Undiagnosed diabetes mellitus in community-acquired pneumonia - A prospective cohort study

Abstract

Background: Diabetes mellitus is an important risk factor for community-acquired pneumonia whereas the prevalence of undiagnosed diabetes mellitus and pre-diabetes in patients with community-acquired pneumonia is largely unknown. Aim: To investigate the prevalence of pre-diabetes, undiagnosed diabetes mellitus and risk factors associated with undiagnosed DM. Methods: A multicenter prospective cohort study. The prevalence of undiagnosed diabetes mellitus and pre-diabetes was estimated based on haemoglobin HbA1c measurements. Logistic regression was used to assess risk factors for undiagnosed diabetes mellitus. Models were adjusted for severity markers and comorbidity. Results: 1961 adults were included. 15.3% had known diabetes mellitus. Among patients without known diabetes mellitus, 5.0% had undiagnosed diabetes mellitus and 37.5% had pre-diabetes. Male sex (OR 2.45 (95%, CI 1.35-4.45)), body mass index ≥ 25 kg/m2 (OR 2.64 (95% CI 1.48-4.72)) and hyperglycaemia at admission (6-11mM: (OR 2.93 (95% CI 1.54-5.60)) and ≥11mM: (OR 44.76 (95% CI 17.58-113.98)) were associated with undiagnosed diabetes mellitus. Patients with undiagnosed diabetes mellitus had a higher 180 days mortality rate (12.1%) compared to patients without diabetes mellitus (3.8%), p=0.001. Conclusion: Undiagnosed diabetes mellitus was prevalent in community-acquired pneumonia. Male sex, overweight and hyperglycaemia at admission were associated with undiagnosed diabetes mellitus. The long term mortality among patients with undiagnosed diabetes mellitus was high compared to patients without diabetes mellitus.