Diabetes and glycemic control in necrotizing otitis externa (NOE)

Although the association between necrotizing otitis externa (NOE) and diabetes mellitus (DM) is well known, there is little knowledge in regards to the effects of DM and glycemic control on the outcome of NOE. The aim of the study was to determine the effects of DM duration and glycemic control, and in-hospital glycemic control on NOE severity.

A retrospective case series analysis, including all patients hospitalized between 1990 and 2018 due to NOE were included. Data collected included NOE disease characteristics, duration of DM, DM-associated comorbidities, glycated hemoglobin (HbA1c), urine microalbumin and in-hospital blood glucose measurements. Disease severity was defined based on duration of hospitalization (above or below 20 days) and need for surgery.

Eighty-nine patients were included in the study. Eighty-three patients (94.3%) had DM. Preadmission HbA1c was 8.13% (5.8-12.6%). Forty-nine patients (65.5%) had mean blood glucose of ≥ 140 mg/dL and 26 (34.5%) had ≤ 140 mg/dL. DM duration was 157.88 months among NOE patients who required surgery, and 127.6 months among patients who were treated conservatively (p value 0.25). HbA1c in patients hospitalized < 20 days was 7.6%, and 8.7% among NOE hospitalized ≥ 20 days (p value 0.027). Seven patients with mean blood glucose of ≤ 140 mg/dL had Pseudomonas Aeruginosa (PA-NOE) (26.7%), in comparison to 25 (51.0%) with mean blood glucose measurement of ≥ 140 mg/dL (p = 0.045).

HbA1c at admission is associated with longer hospitalization duration among NOE patients. Mean blood glucose during hospitalization was associated with a higher likelihood of PA infection, however, it had no effect on disease outcome.