Hypokalemia as a Surrogate Marker of Severity in COVID 19 Infection

Introduction: Patients with COVID-19 infection present with a variety of clinical symptoms such as fever, diarrhea, dyspnea, anosmia and various electrolyte abnormalities. Hypokalemia is an important electrolyte abnormality associated with infection due to SARS-CoV-2 as it may be associated with life threatening cardiac abnormalities Objective: To investigate the prevalence and clinical implications of of hypokalemia and its association with disease severity and various laboratory markers of inflammation. Materials and methods-design, setting and participants: This retrospective study was conducted at Peerless Hospital, Kolkata, West Bengal, India, from March 15, 2020, to September 30, 2020. Participants included patients who received a diagnosis of COVID-19 after testing positive by RT-PCR test and were admitted to the hospital. The patients were classified as having severe hypokalemia (plasma potassium <3 mmol/L), hypokalemia (plasma potassium 3-3.5 mmol/L), and normokalemia (plasma potassium >3.5 mmol/L). We categorized patients into 3 groups of disease severity- mild (fever/uncomplicated upper respiratory tract infection without hypoxemia), moderate (pneumonia with no signs of severe disease, respiratory rate > 24/min OR spO2 <94% in room air) and severe (respiratory distress requiring mechanical ventilation- NIV or invasive, respiratory rate > 30/min Or SpO2 <90% in room air). The clinical features, lab and ECG abnormalities, were compared between the 3 groups. Data analysis was conducted in October 2020. Interventions: The patients were given general support and antiviral therapy. Their epidemiological and clinical features were collected. Results: 122 patients(38.4%) had hypokalemia and 58 patients(18.2%) had severe hypokalemia. There was significant association between disease severity and hypokalemia. Fever had significant association with hypokalemia and severe hypokalemia. There was also significant association between dyspnea, anosmia, decreased oxygen saturation, ECG abnormalities and mortality with hypokalemic patients. Also there was significant association between degree of hypokalemia and markers of systemic inflammation such as IL-6 and CRP. Conclusions: The high prevalence of hypokalemia among patients with coronavirus disease 2019 suggests the presence of disordered rennin angiotensin system activity, which is increased as a result of the reduced counteractivity of angiotensin converting enzyme 2, which is bound by severe acute respiratory syndrome coronavirus. The study also indicates the need to monitor this group of patients for cardiac rhythm disturbances, especially when drugs like hydroxychloroquine and azithromycin, which are known to prolong the QTc interval and are known to reduce the rate of cardiac conduction and cause arrythmias, are used off-label to treat COVID-19.