MO318: Utility of D-Dimer Levels in Predicting the Renal Outcome of Acute Kidney Injury in Moderate and Severe COVID-19: A Retrospective Study

Abstract

BACKGROUND AND AIMSAcute kidney injury (AKI) is a potential complication of COVID-19 and the hypercoagulation tendency of SARS-CoV-2 infection is considered one of the underlying mechanisms. Fibrinolysis markers have been described as severity parameters, independent of clinically manifested thromboembolic events. The aim of this study is to evaluate the contribution of D-dimer testing in appreciating the extent of AKI and renal function recovery in COVID-19.METHODWe have conducted a retrospective study on 253 AKI adult patients confirmed with SARS-CoV-2 infection by molecular testing and hospitalized in two emergency university hospitals over the course of 6 months. Diagnosis and staging of AKI were performed with KDIGO 2012 criteria. We analysed the impact of peak D-dimers on the severity of AKI, recovery of renal function and need for renal replacement therapy (RRT). Additionally, we searched the relationship between D-dimers and survival and COVID-19 severity parameters. Severity of respiratory failure was classified as mild-moderate (no support or low-flow oxygen) and severe (mechanical ventilation: continuous positive airway pressure and endotracheal intubation). All data was analysed using IBM SPSS Statistics v.25 (IBM, Corp.).RESULTSThe average age was 72.4 ± 13.33 years, 159 patients were male (62.84%). According to KDIGO staging, 79 patients were in stage 1, 74 in stage 2 and 100 patients in stage 3. Overall mortality was 50.59% (N = 128). The mean peak of D-dimers was 6.08 ± 6.53 µg/mL. We found a significant direct relationship between D-dimers and AKI stage (3.72 ± 5.84 µg/mL—stage 1; 6.67 ± 6.60 µg/mL—stage 2; 7.50 ± 6.46 µg/mL—stage 3; P < .0001). There was a significant inverse relationship between D-dimers and odds of renal recovery, lower values being noted in the complete renal recovery group (3.79 ± 5.10 µg/mL, N = 77) compared with partial recovery (5.22 ± 6.89 µg/mL, N = 57; P < .02), while D-dimers were strikingly high in patients needing RRT (8.11 ± 5.92 µg/mL, N = 29). Regarding the severity of respiratory failure, we found that mild-moderate cases had lower D-dimers (4.23 ± 5.46 µg/mL, N = 146) compared with severe failure (8.60 ± 7.00 µg/mL, N = 107; P < .003). Intensive care unit (ICU) admission was also correlated with levels of D-dimers (8.55 ± 6.76 µg/mL, N = 107 versus non-ICU 4.27 ± 5.70 µg/mL, N = 146; P < .01). D-dimers were higher in deceased patients (7.91 ± 6.60 µg/mL) compared with survivors (4.20 ± 5.88 µg/mL; P < 0.001) (Table 1).Table 1.CountN (%)Peak D-dimer levels (average ± SD; µg/mL)Statistical significance (P-value)Entire cohort2536.08 ± 6.53AKI severityKDIGO stage 1KDIGO stage 2KDIGO stage 3 79 (31.22)74 (29.24)100 (39.52) 3.72 ± 5.846.67 ± 6.607.50 ± 6.46 P < .0001*Kruskal–Wallis H TestRecovery of renal functionTotalPartialNeed for HDNone (excl. death) 77 (30.43)57 (22.52)29 (11.46)8 (3.16) 3.79 ± 5.105.22 ± 6.898.11 ± 5.926.25 ± 5.75 P < .02*Kruskal–Wallis H TestAKI timingAt admissionDuring hospitalization 172 (67.98)81 (32.01) 5.75 ± 6.336.77 ± 6.86 P = .307, ns**Mann–Whitney U TestRespiratory supportNone/low-flow oxygenCPAP/ETI 146 (57.7)107 (42.29) 4.23 ± 5.468.60 ± 7.00 P < .003**Mann–Whitney U TestICUNon-ICU107 (42.29)146 (57.70)8.55 ± 6.764.27 ± 5.70 P < .001**Mann–Whitney U TestMortalitySurvivedDeceased 125 (49.40)128 (50.59) 4.20 ± 5.887.91 ± 6.60 P < .001**Mann–Whitney U TestSD, standard deviation; HD, haemodialysis; CPAP, continous positive airway pressure; ETI, endotracheal intubation; ICU, intensive care unit; and ns, not significant.CONCLUSIONIncreased D-dimer levels in COVID-19-associated AKI have a negative impact on the severity of AKI, need for RRT and recovery of renal function. AKI patients with high levels of D-dimers are more often admitted to the ICU, have an increased need for mechanical ventilation and have poor survival. Due to the additional negative impact of AKI in COVID-19 and possible preventability of severe disease, D-dimers may be a useful tool to assess the need and duration of adequate prophylactic anticoagulation.