Table 2.

Distribution of selected baseline characteristics in initiators of dipeptidyl-peptidase-4 inhibitors (DPP-4i) and thiazolidinediones (TZD) ^a

	DPP-4i (n = 29,366)		TZD (n = 26,332)		Effect of channelingb			weighted TZDc
	N	%	N	%	Odds ratio	95% CI		%
Age Mean (SD)	75.61 (7.10)		74.64 (6.70)		0.945	0.901	0.992	75.62 (7.50)
66 to 75 years old	16407	55.87	16100	61.14	-	-	-	55.60
76 to 85 years old	9782	33.31	8130	30.87	-	-	-	33.65
86 years and above	3177	10.82	2102	7.98	-	-	-	10.74
Male	10590	36.06	10609	40.29	0.884	0.852	0.916	35.94
White	22245	75.75	18628	70.74	1.321	1.259	1.387	75.77
Black	3059	10.42	3140	11.92	1.060	0.99	1.134	10.40
Other	4062	13.83	4564	17.33	(reference)			13.83
Comorbiditiesd
Connective tissue disease	9966	33.94	7763	29.48	1.108	1.067	1.15	34.08
Depression	4709	16.04	3712	14.10	1.003	0.955	1.054	16.15
Chronic obstructive pulmonary disease	5595	19.05	3999	15.19	1.080	1.030	1.133	18.88
Chronic kidney disease	5790	19.72	4031	15.31	1.114	1.058	1.172	19.70
Congestive heart failure	7740	26.36	4373	16.61	1.430	1.361	1.502	26.41
Diabetic neuropathy	6478	22.06	4813	18.28	1.114	1.066	1.164	22.24
Diabetic nephropathy	2660	9.06	1954	7.42	1.040	0.971	1.114	9.12
Diabetic retinopathy	5260	17.91	4432	16.83	1.010	0.965	1.058	17.92
Diabetic cataract	83	0.28	73	0.28	0.988	0.716	1.364	0.28
Gastrointestinal disorders	256	0.87	208	0.79	1.006	0.834	1.215	0.86
Alcohol use e	316	1.08	258	0.98	1.132	0.954	1.342	1.10
Tobacco use e	78	0.27	59	0.22	1.086	0.769	1.534	0.26
Pancreatitis	318	1.08	243	0.92	1.071	0.902	1.273	1.08
Medication usef
Insulin	5409	18.42	4445	16.88	0.977	0.932	1.024	18.51
Metformin	16805	57.23	14282	54.24	1.208	1.165	1.253	57.68
Sulfonylureas	13530	46.07	11352	43.11	1.051	1.015	1.089	46.25
Angiotensin converting enzyme inhibitors	10907	37.14	9899	37.59	0.949	0.914	0.986	37.20
Angiotensin receptor blockers	8184	27.87	5982	22.72	1.216	1.166	1.269	28.11
Statins	19331	65.83	15466	58.73	1.206	1.163	1.252	65.85
Loop diuretics	8294	28.24	5025	19.08	1.245	1.189	1.304	28.26
Other diuretics	7831	26.67	6861	26.06	0.99	0.952	1.03	26.48
Beta blockers	15350	52.27	11288	42.87	1.217	1.174	1.261	52.23
Calcium channel blockers	10334	35.19	8440	32.05	1.049	1.011	1.088	35.39
Healthcare utilizationd
Blood tests	2675	9.11	2261	8.59	1.032	0.972	1.096	9.08
Lipid panel	25483	86.78	22105	83.95	1.196	1.138	1.258	87.01
Influenza vaccinations	16325	55.59	13427	50.99	1.112	1.074	1.151	55.79

^aInitiation defined as no dispensed prescriptions for DPP-4i or TZD during the 6 months before initiation and filling a second prescription of the same drug/drug class within 6 months after the first prescription

^bChanneling between initiation of DPP-4i versus initiation of TZD; odds ratios from multivariable logistic regression model including all covariates presented in the table (i.e., the propensity score model); odds ratios >1.0 indicate more likely to be initiated on DPP-4i than TZD

^cPseudo-population of TZD initiators weighted to the distribution of covariates of the DPP-4i initiators using the propensity score to balance covariates (and therefore control for confounding)

^dMeasured in the 12 months before drug initiation

^eTobacco use and alcohol use and abuse defined using ICD-9-CM codes may be underestimated.

^fMeasured in the 6 months before drug initiation