Appendix 1. Clinical Characteristics of the Entire Cohort Divided by HCV Infection and Exposure .
| Clinical Characteristic | Uninfected a | Infected b | Seroconvertingc | Exposedd |
|---|---|---|---|---|
| Total participants, No. | 61 | 95 | 6 | 36 |
| Sex e, No. (%) | ||||
| Male | 39 (64) | 61 (64) | 2 (33) | 23 (64) |
| Female | 22 (36) | 34 (36) | 4 (67) | 13 (36) |
| Median age, IQR f , No. (%), y | 24 (22-27) | 25 (21-27) | 21 (20-23) g | 26 (23-35) g |
| Ethnicity h, No. (%) | ||||
| Caucasian | 51 (83) | 62 (65) g | 4 (67) | 32 (89) |
| Other | 10 (17) | 33 (35) | 2 (33) | 4 (11) |
| Estimated duration of injecting f, No. (%), y | ||||
| Median (IQR) | 7 (3-10) | 7 (5-11) | 3 (2-4) g | 9 (7-15) i |
| Number of injections in the past month f, No. (%) | ||||
| Median (IQR) | 20 (10-40) | 29 (10-70) | 21 (20-45) | 40 (20-61) |
| Reported sharing needles ever h, No. (%) | 33 (54) | 69 (73) | 3 (50) | 26 (74) |
| Reported sharing needles in the past three months h, No. (%) | 13 (21) | 31 (33) | 3 (50) | 7 (20) |
| Main drug injected in the past three months h, No. (%) | ||||
| Heroin | 36 (60) | 66 (69) | 5 (100) | 27 (77) |
| Other | 24 (40) | 29 (31) | 0 (0) | 8 (23) |
| Ever received treatment for drug use h, j j, No. (%) | 40 (66) | 91 (96) e | 3 (50) | 33 (94) i |
| HLA type h, k, No. (%) | ||||
| C1C1 | 18 (33) | 35 (44) | 3 (50) | 12 (35) |
| C1C2 | 27 (50) | 34 (43) | 3 (50) | 19 (56) |
| C2C2 | 9 (17) | 11 (14) | 0 (0) | 3 (9) |
| IFNL3 genotype h, k, No. (%) | ||||
| rs8099917 - TT | 37 (67) | 54 (67) | 4 (80) | 27 (79) |
| - GT | 15 (27) | 23 (28) | 1 (20) | 6 (18) |
| - GG | 3 (5) | 4 (5) | 0 (0) | 1 (3) |
| rs12980275 - AA | 31 (56) | 46 (57) | 4 (67) | 22 (63) |
| - GA | 18 (33) | 28 (35) | 2 (33) | 12 (34) |
| - GG | 6 (11) | 7 (9) | 0 (0) | 1 (3) |
| rs12979860 - CC | 30 (55) | 44 (56) | 3 (60) | 24 (69) |
| - CT | 17 (31) | 29 (37) | 2 (40) | 10 (29) |
| - TT | 8 (15) | 6 (8) | 0 (0) | 1 (3) |
| Favourable HLA and , No. (%) IFNL3 , No. (%) h, k | ||||
| rs8099917 – TT and HLA C1C1 | 12 (22) | 23 (29) | 2 (40) | 10 (30) |
| rs12980275 – AA and HLA C1C1 | 9 (17) | 20 (25) | 3 (50) | 6 (18) |
| >rs12979860 – CC and HLA C1C1 | 8 (15) | 17 (22) | 2 (40) | 7 (21) |
a Uninfected participants were anti-HCV and HCV RNA negative.
b Infected participants were defined as anti-HCV and HCV RNA positive.
c Seroconverting participants were defined as anti-HCV negative and HCV RNA positive.
d Exposed participants were defined as anti-HCV positive and HCV RNA negative.
e P value for comparison with the uninfected group < 0.001.
f For continuous variables, the Kruskal Wallis test was used to detect differences between all four groups. If this was statistically significant, then the Wilcoxon ranksum test was used for pairwise comparisons between groups. Please refer to Appendix 2 for pairwise comparisons.
g P value for comparison with the uninfected group < 0.05.
hFor categorical variables Fisher exact and Chi-squared tests for differences in proportion were used. First tested for differences between all four groups using Fisher exact tests and if statistically significant, pairwise comparisons between groups were made. For pairwise comparisons, a Chi-squared test was used if the expected number of participants in each cell was greater than or equal to five; otherwise Fisher’s exact tests were used.
iP value for comparison with the uninfected group < 0.01.
j Treatment for drug use may include pharmacotherapy, detoxification, and counseling.
k The HLA typing and IFNL3 genotype does not equal 100% as some participants were untypeable. Favourable HLA type and IFNL3 genotype are in bold