The predictive value of anticholinergic drug exposure and the outcome of pneumonia: a Danish database study

Introduction: Older adults are susceptible to anticholinergic effects. Dysphagia and pneumonia are associated with anticholinergic usage, though a definitive causative relationship has not been established. There is no effective way to predict the prognosis of older adults with pneumonia; therefore, this study investigates the predictive value of anticholinergic burden. Methods: Patients aged 65 years and above admitted for community-acquired pneumonia from 2011 to 2018 in Denmark were included through Danish registries. We calculated anticholinergic drug exposure using the CRIDECO Anticholinergic Load Scale (CALS). The primary outcome was in-hospital mortality, and other outcomes included intensive care unit admission, ventilator usage, length of stay, 30-day/90-day/1-year mortality, institutionalisation, home care utilisation and readmission. Results: 186,735 patients were included in the in-hospital outcome analyses, 165,181 in the readmission analysis, 150,791 in the institutionalisation analysis, and 95,197 and 73,461 patients in the home care analysis at follow-up. Higher CALS score was associated with higher in-hospital mortality, with a mean risk increasing from 9.9% (CALS 0) to 16.4% (CALS >10), though the risk plateaued above a CALS score of 8. A higher CALS score was also associated with greater mortality after discharge, more home health care, more institutionalizations and higher readmission rates. Conclusions: High anticholinergic burden levels were associated with poor patient outcomes including short-/long-term mortality, dependence and readmission. It may be useful to calculate the CALS score on admission of older patients with pneumonia to predict their prognosis. This also highlights the importance of avoiding the use of drugs with a high anticholinergic burden in older patients.