Table 2.

Baseline Factors Associated with NNRTI Substitution

	NNRTI substitutions	Patient years follow-up	Rate per 100 patient-years (95%CI)	Univariate HR (95%CI)	p	Multivariate HR (95%CI)	p
Overall	108	2197.9	4.9 (4.1 – 5.9)
Cotrimoxazole prophylaxis⋄
Yes	68	1585.4	4.3 (3.4 – 5.4)	1.0		1.0
No	40	612.5	6.5 (4.8 – 8.9)	1.5 (1.0 – 2.3)	0.03	1.5 (1.0 – 2.2)	0.05
Country income status⋄
High-middle	95	1810.4	5.2 (4.3 – 6.4)	1.5 (0.9 – 2.7)	0.14	1.4 (0.8 – 2.5)	0.23
Low/low-middle	13	387.5	3.4 (1.9 – 5.8)	1.0		1.0
Age
Every one year older	108	2197.9	4.9 (4.1 – 5.9)	1.0 (0.9 – 1.1)	0.79	1.0 (0.9 – 1.1)	0.73
Sex
Male	44	907.0	4.9 (3.6 – 6.5)	1.0		1.0
Female	64	1290.8	5.0 (3.9 – 6.3)	1.0 (0.7 – 1.5)	0.88	1.0 (0.7 – 1.5)	0.85
CD4+ cell count
>200	25	662.2	3.8 (2.6 – 5.6)	1.0		1.0
≤200	59	1244.5	4.7 (3.7 – 6.1)	1.2 (0.8 – 2.0)	0.40	1.4 (0.9 – 2.3)	0.15
Missing	24	291.1	8.2 (5.5 – 12.3)	-		-
Initial NNRTI-based regimen
3TC/AZT/EFV	22	386.3	5.7 (3.7 – 8.6)	1.1 (0.7 – 1.9)	0.65	1.2 (0.7 – 1.9)	0.56
3TC/d4T/EFV	14	375.7	3.7 (2.2 – 6.3)	0.8 (0.4 – 1.4)	0.36	0.7 (0.4 – 1.3)	0.31
3TC/AZT/NVP	25	483.6	5.2 (3.5 – 7.7)	1.0 (0.6 – 1.6)	0.94	0.9 (0.6 – 1.5)	0.79
3TC/d4T/NVP	47	920.7	5.1 (3.8 – 6.8)	1.0		1.0
3TC/TDF/EFV or NVP	0	31.5	0.0 (0.0 – 0.0)	nc		nc

Multivariate HRs for variables not included in the final model show the effect of adjusting for included variables. HRs for missing categories are not shown.

^⋄Included in final multivariate model (cotrimoxazole prophylaxis, country income status).

NNRTI; non-nucleoside reverse transcriptase inhibitor, 95%CI; 95% confidence interval, HR; hazard ratio, 3TC; lamivudine, AZT; zidovudine, EFV; efavirenz, d4T; stavudine, NVP; nevirapine, TDF; tenofovir, nc; non-calculable.