The Effect of Hospital Admission on Glycemic Control in Elderly People with Diabetes Mellitus

Aim: Hemoglobin A1c is a known independent risk factor for recurrent hospitalizations. However, the influence of hospitalization on glycemic control has not been reported. Our aim was to assess admission effects on Hemoglobin A1c levels as well as short- and long-term mortality risk following hospitalization, according to Hemoglobin A1c levels prior to the index admission.

Methods: Medical records of ≥ 65 year old patients with Type II Diabetes Mellitus, hospitalized between 2011 and 2014 in Rabin Medical Center were manually screened. Hemoglobin A1c levels before and after admission, demographic, clinical and biochemical data were recorded. Total follow-up time was up to 6 years.

Results: The final cohort included 2,000 participants. The average age was 77 years, and 76% had Diabetes Mellitus for 10 years or more. Comparing Hemoglobin A1c before and after hospitalization has shown a significant reduction in Hemoglobin A1c levels in the groups of patients with Hemoglobin A1c levels between 8-8.9% and >9% (0.38 ± 1.2% and 1.18 ± 1.2%, respectively, P<0.001). Hospitalization rate in patients with Hemoglobin A1c >9% was 20% higher compared to a reference group of patients with Hemoglobin A1c between 6.5-6.9% (4 vs. 3, HR=1.2, p<0.01). Mortality at end of follow-up was greater in patients with Hemoglobin A1c >9% (43%) and <6.5% groups (42%), compared to Hemoglobin A1c 6.5-6.9% (34%), (HR 1.57, 1.36, respectively, p<0.01).

Conclusions: This study is the first to address the impact of hospitalization on glycemic control, demonstrating an improvement in glycemic control among patients with poorly controlled Diabetes Mellitus, as reflected by Hemoglobin A1c reductions when preadmission Hemoglobin A1c was 8% or higher. Mortality among patient with poorly controlled Hemoglobin A1c prior admission was 57% higher than the reference group.