Table 2.

Odds ratio for risk of future HIV viral load ≥20 copies/mL by concentration of emtricitabine triphosphate (FTC-TP) in dried blood spots (DBS) at current visit (n=667 paired assessments).

FTC-TP	Paired assessments n (%)	OR future viremia (95% CI)	p-value	*aOR future viremia (95%; CI)	p-value
BLQ**	56 (8%)	4.1 (2.3, 7.2)	<0.0001	3.4 (1.8, 6.5)	0.0002
Quantifiable	611 (92%)	1	REF	1	REF
Including TFV-DP in DBS
BLQ	56 (8%)	2.6 (1.3, 5.2)	0.006	1.9 (0.9, 4.1)	0.090
Quantifiable	611 (92%)	1	REF	1	REF

FTC-TP: emtricitabine triphosphate; BLQ: below limit of quantification; OR: odds ratio; aOR: adjusted odds ratio; 95% CI: 95% confidence interval; TFV-DP: tenofovir diphosphate.

^*Adjusted for age, gender, race, body mass index, estimated glomerular filtration rate, hematocrit, CD4⁺ T-cell count, and ART class.

^**FTC-TP in DBS was considered BLQ if it was <0.1 pmol/sample.