Frequency of hypoglycemia and its impact on length of stay, mortality, and short-term readmission in patients with diabetes hospitalized in internal medicine wards.

OBJECTIVE: To evaluate whether hypoglycemia is associated with increases in length of stay (LOS), inpatient mortality, and readmission among patients with diabetes hospitalized in internal medicine wards.
METHODS: A retrospective cohort study was carried out using the Basic Minimum Data Set registry of the Spanish National Health System, which contains clinical and administrative information for every patient discharged from system hospitals. The analysis included patients discharged between January 2005 and December 2010 and had a primary (i.e., reason for the admission) or secondary diagnosis of diabetes and a secondary diagnosis of hypoglycemia. The associations between hypoglycemia and the study outcomes (mortality, readmission, and LOS) were evaluated using multivariate and multilinear regression models that included age, sex, and the Charlson index as covariates.
RESULTS: During the study period, 3,361,104 patients were admitted to internal medicine wards in the National Health System. Of these, 921,306 (27.4%) had diagnoses of diabetes, and among these patients, 46,408 (5%) had secondary hypoglycemia. A total of 4,754 (10.2%) patients with secondary hypoglycemia died during their hospital stays, compared with 83,508 (9.5%) patients without hypoglycemia. The multivariate/multilinear regression models demonstrated significant associations between the presence of secondary hypoglycemia and greater inpatient mortality (odds ratio [OR] 1.24, 95% confidence interval [CI] 1.20-1.28), a greater likelihood of readmission (OR 1.20, 95% CI 1.17-1.23), and an increased LOS (β 1.24, 95% CI 1.15-1.35).
CONCLUSION: Hypoglycemia in patients with diabetes hospitalized in internal medicine wards is associated with increases in the LOS, inpatient mortality, and early readmission.