Table 2.
Association between volume, individual quality measures, and resource use
| Value | Length of stay | Costs | ||||
|---|---|---|---|---|---|---|
| Unadjusted % difference (95%CI) | Adjusted* % difference (95% CI) | Adjusted** % difference (95% CI) | Unadjusted % difference (95%CI) | Adjusted* % difference | Adjusted** % difference (95% CI) | |
| Hospital volume | ||||||
| 1st quartile | −7.0 (−8.0, −6.1) P<0.0001 |
1.1 (−5.9, 8.7) P=0.7508 |
1.6 (−5.1, 8.8) P=0.6473 |
13.2 (12.2, 14.1) P<0.0001 |
19.8 (3.9, 38.0) P=0.0126 |
18.3 (2.0, 36.3) P=0.0196 |
| 2nd quartile | −7.6 (−8.6, −6.7) P<0.0001 |
0.9 (−7.2, 7.9) P=0.9758 |
0.2 (−6.7, 7.5) P=0.9627 |
−6.9 (−7.7, −6.0) P<0.0001 |
−0.2 (−14.1, 16.0) P=0.9764 |
−1.0 (−14.7, 15.0) 0.8972 |
| 3rd quartile | −7.3 (−8.2, −6.7) P<0.0001 |
−1.6 (−9.1, 6.6) P=0.6978 |
−0.7 (−7.9, 7.0) P=0.8447 |
−4.4 (−5.2, −3.5) P<0.0001 |
0.3 (−14.4, 17.5) P=0.9728 |
0.5 (−14.2, 17.7) P=0.9528 |
| 4th quartile | Referent | Referent | Referent | Referent | Referent | Referent |
| Physician volume | ||||||
| 1st quartile | 0.4 (−0.7, 1.4) P=0.4897 |
1.1 (−1.1, 3.4) P=0.3082 |
0.9 (−1.3, 3.2) P=0.4365 |
10.7 (9.8, 11.7) P<0.0001 |
3.4 (0.9, 6.0) P=0.0086 |
3.1 (0.6, 5.6) 0.0148 |
| 2nd quartile | −3.9 (−4.9, −3.0) P<0.0001 |
−1.0 (−3.3, 1.3) P=0.3958 |
−1.2 (−3.5, 1.2) P=0.3285 |
3.5 (2.5, 4.4) P<0.0001 |
1.1 (−1.6, 3.9) P=0.4320 |
1.0 (−1.7, 3.7) P=0.4831 |
| 3rd quartile | 0.9 (−0.1, 1.9) P=0.0778 |
0.6 (−1.7, 3.0) P=0.5790 |
0.9 (−1.4, 3.3) P=0.4406 |
−0.6 (−1.4, 0.3) P=0.2155 |
−0.5, −3.2, 2.2) P=0.7031 |
−0.3 (−2.9, 2.3) P=0.8027 |
| 4th quartile | Referent | Referent | Referent | Referent | Referent | Referent |
| Measure | ||||||
| Serial compression devices not used | −1.3 (−2.2, −0.5) P=0.0019 |
12.9 (11.7, 14.1) P<0.0001 |
12.5 (11.3, 13.7) P<0.0001 |
−3.8 (−4.5, −3.1) P<0.0001 |
6.0 (5.1, 6.9) P<0.0001 |
6.0 (5.1, 6.9) P<0.0001 |
| Statin not administered | −9.9 (−10.6, −9.2) <0.0001 |
−9.8 (−10.4, −9.1) P<0.0001 |
−9.8 (−10.5, −9.2) P<0.0001 |
−7.9 (−8.4, −7.3) P<0.0001 |
−3.6 (−4.1, −3.1) P<0.0001 |
−3.6 (−4.1, −3.1) P<0.0001 |
| Antibiotics not discontinued | 44.9 (43.9, 45.8) P<0.0001 |
23.1 (22.4,23.8) P<0.0001 |
23.1 (22.4, 23.9) P<0.0001 |
32.2 (31.4, 33.0) P<0.0001 |
14.7 (14.2, 15.2) P<0.0001 |
14.7 (14.2, 15.2) P<0.0001 |
| Aspirin not administered | −14.7 (−15.4, −14.1) P<0.0001 |
−9.8 (−10.4, −9.1) P<0.0001 |
−9.1 (−9.7, −8.4) P<0.0001 |
−9.5 (−10.2, −9.0) P<0.0001 |
−4.5 (−5.0, −4.0) P<0.0001 |
−4.5 (−5.0, −4.0) P<0.0001 |
| Beta-blocker not administered | −9.6 (−10.4, −8.8) P<0.0001 |
−1.1 (−1.8, −0.4) P=0.0006 |
−1.2 (−1.9, −0.5) P=0.0006 |
−5.5 (−6.2, −4.8) P<0.0001 |
0.4 (−0.1, 1.0) P=0.1346 |
0.4 (−0.1, 1.0) P=0.1363 |
| Prophylactic antibiotics not administered | 2.1 (0.6, 3.6) P=0.0060 |
5.2 (3.6, 6.9) P<0.0001 |
5.1 (3.4, 6.8) P<0.0001 |
3.1 (1.7, 4.4) P<0.0001 |
0.1 (−1.1, 1.3) P=0.9018 |
0.1 (−1.1, 1.3) P=0.9158 |
*
Results of 3 models examining volume and quality measures separately, and adjusting for covariates described in Methods.
**
Results of single model examining volume measures and quality, and adjusting for covariates described in Methods