Effect of transthoracic echocardiography on short-term outcomes in patients with acute kidney injury in the intensive care unit: a retrospective cohort study based on the MIMIC-III database.

Background: Acute kidney injury (AKI) is a common problem in the intensive care unit (ICU). Transthoracic echocardiography (TTE) has become a common test in the ICU. But the effect of TTE on the short-term prognosis in ICU patients with AKI remains unclear. We aimed to analyze the relationship between TTE and short-term prognosis in ICU patients with AKI. Methods: AKI patients in the Medical Information Mart for Intensive Care (MIMIC)-III database were retrospectively enrolled according to inclusion and exclusion criteria, and their clinical information was extracted. TTE was conducted during ICU stay. AKI was diagnosed according to KIDGO criteria. The primary endpoint was the outcome of 28-day ICU stay. The doubly robust estimation method was used to analyze the association of TTE with the primary and secondary outcomes of patients with AKI in ICU. The gradient boosted model (GBM) was used to estimate the propensity score of patients to undergo TTE examination, thereby minimizing the variable imbalance between the TTE and non-TTE groups. Weighted cohorts were built using the inverse probabilities weighting (IPW) model with estimated propensity scores as weights. The weighted cohort was analyzed using logistic regression and validated using other models. Results: A total of 2,983 patients were included. In the original cohort, 28-day mortality was 37.9% in the TTE group (n=1,684) and 40.8% in the non-TTE group (n=1,299). In the propensity score model (PSM) cohort, 28-day mortality was 34.6% in the TTE group (n=702) and 45.6% in the non-TTE group (n=702). Doubly robust analysis showed that TTE was associated with lower 28-day mortality. Conclusions: TTE examination might decrease the 28-day mortality in patients with AKI in the ICU and should be considered for critical patients when necessary.