Table 4.
Crude and adjusted Cox proportional hazard models assessing the association between BMI trajectory groups and attrition (N=11,263)
| Variable | Number of events/person years | Incidence rate/100 person years (95% CI) | Crude hazard ratio (95% CI) | Adjusted* hazard ratio (95% CI) |
|---|---|---|---|---|
| Overall | 1802/64446 | 2.8 (2.7–2.9) | - | - |
| BMI trajectory groups | ||||
| Group 1 | 775/21534 | 3.60 (3.35–3.86) | 1.32 (1.19–1.47) | 1.22 (1.09–1.36) |
| Group 2 | 653/24255 | 2.69 (2.49–2.91) | Reference | Reference |
| Group 3 | 294/14293 | 2.06 (1.83–2.31) | 0.77 (0.67–0.89) | 0.85 (0.74–0.98) |
| Group 4 | 80/4364 | 1.83 (1.47–2.29) | 0.70 (0.55–0.88) | 0.85 (0.67–1.09) |
| Gender | ||||
| Female | 992/38653 | 2.57 (2.41–2.73) | Reference | Reference |
| Male | 810/25793 | 3.14 (2.93–3.36) | 1.23 (1.12–1.35) | 1.19 (1.07–1.31) |
| Age at ART initiation | ||||
| 18–24 | 95/2130 | 4.46 (3.65–5.45) | 1.62 (1.31–2.01) | 1.70 (1.37–2.11) |
| 25–29 | 272/7734 | 3.52 (3.12–3.96) | 1.30 (1.13–1.49) | 1.30 (1.13–1.50) |
| 30–39 | 766/28353 | 2.69 (2.51–2.89) | Reference | Reference |
| 40–49 | 460/18551 | 2.48 (2.26–2.72) | 0.93 (0.83–1.04) | 0.97 (0.86–1.09) |
| ≥50 | 209/7577 | 2.76 (2.41–3.16) | 1.04 (0.89–1.21) | 1.11 (0.95–1.29) |
| NRTI | ||||
| tenofovir | 328/26244 | 1.25 (1.12–1.39) | Reference | Reference |
| zidovudine | 41/1497 | 2.74 (2.02–3.72) | 2.08 (1.50–2.87) | 2.14 (1.54–2.97) |
| stavudine | 1433/36705 | 3.90 (3.71–4.11) | 2.85 (2.53–3.21) | 2.63 (2.32–2.98) |
| NNRTI | ||||
| efavirenz | 1690/60907 | 2.77 (2.65–2.91) | Reference | Reference |
| nevirapine | 112/3539 | 3.16 (2.63–3.81) | 1.12 (0.93–1.36) | 1.01 (0.84–1.23) |
| CD4 count at ART initiation (per 100 cells/μl) | ||||
| 0–49 | 556/17767 | 3.13 (2.88–3.40) | 1.97 (1.29–3.02) | 1.31 (0.83–2.05) |
| 50–99 | 362/11903 | 3.04 (2.74–3.37) | 1.92 (1.25–2.95) | 1.33 (0.84–2.09) |
| 100–199 | 663/20851 | 3.18 (2.95–3.43) | 2.00 (1.31–3.05) | 1.49 (0.95–2.33) |
| 200–349 | 199/12457 | 1.60 (1.39–1.84) | 1.05 (0.68–1.64) | 1.01 (0.64–1.61) |
| 350+ | 22/1467 | 1.50 (0.99–2.28) | Reference | Reference |
| WHO stage at ART initiation | ||||
| I/II | 1303/50631 | 2.57 (2.44–2.72) | Reference | Reference |
| III/IV | 499/13815 | 3.61 (3.31–3.94) | 1.37 (1.24–1.52) | 1.17 (1.04–1.30) |
| Hemoglobin at ART initiation (g/dL) | ||||
| <10 | 392/11941 | 3.28 (2.98–3.62) | 1.20 (1.07–1.34) | 1.06 (0.94–1.20) |
| ≥10 | 1375/50952 | 2.70 (2.56–2.85) | Reference | Reference |
| Change in BMI** | - | - | 0.92 (0.91–0.93) | 0.91 (0.89–0.92) |
CI=confidence interval; BMI=body mass index; NNRTI=Non-Nucleoside Reverse Transcriptase Inhibitor; WHO=World Health Organization
All predictors are measured at ART initiation. Model adjusted for gender, BMI, age, NRTI, NNRTI, WHO stage, CD4 count at ART initiation, hemoglobin levels at ART initiation.
HR shows the change in hazard for every one kg/m2 increase in BMI from ART initiation and last available measurement. Adjusted model includes gender, BMI, age, NRTI, NNRTI, WHO stage, CD4 count at ART initiation, hemoglobin levels at ART initiation. Adjusted model does not include BMI trajectory group due to collinearity with change in BMI variable.