During initial cohort screening, all consenting participants (4,682) found HIV-positive (386) were recruited into the REACH Cohort; 330 individuals consented to participate at baseline. By the time of this analysis, 81 persons were inaccessible, including those deceased (43), relocated out-of-area (16), lost to follow-up (15), withdrawing participation (5), and incarcerated (2), leaving 249 (87% of living participants) available.
The subgroup in this analysis was comparable to the overall REACH Cohort with respect to baseline characteristics including age, gender, ethnicity, initial HCV antibody status, CD4 count, lifetime IDU status, and the proportion homeless over 1 year (P > .05 for all comparisons). Participants inaccessible for the study were more likely to have had a higher baseline HIV viral load (86,054 vs 51,369 copies/ml; P = .029). Otherwise, there were no statistically significant differences between the original and subsequent samples.
At follow-up, the mean age was 44 (range 24 to 75, standard deviation [SD]± 8.4) years; 82% were male; 43% were African American and 6% were Latino; 64% had ever injected drugs, whereas 21% had injected in the prior 30 days; and 24% had spent a night on the street or in a shelter in the last 30 days. Forty-eight percent were on ART, and the overall mean CD4 was 419 cells/µl (SD ± 304). Ninety-four percent had a primary care provider and 40% had a case manager. Seventy-three percent were patients in the public health care system and 3% were patients in Veterans Affairs facilities. Other participant characteristics are shown in .
Population Characteristics of HIV-positive Homeless and Marginally Housed Persons in San Francisco, 1997–2000, by HCV Infection Status at Follow-up
Prevalence of HCV Infection
Of 249 persons studied, 172 (69.1%; 95% CI, 63.3 to 74.8) were found HCV-positive by either antibody or RNA tests at baseline along with 182 (73.1%; 95% CI, 67.6 to 78.6) at follow-up. At follow-up, 155 of 249 (62.2%; 95% CI, 56.2 to 68.3) had active viremia. In univariate analysis, HCV-positive persons at follow-up were more likely current and past injection drug users (P< .001), not on ART (P = .007), more depressed (mean BDI; P = .007), and homeless over 1 year at study baseline (P = .020). They also had higher levels of alanine aminotransferase (ALT; P <.001) and HIV RNA (P =.014). In multivariate analysis, significant independent risk factors of HCV status at follow-up were a history of IDU (OR, 14.0; 95% CI, 7.0 to 28.0) and not receiving ART (OR, 2.1; 95% CI, 1.1 to 4.0).
Of 155 viremic individuals, the median HCV RNA was 1,310,100 IU/ml (SD ± 1.11 M). In univariate analysis, HCV and HIV viral load were significantly correlated with one another (r = .14; P= .047, by Spearman rank correlation test), but there was no significant association between HCV viral load and ALT, CD4, age, or other demographic characteristics.
New HCV Infections
During a median follow-up interval of 28.9 months (range 16 to 60), 10 of 76 (13.2%) HCV-negative individuals became infected as seen by HCV RNA testing, and 8 of 76 (10.5%) developed a positive HCV antibody test, thereby yielding a new infection rate of 4.63% per person-year (ppy; 95% CI, 2.31 to 8.13 ppy).
Of the 22 of 158 persons who were both HCV-negative at baseline and who reported a lifetime history of IDU, 8 of 22 (36.4%) new infections were identified, at a rate of 16.77% ppy (95% CI, 7.62 to 31.27 ppy). Newly infected persons were younger (P = .004), reported IDU (P < .01), had higher mean ALT (P < .001), and had worse depressive symptoms (P = .014). In multivariate analysis, significant independent risk factors of incident HCV infection were a history of IDU (OR, 15.5; 95% CI, 2.6 to 91.7; P < .001) and age younger than 35 (OR, 7.9; 95% CI, 1.5 to 41.4; P= .001).
Among those HCV antibody-positive at baseline, 26 of 173 (15.0%; 95% CI, 9.7 to 20.4) untreated individuals had no evidence of active viremia at follow-up, suggesting resolution of HCV infection without therapy. Lower ALT (P = .031) and homelessness over 1 year at baseline (P =.047) were significant predictors of undetectable HCV viral load. Among baseline HCV-positives, one person was later classified as a false positive on the basis of RNA and RIBA assays.
Seronegative HCV Infection
At the time of interview, 76 participants had no evidence of antibodies to HCV according to a second-generation ELISA. Among them, HCV RNA was detected in 10 individuals for which antibody tests were negative on 2 occasions (8/10) or once following a prior indeterminate result (2/10). The overall prevalence of those with seronegative viremia was 4.0% (10/249; 95% CI, 1.6 to 6.5%), 13.2% (10/76; 95% CI, 5.6 to 20.8) in the subset of those with negative antibody results. Among seronegatives, median HCV viral load was 2,090,380 IU/ml (SD ± 2.00 M). RNA was detected in 2 of 10 at follow-up only; presence of virus without detectable antibody may have reflected acute infection. In the remaining 8, RNA was detected 41.7 (mean) months prior to the last negative HCV antibody result. In this group of persistently seronegative persons, mean HIV RNA was 38,012 copies/ml (vs 14,483 in all negatives; P = .041) and mean CD4 was 215 cells/µl (vs 467; P = .052). HCV seronegative viremia was not significantly associated with ALT, CD4, age, or other demographic characteristics.
Concordance of Self-reported and Objective Findings
Among HCV-positive individuals, 64% (117/182) reported receiving a positive test result prior to interview. Of these, the median self-reported duration of positive status was 2.61 years, 85% (100/117) had a lifetime history of IDU, and 32% (37/117) were currently injecting. Reporting a prior positive antibody test result had a positive predictive value of 98% among the 62% (154/249) who recalled receiving a test result; reporting a negative test result among such persons had a predictive value of 74%.
Thirty-five percent (64/182) of the HCV-positive individuals were unaware of their HCV status. Overall, 12% (29/249) were unsure whether they had undergone testing or were unable to recall their test result. Thirty-two percent (79/249), including 24% (43/182) of HCV-positives, had not been tested. Four percent (11/249) inaccurately stated their test result.
HCV Counseling and Testing
Overall, 61% (152/249) of participants reported having discussed HCV with a health care provider. HCV antibody-positive persons were more likely to identify such encounters (65% vs 49%; P= .026); 76% (139/182) of HCV antibody-positive persons reported having been tested for HCV. In multivariate analyses, nonwhite individuals (OR, 0.26; 95% CI, −0.11 to 0.62; P = .002) and individuals reporting never using injection drugs (OR, 0.14; 95% CI, −0.19 to 0.92; P = .03) were independently associated with not receiving HCV testing.
Forty-seven percent of individuals with prior HCV diagnosis (55/117) indicated behavioral advice had been discussed with a provider, 37% (43/117) had been advised to avoid drinking alcohol, and 30% (35/117) were advised to avoid injection drug use. Concurrently, 38% (45/117) had consumed alcohol at least 1 day in the prior month, though consumption was not significantly associated with secondary prevention advice (P = .668), nor were there significant differences in self-reported drinking compared to HCV antibody-negative persons (P = .661). Forty-nine percent of individuals (57/117) recalled being vaccinated for either hepatitis A or B or both. In serologic testing, 37% (68/182) HCV antibody-positive individuals had evidence of hepatitis B surface antibodies, reflecting either prior HBV exposure or previous vaccination.
Evaluation and Treatment of HCV Infection
Thirty-eight (21%) HCV-positive persons reported referral to a gastroenterology (GI) specialist. Thirteen (7%) had declined liver biopsy, while 21 (12%) had undergone the procedure. Whites were significantly more likely to receive GI referral in a multivariate analysis (OR, 2.86; 95% CI, 1.36 to 5.99; P = .006). Receipt of testing, referral, biopsy, and treatment according to participant characteristics is detailed in .
Receipt of HCV Testing, Gastrointestinal Referral, Liver Biopsy, and HCV Treatment by HIV-positive Homeless and Marginally Housed Persons in San Francisco, 1997–2000, According to Selected Population Characteristics at Study Follow-up
Seven (3.8%; 95% CI, 1.1 to 6.6) HCV-positive persons reported having undergone treatment. Among persons HCV-positive at baseline, 3.5% (6/173) underwent treatment, a crude treatment initiation rate of 1.16% ppy (95% CI, 0.46 to 2.35 ppy). In total, only 18% (32/182) reported having been offered therapy; at follow-up, no one was currently receiving HCV treatment. Of those treated, 4 reported aborted treatment courses ranging from 1 to 6 months (mean 2.75 months) in duration. Three individuals had completed 12 months of treatment with interferon and ribavirin, yet only 1 individual had an undetectable HCV viral load in the 6- to 12-month period following self-reported treatment termination.
Sixty-eight percent (123/182) of HCV-positive persons interviewed were aware HCV treatment was available; however, 3.3% (6/182) indicated that they had declined treatment and 6.6% (12/182) reported their providers had discussed but deferred initiation of therapy. Additionally, 7.7% (14/182) indicated that a plan was made to start therapy in the ensuing 6 months. Finally, to facilitate HCV therapy, 3.8% (7/182) reported treatment for depression, and 1.6% (3/182) reported referral for substance abuse treatment.