Compared with patients without HIV, the poorer cognitive performance of people living with HIV (PLWHIV) was partly mediated by a higher prevalence of depressive symptoms and recreational drug use, according to research results.
This cross-sectional study led by Dr Davide de Francesco at the Institute for Global Health, University College London, Royal Free Campus, enrolled 637 PLWHIV aged ≥50 years (“older”) and 340 PLWHIV aged <50 years (“younger”) and 276 demographically matched individuals without HIV aged ≥50 as control participants. Participant’s cognitive function was assessed using a computerized battery and their depressive symptoms evaluated via questionnaire.
Both the older and younger groups of PLWHIV scored lower on cognitive assessments (P <.001 and P =.006, respectively) than the older controls after adjustment for socio-demographic factors such as age, gender, ethnicity, and education level. The prevalence of moderate to severe depressive symptoms was 8% in controls. Prevalence of these symptoms was higher in both the older (27%; P <.001) and younger (21%; P <.001) PLWHIV groups.
The two factors associated with lower cognitive function were depressive symptoms (P <.001), and hashish use (P =.01), while alcohol was associated with better scores (P =.02). After further adjusting for these factors, significant differences between older PLWHIV and controls disappeared (P =.08), but differences between younger PLWHIV and controls remained (P =.01).
The cross-sectional nature of the study did not allow for assessment of casual relationships or the direction of associations, which according to the study investigators, is likely to be bi-directional between cognitive performances and depression, alcohol consumption, and recreational drug use. Further, differences in some demographic and lifestyles factors between controls and participants could not be avoided, including the lack of participants
Despite statistical adjustments for age and demographics, the possibility of unmeasured co-founders influencing the results remains. In addition, the study relied on self-reporting of both depressive symptoms and recreational drug use, thus introducing potential reporting biases.
According to the study investigators, depression and cognitive problems are prevalent in PLWHIV and these results “suggest that comparisons of cognitive performances between PLWHIV and HIV-negative controls should take into account depressive symptoms and lifestyle factors.”
The researchers further stressed the importance of gaining a better understanding of HIV pathogenesis in the brain and the interaction between infection and mood disorders on cognitive dysfunction.
Objectives: We investigated whether differences in cognitive performance between people living with HIV (PLWH) and comparable HIV‐negative people were mediated or moderated by depressive symptoms and lifestyle factors.
Methods: A cross‐sectional study of 637 ‘older’ PLWH aged ≥ 50 years, 340 ‘younger’ PLWH aged < 50 years and 276 demographically matched HIV‐negative controls aged ≥ 50 years enrolled in the Pharmacokinetic and Clinical Observations in People over Fifty (POPPY) study was performed. Cognitive function was assessed using a computerized battery (CogState). Scores were standardized into Z‐scores [mean = 0; standard deviation (SD) = 1] and averaged to obtain a global Z‐score. Depressive symptoms were evaluated via the Patient Health Questionnaire (PHQ‐9). Differences between the three groups and the effects of depression, sociodemographic factors and lifestyle factors on cognitive performance were evaluated using median regression. All analyses accounted for age, gender, ethnicity and level of education.
Results: After adjustment for sociodemographic factors, older and younger PLWH had poorer overall cognitive scores than older HIV‐negative controls (P < 0.001 and P = 0.006, respectively). Moderate or severe depressive symptoms were more prevalent in both older (27%; P < 0.001) and younger (21%; P < 0.001) PLWH compared with controls (8%). Depressive symptoms (P < 0.001) and use of hashish (P = 0.01) were associated with lower cognitive function; alcohol consumption (P = 0.02) was associated with better cognitive scores. After further adjustment for these factors, the difference between older PLWH and HIV‐negative controls was no longer significant (P = 0.08), while that between younger PLWH and older HIV‐negative controls remained significant (P = 0.01).
Conclusions: Poorer cognitive performances in PLWH compared with HIV‐negative individuals were, in part, mediated by the greater prevalence of depressive symptoms and recreational drug use reported by PLWH.
D De Francesco, J Underwood, E Bagkeris, M Boffito, FA Post, PWG Mallon, JH Vera, I Williams, J Anderson, M Johnson, CA Sabin, A Winston
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[link url="https://onlinelibrary.wiley.com/doi/full/10.1111/hiv.12714"]HIV Medicine abstract[/link]