Abstract
BACKGROUND: Hepatitis C virus (HCV) remains a global health concern, with cascade gaps hindering elimination. We aim to assess and compare HCV care cascades in four key populations: people living with HIV (PLHIV), people who inject drugs (PWID), men who have sex with men (MSM), and incarcerated individuals. METHODS: We conducted a systematic review and meta-analysis of observational studies (Jan 2019-Sept 2025) reporting ≥1 care cascade stage, including screening, confirmatory testing, linkage to care, treatment uptake and completion, and cure, among key populations (PROSPERO CRD42024577740). Four databases were searched. Pooled stage-specific proportions were estimated using random-effects meta-analysis, stratified by population and region. FINDINGS: We included 219 studies (884,450 individuals) from 46 countries. HCV screening coverage remained suboptimal across populations and was lowest in MSM, below 70% in half of countries. Linkage-to-care data were limited yet indicated low linkage in most countries. Treatment uptake was the weakest stage: <70% of PLHIV initiated treatment in 11 of 19 countries, PWID in 16 of 24, MSM in 3 of 10, and incarcerated individuals in 9 of 14. Treatment completion was generally favourable. SVR assessment and SVR among those initiating treatment were lowest in incarcerated individuals, with both indicators falling to about 40% in the poorest-performing countries. Analyses showed better performance in high-income settings. Western Europe performed best, with screening coverage 56.2-87.0%, confirmatory diagnosis 86.8-95.5%, 92.2-97.6% of diagnosed linked to care, and 46.9-79.2% initiating treatment; >90% of those treated completed therapy and >85% were assessed for SVR. In contrast, indicators were substantially worse in lower-income countries, with gaps across stages. INTERPRETATION: Suboptimal HCV screening, weak care linkage, treatment gaps, and regional inequities persist. Enhanced integrated services, better screening, expanded access, and robust data systems are critical to accelerate elimination in resource-limited settings. FUNDING: National Natural Science Foundation of China.