Anaemia of acute inflammation: a higher acute systemic inflammatory response is associated with a larger decrease in blood haemoglobin levels in patients with COVID-19 infection

The study tests the hypothesis that a higher acute systemic inflammatory response was associated with a larger decrease in blood hemoglobin levels in patients with Coronavirus 2019 (COVID-19) infection. All patients with either suspected or confirmed COVID-19 infection admitted to a busy UK hospital from February 2020 to December 2021 provided data for analysis. The exposure of interest was maximal serum C-reactive protein (CRP) level after COVID-19 during the same admission. A maximal serum CRP >175mg/L was associated with a decrease in blood haemoglobin (−5.0 g/L, 95% confidence interval: −5.9 to −4.2) after adjustment for covariates, including the number of times blood was drawn for analysis. Clinically, for a 55-year-old male patient with a maximum haemoglobin of 150 g/L who was admitted for a 28-day admission, a peak CRP >175 mg/L would be associated with an 11 g/L decrease in blood haemoglobin, compared with only 6 g/L if the maximal CRP was