Table 3.

Multiple Variable Cox Proportional Hazards Regression Models 1 and 2 for Time to First Dental Visit for Newly Medicaid-Enrolled Children Age 3–14 in Iowa

	Model 1: Regression Model For Total Study Population (N=10,270)		Model 2: Regression Model For Children with a Chronic Condition (N=1,355)
Covariate	Adjusted Hazard Ratio	95% Confidence Interval	Adjusted Hazard Ratio	95% Confidence Interval
MAIN INDEPENDENT VARIABLES
Has a chronic condition
Yes	1.17	1.09, 1.25	n/a	n/a
No*	1.00	-	n/a	n/a
Chronic condition severity
Less severe chronic condition*	n/a	n/a	1.00	-
More severe chronic condition	n/a	n/a	1.05	0.91, 1.20
ASCRIBED FACTORS
Age (years)
3 to 7	1.05	0.97, 1.13	0.92	0.77, 1.09
8 to 12	1.11	1.03, 1.20	0.96	0.81, 1.14
13 to 14*	1.00	-	1.00	-
Sex
Female	1.07	1.02, 1.13	1.04	0.91, 1.18
Male*	1.00	-	1.00	-
PROXIMAL FACTOR
Child used primary medical care in 2005
Yes	1.43	1.34, 1.52	1.20	0.97, 1.49
No*	1.00	-	1.00	-
IMMEDIATE FACTORS
At least one Medicaid-enrolled sibling in the household	int	-	int	-
At least one Medicaid-enrolled adult in the household	int	-	int	-
Interaction between having at least one Medicaid- enrolled sibling and adult variables
No enrolled sibling/no enrolled adult*	1.00	1.00	1.00	-
No enrolled sibling/enrolled adult	1.03	0.92, 1.15	0.99	0.75, 1.29
Enrolled sibling/no enrolled adult	1.36	1.12, 1.64	1.67	1.10, 2.55
Enrolled sibling/enrolled adult	1.86	1.43, 2.41	2.68	1.48, 4.85
INTERMEDIATE FACTOR
Degree of rurality of child’s county of residence
Metropolitan*	1.00	-	1.00	-
Urban adjacent to metropolitan	0.90	0.84, 0.96	0.76	0.64, 0.90
Urban non-adjacent to metropolitan	0.90	0.84, 0.96	0.83	0.71, 0.97
Rural	1.06	0.96, 1.18	0.75	0.57, 0.99
DISTAL FACTOR
Resides in a dental Health Professional Shortage Area
Yes	0.94	0.89, 0.99	0.94	0.82, 1.07
No*	1.00	-	1.00	-

^*reference group

n/a variable not included in the model

int significant interaction; refer to results for each combination of factor levels below