Table 1. Baseline Characteristics.

Characteristic	ECG on Methadone (n=134)	ECG off Methadone (n=404)	P
Age at time of ECG, years (SD)	45.2 (12.2)	41.5 (10.8)	<0.001
Male (%)	69 (51.5)	212 (52.5)	NS
Race (%)			<0.0001
Caucasian	67 (50.0)	205 (50.7)
African American	33 (24.6)	145 (35.9)
Asian	23 (17.1)	13 (3.2)
Other	11 (8.2)	41 (10.2)
ECG Setting (%)			NS
Emergency department	97 (72.4)	278 (69.0)
Inpatient	16 (11.9)	31 (7.7)
Outpatient	21 (15.7)	95 (23.3)
QTc, msec (SD)	436 (36)	423 (33)	<0.001
QTc ≥ 500 msec (%)	4 (3.0)	6 (1.5)	NS
Dose, mg (range) (SD)*	77 (1-285) (41)	--

^*Dose data missing in 12 patients