Baseline characteristics
| Total no. of index admissions N=24 905 | Normal saline N=12 338 | Ringer’s lactate N=12 567 | |
| Sex, female, n (%) | 13 977 (56.1%) | 6976 (56.5%) | 7001 (55.7%) |
| Age, mean±SD | 59.2±20.5 | 59.4±20.6 | 59.0±20.5 |
| Age group, n (%) | |||
| 1 month to 18 years | 168 (0.7%) | 75 (0.6%) | 93 (0.7%) |
| >18 to 65 | 13 792 (55.4%) | 6756 (54.8%) | 7036 (56.0%) |
| >65 to 80 | 6771 (27.2%) | 3368 (27.3%) | 3403 (27.1%) |
| >80 | 4174 (16.8%) | 2139 (17.3%) | 2035 (16.2%) |
| Case mix group, n (%) | |||
| Medicine | 10 773 (43.3%) | 5449 (44.2%) | 5324 (42.4%) |
| Surgery | 10 377 (41.7%) | 5080 (41.2%) | 5297 (42.2%) |
| Pregnancy and childbirth | 3614 (14.5%) | 1744 (14.1%) | 1870 (14.9%) |
| Mental health | 141 (0.6%) | 65 (0.5%) | 76 (0.6%) |
| Type of surgical admission, n (%) | |||
| Elective | 5796 (55.9%) | 2852 (56.1%) | 2944 (55.6%) |
| Urgent | 4581 (44.2%) | 2228 (43.9%) | 2353 (44.4%) |
| Surgical admission <24 hours, n (%) | 950 (9.2%) | 484 (9.5%) | 466 (8.8%) |
| Severity of illness | |||
| Admission to ICU, n (%) | 3034 (12.2%) | 1494 (12.1%) | 1540 (12.3%) |
| Infection alone and infection and organ dysfunction, n (%) | 2734 (11.0%) | 1365 (11.1%) | 1369 (10.9%) |
| Infection alone and infection and organ dysfunction and ICU admission, n (%) | 579 (2.3%) | 292 (2.4%) | 287 (2.3%) |
| Trauma+ICU, n (%) | 176 (0.7%) | 92 (0.8%) | 84 (0.7%) |
| Traumatic brain injury, n (%) | 121 (0.6%) | 68 (0.6%) | 53 (0.4%) |
| Traumatic brain injury+ICU, n (%) | 64 (0.3%) | 35 (0.3%) | 29 (0.2%) |
| Comorbidities | |||
| Elixhauser comorbidity score, mean±SD | 5.3±6.0 | 5.4±6.1 | 5.3±6.0 |
| Elixhauser comorbidities, n (%) | |||
| Diabetes, complicated | 2819 (11.3%) | 1396 (11.3%) | 1423 (11.3%) |
| Hypertension, uncomplicated and complicated | 2574 (10.3%) | 1207 (9.8%) | 1367 (10.9%) |
| Cardiac arrhythmias | 2263 (9.1%) | 1143 (9.3%) | 1120 (8.9%) |
| Solid tumour without metastasis | 2105 (8.5%) | 1004 (8.1%) | 1101 (8.8%) |
| Fluid and electrolyte disorders | 1886 (7.6%) | 944 (7.7%) | 942 (7.5%) |
| Diabetes, uncomplicated | 1374 (5.5%) | 686 (5.6%) | 688 (5.5%) |
| Congestive heart failure | 1187 (4.8%) | 606 (4.9%) | 581 (4.6%) |
| Metastatic cancer | 1008 (4.1%) | 487 (4.0%) | 521 (4.2%) |
| Chronic pulmonary disease | 971 (3.9%) | 536 (4.3%) | 435 (3.5%) |
| Other neurological disorders | 946 (3.8%) | 490 (4.0%) | 456 (3.6%) |
| Peripheral vascular disorders | 732 (2.9%) | 348 (2.8%) | 384 (3.1%) |
| Coagulopathy | 495 (2.0%) | 230 (1.9%) | 265 (2.1%) |
| Valvular disease | 472 (1.9%) | 242 (2.0%) | 230 (1.8%) |
| Obesity | 460 (1.9%) | 248 (2.0%) | 212 (1.7%) |
| Renal failure | 450 (1.8%) | 239 (1.9%) | 211 (1.7%) |
| Paralysis | 379 (1.5%) | 209 (1.7%) | 170 (1.4%) |
| Liver disease | 360 (1.5%) | 173 (1.4%) | 187 (1.5%) |
| Alcohol abuse | 348 (1.4%) | 171 (1.4%) | 177 (1.4%) |
| Pulmonary circulation disorders | 300 (1.2%) | 147 (1.2%) | 153 (1.2%) |
| Depression | 253 (1.0%) | 105 (1.0%) | 148 (1.2%) |
| Deficiency anaemia | 248 (1.0%) | 120 (1.0%) | 128 (1.0%) |
| Lymphoma | 247 (1.0%) | 125 (1.0%) | 122 (1.0%) |
| Drug abuse | 199 (0.8%) | 96 (0.8%) | 103 (0.8%) |
| Rheumatoid arthritis/collagen vascular diseases | 168 (0.7%) | 87 (0.7%) | 81 (0.6%) |
| Hypothyroidism | 156 (0.6%) | 78 (0.6%) | 78 (0.6%) |
| Weight loss | 152 (0.6%) | 67 (0.5%) | 85 (0.7%) |
| Psychoses | 97 (0.4%) | 51 (0.4%) | 46 (0.4%) |
| Blood loss anaemia | 56 (0.2%) | 28 (0.2%) | 28 (0.2%) |
| Peptic ulcer disease excluding bleeding | 35 (0.1%) | 20 (0.2%) | 15 (0.1%) |
| AIDS/HIV | 21 (0.1%) | 11 (0.1%) | 10 (0.1%) |
ICU, intensive care unit; n, number.