Increasing methamphetamine injection among non-MSM who inject drugs in King County, Washington.

Background: In King County, Washington, the HIV prevalence among men who have sex with men (MSM) who inject methamphetamine is high, while it is low among other people who inject drugs (PWID). Local drug problem indicators suggest that methamphetamine use is increasing. The extent to which this increase affects MSM and non-MSM, and whether MSM and non-MSM networks are connected through injection equipment sharing, is unknown.

Methods: We used data from two serial cross-sectional surveys of PWID including five biannual surveys of Public Health-Seattle and King County Needle and Syringe Exchange Program clients (NSEP, N=2135, 2009-2017) and three National HIV Behavioral Surveillance IDU surveys (NHBS, N=1709, 2009-2015).

Results: The proportion of non-MSM PWID reporting any recent methamphetamine injection increased significantly from approximately 20% in 2009 to 65% in 2017. Most of this increase was attributable to injecting methamphetamine in combination with heroin (goofballs). PWID who injected goofballs were more likely to be younger, homeless or unstably housed, report daily injection, and self-report an opioid overdose in the past year than other PWID. The majority of PWID who injected methamphetamine reported sharing any injection equipment. Among these PWID, 43% of MSM had last shared injection equipment with a non-MSM. Eight percent of non-MSM men and 15% of women had last shared equipment with an MSM.

Conclusions: Given non-trivial rates of sharing injection equipment with methamphetamine-using MSM, a population with an HIV prevalence of 40%, non-MSM who inject methamphetamine could be an emerging population at risk for acquiring HIV.