Introduction:
Diabetes mellitus (DM), a chronic condition, contributes to heightened hospitalizations, disability, and early mortality due to related complications. This study aimed to explore the incidence, clinical traits, and prognostic implications of DM in patients treated in Silesian intensive care units (ICUs).

Material and methods:
The paper is a retrospective, multicenter study containing patient data from the Silesian Intensive Care Unit Registry. Patients were treated in multi-profile ICUs in the Silesian Voivodeship. The registry collected clinical data of patients before admission to the ICU during hospitalization, as well as the results of ongoing treatment. To determine the effect of diabetes on the variables analyzed (51 variables), patients were divided into two groups: patients with a history of DM (regardless of its type) and patients without DM. Intergroup differences were compared for quantitative variables using parametric (Student’s t-test) or non-parametric (Mann–Whitney U) tests, depending on the type of distribution.

Results:
The study population of 25,456 included 6,393 patients (25.1%) with DM. DM patients were typically older (71 vs. 64 years, p = 0.001) and predominately female (49% vs. 39%, p < 0.001). Statistically significant comorbidities amongst DM patients included coronary artery disease (OR = 2.96), hypertension (OR = 3.62), chronic renal failure (OR = 4.29; requiring dialysis, OR = 2.98), and morbid obesity (OR = 4.01), all with p < 0.001. Primary reasons for ICU admission in DM patients were notably multiple organ failure (OR = 1.18), shock (OR = 1.20), and infection/sepsis (OR = 1.35/1.16), each with p < 0.001. An elevated risk of ICU death by 24% was observed in DM patients (p < 0.001).

Conclusions:
These findings underscore the substantial influence of DM on the clinical presentation and therapeutic outcome in critically ill patients, regardless of its role as a comorbidity rather than a primary admission cause.