The objectives of the study are to evaluate the safety and clinical and virologic outcomes of dose-adjusted nirmatrelvir-ritonavir in patients with eGFR lower than 30 ml/min/1.73 m\^2. Patients with eGFR greater than 30 ml/min/1.73 m2 and prescribed nirmatrelvir-ritonavir will be used for comparison.
In the single-centre study, patients with stage 4 and 5 chronic kidney disease prescribed early treatment dose-adjusted nirmatrelvir-ritonavir will be assessed for the primary endponts of adverse events during or after treatment with nirmatrelvir-ritonavir (starting on or before day 30), serious adverse events and adverse events leading to discontinuation of nirmatrelvir-ritonavir.