Table 4

The adjusted association between COC and care outcomes among COC indices – results of the GEE model
        Integrated index (ICOC)         Density (UPC)         Dispersion (COCI)         Sequence (SECOC)
Exp(β) Pr > ChiSq Exp(β) Pr > ChiSq Exp(β) Pr > ChiSq Exp(β) Pr > ChiSq
Model of Utilization rate of ED service
Parameter estimate (β)
COC index of medical facility level
 All chronic conditions 0.800 0.0002 0.779 0.0002 0.804 0.0001 0.856 0.0041
 Major chronic condition 0.681 <.0001 0.642 <.0001 0.724 <.0001 0.696 <.0001
COC index of physician level
 All chronic conditions 2.116 <.0001 2.216 <.0001 2.014 <.0001 1.727 <.0001
 Major chronic condition 0.591 <.0001 0.544 <.0001 0.636 <.0001 0.646 <.0001
GEE fit criterion
 QIC 101,066 101,090 101,086 101,133
 QICu 101,063 101,087 101,083 101,130
Model of Hospitalization
Parameter estimate (β)
COC index of medical facility level
 All chronic conditions 0.925 0.0212 0.870 0.0003 0.899 0.0008 1.011 0.7063
 Major chronic condition 0.630 <.0001 0.601 <.0001 0.683 <.0001 0.641 <.0001
COC index of physician level
 All chronic conditions 1.688 <.0001 1.842 <.0001 1.596 <.0001 1.423 <.0001
 Major chronic condition 0.634 <.0001 0.577 <.0001 0.686 <.0001 0.679 <.0001
GEE fit criterion
 QIC 250,260 250,344 250,334 250,390
 QICu 250,257 250,340 250,331 250,387

Note: QIC: quasi-likelihood information criterion for alternating logistic regressions; QICu: QIC for the unstructured working correlation model.

Chan et al.

Chan et al. BMC Health Services Research 2012 12:405   doi:10.1186/1472-6963-12-405

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