Table 3.
Comparison of Adjusted Utilization (per 1,000 patients per month) Over 12 and 21 Months at Medical Home Prototype and 19 Other Group Health Clinics
| Utilization visits per 1,000 patients per month (95% confidence interval) | Interval | PCMH prototype (n = 1,947) | Other clinics (n = 39,396) | Relative difference | p Value |
| Primary care | 12 Month | 424 (409, 441) | 442 (438, 445) | 96% (93%, 100%) | .052 |
| 21 Month | 406 (391, 421) | 434 (430, 438) | 93% (90%, 97%) | <.001 | |
| Specialty care | 12 Month | 438 (419, 458) | 406 (402, 411) | 108% (103%, 113%) | .001 |
| 21 Month | 445 (427, 463) | 425 (421, 430) | 105% (100%, 109%) | .036 | |
| Emergency department and urgent care | 12 Month | 39 (36, 43) | 50 (49, 51) | 78% (72%, 84%) | <.001 |
| 21 Month | 44 (41, 47) | 56 (55, 57) | 79% (73%, 85%) | <.001 | |
| Inpatient admissions (ambulatory care-sensitive conditions only) | 12 Month | 1.1 (1.0, 1.3) | 1.5 (1.5, 1.6) | 75% (65%, 87%) | <.001 |
| 21 Month | 1.5 (1.3, 1.7) | 1.8 (1.7, 1.8) | 82% (72%, 93%) | .002 | |
| Inpatient admissions (all causes) | 12 Month | 13 (11, 14) | 13 (13, 13) | 98% (89%, 107%) | .625 |
| 21 Month | 14 (13, 15) | 15 (14, 15) | 95% (88%, 104%) | .265 | |
| Consulting nurse calls | 12 Month | 122 (114, 130) | 133 (131, 135) | 91% (85%, 98%) | .007 |
| 24 Month | 119 (112, 126) | 139 (138, 141) | 85% (80%, 90%) | <.001 | |
| Secure messages | 12 Month | 241 (227, 255) | 116 (113, 118) | 208% (196%, 221%) | <.001 |
| 24 Month | 269 (255, 284) | 134 (132, 137) | 200% (189%, 212%) | <.001 | |
| Telephone encounters | 12 Month | 540 (518, 564) | 462 (458, 468) | 117% (112%, 122%) | <.001 |
| 24 Month | 541 (520, 563) | 492 (487, 497) | 110% (106%, 115%) | <.001 |
Note: PCMH = patient-centered medical home. Adjusted rates and rate ratios estimated from generalized linear models run using a log link, Poisson error, correcting for over dispersion, and adjusting for age, gender, and diagnostic cost group (DxCG score) at baseline (2006).