CRP and chronic kidney disease: Multivariable logistic regression confirmed only seven of these variables as independent risk factors for ICU-admission bacterial pulmonary co-infection: vaccination status (OR 7.01; 95% CI, 1.73–28.39); chronic kidney disease (OR 3.16; 95% CI, 1.15–8.71); pre-ICU hospital LOS ≥ 5 days (OR 1.94; 95% CI, 1.11–3.4); neutrophils ≥ 9.4 × 109/L (OR 1.96; 95% CI, 1.16–3.30); PCT ≥ 0.2 ng/mL (OR 5.09; 95% CI, 2.93–8.84); CRP ≥ 108 mg/L (OR 1.99, 95% CI, 1.15–3.46); and Brixia chest X-ray score ≥ 9 (OR 2.03; 95% CI, 1.19–3.45).