Table 1.
Summary of included studies
| First author, year country | Study design | Total sample size % male average age | COVID-19 diagnosis method | COVID-19 baseline severity | Electrolyte imbalances studied | Definition of electrolyte imbalance | Timepoint of electrolyte measurement | Outcomes studied | Covariates | NOS score (out of 9) |
|---|---|---|---|---|---|---|---|---|---|---|
| Alfano, 2020 Italy | Retrospective cohort |
320 65.9 64.8 (Mean) |
WHO interim guidelines | N.S | Hypokalemia | < 3.5 mmol/L | At any time during hospitalization | 1, 2, 5, 6, 7 | Sex, age and SOFA score | 7 |
| Asghar, 2020 Pakistan | Prospective cohort |
373 67.0 52.9 (Mean) |
RT-qPCR | N.S | Hypernatremia | > 145 mmol/L | At admission | 1, 3 | N.A | 7 |
| Atila, 2021 Switzerland | Prospective cohort |
172 55.8 60.0 (Mean) |
RT-qPCR | N.S | Hyponatremia, Hypernatremia | Hyponatremia: < 135 mmol/L Hypernatremia: > 145 mmol/L | At admission | 1, 2, 3, 4, 7, 8 | Sex, age, no. of comorbidities (presence of coronary heart disease, heart failure, arterial hypertension, pneumopathy, renal failure, hepatopathy, obesity, rheumatological disease, immunosuppression inclusive HIV infection, cerebrovascular disease, active neoplastic disease and diabetes mellitus) | 9 |
| Bennouar, 2020 Algeria | Prospective cohort |
120 69.2 62.3 (Mean) |
According to WHO criteria | 100% Severe according to WHO guidelines | Hypocalcemia | < 2.20 mmol/L | At admission | 1 | Sex, age, acute kidney injury, cardiac injury, blood glucose, C-reactive protein levels, neutrophil–lymphocyte-ratio, lactate dehydrogenase, albumin and total cholesterol | 7 |
| Berni, 2021 Italy | Retrospective cohort |
380 61.6 67.5 (Median) |
Laboratory confirmed (details N.S.) | N.S | Hyponatremia, Hypernatremia | Hyponatremia: < 135 mmol/L Hypernatremia: > 145 mmol/L | At admission | 1, 2, 3, 6, 8 | Sex and age | 8 |
| De Carvalho, 2021 France | Retrospective cohort |
296 53.7 68.4 (Mean) |
RT-qPCR | N.S | Hyponatremia | < 135 mmol/L | Within 24 h of COVID-19 suspicion | 1, 2, 3, 6, 7 | Sex, age, tympanic temperature, diabetes, serum creatinine, ALT, lymphocyte count and oxygen flow rate at admission | 7 |
| Chen, 2020 China | Retrospective cohort |
179 50.3 45 (Mean) |
According to the criteria by National Health Commission of China | 21% severe, 2% critical according to WHO guidelines | Hypokalemia | Mild hypokalemia: 3—3.5 mmol/L Severe hypokalemia: < 3 mmol/L | N.S | 6, 7 | N.A | 6 |
| Frontera, 2020 USA | Retrospective cohort |
4645 62.9 62.5 |
RT-qPCR | N.S | Hyponatremia | Mild hyponatremia: 130 – 134 mmol/L moderate hyponatremia: 121 – 129 mmol/L Severe hyponatremia: < 120 mmol/L | At admission | 1, 3, 5, 6, 8 | Sex, age, race, BMI, past medical history, admission laboratory abnormalities, admission SOFA score, renal failure, encephalopathy and mechanical ventilation | 8 |
| Hirsch, 2021 USA | Retrospective cohort |
9946 59.4 66.4 (Mean) |
RT-qPCR | N.S | Hyponatremia, Hypernatremia | Mild hyponatremia: 130 – 135 mmol/L Severe hyponatremia: < 130 mmol/L Mild hypernatremia: 145 – 149 mmol/L Severe hypernatremia: ≥ 150 mmol/L | At admission | 1, 6, 7 | Sex, age, race, BMI, diabetes, hypertension, cardiovascular diseases, respiratory diseases, chronic kidney disease, chronic liver disease, cancer, oxygen saturation, systolic blood pressure, hemoglobin, lymphocyte, red cell distribution width, platelet, serum creatinine, bilirubin and albumin, CRP, serum ferritin | 8 |
| Hu, 2020 China | Retrospective cohort |
1254 51.1 56 (Median) |
According to the criteria by National Health Commission of China | 15.9% severe, 6.7% critical, according to National Health Commission of China guidelines | Hyponatremia, Hypernatremia | Hyponatremia: < 135 mmol/L Hypernatremia: > 145 mmol/L | N.S | 1, 3, 5, 6 | N.A | 5 |
| Hu, 2021* China | Retrospective cohort |
206 48.1 53.7 (Mean) |
RT-qPCR | 4.9% severe, 2.4% critical, according to National Health Commission of China guidelines | Hyponatremia, Hypokalemia | Hyponatremia: < 135 mmol/L Hypokalemia: < 3.5 mmmol/L | At admission | Prolonged hospitalization | N.A | 6 |
| Liu, 2020 China | Retrospective cohort |
107 48.6 68 (Median) |
According to WHO interim guidance criteria | 100% severe according to National Health Commission of China guidelines | Hypocalcemia | < 2.15 mmol/L | Within 24 h of admission | A composite of 1, 2 and 3, as well as 6 and 7 | Sex, age, hypertension, diabetes, C-reactive protein, procalcitonin, interleukin-6 and D-dimer | 7 |
| Ma, 2020* China | Retrospective cohort |
1160 52.2 46 (Median) |
Laboratory confirmed (details N.S.) | N.S | Hyponatremia, Hypokalemia | N.S | N.S | Unfavourable outcome defined as mortality or disease progression from moderate to severe illness | Sex, age, BMI and first onset COVID-19 symptoms | 8 |
| Moreno, 2020 Spain | Retrospective cohort |
306 57.8 65 (Median) |
RT-qPCR | N.S | Hypokalemia | Mild hypokalemia: 3–3.5 mmol/L Severe hypokalemia: < 3 mmol/L | Within 72 h of hospital admission | 1, 2, 3, 8 | Age, sex, dyspnea, PaO2, lactate dehydrogenase, procalcitonin, CRP, BNP, lymphocyte count, opacity of lung x ray | 9 |
| Nasomsong, 2021 Thailand | Cross-sectional |
36 63.9 42.6 (Mean) |
RT-qPCR | N.S | Hypokalemia | < 3.5 mmol/L | At COVID-19 diagnosis | 3, 6, 8 | N.A | 5 |
| Osman, 2021 Oman | Retrospective cohort |
445 62 50.8 (Mean) |
N.S | 33.6% had an admission score of 5–8 based on the WHO Ordinal Scale for Clinical Improvement | Hypocalcemia | < 2.1 mmol/L | At admission | 1, 2, 3, 4, 7, 8 | N.A | 5 |
| Quilliot, 2020 France | Prospective cohort |
300 60.7 68 (Median) |
RT-qPCR and/or chest CT scans | 36% were severe, 49.7% were critical according to WHO guidelines | Hypomagnesemia | < 0.75 mmol/L | 5.29 ± 5.02 days after admission | 2, 3 | N.A | 5 |
| Raesi, 2021 Iran | Case–control |
91 60.4 55.4 (Mean) |
RT-qPCR | 55.9% were severe according to WHO guidelines | Hypocalcemia | < 2.15 mmol/L | Within 24 h of admission | 1, 2, 8 | N.A | 5 |
| Ruiz-Sánchez, 2020 Canada, Germany, China, Ecuador, Cuba, Italy, Spain | Retrospective cohort |
4464 58 66 (Median) |
RT-qPCR | All had pneumonia | Hyponatremia, Hypernatremia | Hyponatremia: < 135 mmol/L Hypernatremia: > 145 mmol/L | At admission | 1, 8 | Sex, age, hypertension, dyslipidemia, diabetes, obesity, smoking, chronic kidney disease, chronic liver disease, cardiovascular disease, cerebrovascular disease, chronic lung disease, cancer, immunosuppression, use of angiotensin-converting enzyme inhibitors/angiotensin-2-receptor antagonists, oxygen saturation, serum creatinine and type of pneumonia | 9 |
| Sarvazad, 2020 Iran | Cross-sectional |
58 56.9 62 (Median) |
RT-qPCR and/or chest CT scans | N.S | Hyponatremia, Hypernatremia, Hypokalemia, Hyperkalemia, Hypomagnesemia, Hypermagnesemia | Hyponatremia: 121—134 mmol/L Hypernatremia: > 146 mmol/L Mild hypokalemia: 3—3.4 mmol/L Severe hypokalemia: < 3 mmol/L Hyperkalemia: > 5.5 mmol/L Mild hypomagnesemia: 0.52—0.7 mmol/L Severe hypomagnesemia: < 0.51 mmol/L Hypermagnesemia: > 1.07 mmol/L | At admission | 2 | 5 | |
| Sun, 2020 China | Retrospective cohort |
241 46.5 65 (Median) |
RT-qPCR | 69.3% severe, 10.5% critical, according to National Health Commission of China guidelines | Hypocalcemia | Mild hypocalcemia: 2.0—2.2 mmol/L Severe hypocalcemia: < 2.0 mmol/L | At admission | 1, 3, 4, 5, 6, 7 | N.A | 6 |
|
Tezcan, 2020 Turkey |
Retrospective cohort |
408 46.1 54.3 (Mean) |
RT-qPCR or according to Turkey’s national guidelines | N.S | Hypocalcemia, Hyponatremia, Hypokalemia, Hypochloremia | N.S | At admission | 1 | Sex, age, disease severity, time between disease onset and hospitalization, co-morbidities, pulmonary infiltrations, fever and hypoxemia during hospitalization | 8 |
| Torres, 2021 Spain | Retrospective cohort |
316 65 65 (Median) |
RT-qPCR or clinical, radiologic and lab findings that are consistent with other COVID-19 patients | N.S | Hypocalcemia | < 2.12 mmol/L | Within 72 h of hospital admission | 1, 2, 3, 6, 7 | Sex, advanced life support, SpO2/FiO2, lymphocyte count, C-reactive protein, D dimer and potassium levels | 7 |
|
Trecarichi, 2020 Italy |
Retrospective cohort |
50 57.1 80 (Mean) |
Positive SARS-CoV-2 molecular test conducted on nasopharyngeal swab | 52% severe, according to Italy National Institute of Health criteria | Hypernatremia | > 145 mmol/L | At admission | 1 | Lymphocyte count, cardiovascular disease excluding hypertension, interleukin-6 levels | 6 |
| Tzoulis, 2021 UK | Retrospective cohort |
488 56.8 68 (Median) |
RT-qPCR | N.S | Hyponatremia, Hypernatremia | Hyponatremia: < 135 mmol/L Hypernatremia: > 145 mmol/L | First 5 days of admission | 1, 3 | Sex, age, ethnicity, smoking status, number of co-morbidities, urea and C-reactive protein levels | 8 |
| Wu, 2020* China | Retrospective cohort |
125 52.8 55 (Median) |
Detection of SARS-CoV-2 RNA | 1.6% were severe, defined as dyspnea, hypoxemia and/or lung infiltrates > 50% | Hyponatremia, Hypernatremia, Hypocalcemia, Hypokalemia, Hyperkalemia, Hypochloremia | Hyponatremia: < 136 mmol/L Hypernatremia: > 145 mmol/L Hypocalcemia: < 2.2 mmol/L Hypokalemia: < 3.5 mmol/L Hyperkalemia: > 5.1 mmol/L Hypochloremia: < 99 mmol/L | At admission | Prolonged hospitalization | Age and comorbidities | 7 |
| Zheng, 2021 China | Retrospective cohort |
161 62.8 64 (Median) |
RT-qPCR | All were ICU patients | Hypocalcemia | < 1.8 mmol/L | At admission | 1 | N.A | 5 |
| Zhou, 2020* China | Retrospective cohort |
127 N.S N.S |
RT-qPCR | All had pneumonia | Hypocalcemia | < 2.2 mmol/L | Within 24 h of admission | Progression from mild/moderate infection to severe/critical infection | N.A | 5 |
*Not included in meta-analyses; NS not stated; NA not applicable; 1, Mortality; 2, ICU admission; 3, Respiratory support; 4, Acute respiratory distress syndrome; 5, Acute kidney injury; 6, Serum creatinine; 7, C-reactive protein; 8, Hospitalization time