Table 3. Adjusted hazard ratio (95% Confidence intervals) of switching from first-line to second-line due to virological failure.

Variables	Model 1: Calendar time		Model 2: Calendar time and regimen type
	Hazard Ratio (95% CI)	P-value	Hazard Ratio (95% CI)	P-value
Calendar period
1996–2000	1.69 (1.30–2.23)	0.0002	0.83 (0.50–1.35)	0.45
2001–2005	1.81 (1.46–2.25)	<.0001	1.86 (1.31–2.62)	0.001
2006–2010	[Reference]		[Reference]
Demographic
Age
5-year increased from 18 years old	0.95 (0.91–1.01)	0.07	0.98 (0.93–1.04)	0.47
Sex
Male	[Reference]		[Reference]
Female	0.91 (0.67–1.23)	0.53	0.74 (0.52–1.04)	0.08
Region of Origin
Netherlands	[Reference]		[Reference]
European	0.91 (0.61–1.35)	0.63	0.94 (0.61–1.45)	0.79
Sub-Saharan Africa	1.28 (0.94–1.75)	0.11	1.48 (1.06–2.08)	0.02
Other	1.03 (0.78–1.35)	0.85	1.08 (0.80–1.45)	0.61
Route of transmission
Heterosexual	0.90 (0.69–1.17)	0.42	1.10 (0.82–1.46)	0.54
MSM	[Reference]		[Reference]
Injecting Drug Use	0.85 (0.37–1.96)	0.71	0.82 (0.30–2.23)	0.69
Other	0.84 (0.57–1.24)	0.37	0.77 (0.49–1.21)	0.25
Clinical
CD4 cell count at start of cART
CD4<200	2.92 (1.83–4.67)	<.0001	3.16 (1.83–5.46)	<.0001
CD4 201–350	1.50 (0.92–2.44)	0.11	1.64 (0.93–2.89)	0.09
CD4 351–500	[Reference]		[Reference]
CD4 >501	1.36 (0.66–2.81)	0.40	1.20 (0.50–2.86)	0.69
RNA at start of cART
RNA<100 000	[Reference]		[Reference]
RNA 100 000–1 000 000	1.60 (1.27–2.01)	<.0001	1.87 (1.44–2.43)	<.0001
RNA >1 000 000	2.46 (1.68–3.60)	<.0001	3.3 (2.16–5.13)	<.0001
cART Type
3TC/d4T+PI			3.05 (1.79–5.19)	<.0001
3TC/d4T+Boosted-PI			0.87 (0.40–1.90)	0.72
3TC/d4T+NNRTI			1.03 (0.43–2.44)	0.95
3TC/AZT+PI			2.65 (1.65–4.24)	<.0001
3TC/AZT+Boosted-PI			0.60 (0.40–0.92)	0.02
3TC/AZT+NNRTI			0.69 (0.45–1.04)	0.08
TDF/FTC or TDF/3TC+Boosted-PI			0.51 (0.30–0.87)	0.01
TDF/FTC or TDF/3TC+NNRTI			[Reference]