Anion gap is a significant predictor of 28-day all-cause mortality in patients with chronic total coronary occlusion admitted to the ICU, with the highest quartile showing markedly elevated risk (HR 21.22) compared to the lowest quartile.
Anion gap was significantly associated with 28-day all-cause mortality in CTO ICU patients in univariate analysis.
After adjustment for clinical and laboratory parameters, anion gap remained a significant independent predictor of 28-day all-cause mortality.
Mortality risk increased across anion gap quartiles, with the highest risk observed in the fourth (highest) quartile.
Subgroup analyses revealed significant interactions between anion gap and both gender and heart failure status on 28-day mortality.
The study used a retrospective cohort design drawing from a large critical care database, excluding patients with missing anion gap data or non-first-time ICU admissions.
This research suggests that a simple blood test measurement called the anion gap — which reflects the balance of electrically charged particles in the blood and can indicate metabolic stress or acid-base disturbances — is strongly linked to the risk of dying within 28 days among patients with a condition called chronic total coronary occlusion (CTO) who are admitted to intensive care. CTO means that one or more coronary arteries are completely blocked, representing a severe form of heart disease. The study analyzed records from 830 such patients admitted to ICUs between 2008 and 2019, finding that for every unit increase in anion gap, mortality risk rose by about 15% after accounting for other health factors. The association was particularly striking when patients were divided into four groups based on their anion gap levels: those in the highest group had roughly 21 times the mortality risk of those in the lowest group. The study also found that the relationship between anion gap and mortality differed depending on whether patients were male or female and whether they had heart failure, suggesting these factors may modify how anion gap reflects disease severity in CTO patients. This research suggests that routinely measuring anion gap — an inexpensive and widely available test — could help clinicians identify which critically ill CTO patients are at the greatest risk of short-term death, potentially enabling earlier or more intensive intervention. However, because this was a retrospective observational study, it cannot prove that anion gap causes worse outcomes, and the authors call for further research to confirm these findings and understand the underlying biological mechanisms.
Yang J, Huang M, Zhu G, Cai Z, Tu G. (2026). Relation between anion gap and 28-day all-cause mortality in patients with chronic total coronary occlusion: A retrospective cohort analysis.. Medicine. https://doi.org/10.1097/MD.0000000000050537