Aim: To examine the association of in-hospital diabetes regimen intensification with subsequent 30-day risk for unplanned readmission/emergency department admission.

Methods: We retrospectively studied 1949 adults with Type 2 diabetes receiving primary care within an academic health network admitted to the hospital between January 2007 and December 2009. Glucose therapy intensification was defined as new start of insulin or oral hypoglycaemic agents, or addition of prandial insulin or insulin mixtures. The association of glucose therapy intensification with subsequent 30-day risk for unplanned readmission/emergency department admission was examined, with focus on medicine service patients with poorly controlled glycaemia (baseline HbA(1c) ≥ 64 mmol/mol).

Results: One in six patients (324/1949, 17%) had early readmission/emergency department admission. Compared with patients without early readmission, readmitted patients were more often male (58 vs. 52%, P = 0.03), had higher Charlson co-morbidity score [mean (sd) 3.0 (2.0) vs. 2.8 (1.8), P = 0.02], longer length of stay [5 (4.4) vs. 3.9 (3.3) days, P < 0.01] and were more often discharged home with nursing services (38 vs. 32%, P = 0.03). Overall, glucose therapy intensification was not associated with early hospital readmission/emergency department admission (odds ratio 0.94, 95% CI 0.64-1.37, P = 0.74). However, among medicine service patients with baseline HbA(1c) ≥ 64 mmol/mol (8%), glucose therapy intensification was associated with a significantly decreased early readmission risk (adjusted odds ratio 0.33, 95% CI 0.12-0.88, P = 0.03) and lower post-discharge HbA(1c) {mean decrease (sd): 20 (26) mmol/mol [1.8 (2.4)%] vs. 7 (15) mmol/mol [0.6 (1.4)%], P < 0.01}.

Conclusions: Diabetes medical regimen intensification during hospitalization was not associated with early readmission. Among patients with elevated HbA(1c) , glucose therapy intensification was associated with a decreased 30-day readmission/emergency department admission risk and lower outpatient HbA(1c) levels. Our findings support the safety and durable impact of diabetes regimen optimization during hospital admission.