Does glycemic variability affect development of chronic critical illness and mortality in the intensive care unit?

Glycemic variability (GV) is higher among critically-ill patients and can be one of the indicators of worse outcomes. The purpose of the study is to determine whether GV effects development of chronic critical illness (CCI) and mortality. Patients and methods In this prospective, observational, single-center study, patients admitted to medical ICU between 22 February 2023 and 30 May 2023 who had at least three blood glucose samples per day have been included. Blood glucose values during the first 24 h and the first week were used to determine GV by calculating standard deviation (SD), coefficient of variation (CV) (CV=SD/mean), maximal blood glucose difference (MGD) (absolute maximum-minimum glucose level), mean absolute glucose (MAG) ((Σ∣ΔBG∣) / (Δ total time of observation)) and the absolute mean of daily differences (MODD). CCI was defined as ICU length of stay ≥14 days and SOFA score ≥ 2 on day 14. Results A total 79 patients were included in the study. Median (IQR) age was 65 (49–77), median APACHE II was 23 (19–27) and median SOFA score was 5 (4–8). Nineteen (24.1%) patients developed CCI and 8 of them (42.1%) died. Totally 17 (21.5%) patients died in the ICU. On the first day of ICU admission, median (IQR) SD was 20.9(14.4–33.2), CV was 15.1% (11.5–22.4), MGD was 55 mg/dL(39–91) and MAG was 5.5 mg/dL(2.9–8.1). First week mean glucose level was 139.1 ± 31.1 mg/dL, median SD was 28.5 (18.3–45.6), CV was 20.6% (16.7–26.1), MGD was 117.0 mg/dL (75.0–191.0), MAG was 4.5 mg/dL (2.8–8.6), MODD was 26.5 mg/dL (14.6–37.8). Comparisons of GV parameters between patients with CCI and without CCI (Table 1) and between patients who died and survived were not different (p > 0.05 for all). Conclusion Glycemic variability was not found to be associated with the development of CCI and ICU mortality in critically-ill patients. However, the study might be underpowered to determine the effect of GV on outcome.