Summary of demographics, serum sodium and water intake volumes in the case reports/case series
| All | Mild hyponatraemia (130–134 mmol/L) | Moderate hyponatraemia (125–129 mmol/L) | Severe hyponatraemia (<125 mmol/L) | |
| Mean age (years) (95% CI)* | 46±16 (43.6 to 48.0) | 38±10 (30.3 to 45.0) | 41 (35 to 47) | 47 (45 to 49) |
| Male:female (%)† | 53:47 | 67: 17 | 62: 38 | 52:48 |
| Comorbidities (%) | ||||
| None | 31% (69/223) | 50% (5/10) | 44% (12/27) | 28% (52/186) |
| Medical condition | 15% (33/223) | 0% (0/10) | 11% (3/27) | 16% (30/186) |
| Psychiatric disorder | 52% (117/223) | 50% (5/10) | 41% (11/27) | 54% (101/186) |
| Both (medical +psychiatric) | 2% (4/223) | 0% (0/10) | 4% (1/27) | 2% (3/186) |
| Concomitant medications (%) | ||||
| Not reported | 31% (70/223) | 30% (3/10) | 44% (12/27) | 30% (55/186) |
| No medications | 23% (51/223) | 50% (5/10) | 26% (7/27) | 21% (39/186) |
| Associated with hyponatraemia | 41% (92/223) | 20% (2/10) | 30% (8/27) | 44% (82/186) |
| Not associated with hyponatraemia | 5% (10/223) | 0% (0/10) | 0% (0/27) | 5% (10/186) |
| Reason for water intake | ||||
| Exercise | 12% (27/223) | 50% (5/10) | 29.6% (8/27) | 8% (14/186) |
| Iatrogenic | 13% (29/223) | 0% (0/10) | 18.5% (5/27) | 13% (24/186) |
| Habitual/dipsogenic | 7% (15/223) | 0% (0/10) | 11.1% (3/27) | 6% (12/186) |
| Psychogenic | 55% (123/223) | 40% (4/10) | 33.3% (9/27) | 59% (110/186) |
| Multiple reasons | 2% (5/223) | 0% (0/10) | 3.7% (1/27) | 2% (4/186) |
| Other | 11% (24/223) | 10% (1/10) | 3.7% (1/27) | 12% (22/186) |
| Mean serum sodium (mmol/L) (95% CI) | 118 (116 to 118) | 132 (131 to 133) | 127 (126 to 127) | 114 (113 to 115) |
| Median water intake per day‡ (litres) (95% CI) | 8.0 (8.9 to 12.2) | 5.0 (−2.2 to 14.5) | 8.0 (5.3 to 9.7) | 9.0 (9.2 to 13.0) |
| Median water intake over 4-hour period (litres) (95% CI)§ | 5.3 (5.3 to 8.6) | 3.1 (−0.3 to 8.3) | 6.2 (3.3 to 9.1) | 7.5 (5.4 to 9.6) |
*Age was not reported in n=25 individuals.
†Gender was not reported in n=64 individuals.
‡Data are from n=76 case report/case series.
§Data are from n=49 case report/case series.