OBJECTIVE: Whilst life expectancies of people living with HIV (PLWH) have increased through the successes of antiretroviral treatment, cognitive impairment remains a pressing concern. Prevalence estimates vary worldwide as different definitions for cognitive impairment are used and resource availability differs across geographical settings. We aim to explore this heterogeneity and estimate the global cognitive impairment burden in PLWH. DESIGN: Systematic literature review & meta-analysis. METHODS: We searched PubMed, Embase, SCOPUS and Web of Science for studies reporting on cognitive impairment prevalence in PLWH. Nine factors were investigated for their potential association with the prevalence using univariate meta-analysis and a meta-regression: assessment method, geographical region, country income, exclusion criteria, study quality, age, gender, publication year, and sample size. RESULTS: The literature search identified 8539 records, of which 225 were included. The adjusted prevalence was significantly lower in males than females. Across 44 countries, twelve assessment methods were used; the HAND/Frascati criteria, known for high false-positive rates, was employed in 44.4% of studies. The pooled cognitive impairment prevalence estimate in PLWH, including asymptomatic cases, is 39.6% [95% CI: 37.2-42.1%; range: 7-87%]. The meta-regression explained 13.3% of between-study variation, with substantial residual heterogeneity (I2 = 97.7%). CONCLUSION: Lack of data from >70% of the world's countries, cohorts being unselected for symptoms in most research studies, and limitations of the HAND/Frascati criteria restrict the ability to accurately determine the global burden of cognitive impairment in PLWH. More studies in low-resource settings and a standardised approach to assessing cognitive impairment, bridging research and clinical realms, are needed
