The profound effect of diabetes mellitus control on outcomes of coccidioidomycosis.

Coccidioidomycosis is an endemic fungal infection caused by the soil-dwelling Coccidioides immitis/posadasii. One prior study showed that persons with diabetes mellitus (DM) with elevated glucose at the time of coccidioidomycosis had poorer coccidioidal outcomes compared to persons without DM. The purpose of this study was to assess the association between hemoglobin A1C (A1C) and outcomes among persons with coccidioidomycosis and co-existing DM. We conducted a retrospective case-control study of patients with DM (cases) and without DM (controls) with coccidioidomycosis, to assess the effect of glycemic control on outcomes in patients with DM. From January 1, 2017 to October 13, 2022, we identified 138 DM patients with coccidioidomycosis and compared with 283 non-DM control patients with coccidioidomycosis. Compared with controls, patients with DM were more likely to require hospitalization (OR 1.20, P < 0.001), have a lung cavity (OR 1.36, P < 0.001) and cavitary complications (OR 1.09, P = 0.001), require surgical management (OR 1.07, P = 0.016), and experience relapsed infection (OR 1.09, P = 0.041). Among the DM group, when baseline A1C was assessed as a continuous variable, each 1-unit increase of A1C had a significant effect on coccidioidomycosis-related hospitalizations (A1C OR 1.59, P = 0.005) and presence of cavities (OR 1.42, P = 0.01). Controlling for Charlson Comorbidity Index did not change the significance of A1C influence on outcomes of hospitalization and lung cavities. Compared with DM patients with A1C > 8.0, those with A1C levels ≤ 8.0 at presentation did not have increased adverse coccidioidomycosis outcomes. In summary, glycemic control profoundly impacts the outcomes of diabetic patients with coccidioidomycosis.