Low estimated glomerular filtration rate and pneumonia in stroke patients: findings from a prospective stroke registry in the East of England

Purpose: Low estimated glomerular filtration rate (eGFR) (< 60 mL/min/1.73 m(2)) is a recognized risk factor for pneumonia in general population. While pneumonia is common after stroke, the association between levels of eGFR and pneumonia in stroke patient population has not yet been examined thoroughly. Patients and methods: Using data of 10,329 patients from the Norfolk and Norwich Stroke Registry between January 2003 and April 2015, we examined the association of poststroke pneumonia (in-hospital and after discharge) with low eGFR and when eGFR is divided into the complete spectrum of clinically relevant categories; (>= 90) (ref.), 60-89, 45-59, 30-44, 15-30, and < 15 mL/min/1.73 m(2)). Results: In all, 1,519 (14.7%) developed in-hospital pneumonia and 1,037 (12.9%) developed pneumonia after hospital discharge. In age- and sex-adjusted model, low eGFR was associated with in-hospital pneumonia (subdistribution hazard ratio (sHR): 1.13; 95% CI: 1.01-1.25) and pneumonia after discharge (sHR: 1.20; 95% CI: 1.07-1.38). In fully adjusted model, association remained significant for pneumonia after hospital discharge. When eGFR was categorized in all clinically relevant categories, association with in-hospital pneumonia tended to be "U" shaped (eg, compared to eGFR >= 90, sHR for 60-89 was 0.78; 95% CI: 0.62-0.99 and for < 15 was 1.06; 95% CI: 0.71-1.60) and association with pneumonia after discharge tended to increase with decline in eGFR level such that risk was almost two fold higher at eGFR < 15 (sHR: 1.85; 95% CI: 1.01-3.51). Association for in-hospital pneumonia was driven mainly by aspiration pneumonia, whereas association in stroke survivors was predominantly for nonaspiration pneumonia. Conclusion: In stroke patients, low eGFR at admission was associated with pneumonia, particularly severely reduced eGFR with nonaspiration pneumonia after hospital discharge. eGFR could form the basis for identifying patients at high risk of poststroke pneumonia.