Background & Aims: Novel Coronavirus 2019 (COVID-19) is an emerging infectious disease caused by the SARS-coV-2 virus. The epidemic started in Wuhan Province, China in December 2019 and quickly spread to 200 countries. As of February 21, 2021, 111419939 cases of conflict and 2470772 deaths have been reported. COVID-19 is characterized by acute respiratory disease. Of course, the clinical symptoms have varied since the onset of the epidemic and over time, but in total 80% of cases present with flu-like symptoms and 20% of patients may have severe clinical manifestations leading to Involve several organs (such as kidney, heart, central nervous system). Renal involvement in COVID-19 varies from an abnormal urine analysis to acute renal failure (AKI), in which AKI is a serious complication due to its high prevalence and mortality. Acute renal failure results in a sudden decrease in renal function and lead to accumulation of urea and other nitrogenous products, volume and electrolyte disturbances. In the occurrence of this complication in patients with Covid-19, several mechanisms such as direct effect of viral infection and secondary inflammation due to complement activation and micro-thrombosis have been proposed. Acute renal failure is a common complaint among hospitalized patients with a wide range of diagnoses. The cause of AKI in patients with Covid-19 is not fully understood. The close association between the incidence of respiratory failure and acute renal failure suggests acute ischemic tubular necrosis. Abnormal coagulation status seen in some patients with Covid-19 suggests other pathological causes of renal failure. It may also be one of the causes of ARF in patients with acute corneal nephropathy. In this case, determining the serum level of uric acid in patients with ARF may be useful in controlling the course of the disease and determining the course of treatment. However, AKI among COVID-19 hospitalized patients specially in our country (IRAN) is not well described.
In this study, we aimed to evaluate the incidence of acute renal failure, its clinical and laboratory features in patients admitted with coronavirus 19 diagnosis in one of the referral centers for this disease in Tehran.
Methods: A retrospective observational study was designed and patients admitted to Firoozabadi Hospital in Tehran from April to September 1999 who were diagnosed with Covid 19 by laboratory (PCR) or imaging (CT scan of the lungs) were included in the study. Patients with Kidney transplant, positive history of underlying kidney disease, chronic renal failure, and chemotherapy were excluded from the study. This clinical study was approved by the ethics committee of Iran University of Medical Sciences with the code IR.IUMS.REC.1399.229 and at the beginning of the study, written informed consent was obtained from all patients.
Patients were admitted as acute renal failure so nephrotoxic drugs were not given to them and in cases where they had to use these drugs as necessary, the drug was adjusted and creatinine changes were recorded. Acute renal failure (AKI) is a sudden decrease in kidney function that leads to the accumulation of urea and waste products and a disorder in the regulation of extracellular volume and electrolytes. Acute renal failure in adults is defined as follows: Increase in serum creatinine level greater than or equal to 0.3 mg / dL within 48 hours or Increase in serum creatinine 1.5 times the baseline level in the last 7 days or Urine volume less than 0.5 cc / kg / hr for 6 hours According to the above guideline, acute renal failure is divided into three stages. All data were collected from the patients’ file information and recorded in a pre-prepared questionnaire. This information includes demographic data, clinical signs at the time of referral (fever, heart rate, respiration rate, level of consciousness, blood pressure and oxygen saturation), comorbidities (diabetes mellitus, hypertension, myocardial infarction, malignancy), Drug history, computed tomography scan (CT scan) and ultrasound findings of the kidneys (if any), laboratory findings (blood sugar, blood cell count, liver tests, kidney tests) and final status (discharge or death).
Results: A total of 205 patients with Covid-19 were admitted to Firoozabadi Hospital in Tehran from April to September 1999 and 183 patients were included in this study. The mean age of Covid-19 patients with renal insufficiency (group A) was 71.50 and Covid-19 patients without renal insufficiency (group B) were 59.60 years (P-value <0.001). In the group with renal failure (group A) 61.1% (n = 55) patients were male and 38.8% (n = 35) were female, and this ratio in the group of Covid-19 patients without renal insufficiency (group B) were 49.5% (n = 46) and 50.53 % (n=47) respectively. Comorbidities such as hypertension, diabetes mellitus and heart disease in patients with Covid-19 were reported 63% (29 cases), 66.7% (32 cases) and 44.1% (15 cases) in group A and 29% (27 cases), res37.6% (35 cases) and 17.2% (16 cases) in group B (P-value <0.001). Blood oxygen saturation at baseline was slightly lower in group A than in group B. There was no significant difference between the two groups in other clinical signs. Urine analysis was performed in patients with Covid-19(group A) witch 32.1% (27 cases) had proteinuria and 33.3% (28 cases) had hematuria. The laboratory findings of the two groups were compared with each other. Group A showed significantly higher levels of white blood cells, polymorph nuclear cells, hemoglobin and also lymphopenia. Liver enzyme levels were higher in patients with Covid-19 disease, but no significant difference was reported between the two groups. Serum uric acid levels were checked in 29 Covid-19 patients and renal insufficiency, of which the lowest was 2.5 mmol / L, the highest was 19.60 mmol / L and the mean was 9.85 mmol / L. Mortality rate was reported in group A 49.4% (41 cases) and in group B 20.4% (19 cases) that the difference between the two groups was significant (P-value <0.001) . The limitations of this study include the following: Deficiency of the recorded data, failure to register information by a specific person, impossibility of performing a kidney biopsy for further investigation. Also, the findings of this study cannot be generalized to outpatients.
Conclusion: This study showed that acute renal failure during Covid-19 patients leads to a significant increase in mortality of hospitalized patients. We recommend that all hospitalized patients with Covid-19 be evaluated for acute renal failure, and to follow up after discharge for possible complications, including chronic renal failure.