Factors associated with Status First Nations peoples who underwent testing for hepatitis C virus (HCV) RNA after a positive HCV antibody test (n = 4771)*
| Variable | Unadjusted* hazard ratio (95% CI) | Adjusted hazard ratio (95% CI) |
|---|---|---|
| Sex | ||
| Male | Ref. | Ref. |
| Female | 1.07 (1.01–1.15) | 1.12 (1.05–1.19) |
| Age category (RNA testing ≤ 1 yr after testing positive for antibody)*, yr | ||
| 0–20 | 0.93 (0.78–1.11) | 0.94 (0.79–1.13) |
| 21–40 | Ref. | Ref. |
| 41–60 | 1.15 (1.06–1.25) | 1.30 (1.19–1.41) |
| ≥ 61 | 1.68 (1.36–2.06) | 1.47 (1.18–1.81) |
| Age category (RNA testing > 1 yr after testing positive for antibody)*, yr | ||
| 0–20 | 1.05 (0.82–1.34) | 1.11 (0.86–1.42) |
| 21–40 | Ref. | Ref. |
| 41–60 | 0.96 (0.84–1.09) | 1.03 (0.90–1.17) |
| ≥ 61 | 0.97 (0.55–1.72) | 1.06 (0.60–1.88) |
| Urbanicity of residence | ||
| Urban | Ref. | Ref. |
| Rural | 1.43 (1.34–1.53) | 1.20 (1.10–1.30) |
| Community residence | ||
| Outside of First Nations community | Ref. | Ref. |
| Within First Nations community | 1.54 (1.42–1.66) | 1.19 (1.08–1.31) |
| Comorbidities† | ||
| ADG score, 1 year before index date | 0.98 (0.97–0.99) | 0.99 (0.98–0.99) |
| Coinfection with HBV or HIV | ||
| No record | Ref. | Ref. |
| Record before index date | 0.96 (0.79–1.17) | 1.09 (0.89–1.33) |
| Substance use or addictive disorders (RNA testing ≤ 1 yr after testing positive for antibody)* | ||
| No record | Ref. | Ref. |
| Record before index date | 0.91 (0.84–1.00) | 0.88 (0.80–0.96) |
| Substance use or addictive disorders (RNA testing > 1 yr after testing positive for antibody)* | ||
| No record | Ref. | Ref. |
| Record before index date | 1.36 (1.18–1.58) | 1.38 (1.18–1.60) |
| Treatment era | ||
| Index date before Dec. 31, 2013 (pre-DAA era) | Ref. | Ref. |
| Index date after Dec. 31, 2013 (post-DAA era) | 2.06 (1.92–2.21) | 1.99 (1.85–2.15) |
Note: ADG = aggregated diagnosis groups, CI = confidence interval, DAA = direct-acting antiviral, HBV = hepatitis B virus, Ref. = reference.
↵* Model was run with people who had an index date that corresponded to their positive antibody test. Those who did not have an HCV RNA test were censored at date of death, 10 years after date of last contact with the health care system or on Dec. 31, 2018, whichever occurred first. The model was run with 4771 people and consisted of 3753 events and 1018 individuals censored. In total, the model had 14 degrees of freedom. The proportional hazards assumption was checked for each model covariate using time-to-event curves and weighted Schoenfeld residuals (at a threshold of p < 0.05). For covariates that violated the assumption, piecewise regression was used where the time interval was split into ≤ 1 year and > 1 year after testing positive for HCV antibody. For covariates that violated the proportional hazards assumption, univariate analyses consisted of the covariate run piecewise over both time intervals.
↵† ADG score was derived using the John Hopkins ACG System.