Table 1.

Summary of individuals with virological failure (VF) on a first-line TDF-containing regimen and two comparison groups: (i) antiretroviral therapy (ARV)-naïve individuals and (ii) individuals with VF on a first-line thymidine analog-containing regimen according to treatment regimen, region and subtype.

Characteristics	TDF-containing regimen (n = 2,873)	Comparison groups
		ARV-naïve (n = 50,803)	Thymidine analog-containing regimen (n = 5,805)
NRTs	TDF + 3TC (64%), TDF + FTC (36%)	None	D4T + 3TC (64%), AZT + 3TC (36%)
NNRTIs	EFV (79%), NVP (21%)	None	EFV (53%), NVP (47%)
Regimens	TDF + 3TC + EFV (49%), TDF + FTC + EFV (30%), TDF + 3TC + NVP (15%), TDF + FTC + NVP (6%)	None	D4T + 3TC + EFV (35%), D4T + 3TC + NVP (30%), AZT + 3TC + EFV (18%), AZT + 3TC + NVP (17%)
Region	LMIC (72%)  Sub-Saharan Africa (56%), South/Southeast Asia (15%), Latin America (1%)	LMIC (49%)  Sub-Saharan Africa (23%), South/Southeast Asia (13%), Latin America/Caribbean (11%), Former Soviet Union (3%)	LMIC (88%)  Sub-Saharan Africa (65%), South/Southeast Asia (19%), Latin America (2%), Former Soviet Union (2%)
	UIC (28%)  Europe (22%), North America (6%)	UIC (51%)  Europe (23%), North America (18%), Asia UICs (10%)	UIC (12%)  Europe (6%), North America (6%), Asia UICs (1%)
Subtype	C (53%), B (20%), CRF01_AE (13%), G (5%), A (4%), Other (6%)	B (53%), C (15%), CRF01_AG (11%), A (7%), CRF02_AG (5%), Other (10%)	C (52%), CRF01_AE (16%), B (10%), A (7%), CRF02_AG (5%), Other (11%)
Sample year, median (IQR)	2012 (2010 − 2013)	2006 (2003–2008)	2008 (2006–2011)
Duration of therapy available, median (IQR) in weeks	63%, 43 (21–85)		39%, 97 (52–171)

Abbreviation: TDF – tenofovir disoproxil fumarate; FTC – emtricitabine; 3TC – lamivudine; AZT – zidovudine; D4T – stavudine; NVP – nevirapine; EFV – efavirenz; LMIC – low/middle-income country; UIC – upper-income country.