Table 2.
PAR of HIV seroconversion risk factors including UAI by HIV status of sexual partners
| Risk factor | PAR (95% CI) Crude model |
PAR (95% CI) Adjusted model |
Average annual number of HIV cases |
Average lifetime HIV costs (range)(1) AUD$million, 2010 dollars |
||
|---|---|---|---|---|---|---|
| 1% discounting | 3% discounting | 5% discounting | ||||
| All risk factors | - | 0.91 (0.81,0.97) | 637 | 434 (403-471) | 274 (249-304) | 180 (160-205) |
| UAI by HIV status of sexual partners(2) | 0.85 (0.75,0.94) | 0.77 (0.66,0.89) | 539 | 367 (341-399) | 232 (211-257) | 152 (136-174) |
| UAI with HIV-negative only (serosorting) | 0.15 (0.11,0.22) | 0.10 (0.07,0.19) | 70 | 48 (44-52) | 30 (27-33) | 20 (18-23) |
| UAI with some unknown HIV status | 0.34 (0.27,0.43) | 0.33 (0.26,0.42) | 231 | 157 (146-171) | 99 (90-110) | 65 (58-74) |
| UAI with any HIV-positive | 0.36 (0.26,0.45) | 0.34 (0.24,0.44) | 238 | 162 (151-176) | 102 (93-114) | 67 (60-77) |
| Circumcision status(3) | ||||||
| Uncircumcision | 0.08 (0.04,0.16) | 0.07 (0.03,0.14) | 49 | 33 (31-36) | 21 (19-23) | 14 (12-16) |
| Number of sexual partners | ||||||
| 10+ casual sexual partners in the last 6 m | 0.26 (0.18,0.36) | 0.19 (0.09,0.34) | 133 | 91 (84-98) | 57 (52-64) | 38 (33-43) |
| STIs(4) | ||||||
| Anal warts between study visits | 0.14 (0.10,0.18) | 0.13 (0.09,0.19) | 91 | 62 (58-67) | 39 (36-43) | 26 (23-29) |
| Anal gonorrhoea at study visit | 0.06 (0.04,0.07) | 0.02 (0.01,0.03) | 14 | 10 (9-10) | 6 (5-7) | 4 (4-5) |
CI = Confidence interval, PAR = population attributable risk, UAI = Unprotected anal intercourse, m = months
1. The average healthcare costs incurred from HIV seroconversions associated with specific risk factors were calculated by multiplying the PAR percent for each specific risk factor, by the 700 HIV infections associated with male homosexual exposure, by the average healthcare costs per HIV-infected person. We performed sensitivity analyses by rate of discounting and according to the bounds in delays in durations of time between infection and diagnoses and commencement of antiretroviral treatment but calculations were based on the best estimated PAR of the risk factors and not the 95% CI of the PAR.
2. Adapted from Jin et al [8]
3. Adapted from Templeton et al [9]
4. Adapted from Jin et al [21]