Association between anticholinergic medication uses and the risk of pneumonia in elderly adults: a meta-analysis and systematic review

To conduct a meta-analysis and systematic review on the association between anticholinergic medication uses and the risk of pneumonia in elderly adults. Medical databases were searched included PubMed, Web of Science, EBSCO and Google Scholar (up to December 7, 2022). Studies evaluating association between anticholinergic medication uses and the risk of pneumonia in elderly adults were included. Studies without available data were excluded. We made meta-analysis by using adjusted odds ratio (aOR) with 95% confidence intervals (CIs) from random-effects model. The risk of bias was assessed using ROBINS-I tool and statistical heterogeneity using the I2 statistic. Registration: INPLASY202330070. A total of six studies with 107,012 participants were included. Meta-analysis results showed that anticholinergic medication uses was related with an increased risk of pneumonia (aOR = 1.59; 95%CI, 1.32–1.92) and stroke-associated pneumonia (aOR = 2.02; 95%CI, 1.76–2.33). Moreover, risk estimates of pneumonia for high-potency anticholinergics (aOR = 1.96; 95%CI, 1.22–3.14) were higher than those for low-potency anticholinergics (aOR = 1.58; 95%CI, 1.27–1.97). And increased risk of pneumonia was associated with the anticholinergic medication uses within 30 days (aOR = 2.13; 95%CI, 1.33–3.43), within 90 days (aOR = 2.03; 95%CI, 1.26–3.26) and chronic use (aOR = 1.65; 95%CI, 1.09–2.51). The risk of pneumonia is increased in elderly adults with anticholinergic medication, especially with higher-potency anticholinergic drugs and in the initiation phase of anticholinergic medication. Clinicians should monitor their use in older patients carefully, especially when the pneumonia-related signs and symptoms are identified. Anticholinergic medication could increase the risk of pneumonia in elderly adults.The risk of pneumonia was higher in the initiation phase of anticholinergic medication and when the older patients was medicated with higher-potency anticholinergic drugs.Clinicians should monitor anticholinergic drugs use in older patients carefully, especially when the pneumonia-related signs and symptoms are identified. Anticholinergic medication could increase the risk of pneumonia in elderly adults. The risk of pneumonia was higher in the initiation phase of anticholinergic medication and when the older patients was medicated with higher-potency anticholinergic drugs. Clinicians should monitor anticholinergic drugs use in older patients carefully, especially when the pneumon