Association between perioperative platelet distribution width changes and postoperative acute kidney injury in patients with renal insufficiency: a retrospective study.

Background: Acute kidney injury (AKI) is a major complication following cardiac surgery with a high incidence in those with existing kidney dysfunction. Platelet distribution width (PDW) reflects variability in platelet size and serves as an indicator of platelet activation. Recent investigations linked PDW changes to kidney pathology, suggesting its utility in identifying individuals at risk for AKI, thus necessitating exploration of its predictive value.

Methods: Patients with preoperative renal dysfunction [15 ≤ estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73m²] who underwent cardiac surgery from January 2018 to December 2021 were retrospectively enrolled. PDW values were measured preoperatively and again upon admission to the ICU immediately after cardiac surgery, with the change in PDW (dPDW) defined as the difference between these two measurements. The primary outcome was postoperative AKI, defined base on the Kidney Disease: Improving Global Outcomes (KDIGO) definition and staging criteria. Multivariate regression models were performed to identify the association between dPDW and AKI and its potential trend. Restricted cubic spline analysis assessed non-linear associations between dPDW and AKI. The Youden index identified an optimal dPDW cut-off for AKI prediction. Subgroup analysis was performed to elucidate the consistency of these associations across the various subgroups.

Results: AKI occurred in 53.10% (513/966) of patients, accompanied by significant PDW increases in cases of AKI (P < 0.001). After adjusting confounders, dPDW was identified as a significant risk factor for AKI [odds ratio (OR) = 1.09, 95% confidence interval (CI): (1.02 ~ 1.16), P = 0.012]. Patients in the highest dPDW quartile (Q4) had a 195% higher AKI risk compared to those in the lowest quartile (Q1) (OR = 2.95, 95% CI:1.78 ∼ 4.90, P < 0.001). Trend analysis indicates that the risk of AKI increased with higher dPDW quartiles (P for trend < 0.001). Youden index showed that dRDW = 1.1 was identified as the optimal diagnostic cut-off value for AKI. Subgroup analyses and interaction tests showed a robust association between dPDW and AKI in all subgroups (P for interaction > 0.05).

Conclusions: This study underscored perioperative PDW changes as a significant predictor of postoperative AKI in patients with renal insufficiency, highlighting its potential in refining risk stratification and management strategies.

Clinical trial number: Not applicable for this observational retrospective study.