Elevated Liver Enzymes as a Predictor of Acute Kidney Injury in Hospitalized Patients With COVID-19

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) affects multiple organ systems and imparts significant morbidity and mortality [1]. Approximately 5% to 14% of patients affected with SARS-CoV-2 will become critically ill [2-4]. While coronavirus disease 2019 (COVID-19) generally begins as a respiratory tract infection, it can damage any organ system. Thus, to improve outcomes, clinicians should search actively for multi-organ involvement to guide appropriate early management [5].

Among affected organs, the kidney is particularly susceptible to COVID-19. Indeed, SARS-CoV-2 has been shown to share the same functional receptor, angiotensin-converting enzyme 2 (ACE2), with a wide variety of organs (such as lung, heart, kidney) [6]. SARS-CoV-2 initiates its infection process by binding to functional receptors on the membrane of a host cell. Postmortem examination of COVID-19 patients revealed varying degrees of acute tubular necrosis, lymphocytic infiltration, and viral RNA, suggesting direct invasion of kidney tubules [7]. In addition to direct kidney damage by the virus, acute kidney injury (AKI) can occur through several proposed mechanisms including acute tubular necrosis induced by sepsis, hypoxia, hypoperfusion, rhabdomyolysis, nephrotoxic drugs, etc.

In critically ill patients, AKI is a common complication of COVID-19 infection, occurring in 23% to 43% of cases, and was correlated with poor clinical outcomes. AKI was defined as per Kidney Disease Improving Global Outcomes (KDIGO) criteria: a change in the serum creatinine of 0.3 mg/dL over 48 h period or 50% increase in baseline creatinine.

An increase in liver function tests ( LFTs) has been found in patients with COVID-19 ranging 14%-75% Some studies found higher levels of transaminases in patients with severe COVID-19 pneumonia and in patients dying for COVID-19.

The clinical relevance of LFTs abnormalities has been controversial, with some studies suggesting its association with the severity of COVID-19 pneumonia, whereas others not.Some limitations affected those studies involving the lack of information about concomitant or previous use of hepatotoxic drugs among the others.