Table 2. Comparison of the estimates for the effect of first HAART regimen and history of injection drug use on the probability of achieving viral suppression at 6 months according to different methods to control for confounding.

	Odds ratio (95% confidence interval)
	No history of injection drug use	History of injection drug use
Crude model
First HAART regimen (ATA/r vs. EFV)	1.66 (1.18–2.33)	1.51 (1.03–2.23)
Different modeling techniques
First HAART regimen (ATA/r vs. EFV)
Multivariable model	1.51 (1.04–2.18)	1.95 (1.25–3.04)
Confounder model	1.51 (1.05–2.17)	1.95 (1.27–2.98)
Regression adjusted using propensity score	1.45 (1.01 –2.07)	1.76 (1.17–2.63)
Regression adjusted using quintiles of the propensity score	1.43 (1.00–2.04)	1.77 (1.18–2.66)
Regression adjusted using IPTW	1.46 (1.15–1.86)	1.74 (1.32–2.28)

ATA/r, atazanavir boosted with 400 mg/day or less of ritonavir; EFV, efavirenz; IPTW, inverse probability of treatment weighted.