. 2014 Nov 21;14:570. doi: 10.1186/s12913-014-0570-9

Table 3.

Regression analysis results for the association between type of health insurance and utilization of hypertension-related inpatient services among patients with hypertension

	Hospital admission	Length of stay	Hospitalization costs
	Odds ratio [95% CI]	Factor change ^a [95% CI]	Factor change ^a [95% CI]
Type of insurance
Medical Aid Class I^b	1.710^***	1.305^***	1.412^***
Medical Aid Class I^b	[1.632-1.792]	[1.243-1.370]	[1.289-1.545]
Medical Aid Class II^c	1.413^***	1.419^***	1.103
Medical Aid Class II^c	[1.271-1.570]	[1.263-1.594]	[0.907-1.340]
Health Insurance [ref]	-	-	-
Age	1.029^***	1.014^***	1.037^***
Age	[1.028-1.030]	[1.013-1.016]	[1.035-1.040]
Gender
Male	0.999	0.992	0.893^**
Male	[0.969-1.030]	[0.959-1.027]	[0.839-0.951]
Female [ref]	-	-	-
Total costs for insurance-covered services (all causes) ^d	1.013^***	1.012^***	1.024^***
	[1.012-1.014]	[1.011-1.013]	[1.022-1.027]
Total No. outpatient visits (all causes)	0.981^***	0.970^***	0.988^*
Total No. outpatient visits (all causes)	[0.975-0.986]	[0.966-0.974]	[0.978-0.998]
Elixhauser comorbidity index	1.577^***	1.074^***	1.784^***
Elixhauser comorbidity index	[1.563-1.592]	[1.064-1.084]	[1.749-1.822]
Ownership of institution
Non-government owned	1.004	0.891	1.197^*
Non-government owned	[0.910-1.107]	[0.805-0.986]	[1.013-1.416]
Government owned [ref]	-	-	-
Type of institution
Tertiary hospital	2.117^***	0.544^***	1.240^**
Tertiary hospital	[2.005-2.235]	[0.505-0.585]	[1.091-1.409]
General hospital	1.923^***	0.713^***	1.065
General hospital	[1.844-2.006]	[0.670-0.758]	[0.949-1.194]
Hospital^e [ref]	2.240^***	-	-
Hospital^e [ref]	[2.126-2.360]
Long-term care facility	5.213^***	2.919^***	2. 474^***
Long-term care facility	[4.580-5.933]	[2.583-3.300]	[2.024-3.022]
Public health center	1.260^***	0.696^***	0.880
Public health center	[1.130-1.406]	[0.616-0.786]	[0.715-1.084]
Clinic^f [ref]	-	0.673^***	0.549^***
Clinic^f [ref]		[0.636-0.712]	[0.496-0.607]
Location of institution
Six major cities	1.134^***	1.358^***	0.992
Six major cities	[1.085-1.185]	[1.293-1.426]	[0.907-1.085]
Nine provinces	1.248^***	1.145^***	1.046
Nine provinces	[1.200-1.298]	[1.096-1.196]	[0.968-1.131]
Seoul [ref]	-	-	-
c -statistic	0.778
Dispersion parameter		1.481
P -value for LR test ^g		< 0.0001
Vuongstatistic ^h		93.73^***

All inpatient services were hypertension-related, with a primary, secondary, tertiary, or quaternary diagnosis of hypertension; Robust standard errors in parenthesis; All covariates at index-date otherwise specified; ^aExp (coefficient estimate) = factor change in expected hospitalization costs for a unit increase in a covariate; ^bBeneficiaries of Medical Aid who are not able to work at all; ^cBeneficiaries of Medical Aid who are able to work; ^dInsurance-covered medical costs during the 6-month baseline period in 2006 Korean won (one US dollar approximately equals 1,200 Korean won); ^eHospital used as a reference for length-of-stay and hospitalization costs variable; ^fClinic used as a reference for the hospital admission variable; ^gLikelihood Ratio (LR) test comparing negative binomial model against Poisson model; ^hComparing zero-inflated negative binomial model against negative binomial model; * p <0.05; ** p <0.001; *** p <0.0001; SE = standard error; 95% CI =95% confidence interval.