Assessment of Hypokalemia and Clinical Characteristics in Patients With Coronavirus Disease 2019 in Wenzhou, China

Abstract

Importance: Severe acute respiratory syndrome coronavirus 2 has caused a global outbreak of coronavirus disease 2019 (COVID-19). Severe acute respiratory syndrome coronavirus 2 binds angiotensin-converting enzyme 2 of the rennin-angiotensin system, resulting in hypokalemia.

Objective: To investigate the prevalence, causes, and clinical implications of hypokalemia, including its possible association with treatment outcomes, among patients with COVID-19.

Design, setting, and participants: This cohort study was conducted at Wenzhou Central Hospital and Sixth People's Hospital of Wenzhou, Wenzhou, China, from January 11, 2020, to February 15, 2020. Participants included patients who received a diagnosis of COVID-19 according to the criteria issued by the Chinese Health Bureau 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). The clinical features, therapy, and outcomes were compared between the 3 groups. Data analysis was conducted in March 2020.

Interventions: The patients were given general support and antiviral therapy. Their epidemiological and clinical features were collected.

Main outcomes and measures: The prevalence of hypokalemia and response to treatment with potassium supplements were measured by analyzing plasma and urine potassium levels.

Results: One hundred seventy-five patients (87 female patients [50%]; mean [SD] age, 45 [14] years) were classified as having severe hypokalemia (31 patients [18%]), hypokalemia (64 patients [37%]), and normokalemia (80 patients [46%]). Patients with severe hypokalemia had statistically significantly higher body temperature (mean [SD], 37.6 °C [0.9 °C]) than the patients with hypokalemia (mean [SD], 37.2 °C [0.7 °C]; difference, 0.4 °C; 95% CI, 0.2-0.6 °C; P = .02) and the patients with normokalemia (mean [SD], 37.1 °C [0.8 °C]; difference, 0.5 °C; 95% CI, 0.3-0.7 °C; P = .005). Patients with higher levels of hypokalemia also had higher creatine kinase levels (severe hypokalemia, mean [SD], 200 [257] U/L [median, 113 U/L; interquartile range {IQR}, 61-242 U/L]; hypokalemia, mean [SD], 97 [85] U/L; and normokalemia, mean [SD], 82 [57] U/L), higher creatine kinase-MB fraction (severe hypokalemia, mean [SD], 32 [39] U/L [median, 14 U/L; IQR, 11-36 U/L]; hypokalemia, mean [SD], 18 [15] U/L; and normokalemia, mean [SD], 15 [8] U/L), higher lactate dehydrogenase levels (mean [SD], severe hypokalemia, 256 [88] U/L; hypokalemia, 212 [59] U/L; and normokalemia, 199 [61] U/L), and higher C-reactive protein levels (severe hypokalemia, mean [SD], 29 [23] mg/L; hypokalemia, mean [SD], 18 [20] mg/L [median, 12, mg/L; IQR, 4-25 mg/L]; and normokalemia, mean [SD], 15 [18] mg/L [median, 6 U/L; IQR, 3-17 U/L]). Of 40 severely and critically ill patients, 34 (85%) had hypokalemia. Patients with severe hypokalemia were given potassium at a dose of 40 mEq per day, for a total mean (SD) of 453 (53) mEq potassium chloride, during the hospital stay. The patients responded well to potassium supplements as they recovered.

Conclusions and relevance: The correction of hypokalemia is challenging because of continuous renal potassium loss resulting from the degradation of angiotensin-converting enzyme 2. The high prevalence of hypokalemia among patients with COVID-19 suggests the presence of disordered rennin-angiotensin system activity, which increases as a result of reduced counteractivity of angiotensin-converting enzyme 2, which is bound by severe acute respiratory syndrome coronavirus 2.

Conflict of interest statement

Conflict of Interest Disclosures: None reported.

Figures

Figure 1.. Distribution of Commonly Abnormal Indices Between Patients With Severe Hypokalemia, Hypokalemia, and Normokalemia

Lines within boxes denote medians, diamonds denote means, tops and bottoms of boxes denote 75th and 25th percentiles, respectively, circles denote data for individual patients, and error bars denote 95% CIs. SI conversion factors: to convert creatine kinase to microkatals per liter, multiply by 0.0167; lactate dehydrogenase to microkatals per liter, multiply by 0.0167.

Figure 2.. Trend in Plasma Potassium and pH, and the Response to Potassium Supplement for 2 Patients With Coronavirus Disease 2019 (COVID-19)

A, Patient with a severe case of COVID-19. The failure of potassium supplements is associated with the increased loss of urinary potassium. The urinary potassium levels were 41, 50, and 38 mmol/g of creatinine at points A, B, and C, respectively. B, Patient with a mild case of COVID-19. The loss of urinary potassium is relieved, ensuring the effective treatment by potassium supplements. Urinary potassium levels were 32, 21, and 9 mmol/g of creatinine at time points D, E, and F, respectively.