Calibration and discrimination ability of the Dat'AIDS score in people living with HIV aged 70 years and older from the Dat'AIDS cohort

Abstract Objective The Dat'AIDS score was developed to predict 5‐year mortality risk in people living with HIV aged 60 and older. However, its validity in people living with HIV aged 70 years and older needed confirmation. Methods This was a multicentre prospective cohort study in the Dat'AIDS French cohort. We calculated the Dat'AIDS score and Veterans Aging Cohort Study (VACS) indices 1.0 and 2.0 in people living with HIV aged 70 or older, at their first medical visit between 01/06/2014 and 31/12/2017. Participants were followed until 31 December 2019 (before the COVID‐19 era). Discrimination and calibration of the Dat'AIDS score were assessed using Harrell's C‐statistic and comparisons of predicted versus observed survival probabilities. The comparison of the discriminative capacity of the Dat'AIDS score with the VACS indices was performed. Results A total of 1330 participants (75.5% male, median age: 73.7 years, median time since HIV diagnosis: 21.7 years, median time under combination antiretroviral therapy (cART): 19.9 years, median CD4 cell count: 553 cells/μL, HIV‐1 RNA ≤50 copies/mL: 88.7%) were included. Overall, 221 (16.6%) deaths were recorded during 5598 patient‐years of follow‐up. The Dat'AIDS score showed good discrimination (C‐statistic: 0.72; 95% confidence interval CI; 0.68–0.75). Calibration was good except for the moderate‐risk group (5% difference). The Dat'AIDS score showed better discrimination than VACS 1.0 and 2.0 with albumin, aspartate aminotransferase (AST) and alanine transaminase (ALT) normal value imputation (C‐statistic: 0.72 vs. 0.69 for both) and was similar to VACS 2.0 without imputation (0.72 vs. 0.71), that could be calculated in 99.1%, 98.6% and 34.0%, respectively. Conclusions The Dat'AIDS score showed good discrimination and calibration in people living with HIV aged 70 years and older, providing an easy and valuable tool for clinical decision‐making and research.