A retrospective analysis of the clinical characteristics, etiology and prognosis of fungal keratitis with diabetes mellitus

Background: The incidence of fungal keratitis is increasing and it is one of the leading causes of infectious corneal blindness. Fungal keratitis with diabetes mellitus (DM) also has an increasing trend, but the study on the disease is still relatively scarce. Objective: This study was to analyze the clinical characteristics, etiology and prognosis of fungal keratitis with DM. Methods: The clinical data of 87 cases of fungal keratitis with DM and 40 cases of fungal keratitis without systemic disease were retrospectively reviewed, and the demographic characteristics, clinical symptoms, pathologic examination and the prognosis of the patients were analyzed and compared. Results: Poor glycemic control and trauma were more likely precipitating factors of fungal keratitis with DM. The proportion of vegetable injury was 36.8% in the fungal keratitis with DM group, and it was lower than 57.5% in the fungal keratitis without systemic disease group(χ² =6.06, P < 0.05). The age at onset for fungal keratitis in the fungal keratitis with DM group was higher than that in the fungal keratitis without systemic disease group. The majority of patients in the fungal keratitis with DM group was farmers(34.5%) and physical workers(26.4%), with a mean history of DM for (13.0 ± 4.9) years. Laboratory examination showed that Fusarium was the primary pathogenic fungi for the fungal keratitis with a proportion of 60.0% and next was Aspergillus (20.0%) and Candida (20.0%). The proportion of Candida infection was higher in the fungal keratitis with DM group than that in the fungal keratitis without systemic disease group(20.0% versus 10.0%) (χ² =3.92, P < 0.05). The cure rate for fungal keratitis with DM patients was 46.0%, and that for fungal keratitis without systemic disease patients was 62.5%, showing a significant difference between them(χ² =5.48, P < 0.05). In addition, the ineffective rate of treatment for fungal keratitis with DM patients was 14.9%, which was higher than that of fungal keratitis without systemic disease patients (5.0%) (χ² =5.47, P < 0.05). Conclusions: Fungal keratitis with DM possesses its own characteristics. DM is an important risk factor of pathogenesis of fungal keratitis. Sustained high blood glucose levels might affect the demographic characteristics, clinical symptom, pathogenic types and prognosis of fungal keratitis patients.