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. Author manuscript; available in PMC: 2008 Feb 8.
Published in final edited form as: Inquiry. 2006;43(2):150–159. doi: 10.5034/inquiryjrnl_43.2.150

Table 4.

Incidence rate rations from negative binomial models

No fixed effects
 With hospital fixed effects
All centers
 All centers
 >10 registrations
 >20 registrations
Sample IRR 95% CI (1) IRR 95% CI (2) IRR 95% CI (3) IRR 95% CI (4)
Performance = actual graft survival rate - expected graft survival rate
 All registrants 3.66 [1.69, 7.96]** 1.10 [.77, 1.57] 1.07 [.73, 1.57] 1.14 [.75, 1.73]
 College degreea 6.01 [1.95, 18.56]** 1.84 [.76, 4.45] 1.98 [.74, 5.34] 3.39 [1.09, 10.53]**
 Age 18-40 4.81 [1.96, 11.77]** 2.07 [1.27, 3.35]** 2.03 [1.21, 3.40]** 2.35 [1.33, 4.13]**
 Private insurance 5.21 [2.11, 12.84]** 1.19 [.70, 2.03] 1.09 [.61, 1.97] 1.39 [.72, 2.67]
 Living donor 2.90 [1.06, 7.93]** 1.34 [.83, 2.16] 1.37 [.82, 2.28] 1.13 [.65, 1.96]
Performance = actual graft survival rate
 All registrants 3.00 [1.50, 6.00]** 1.16 [.82, 1.63] 1.04 [.72, 1.52] 1.19 [.80. 1.77]
 College degreea 4.04 [1.54, 10.58]** 1.50 [.64, 3.53] 1.59 [.61, 4.16] 2.98 [1.00, 8.84]**
 Age 18-40 3.83 [1.73, 8.49]** 2.06 [1.30, 3.25]** 1.92 [1.18, 3.12]** 2.21 [1.30, 3.76]**
 Private insurance 4.39 [1.95, 9.85]** 1.23 [.74, 2.07] 1.06 [.60, 1.88] 1.45 [.77, 2.72]
 Living donor 3.09 [1.27, 7.52]** 1.47 [.93, 2.32]* 1.42 [.87, 2.31] 1.24 [.73, 2.10]
Performance = observed/expected graft failureb
 All registrants .89 [.82, .96]** .99 [.96, 1.03] 1.00 [.96, 1.04] 1.00 [.96, 1.04]
 College degreea .84 [.75, .94]** .95 [.87, 1.04] .96 [.87, 1.06] .93 [.83, 1.05]
 Age 18-40 .87 [.79, .96]** .94 [.89, .98]** .94 [.89, .99]** .93 [.87, .98]**
 Private insurance .85 [.78, .94]** .97 [.92, 1.03] .99 [.93, 1.05] .97 [.91, 1.04]
 Living donor .93 [.84, 1.03] .99 [.94, 1.04] .98 [.93, 1.04] 1.00 [.94, 1.06]
Performance = z-score
 All registrants 1.04 [1.02, 1.07] 1.00 [.99, 1.01] 1.00 [.99, 1.01] 1.00 [.99, 1.02]
 College degreea 1.08 [1.04, 1.11]** 1.02 [1.00, 1.05]* 1.02 [1.00, 1.05]* 1.03 [1.00, 1.06]**
 Age 18-40 1.05 [1.03, 1.08]** 1.02 [1.01, 1.03]** 1.02 [1.01, 1.03]** 1.02 [1.01, 1.03]**
 Private insurance 1.06 [1.03, 1.08]** 1.01 [.99, 1.02] 1.01 [.99, 1.02] 1.01 [.99, 1.03]
 Living donor 1.04 [1.01, 1.07]** 1.00 [.99, 1.02] 1.00 [.99, 1.02] 1.00 [.99, 1.01]
Number of hospitals 206 206 151 104
Number of observationsc 1,005 1,005 745 513

Note: IRR = incidence rate ratio; CI = confidence interval.

a

We observe educational attainment only for patients who registered on the waiting list, not for the 68% of living donor recipients who did not register prior to transplantation.

b

Higher values indicate worse perfomance.

c

Each center is observed for, at most, five periods.

*

p < .10.

**

p < .05.