Hospital admission represents an opportunity to diagnose and manage diabetes mellitus. As HbA1c measurement is superior to other tests for diabetes diagnosis in the hospital setting1, we aimed to investigate the prevalence of undiagnosed diabetes and poor glycaemic control using routine HbA1c testing in inpatients at Austin Health, a tertiary referral centre.
Patients (aged ≥54 years) admitted between June 2013 and January 2014 had routine HbA1c testing via an automated order using the Cerner Millenniumⓒ Health IT System. Patients were classified as having diabetes if the HbA1c was ≥6.5% and poor glycaemic control if the Hba1c≥8.5%1. A history of diabetes was obtained from the hospital medical record.
Patients (n=5083, 6716 admissions, mean age 72.9±10.8 years) were divided into three categories: those with a prior history of diabetes (28.6%, CI 27.3-29.8%, n=1453), no prior history of diabetes and HbA1c<6.5% (66.1%, CI 64.8-67.4%, n=3359), and no prior history of diabetes (5.3%, CI 4.7-6.0%, n=271) and HbA1c ≥6.5%. Medical units had a higher rate of undiagnosed diabetes compared to surgical units (5.9%, [CI 5.1-6.9%] vs 4.3% [CI 3.4-5.3%] p=0.008). Readmissions during the study period were higher in patients with an HbA1c ³6.5% with and without a prior history of diabetes (26%, CI 23.6-28.2% and 23%, CI 18.4-28.7%, respectively), compared to patients with an HbA1c <6.5% and no prior history of diabetes (21%, CI 20.4-23.2%) (p=0.007). No significant differences in rates of intensive care unit admission (9.1%, CI [8.1-10%], 10.6% [CI 9.1-12.3%] and 7.0% [CI 4.2-10.7%] respectively, p=0.105) or inpatient mortality (11.4%%, CI [10.3-12.5%], 11.8% [CI 10.2-13.5%] and 14.4% [CI 10.4-19.1%] respectively, p=0.324) were observed between the groups.
Approximately 5% of inpatients ≥54 years attending our tertiary hospital have undiagnosed diabetes. Routine inpatient HbA1c testing addresses a currently missed opportunity to identify patients with newly diagnosed diabetes and poor glycaemic control. The impact of early identification and treatment of poor glycaemic control on patient outcomes requires further study.