Examining Age as Moderating Associations Between Methamphetamine Abstinence and Cognitive Function in People with HIV

Objective This study examined associations of days of methamphetamine (METH) abstinence with neurocognitive functioning and whether age moderates this relationship in people with HIV (PWH). Methods Retrospective data from 122 PWH with lifetime METH use disorder (MUD) were analyzed. Linear, piecewise, and curvilinear models were compared to characterize the association between length of METH abstinence and Global neuropsychological test T-scores. An interaction term between METH Abstinence Days and Age Group (<42, 42-48, >49) was added to the best model to test moderation both globally and by domain. Results A curvilinear model with log-transformed METH Abstinence Days provided the best model fit, with higher METH Abstinence Days associated with higher Global T-scores and a decreasing positive slope over time. Age Group did not moderate Global T-scores. At the domain level, Age Group moderated associations between METH Abstinence Days and Information Processing Speed, with steepest slopes in the youngest age group. Conclusions Length of METH abstinence is curvilinearly associated with neurocognitive functioning, with the steepest associations occurring in early abstinence, and is largely independent of age. These results emphasize that most neurocognitive recovery in domains impacted by MUD occurs during early abstinence across age groups and may inform the timing of neurocognitive assessment and intervention.