Table 3.
Comparison of clinical outcomes between COVID-19 patients with hyponatraemia, normonatremia and hypernatraemia
| Outcome | Hyponatraemia Na≤134 mmol/L N=2677 |
Normonatremia Na 136–145 mmol/L N=5008 |
Hypernatraemia Na≥146 mmol/L N=126 |
| Duration of admission (median days (IQR)) | N=2372 7 (4–16) P<0.001 |
N=4116 7 (3–14) |
N=103 8 (4–15) P=0.998 |
| Death or palliative discharge (N (%)) | 405/2360 (17.2%) AOR 1.04 (0.91–1.20) P=0.56 |
729/4568 (16.0%) | 42/119 (35.3%) AOR 2.25 (1.49–3.41) P<0.001 |
| ICU admission (N (%)), ‘do not intubate’ excluded |
439/1923 (22.8%) AOR 1.27 (1.11–1.46) P<0.001 |
710/3778 (18.8%) | 32/80 (40.0%) AOR 2.89 (1.83–4.58) P<0.001 |
| Duration of ICU admission (days (IQR)) ‘do not intubate’ excluded |
N=299 8 (3–19) P=0.356 |
N=437 10 (4–19) |
N=25 11 (3.5–19) P=0.356 |
| Invasive ventilation (N (%)), ‘do not intubate’ excluded |
352/1889 (18.6%) AOR 1.12 (0.97–1.30) P=0.121 |
623/3706 (16.8%) | 29/77 (37.7%) AOR 2.95 (1.83–4.74) P<0.001 |
| Discharge alive within 42 days; N indicating the number of non-censored cases | N=1527 AHR 0.96 (0.90–1.02) P=0.15 |
N=2747 | N=52 AHR 0.78 (0.59–1.03) P=0.08 |
| Use of tocilizumab, sarilumab or anakinra (N (%)) | 134/688 (19.5%) AOR 1.256 (0.984–1.604) P=0.068 |
199/1245 (16.0%) | 3/34 (8.8%) AOR 0.550 (0.165–1.830) P=0.330 |
| Complications |
Na≤134 mmol/L
N=2677 |
Na 136–145 mmol/L
N=5008 |
Na≥146 mmol/L
N=126 |
| Bacterial pneumonia (N (%)) | 289/2212 (13.1%) AOR 1.12 (0.96–1.31) P=0.14 |
501/4307 (11.6%) | 18/109 (16.5%) AOR 1.44 (0.85–2.40) P=0.17 |
| Aspergillosis pneumonia (N (%)) | 67/1915 (3.5%) AOR 1.44 (1.03–1.99) P=0.031 |
83/3442 (2.4%) | 5/90 (5.6%) AOR 2.26 (0.89–5.74) P=0.084 |
| ARDS (N (%)) | 224/2223 (10.1%) AOR 1.08 (0.91–1.29) P=0.377 |
404/4323 (9.3%) | 17/110 (15.5%) AOR 1.78 (1.05–3.04) P=0.033 |
| Treatment for septic shock (N (%))* | 94/2153 (4.4%) AOR 1.33 (1.01–1.74) P=0.04 |
135/4175 (3.2%) | 12/109 (11.0%) AOR 3.37 (1.80–6.33) P<0.001 |
| Congestive heart failure (N (%)) | 64/2235 (2.9%) AOR 0.95 (0.70–1.29) P=0.73 |
125/4352 (2.9%) | 2/111 (1.8%) AOR 0.48 (0.12–1.96) P=0.31 |
| Physical decline (N (%)) | 576/2116 (27.2%) AOR 1.22 (1.08–1.38) P<0.001 |
950/4126 (23.0%) | 30/106 (28.3%) AOR 1.18 (0.77–1.82) P=0.44 |
| Delirium (N (%)) | 237/2136 (11.1%) AOR 0.99 (0.83–1.17) P=0.88 |
451/4146 (10.5%) | 27/107 (25.7%) AOR 2.25 (1.42–3.56) P<0.001 |
Significance was assessed using a Cox proportional hazard model at the mean of the covariates (discharge alive) or logistic regression (all other values). P values for all groups indicate significance when compared with the normonatremia group.
*Treatment for septic shock was defined as the need for vasopressors in order to maintain mean arterial blood pressure>65 mm Hg and blood lactate level <2 mmol/L, in the absence of other causes including hypovolaemia.
AHR, adjusted HR; HR adjusted for sex assigned at birth, age, a history of chronic kidney disease and a history of hypertension; AOR, adjusted OR; OR adjusted for sex assigned at birth, age, a history of chronic kidney disease and a history of hypertension; ARDS, acute respiratory distress syndrome; ICU, intensive care unit.