Table 1.

Relationship between METH use and HIV outcomes

Indicator	Study, Year, Country	Population	Sample Size	Study Design	Study Purpose	Findings
ART adherence	Parsons et al. (2013) USA	HIV-positive gay and bisexual men ART regimen	210	RCT – baseline data	To examine aggregate, threshold, and day-level associations of METH use and non-adherence.	There was a significant association between days of meth use and 90% dose adherence, such that for every additional day of meth use, the odds of being less than 90% adherent increased by 20%.
	Carrico et al. (2010) USA	MSM or transgendered people on ART	122	Cross-sectional	To examine affective correlates of stimulant use and ART adherence among HIV-positive methamphetamine users.	Elevated negative effect was independently associated with a greater likelihood of reporting METH use at least weekly.
	Hinkin et al. (2007) USA	HIV-positive individuals receiving highly active ART	150	Prospective cohort study	To examine the impact of drug use and abuse on medication adherence	Results of logistic regression revealed that drug use was associated with a 4.1 times greater risk of being a poor adherance. 70% of drug users in this study used METH
Viral Load	Fairbairn et al. (2011) Canada	HIV-positive, injection drug users initiating ART	384	Prospective RCT	To demonstrate the association (if any) between crystal METH use and HIV RNA suppression.	Crystal methamphetamine injection was negatively associated with viral load suppression (RH, 0.63; 95% CI, 0.40–0.98).
	King et al. (2009) USA	MSM and/or drug users	835	Cross-sectional	To examine the predisposing, enabling, and need factors associated with detectable viral load (VL).	Participants reporting drug use in the past 30 days, were significantly more likely to have detectable viral loads. The association of recent reported METH use with viral load is about 45% stronger than recent use of other drugs.
	Ellis et al. (2003) USA	HIV-positive METH users and nonusers	230	Cross-sectional – lab measures	To determine whether meth increases HIV replication in humans	METH-use was significantly related to plasma virus load among the subgroup receiving ART.
	Carrico et al. (2007) USA	HIV-positive individuals	936	Randomized behavioral prevention trial	To examine the association among affect regulation, substance use, non-adherence to ART, and immune status.	Among individuals currently on ART, regular stimulant users had a five-fold higher HIV viral load than those who denied regular stimulant use.
CD4+ Count	Shoptaw et al. (2012) USA	Gay and bisexual men	2789	Prospective Cohort – Multicenter AIDS Cohort Study	To examine associations between stimulant use and other substances with immune function biomarkers among HIV+	Significant negative associations were noted for HIV+ ART-using men between CD4+/CD8+ ratios and METH use.