398 Table 1 Characteristics of HIV-infected participants in San Francisco by survey site, 2008 AIDS Behav (2012) 16:396–403 Clinic site Age Median (IQR) Race/ethnicity White Black Latino Other Gender/sexual orientation MSM Heterosexual men Women Transgender Monthly income Less than $2,000/month More than $2,000/month SFGH N = 504 (%) Mofﬁtt N = 153 (%) Total N = 657 (%) 45 (39–51) 45 (40–54) 45 (39–51) z = -1.72, P [ |z| = 0.08 222 (44) 133 (27) 65 (13) 81 (16) 319 (70) 64 (14) 53 (12) 20 (4) 420 (86) 68 (14) 88 (58) 25 (16) 16 (11) 23 (15) 116 (79) 8(5) 19 (13) 3 (2) 70 (46) 81 (54) 310 (47) 158 (24) 81 (12) 104 (16) 435 (72) 72 (12) 72 (12) 23 (4) 490 (77) 149 (23) v2 = 10.09, P = 0.02 v2 = 9.90, P = 0.02 v2 = 101.69, P \ 0.001 from HIV-uninfected respondents (81) leaving 657 surveys for analysis: 77% (504) were from the County and 23% (153) were from the University. The demographics of survey participants varied between the two sites (see Table 1). Methamphetamine Use, 2008 Prevalence of reported methamphetamine use ranged from 11% among women to 35% among MSM in 2008 (Fig. 1a). The mean (±SD) age of methamphetamine users was 42.7 ± 8.7 vs. 46.1 ± 9.3 years in non-users (t = 4.304, P \ 0.001). Methamphetamine users versus non-users were more likely to be MSM (75 vs. 62%, v2 = 10.65, P \ 0.001), white (56 vs. 43%, v2 = 8.97, P \ 0.01), and earn less than $2,000/month (90 vs. 71%, v2 = 27.16, P \ 0.001) (Fig. 1b, c). For MSM, further subgroup anal- ysis revealed that methamphetamine use was higher at the County than at the University (40 vs. 22%, v2 = 10.92, P = 0.001), though this difference was not signiﬁcant within similar income groups. For white participants, methamphetamine use was also higher at the County than at the University (83 vs. 17%, v2 = 11.72, P = 0.001), but again this difference was not signiﬁcant when stratiﬁed by income group. There was no signiﬁcant difference in methamphetamine use between clinic sites in any other gender/orientation group or race/ethnicity group. Of those who reported using methamphetamine in the past 12 months in 2008, 53% met criteria for dependency on the Substance Dependence Scale (SDS, a screening tool developed to assess opiate dependence [25] and subse- quently validated by the DSM III for assessing amphet- amine dependence [26]). 123 Methamphetamine Use, 2004, 2006, 2008 Similar surveys were conducted in an identical manner in 2004 and 2006. This series of cross-sectional analyses provided an opportunity to assess the trends in the rate of methamphetamine use in three samples of the same underlying population over time. At the County clinic, the difference in methamphetamine use among MSM between 2004 and 2008 was not statistically signiﬁcant (v2 = 0.03, P = 0.86), and the difference between 2006 and 2008 was insigniﬁcant when controlled for age and race (z = 1.61, P [ |z| = 0.11). At the University clinic, the difference in methamphetamine use between 2006 and 2008 was not statistically signiﬁcant (v2 = 1.76, P = 0.19), and the difference between 2004 and 2008 was insigniﬁcant (z = 1.93, P [ |z| = 0.053) when controlled for age. Methamphetamine Use and Sexual Behavior, 2008 MSM who reported methamphetamine use in the past 12 months reported a median of 3 sex partners (inter- quartile range (IQR): 1–7) in the past 6 months versus a median of 1 sex partner (IQR: 0–2) among those who denied using methamphetamine in the past 12 months (z = -6.51, P [ |z| = 0.00). This trend was less pro- nounced among women, as both those who reported and denied methamphetamine use in the past 12 months had a median of 1 sex partner in the past 6 months, though the ranges varied (IQR: 1–3 vs. IQR: 0–1, z = -2.32, P [ |z| = 0.02). Among MSM who reported methamphet- amine use in the past 12 months, 27% reported having had unprotected sex sometimes, often or always in the past 6 months vs. 10% of MSM who denied methamphetamine