Table 1.
Number of Ambulatory Visits, Referrals, and Referral Rates in the US by Patient and Practice Characteristics, 1999–2009
| Year | Ambulatory Visits, millions (SE) | Percentage of Ambulatory Visits Resulting in Referral, % (SE) | Ambulatory Visits Resulting in Referral, millions (SE) | p-value | |||
|---|---|---|---|---|---|---|---|
| 1999 | 2009 | 1999 | 2009 | 1999 | 2009 | ||
| All | 841 (65.6) | 1130 (94.7) | 4.83 (0.26) | 9.29 (0.48) | 40.6 (3.8) | 105 (10.1) | <0.001 |
| Age (years) | |||||||
| 0–3 | 52.1 (5.4) | 69.4 (8.1) | 3.74 (0.79) | 4.93 (0.71) | 1.95 (0.5) | 3.42 (0.6) | 0.124 |
| >3–18 | 105 (9.6) | 137 (12.9) | 4.69 (0.54) | 7.64 (0.82) | 4.93 (0.7) | 10.5 (1.5) | <0.001 |
| >18–45 | 257 (22.0) | 287 (25.1) | 5.01 (0.39) | 9.98 (0.71) | 12.9 (1.4) | 28.7 (3.3) | <0.001 |
| >45–65 | 223 (18.2) | 345 (31.1) | 5.43 (0.49) | 9.75 (0.58) | 12.1 (1.5) | 33.7 (3.5) | <0.001 |
| >65 | 205 (16.7) | 295 (25.6) | 4.30 (0.47) | 9.86 (0.72) | 8.79 (1.2) | 29.1 (3.2) | 0.004 |
| Gender | |||||||
| Male | 497 (40.1) | 669 (55.3) | 4.55 (0.25) | 9.30 (0.51) | 22.6 (2.3) | 62.2 (6.0) | <0.001 |
| Female | 345 (26.3) | 465 (40.1) | 5.23 (0.37) | 9.28 (0.52) | 18.0 (1.8) | 43.1 (4.4) | <0.001 |
| Race | |||||||
| White | 718 (57.8) | 947 (80.7) | 4.91 (0.28) | 9.01 (0.47) | 35.3 (3.5) | 85.3 (8.3) | <0.001 |
| Black | 91.8 (10.2) | 135 (17.4) | 4.60 (0.56) | 11.2 (0.95) | 4.22 (0.6) | 15.1 (2.4) | 0.014 |
| Other | 31.3 (7.2) | 51.7 (6.4) | 3.53 (0.85) | 9.44 (1.22) | 1.11 (0.2) | 4.88 (0.8) | 0.108 |
| Insurance Type | |||||||
| Private | 451 (37.9) | 594 (50.1) | 4.90 (0.32) | 8.95 (0.55) | 22.1 (2.4) | 53.1 (5.1) | <0.001 |
| Medicare | 169 (15.2) | 281 (25.8) | 4.15 (0.38) | 9.74 (0.74) | 7.02 (0.9) | 27.3 (3.3) | 0.003 |
| Medicaid | 76.7 (8.9) | 144 (15.7) | 4.95 (0.53) | 9.24 (0.99) | 3.80 (0.6) | 13.3 (1.9) | <0.001 |
| Other/Uninsured | 145 (12.5) | 116 (12.0) | 5.33 (0.70) | 9.99 (1.02) | 7.72 (1.3) | 11.5 (1.8) | 0.014 |
| Region | |||||||
| Northeast | 193 (28.8) | 196 (38.5) | 4.51 (0.56) | 9.49 (1.27) | 8.70 (1.7) | 18.6 (4.1) | 0.128 |
| Midwest | 177 (27.8) | 259 (40.1) | 5.11 (0.58) | 9.96 (0.97) | 9.04 (1.7) | 25.8 (4.4) | 0.001 |
| South | 278 (42.4) | 449 (65.8) | 4.64 (0.40) | 8.93 (0.74) | 12.9 (2.4) | 40.1 (7.1) | 0.020 |
| West | 193 (30.1) | 230 (39.3) | 5.16 (0.60) | 9.07 (1.08) | 9.97 (1.8) | 20.9 (4.1) | <0.001 |
| Practice Setting | |||||||
| Office-Based | 757 (59.5) | 1040 (87.7) | 4.36 (0.28) | 8.61 (0.47) | 33.0 (3.4) | 89.4 (8.8) | 0.001 |
| Outpatient Dept. | 84.6 (9.7) | 96.1 (12.1) | 8.99 (0.99) | 16.6 (1.80) | 7.61 (1.0) | 16.0 (2.6) | 0.002 |
p-values calculated using logistic regression for trend over interval from 1999–2009 in each subgroup.