TABLE 3.
Factors Associated With Having Laboratory Evidence of HIV Care Within 90 Days of a Positive HIV Test in Poisson Risk Models, for 775 Clients Tested in LA and San Francisco, CA, August 2007–March 2009
| Model 1 |
Model 2 |
Model 4 |
||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Total |
Linked < 90 d |
|||||||||||
| n | % | n | % | RR* | 95% CI | aRR1† | 95% CI | aRR2‡ | 95% CI | aRR4§ | 95% CI | |
| Exposure variables | ||||||||||||
| Received result and referral (model 4) |
||||||||||||
| Yes | 461 | 59.5 | 307 | 66.7 | 1.33 | 1.16 to 1.51 | 1.35 | 1.20 to 1.51 | ||||
| No | 314 | 40.5 | 158 | 50.3 | ||||||||
| Tested with the rapid test algorithm (RTA) (models 2 and 4) |
||||||||||||
| Overall | 179 | 23.1 | 111 | 62.0 | 1.04 | 0.91 to 1.19 | 1.09 | 0.98 to 1.23 | ||||
| 596 | 76.9 | 354 | 59.4 | |||||||||
| Model interaction terms, strata of exposure and covariates |
||||||||||||
| Neither exposed to the RTA nor MSM |
177 | 22.8 | 106 | 59.9 | Ref | Ref | ||||||
| MSM but not exposed to the RTA |
419 | 54.1 | 248 | 59.2 | 0.99 | 0.79 to 1.24 | 1.02 | 0.89 to 1.16 | 1.01 | 0.89 to 1.15 | ||
| Exposed to the RTA but not MSM |
43 | 5.5 | 35 | 81.4 | 1.36 | 0.93 to 1.99 | 1.43 | 1.11 to 1.84 | 1.25 | .97 to 1.62 | ||
| Both exposed to the RTA and MSM |
136 | 17.5 | 76 | 55.9 | 0.93 | 0.69 to 1.25 | 0.98 | 0.80 to 1.21 | 0.87 | 0.70 to 1.07 | ||
| Not exposed to the RTA and not previously diagnosed |
476 | 61.4 | 280 | 58.8 | Ref | Ref | ||||||
| Not exposed to the RTA and previously diagnosed |
120 | 15.4 | 74 | 61.7 | 1.05 | 0.81 to 1.36 | 1.03 | 0.89 to 1.20 | 1.08 | 0.95 to 1.22 | ||
| Exposed to the RTA and not previously diagnosed |
173 | 22.3 | 106 | 61.3 | 1.04 | 0.83 to 1.30 | 1.43 | 1.11 to 1.84 | 1.25 | 0.97 to 1.62 | ||
| Exposed to the RTA and previously diagnosed |
6 | 0.8 | 5 | 88.3 | 1.42 | 0.58 to 3.44 | 1.81 | 1.00 to 3.28 | 1.57 | 0.85 to 2.89 | ||
| Random effect for study site mixture test P value∥ |
0.0075 | 0.0154 | 0.2213 | |||||||||
RR, unadjusted ratio of the probability of having laboratory evidence (at least one HIV-1 VL reported to HIV surveillance) within 90 days of the study HIV test date, relative to the same probability in the reference category for each characteristic listed in the first column.
aRR1 obtained from a Poisson risk model23 that included a random intercept for study site; model 1 includes the main effect of the intervention (rapid test algorithm with same-day referral) overall and indicator variables for race, ethnicity, homeless status, history of any HIV test, and whether the participant received the result of their most recent test. Neither the interaction terms nor an indicator for receipt of results and referral (hypothesized to be an intermediate effect of the intervention on the probability of having laboratory evidence of HIV care within 90 days of the date of HIV testing) were included in this model.
aRR2 for model 2. The model was exactly the same as model 1 except it also included multiplicative interaction terms for the effect of RTA by risk group (categorized as MSM and non-MSM) and a multiplicative interaction term for the effect of RTA across categories of client self-report of a positive HIV test result before the current study HIV test date.
aRR4 for model 4. Same as model 2, with the addition of the hypothesized intermediate variable indicating receipt of results and referral.
Mixture test P value for the effect of the site random intercept term in each model. Models with P <0.05 indicate significant unexplained heterogeneity in the baseline probability of being in HIV care within 90 days of the HIV test date across study sites.
aRR, adjusted relative risk; CI, confidence interval; RR, relative risk.