Table 2. Multivariate Regression Analysis of Safety-Net Burden on Outcomes.
| Patient Characteristics | Laparoscopy, % Difference (95% CI) |
Complications, Log % (95% CI) |
Negative Appendectomy, Log % (95% CI) |
Perforated Appendicitis, Log % (95% CI) |
LOS, Relative Risk (95% CI) |
Cost, Log $ (95% CI) |
|---|---|---|---|---|---|---|
| Safety-net burden | ||||||
| Low-burden | 1 [Reference] |
1 [Reference] |
1 [Reference] |
1 [Reference] |
1 [Reference] |
1 [Reference] |
| Medium-burden | −10.2 (−16.9 to −3.5)a |
−0.06 (−0.21 to 0.09) |
0.08 (−0.06 to 0.22) |
0.04 (−0.00 to 0.08) |
1.12 (1.07 to 1.18)a |
0.05 (−0.03 to 0.13) |
| High-burden | −16.9 (−26.1 to −7.6)a |
−0.19 (−0.38 to 0.01) |
−0.01 (−0.19 to 0.16) |
0.07 (0.03 to 0.12)b |
1.17 (1.09 to 1.26)a |
−0.02 (−0.11 to 0.07) |
| NPNA | −0.55 (−50.2 to 49.1) |
−0.76 (−1.85 to 0.32) |
−5.71 (−6.54 to −4.87)b |
−2.23 (−2.38 to −2.09)b | 0.16 (0.09 to 0.28)b |
−1.40 (−1.87 to −0.92)b |
| Log negative appendectomy | 6.6 (1.3 to 11.9)b |
0.05 (−0.06 to 0.16) |
NA | −0.15 (−0.18 to −0.13)b |
0.93 (0.90 to 0.96)b |
−0.05 (−0.11 to −0.01)b |
| Log perforation | 0.8 (−18.9 to 20.5) |
0.30 (−0.12 to 0.73) |
−2.10 (−2.43 to −1.77)b |
NA | 0.69 (0.56 to 0.84)b |
−0.31 (−0.50 to −0.12) |
| Log complication | −2.4 (−7.5 to 2.7) |
NA | 0.06 (−0.05 to 0.16) |
0.02 (−0.01 to 0.05) |
1.09 (1.04 to 1.13)b |
0.12 (0.07 to 0.17)b |
| % Teaching hospital | 9.7 (−0.6 to 19.9) |
0.04 (−0.18 to 0.26) |
−0.06 (−0.27 to 0.16) |
0.03 (−0.03 to 0.08) |
1.08 (1.03 to 1.14)b |
0.09 (−0.01 to 0.19) |
| % Laparoscopic | 0.2 (−0.3 to 0.8) |
.001 (−0.004 to 0.001) |
0.003 (0.001 to 0.005)b |
0.00 (−0.00 to 0.00) |
0.998 (0.997 to 0.999)b |
0.002 (0.001 to 0.002)b |
| % Female | 0.25 (−0.27 to 0.76) |
0.70 (−0.43 to 1.80) |
1.4 (0.38 to 2.52)b |
−0.6 (−1.00 to −0.40)b |
NA | NA |
| % White | 0.07 (−0.05 to 0.19) |
0.00 (−0.002 to 0.002) |
0.22 (−0.02 to 0.46) |
−0.00 (−0.01 to 0.00) |
NA | NA |
| Hospital Characteristics | ||||||
| Annual appendectomy volume, No. | ||||||
| 1-230 | 1 [Reference] |
1 [Reference] |
1 [Reference] |
1 [Reference] |
1 [Reference] |
1 [Reference] |
| 231-573 | 3.3 (−4.7 to 11.2) |
−0.16 (−0.33 to 0.01) |
0.04 (−0.12 to 0.21) |
0.03 (−0.01 to 0.07) |
1.03 (0.97 to 1.10) |
−0.07 (−0.15 to 0.01) |
| 574-1217 | 8.5 (−0.2 to 17.1) |
−0.25 (−0.43 to −0.07)b |
0.04 (−0.13 to 0.21) |
0.04 (−0.01 to 0.09) |
1.01 (0.93 to 1.10) |
−0.11 (−0.19 to −0.03)b |
| >1217 | 11.1 (1.7 to 20.5)b |
−0.33 (−0.52 to −0.13)b |
0.12 (−0.06 to 0.30) |
0.06 (0.01 to 0.11)b |
1.04 (0.99 to 1.10) |
−0.11 (−0.19 to −0.02)b |
| Hospital type | ||||||
| Private nonprofit | 1 [Reference] |
1 [Reference] |
1 [Reference] |
1 [Reference] |
1 [Reference] |
1 [Reference] |
| Public | −0.59 (−8.1 to 6.9) |
−0.01 (−0.17 to 0.14) |
−0.07 (−0.22 to 0.09) |
−0.04 (−0.08 to −0.00)b |
0.98 (0.91 to 1.06) |
0.06 (−0.02 to 0.12) |
| Private for-profit | −3.5 (−10.5 to 3.5) |
−0.22 (−0.37 to −0.08)b |
−0.01 (−0.16 to 0.13) |
0.01 (−0.02 to 0.05) |
1.04 (0.97 to 1.11) |
0.05 (−0.02 to 0.11) |
Abbreviations: LOS, length of stay; NA, not applicable; NPNA, normal, nonperforated appendectomy. aP < .01. bP < .05.