Direct-acting antivirals (DAA) have revolutionized the treatment of patients with chronic hepatitis C virus (HCV) infection, possibly leading to HCV elimination by 2030 as endorsed by the World Health Organization (WHO). However, some patients belonging to the so-called unique or special populations are referred to as difficult-to-treat due to unreached sustained virological response, potential drug side effects or interactions or co-morbidities. Several years after the DAA introduction and on the basis of excellent findings in terms of efficacy and safety, some doubts arise around the exact meaning of the special population designation and whether this group of patients actually exists. The aim of this review is to discuss and analyze current evidence on the management and treatment of the so-called "unique populations". We placed particular emphasis on patients with decompensated cirrhosis, chronic kidney disease (CKD), coinfections, rare genotypes, and previous treatment failure, in order to provide physicians with an updated overview of the actual problems and needs in the current scenario.
Keywords: HIV/HBV coinfection; chronic kidney disease; decompensated cirrhosis; end stage renal disease; hepatitis C; rare genotypes; special populations; treatment failure; unique populations.