a, Rate of loss to follow-up, per 100 person years, by last known CD4 count per mm3 (lagged by 3 months), in TREAT Asia HIV Observational Database (TAHOD) and Australian HIV Observational Database (AHOD). Error bars represent 95% confidence intervals. b, Overall estimated all-cause mortality rate in TAHOD (with latest CD4 count <50 cells/mm3), after accounting for assumed mortality rates in those who were lost to follow-up (LTFU), and the comparison with observed rate in AHOD. The higher the assumed mortality in LTFU patients, the similar are the mortality rates between TAHOD and AHOD. Error bars represent 95% confidence intervals.