.7) | 0.64 (0.60–0.68) | 1.04 (1.01–1.08) |
| Moved within quintile 3 | 2,862 | 75.9 (75.7–76.1) | 67.3 (65.5–69.0) | 4.9 (4.1–5.7) | 13.4 (12.9–13.9) | 9.3 (8.9–9.7) | 3.9 (3.7–4.0) | 0.74 (0.70–0.77) | 1.11 (1.08–1.14) |
| Moved to higher-intensity region | 2,448 | 75.6 (75.4–75.9) | 66.6 (64.8–68.5) | 7.5 (6.4–8.5) | 11.8 (11.4–12.3) | 8.3 (7.9–8.7) | 3.3 (3.1–3.5) | 0.61 (0.58–0.65) | 1.01 (0.98–1.04) |
| Resident of quintile 4 | |||||||||
| Did not change HRR of residence | 624,235 | 75.3 (75.3–75.4) | 61.0 (60.9–61.1) | 8.3 (8.3–8.4) | 12.3 (12.2–12.3) | 9.7 (9.7–9.8) | 3.6 (3.5–3.6) | 0.65 (0.64–0.65) | 1.02 (1.02–1.02) |
| Moved to lower-intensity region | 4,509 | 76.1 (76.0–76.3) | 66.0 (64.6–67.4) | 4.9 (4.3–5.6) | 13.4 (12.9–13.8) | 10.2 (9.8–10.5) | 3.8 (3.6–3.9) | 0.68 (0.66–0.71) | 1.07 (1.05–1.10) |
| Moved within quintile 4 | 5,188 | 75.6 (75.4–75.8) | 64.1 (62.8–65.4) | 4.3 (3.8–4.9) | 13.8 (13.4–14.2) | 10.2 (9.9–10.5) | 4.0 (3.9–4.2) | 0.72 (0.69–0.75) | 1.09 (1.07–1.11) |
| Moved to higher-intensity region | 1,211 | 76.7 (76.4–77.1) | 67.1 (64.5–69.8) | 7.9 (6.4–9.5) | 15.0 (14.1–16.0) | 10.8 (10.1–11.6) | 4.2 (3.9–4.6) | 0.74 (0.68–0.79) | 1.16 (1.11–1.22) |
| Resident of quintile 5, region with highest intensity of practice | |||||||||
| Did not change HRR of residence | 529,464 | 75.9 (75.9–75.9) | 62.0 (61.8–62.1) | 9.3 (9.2–9.3) | 14.8 (14.8–14.9) | 12.7 (12.6–12.7) | 3.8 (3.8–3.8) | 0.76 (0.76–0.77) | 1.11 (1.11–1.11) |
| Moved to lower-intensity region | 5,485 | 76.5 (76.3–76.7) | 66.0 (64.7–67.2) | 8.9 (8.1–9.7) | 15.3 (14.9–15.8) | 12.0 (11.7–12.4) | 4.0 (3.9–4.2) | 0.79 (0.76–0.81) | 1.15 (1.13–1.18) |
| Moved within quintile 5 | 9,114 | 76.7 (76.5–76.8) | 66.1 (65.1–67.1) | 7.1 (6.6–7.6) | 18.3 (17.9–18.7) | 14.7 (14.4–15.1) | 4.6 (4.5–4.7) | 0.96 (0.93–0.98) | 1.28 (1.26–1.30) |
The study population comprised Medicare beneficiaries, 65 years of age or older at the beginning of the study, who remained in a fee-for-service practice during the study period. Beneficiaries who moved were stratified according to whether their Hospital Referral Region (HRR) of residence changed between 2001 and 2003 and, if it did, whether the move was to a region with a lower intensity of practice, a region with a higher intensity of practice, or a region with the same intensity of practice as the region from which they had moved. Among beneficiaries who moved, the demographic characteristics and numbers of diagnoses and laboratory tests were based on information from the year before the move. Beneficiaries who did not change their HRR of residence were included in the analysis if they were at least 65 years of age between January 1, 1999, and January 1, 2001. All values, except for percentages, are means. HCC denotes Hierarchical Condition Category.
HCC risk scores are derived from Medicare’s enrollment and claims files with the use of demographic and diagnostic data. Higher scores indicate greater risk. In the 20% sample of beneficiaries in 2004, the scores ranged from 0.30 to 15.26.