Effects of gatifloxacin and levofloxacin on rates of hypoglycemia and hyperglycemia among elderly hospitalized patients.

STUDY OBJECTIVES

To compare rates of hypoglycemia and hyperglycemia among elderly hospitalized patients with normal blood glucose concentrations at baseline who were receiving either gatifloxacin or levofloxacin, and to determine if appropriateness of their doses, according to their package inserts, was associated with hypoglycemia or hyperglycemia.

DESIGN

Retrospective cohort study.

SETTING

Integrated Veterans Administration (VA) health care system.

PATIENTS

Nine hundred thirty-seven elderly (>or= 65 yrs) patients with documented blood glucose levels of 65-140 mg/dl before receiving a fluoroquinolone.

MEASUREMENTS AND MAIN RESULTS

Between January 2003 and April 2004, 405 patients receiving levofloxacin met study criteria. In April 2004, gatifloxacin was substituted for levofloxacin on the formulary of this VA system. Thus, between April 2004 and December 2004, 532 patients received gatifloxacin. All blood glucose concentrations during hospitalization that were measured during fluoroquinolone therapy or within 72 hours of completion of therapy were reviewed. Demographic characteristics, comorbidities, insulin and oral hypoglycemic therapies, disease severity, blood glucose levels, and outcomes were recorded and compared between groups. The two groups were similar at baseline for all characteristics examined except previous hospitalization. In the logistic regression, gatifloxacin was independently associated with both hypoglycemia (adjusted odds ratio [AOR] 2.5, 95% confidence interval [CI] 1.2-5.7, p=0.04) and hyperglycemia (AOR 2.4, 95% CI 1.5-3.6, p<0.001). Improper dosage adjustment based on renal function was not associated with higher rates of hypoglycemia and hyperglycemia for either drug. Of the 532 patients receiving gatifloxacin, 465 (87.4%) received appropriate doses, yet gatifloxacin was associated with higher rates of hypoglycemia and hyperglycemia compared with patients receiving levofloxacin.

CONCLUSIONS

Higher rates of both hypoglycemia and hyperglycemia were noted among elderly hospitalized patients who received gatifloxacin compared with those receiving levofloxacin, irrespective of dosing.