ALB and COVID-19: eGFR (43.6 ± 26.5 mL/min vs. 79.7 ± 31.1 mL/min/1.73 m2, p < 0.001) and serum albumin levels (29.3 ± 6.2 g/L vs. 36.8 ± 6.4 g/L, p < 0.001) were lower in COVID-19 patients with hypernatraemia compared with those with normonatraemia.