Table 5.
Best CD4 Count and Human Immunodeficiency Virus RNA Level Predictors and Final Model for Anal Cancer Risk, North American AIDS Cohort Collaboration on Research and Design, 1996–2014
| Best Predictor | Anal Cancer Cases | Separate Modelsa | Combined Modelsb | |||
|---|---|---|---|---|---|---|
| Model 1 (Final Model) | Model 2 | Model 3 | Model 4 | |||
| HR (95% CI) | HR (95% CI) | HR (95% CI) | HR (95% CI) | HR (95% CI) | ||
| Overall CD4 count nadir, cells/µLc | ||||||
| <50 | 54 | 22.9 (7.1, 73.9) | 13.4 (3.5, 51.0) | 18.4 (5.5, 61.7) | … | 11.7 (3.0, 46.1) |
| 50 to <100 | 20 | 11.2 (3.3, 37.7) | 8.1 (2.1, 31.2) | 10.1 (2.9, 35.0) | … | 7.9 (2.0, 31.0) |
| 100 to <200 | 35 | 7.6 (2.3, 24.8) | 6.2 (1.7, 22.2) | 7.3 (2.2, 24.0) | … | 6.1 (1.7, 22.2) |
| 200 to <350 | 47 | 6.5 (2.0, 20.9) | 6.5 (2.0, 20.9) | 6.4 (2.0, 20.8) | … | 6.4 (2.0, 20.9) |
| 350 to <500 | 11 | 2.6 (0.7, 9.4) | 2.6 (0.7, 9.4) | 2.6 (0.7, 9.4) | … | 2.6 (0.7, 9.4) |
| ≥500 | 3 | 1.0 (ref) | 1.0 (ref) | 1.0 (ref) | … | 1.0 (ref) |
| Global P value | … | <.0001 | <.0001 | <.0001 | … | <.0001 |
| Per 50 cells/µL | … | 0.79 (0.75, 0.84) | 0.85 (0.79, 0.92) | 0.82 (0.77, 0.87) | … | 0.87 (0.80, 0.93) |
| Ptrend | … | <.0001 | <.0001 | <.0001 | … | .0002 |
| AIC | … | 2562 | … | … | … | … |
| Early proportion of time CD4 count <200 cells/µLd |
||||||
| 0.00 | 73 | 1.0 (ref) | 1.0 (ref) | … | 1.0 (ref) | 1.0 (ref) |
| >0.00 to 0.25 | 29 | 2.1 (1.4, 3.3) | 1.4 (0.7, 2.7) | … | 1.9 (1.2, 2.9) | 1.3 (0.7, 2.6) |
| >0.25 to 0.50 | 12 | 2.1 (1.1, 3.8) | 1.1 (0.5, 2.5) | … | 1.7 (0.9, 3.2) | 1.1 (0.5, 2.4) |
| >0.50 to 0.75 | 10 | 2.2 (1.2, 4.3) | 1.1 (0.4, 2.6) | … | 1.8 (0.9, 3.5) | 1.0 (0.4, 2.4) |
| >0.75 to <1.00 | 9 | 2.1 (1.1, 4.3) | 0.9 (0.4, 2.3) | … | 1.6 (0.8, 3.3) | 0.9 (0.3, 2.2) |
| 1.00 | 37 | 7.9 (5.3, 11.9) | 3.1 (1.5, 6.6) | … | 5.8 (3.7, 9.1) | 2.9 (1.4, 6.1) |
| Global P value | … | <.0001 | .0009 | … | <.0001 | .0015 |
| Per 20% of time CD4 <200 cells/µL |
… | 1.39 (1.29, 1.49) | 1.17 (1.05, 1.29) | … | 1.31 (1.20, 1.42) | 1.15 (1.04, 1.28) |
| Ptrend | … | <.0001 | .0030 | … | <.0001 | .0065 |
| AIC | … | 2572 | … | … | … | … |
| Early HIV RNA level average, copies/mLd |
||||||
| ≤500 | 47 | 1.0 (ref) | … | 1.0 (ref) | 1.0 (ref) | 1.0 (ref) |
| >500 to <10 000 | 41 | 1.2 (0.8, 1.9) | … | 0.9 (0.6, 1.3) | 1.1 (0.7, 1.6) | 0.9 (0.6, 1.3) |
| 10 000 to <100 000 | 61 | 2.4 (1.6, 3.5) | … | 1.2 (0.8, 1.8) | 1.6 (1.0, 2.4) | 1.2 (0.7, 1.8) |
| ≥100 000 | 21 | 5.3 (3.1, 8.9) | … | 1.9 (1.0, 3.4) | 2.5 (1.4, 4.5) | 1.7 (0.9, 3.2) |
| Global P value | … | <.0001 | … | .089 | .014 | .15 |
| Per log10 copies/mL | … | 1.58 (1.36, 1.84) | … | 1.17 (0.99, 1.39) | 1.28 (1.09, 1.51) | 1.14 (0.96, 1.35) |
| Ptrend | … | <.0001 | … | .064 | .0030 | .15 |
| AIC | … | 2607 | … | … | … | … |
| Combined models’ AIC | … | 2551 | 2561 | 2567 | 2551 |
Abbreviations: AIC, Akaike information criterion; CI, confidence interval; HR, hazard ratio; HIV, human immunodeficiency virus.
aEach measure was individually included in a cohort-stratified Cox model adjusted for sex, race/ethnicity, and baseline age and calendar period among persons with follow-up >3060 days (N = 34 625; number of anal cancer cases = 170).
bFrom cohort-stratified Cox model with combinations of key predictors as covariates and adjusted for sex, race/ethnicity, and baseline age and calendar period among persons with follow-up >3060 days.
cCD4 count nadir from 3060 to 180 days (approximately 8.5 years to approximately 6 months) in the past.
dProportion of time CD4 count <200 cells/µL and HIV RNA level average from 3060 to 1620 days (approximately 8.5 to approximately 4.5 years) in the past.