Table 2.
Characteristics of the COAST Study cohorts
| Variable | HIV-positive cohort (n=13 907) |
General population comparison cohort (n=5 16 340)* | P value |
| Age at baseline† median (Q1, Q3) (years) | 38 (32, 46) | 35 (23, 48) | <0.0001 |
| Sex, n (%) | <0.0001 | ||
| Male | 11 161 (80.2) | 259 863 (50.3) | |
| Female | 2743 (19.7) | 256 144 (49.6) | |
| Unknown | 3 (0.0) | 333 (0.1) | |
| Health authority,‡ n (%) | <0.0001 | ||
| Fraser | 2915 (21.0) | 166 803 (32.3) | |
| Interior | 913 (6.6) | 83 722 (16.2) | |
| Northern | 465 (3.3) | 30 973 (6.0) | |
| Vancouver Coastal | 7246 (52.1) | 136 747 (26.5) | |
| Vancouver Island | 1560 (11.2) | 84 650 (16.4) | |
| Unknown | 808 (5.8) | 13 445 (2.6) | |
| Follow-up time, median (Q1, Q3) years | 7.1 (2.6, 13.2) | 12.4 (4.8, 16.9) | <0.0001 |
| Lost to follow-up,§ n (%) | 1544 (11.1) | 87 004 (16.9) | <0.0001 |
| Alive as of 31 March 2013, n (%) | 8858 (63.7) | 380 305 (73.7) | <0.0001 |
| Ever been on cART, n (%) | |||
| Yes | 10 210 (73.4) | NA | NA |
| No | 3697 (26.6) |
cART, combination antiretroviral therapy; NA, not applicable; Q1, 25th percentile; Q3, 75th percentile.
*This cohort includes 1388 known HIV-positive individuals who were randomly drawn when the cohort was created. Depending on the research question, the HIV-positive individuals in this cohort can be excluded to have an HIV-negative cohort.
†Baseline is defined as the date of known positive HIV serostatus (if participant is HIV-positive) or the date when the age eligibility was met (≥19 years of age), whichever came second, and a confirmed record of registration with the Medical Services Plan (MSP), the British Columbia (BC) public health insurance programme.
‡Refers to the provincial health care authority/jurisdiction where participants resided at latest known address.
§An individual is lost to follow-up when there has been no record of contact with the health care system as captured through an encounter or service event (eg, MSP registration and/or claim, hospitalisation, plasma viral load test, etc) for at least 18 months prior to the end of the study cut-off date (currently 31 March 2013), in which case the individual’s end of follow-up date corresponds to his/her last contact date.