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Hepatitis C virus infection in First Nations populations in Ontario from 2006 to 2014: a population-based retrospective cohort analysis

Andrew Mendlowitz, Karen E. Bremner, Jennifer D. Walker, William W.L. Wong, Jordan J. Feld, Beate Sander, Lyndia Jones, Wanrudee Isaranuwatchai and Murray Krahn
September 28, 2021 9 (3) E886-E896; DOI: https://doi.org/10.9778/cmajo.20200164

Article Figures & Tables

Figures

  • Figure 1:
    Figure 1:

    Flow diagram showing cohort selection. Testing records for the same person on the same day were combined to be a record of a single sample collection. *People who had a testing or diagnosis date in the year of their death still contributed to their respective annual case count for that respective year. †Up to 5 people were excluded because their testing or diagnosis date was more than a year after their death. Note: HCV = hepatitis C virus.

  • Figure 2:
    Figure 2:

    (A) Annual age- and sex-standardized incidence per 1000 person-years of first test for hepatitis C virus (HCV) infection among Status First Nations people. (B) Annual age- and sex-standardized point prevalence per 100 people of ever having been tested for HCV infection among Status First Nations people measured at Dec. 31 each year. Error bars represent 95% confidence intervals.

  • Figure 3:
    Figure 3:

    (A) Annual age- and sex-standardized incidence per 1000 person-years of diagnosed hepatitis C virus (HCV) infection among Status First Nations people. (B) Annual age- and sex-standardized point prevalence per 100 people of diagnosed HCV infection among Status First Nations people measured at Dec. 31 each year. Error bars represent 95% confidence intervals.

  • Figure 4:
    Figure 4:

    Age- and sex-standardized point prevalence per 100 people of ever having been tested for hepatitis C virus (HCV) infection among Status First Nations people at Dec. 31, 2014, by Local Health Integration Network (LHIN).

  • Figure 5:
    Figure 5:

    Age- and sex-standardized point prevalence per 100 people of diagnosed hepatitis C virus (HCV) infection among Status First Nations people at Dec. 31, 2014, by Local Health Integration Network (LHIN).

  • Figure 6:
    Figure 6:

    Age- and sex-standardized incidence per 1000 person-years of first hepatitis C virus (HCV) test among Status First Nations people from 2006 to 2014, by Local Health Integration Network (LHIN).

  • Figure 7:
    Figure 7:

    Age- and sex-standardized incidence per 1000 person-years of diagnosed hepatitis C virus (HCV) infection among Status First Nations people from 2006 to 2014, by Local Health Integration Network (LHIN).

Tables

  • Table 1:

    Demographic and clinical characteristics of Status First Nations people in Ontario who were tested for HCV for the first time, tested positive for HCV antibodies or RNA, or had no Public Health Ontario HCV testing records

    CharacteristicNo. (%) of people*
    Tested for HCV infection†
    n = 20 481    		Diagnosed with HCV infection‡
    n = 2423    		No test record§
    n = 135 185
    Age, yr
     Mean ± SD34.2 ± 15.636.2 ± 12.329.9 ± 20.8
     Median (IQR)31 (22–44)35 (27–45)27 (12–46)
    Age group, yr
     < 256776 (33.1)451 (18.6)63 570 (47.0)
     25–292902 (14.2)378 (15.6)8829 (6.5)
     30–342209 (10.8)324 (13.4)8356 (6.2)
     35–391849 (9.0)290 (12.0)8638 (6.4)
     40–441666 (8.1)323 (13.3)9012 (6.7)
     45–491466 (7.2)284 (11.7)9572 (7.1)
     50–541201 (5.9)184 (7.6)8091 (6.0)
     ≥ 552412 (11.8)189 (7.8)19 117 (14.1)
    Sex
     Male9247 (45.1)1282 (52.9)69 808 (51.6)
     Female11 234 (54.8)1141 (47.1)65 377 (48.4)
    Birth cohort
     Before 1945899 (4.4)16 (0.7)7858 (5.8)
     1945–19643958 (19.3)628 (25.9)27 981 (20.7)
     1965–19753836 (18.7)630 (26.0)19 496 (14.4)
     1975 or later11 788 (57.6)1149 (47.4)79 850 (59.1)
    Community population size
     ≥ 1 500 0001308 (6.4)239 (9.9)11 092 (8.2)
     500 000–1 499 999837 (4.1)144 (5.9)8699 (6.4)
     100 000–499 9995397 (26.4)1058 (43.7)36 998 (27.4)
     10 000–99 9992019 (9.9)327 (13.5)17 524 (13.0)
     < 10 00010 546 (51.5)633 (26.1)59 712 (44.2)
     Missing/unknown374 (1.8)22 (0.9)1160 (0.9)
    Local Health Integration Network
     Erie St. Clair752 (3.7)158 (6.5)7393 (5.5)
     South West1337 (6.5)196 (8.1)9181 (6.8)
     Waterloo Wellington197 (1.0)31 (1.3)2305 (1.7)
     Hamilton Niagara Haldimand Brant1521 (7.4)251 (10.4)19 020 (14.1)
     Central West109 (0.5)16 (0.7)1548 (1.1)
     Mississauga Halton113 (0.6)12 (0.5)1724 (1.3)
     Toronto Central762 (3.7)164 (6.8)3883 (2.9)
     Central205 (1.0)30 (1.2)2432 (1.8)
     Central East534 (2.6)64 (2.6)6401 (4.7)
     South East554 (2.7)59 (2.4)5337 (3.9)
     Champlain775 (3.8)99 (4.1)8796 (6.5)
     North Simcoe Muskoka443 (2.2)50 (2.1)5176 (3.8)
     North East4686 (22.9)459 (18.9)29 472 (21.8)
     North West8327 (40.7)801 (33.1)29 696 (22.0)
     Missing/unknown166 (0.8)33 (1.4)2821 (2.1)
    First Nations community status
     Within community7523 (36.7)453 (18.7)45 748 (33.8)
     Outside of community12 773 (62.4)1934 (79.8)87 009 (64.4)
     Out of province75 (0.4)13 (0.5)1682 (1.2)
     Missing/unknown110 (0.5)23 (0.9)746 (0.6)
    Comorbidities, ADGs score
     Mean ± SD6.7 ± 4.07.8 ± 4.24.8 ± 3.2
     Median (IQR)6 (4–9)7 (5–11)4 (2–7)
    No. of ADGs categories
     ≤ 34625 (22.6)392 (16.2)45 091 (33.4)
     4–76906 (33.7)771 (31.8)42 542 (31.5)
     8–103743 (18.3)514 (21.2)13 419 (9.9)
     ≥ 113333 (16.3)600 (24.8)6712 (5.0)
     Nonuser/missing1874 (9.1)146 (6.0)27 421 (20.3)
    Mental health conditions
     Anxiety disorder7207 (35.2%)775 (32.0)37 263 (27.6)
     Deliberate self-harm3012 (14.7)661 (27.3)5283 (3.9)
     Bipolar mood disorder318 (1.6)91 (3.8)602 (0.4)
     Depression mood disorder4042 (19.7)540 (22.3)15 193 (11.2)
     Other mood disorder202 (1.0)24 (1.0)364 (0.3)
     Personality disorder390 (1.9)83 (3.4)702 (0.5)
     Schizophrenia spectrum/other psychotic disorder985 (4.8)196 (8.1)2113 (1.6)
     Substance-related/addictive disorder10 094 (49.3)1974 (81.5)20 090 (14.9)
     Trauma-/stressor-related disorder3807 (18.6)501 (20.7)13 217 (9.8)
    Disease-specific flags
     HIV record189 (0.9)98 (4.0)122 (0.1)
     HIV before HCV diagnosis–37 (1.5)–
     HBV record107 (0.5)65 (2.7)50 (0.0)
     HBV before HCV diagnosis–25 (1.0)–
    HCV treatment record**
     Any188 (0.9)201 (8.3)35 (0.0)
     Direct-acting antiviral156 (0.8)162 (6.7)32 (0.0)
     Ribavirin12 (0.1)16 (0.7)0 (0.0)
     Interferon formulation††36 (0.2)40 (1.7)≤ 5

    • Note: ADGs = Aggregated Diagnosis Groups, HBV = hepatitis B virus, HCV = hepatitis C virus, IQR = interquartile range, SD = standard deviation.

    • ↵* Except where noted otherwise.

    • ↵† At earliest testing date.

    • ↵‡ At earliest date of positive test result.

    • ↵§ Midway through the observation period (July 1, 2010).

    • ↵ The person had an out-of-province postal code for the year of the reference date.

    • ↵** People could have multiple claims corresponding to different types of treatments.

    • ↵†† Consisted of a record of interferon, peginterferon, or combination peginterferon and ribavirin treatments.

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CMAJ Open: 9 (3)
Vol. 9, Issue 3
1 Jul 2021

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Hepatitis C virus infection in First Nations populations in Ontario from 2006 to 2014: a population-based retrospective cohort analysis
Andrew Mendlowitz, Karen E. Bremner, Jennifer D. Walker, William W.L. Wong, Jordan J. Feld, Beate Sander, Lyndia Jones, Wanrudee Isaranuwatchai, Murray Krahn
Jul 2021, 9 (3) E886-E896; DOI: 10.9778/cmajo.20200164
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