Table 3.
Multivariate logistic regression of factors associated with phylogenetic clustering, including multi‐risk profiles, among hepatitis C virus (HCV) Core‐E2 sequences (at 5% genetic distance threshold) among participants from five studies of recent HCV infection in Australia and New Zealand recruited between 2004 and 2015
| Characteristic | Overall | Unclustered | Clustered | Membership in cluster n ≥ 2 | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Total n (%) | (n = 237) | (n = 129) | (n = 108) | Unadjusted | Adjusted for HIV infection | Adjusted for multi‐risk profile | ||||||
| Odds ratio | 95% CI | p | Odds ratio | 95% CI | p | Odds ratio | 95% CI | p | ||||
| City | ||||||||||||
| Othera | 40 (17%) | 28 (21%) | 12 (11%) | Ref | – | – | Ref | – | – | Ref | – | – |
| Sydney | 109 (46%) | 57 (44%) | 52 (48%) | 2.13 | 0.98, 4.61 | 0.056 | 1.15 | 0.47, 2.81 | 0.753 | 1.41 | 0.60, 3.29 | 0.433 |
| Melbourne | 88 (37%) | 44 (34%) | 44 (41%) | 2.33 | 1.05, 5.17 | 0.037 | 1.71 | 0.73, 4.02 | 0.217 | 2.18 | 0.93, 5.09 | 0.072 |
| HIV infection | ||||||||||||
| Negative | 114 (48%) | 80 (62%) | 34 (31%) | Ref | – | – | Ref | – | – | NI | NI | NI |
| Positive | 123 (52%) | 49 (38%) | 74 (69%) | 3.55 | 2.07, 6.09 | <0.001 | 2.73 | 1.45, 5.15 | 0.002 | NI | NI | NI |
| HCV genotype | ||||||||||||
| 1a | 131 (55%) | 86 (67%) | 45 (42%) | Ref | – | – | Ref | – | – | Ref | – | – |
| 3a | 89 (38%) | 38 (29%) | 51 (47%) | 2.56 | 1.47, 4.46 | 0.001 | 1.83 | 0.99, 3.37 | 0.052 | 1.94 | 1.06, 3.57 | 0.032 |
| Other | 17 (7%) | 5 (4%) | 12 (11%) | 4.59 | 1.52, 13.83 | 0.007 | 3.28 | 1.02, 10.54 | 0.046 | 4.26 | 1.31, 13.84 | 0.016 |
| Multi‐risk profileb | ||||||||||||
| Class 1 PWID | 59 (25%) | 45 (34%) | 14 (13%) | Ref | – | – | NI | NI | NI | Ref | – | – |
| Class 2 HIV‐positive GBM with low probability of IDU | 97 (41%) | 42 (33%) | 55 (51%) | 4.21 | 2.05, 8.66 | <0.001 | NI | NI | NI | 3.40 | 1.52, 7.60 | 0.003 |
| Class 3 GBM with IDU & sexual risk behaviour | 81 (34%) | 42 (33%) | 39 (36%) | 2.98 | 1.42, 6.26 | 0.004 | NI | NI | NI | 2.22 | 0.96, 5.15 | 0.062 |
Percentages indicate column percentages. Factors remaining significant in adjusted analyses (p < 0.05) are highlighted in bold.
HIV, human immunodeficiency virus; HCV, hepatitis C virus; PWID, people who inject drugs; GBM, gay and bisexual men; IDU, injecting drug use, CI, confidence interval; NI, not included; Ref, reference.
aAdelaide, Newcastle, Auckland, Brisbane or Perth; bmulti‐risk profile assigned corresponds to the profile with the highest posterior probability for that individual.