Fitzpatrick-Lewis et al. BMC Public Health 2011, 11:638 http://www.biomedcentral.com/1471-2458/11/638 substances other than marijuana and alcohol (for com- plete list see [97]). A second study examined the impact of housing on the survival rates for persons with AIDS in the city of San Francisco [98]. The researchers compared the survi- val rates among housed and homeless people using a retrospective chart review of all adults and adolescents (aged ≥ 13 years) in San Francisco who had been diag- nosed with AIDS between 1996 and 2006. To achieve outcome measures, the AIDS registry was computer- matched with a housing database of homeless people who received housing following their AIDS diagnosis. The study population (n = 6,558) was divided between those who had housing (n = 5,917) and those who reported being homeless (n = 641) at diagnosis. Housing was found to significantly impact survival rates for peo- ple with an AIDS diagnosis. Five year survival was 67% for persons who were homeless at diagnosis compared with 81% for housed persons (p < .0001). After adjusting for potentially confounding variables, homelessness was significantly associated with increased mortality (Relative Hazard [RH] 1.20; 95% Confidence Limits [CL] 1.03, 1.41). A third study identified was an RCT that measured the effect of housing assistance on the health and risk behaviours of homeless and unstably housed people with HIV/AIDS [99]. This study included 3 geographic sites, located in Baltimore, Chicago and Los Angeles. Participants were randomized to receive Housing Oppor- tunities for People with AIDS (HOPWA) rental assis- tance with case management (n = 315) or usual care described as customary housing services with case man- agement (n = 315). At 18 months, both groups showed significant improvements in housing status (p < .0001), with greater improvement for the intervention group than control (p < .0001). The proportion of stably housed treatment group members increased from 4.44 to 88.22, while the control group increased from 4.14 to 50.58. Overall, medical care utilization was improved for both groups with no statistically significant difference between groups. Although not statistically significant, decreases in number of sex partners (p = .07), sex trad- ing (p = .07), and unprotected sex with HIV negative/ unknown status partners (p = .08) were observed over time. Self-reported mental and physical health indicated improvement over time for the intervention group, with mean SF-36 Mental Component [100] summary scores increasing from 38.0 to 44.0 (p < 0.0001), and mean SF- 36 Physical Component [100] summary scores increas- ing from 41.7 to 43.9 (p < 0.0001). A fourth study, an observational cohort, examined whether case management was associated with a reduc- tion in acute medical care use and improved biological outcomes in homeless or marginally housed people with Page 8 of 14 HIV [101]. Participants were interviewed every 3 months over a 15 month study period about their use of case managers. A case manager was defined as a person that worked in an agency, talked with participants about ser- vices, and helped participants get services, and case managers could be social workers or nurses but not money managers or doctors. Case management utiliza- tion was categorized based on the percentage of quarters (i.e., 3 month periods) during the 15 month study per- iod during which participants reported meeting with their case manager. Categories of case management uti- lization were defined as: no or rare (reports of ≤25% of quarters), moderate (> 25% but ≤75% of quarters), and consistent (> 75% of quarters). In multivariate models, case management was not associated with changes in primary care utilization, hospitalization or emergency department use. Moderate case management was, how- ever, associated with improved antiretroviral adherence when compared to no or rare case management (b = 0.13; 95% CI, 0.02-0.25). Consistent case management (adjusted odds ratio [AOR], 10.7; 95%CI, 2.3-49.6) and moderate case management (AOR, 6.5; 95% CI, 1.3- 33.0) were both associated with greater than 50% improvement in CD4+ cell count (an indicator of immune function). Interventions for Homeless or Runaway Youth One study examined how age and gender impact change in alcohol and substance misuse and HIV risk beha- viours in a sample of homeless youth [102,103] (see Table 2). The participants were randomly assigned to the Community Reinforcement Approach (CRA) and HIV prevention education (n = 96) or the control usual care group (n = 84). The CRA intervention consisted of 12 weekly sessions to assist the youth with improving their life situations. Within the sessions, the youth iden- tified housing, medical care, job finding, social relations, psychiatric issues, and legal problems as the biggest challenges to improving their lives. Role-playing and homework assignments were incorporated into the ses- sions. The intervention group also received 4 weekly sessions that covered AIDS education and assessment of risk. Overall the intervention group (CRA + HIV educa- tion) reported greater improvement in the use of con- doms than the control group. Univariate analysis revealed a three-way interaction for the frequency of condom use (Wilks’ l = .90, F(2, 111) = 6.48, p < .005, h2 = .11), indicating a change in frequency of level of condom usage as a function of time, age, and treatment type. The youth in the intervention group showed a 37% reduction in substance use compared with the treatment as usual group who showed a 17% reduction in sub- stance use (time effect p < .001; interaction effect p < .05).