GSTM1 and anemia (phenotype): The objectives of the study were: (1) to compare epistaxis severity scores (ESSs) and haemoglobin (Hb) levels in patients with HHT before and during the pandemic, (2) to investigate factors that may have influenced epistaxis severity and anaemia during the COVID-19 pandemic, including facemask use, nasal versus oral swabs to test for SARS-CoV-2, COVID-19 disease and its management, COVID-19 vaccines, and the social impact of the pandemic.