Clinical outcomes and comparative costs
| Usual rule-out strategy | LoDED strategy | ||
| All patients | |||
| Patients successfully discharged within 4 hours (1° outcome) (%) | 114/311 (37) | 141/309 (46) | OR 1.58 (95% CI 0.84 to 2.98)* |
| MACEs at 30 days (%) | 17/313 (5) | 25/316 (8) | OR 1.50 (95% CI 0.76 to 3.02)† |
| MACEs in patients discharged within 4 hours (%) | 1/115 (1) | 0/141 (0) | – |
| Median time to discharge (hours) (IQR) | 5.0 (3.4–7.4) | 4.4 (3.2–6.8) | All patients: 4.8 (3.3–7.0) |
| Patient satisfaction score, median (IQR)‡ | 50 (44–55) | 51 (44–55) | – |
| Mean secondary care costs up to 30 days post discharge (95% CI)§ | £527 (£391 to £720)¶ | £429 (£302 to £651)¶ | Unadjusted incremental cost £98 (£−131 to £332)** |
| Adjusted incremental cost: £151 (£−34 to £336)†† | |||
| Patients with an initial hs-cTn below the LoD ‡‡ | |||
| Patients with an initial hs-cTn below the LoD (%) | 133/304 (44) | 141/307 (46) | All patients: 274/611 (45) |
| Patients with an initial hs-cTn below the LoD successfully discharged within 4 hours (%) | 68/132 (52) | 97/137 (71) | OR 2.51 (95% CI 0.76 to 8.25)† |
| MACEs at 30 days | 0 | 0 | – |
| Median time to discharge (hours) (IQR) | 4.0 (3.0–5.7) | 3.5 (2.7–4.3) | All patients: 3.7 (2.8–5.2) |
| Mean primary and secondary care costs up to 30 days post discharge (95% CI)§§ | £213 (£172 to £273)¶ | £184 (£153 to 243)¶ | Incremental cost: £29 (−£33 to £99)** |
| Site variation | |||
| Patients successfully discharged within 4 hours (1° outcome) (%) | |||
| Royal United Hospital, Bath | 16/34 (47) | 20/35 (57) | |
| Southmead Hospital, Bristol | 6/60 (10) | 25/60 (42) | |
| Derriford Hospital, Plymouth | 10/46 (22) | 11/45 (24) | |
| University Hospital, Southampton | 3/27 (11) | 9/26 (35) | |
| University Hospital of Wales, Cardiff | 11/17 (65) | 11/21 (52) | |
| Royal Devon and Exeter Hospital, Exeter | 21/49 (43) | 20/48 (42) | |
| Royal London Hospital, Barts Health NHS Trust, London | 8/34 (24) | 11/33 (33) | |
| Royal Berkshire Hospital, Reading | 39/44 (89) | 34/41 (83) | |
| Median time to discharge (hours) (IQR) | |||
| Royal united Hospital, Bath | 4.4 (3.1 to 9.7) | 3.5 (2.5 to 6.6) | |
| Southmead Hospital, Bristol | 5.6 (4.7 to 7.1) | 4.5 (3.2 to 6.1) | |
| Derriford Hospital, Plymouth | 6.1 (4.3 to 7.0) | 5.5 (4.1 to 7.1) | |
| University Hospital, Southampton | 5.9 (4.9 to 8.3) | 5.7 (3.4 to 6.2) | |
| University Hospital of Wales, Cardiff | 3.8 (2.8 to 6.5) | 4.0 (3.1 to 5.8) | |
| Royal Devon and Exeter Hospital, Exeter | 5.1 (3.5 to 26.5) | 5.3 (3.5 to 28.4) | |
| Royal London Hospital, Barts Health NHS Trust, London | 5.4 (4.1 to 9.1) | 6.4 (3.9 to 8.2) | |
| Royal Berkshire Hospital, Reading | 2.8 (2.5 to 3.4) | 3.2 (2.5 to 3.8) | |
*Pooled adjusted OR.
†Pooled unadjusted OR.
‡The Group Health Association of America Satisfaction Questionnaire was completed on discharge (online supplementary table S4).27 Scores out of 5 were summed for each of 11 questions, giving a maximum score of 55. 352/629 responses received.
§Data were available to calculate secondary care costs in 295/313 patients in the usual care arm and 295/316 in the intervention. The unit cost template for this analysis is available in the online supplementary material.
¶Mean cost with 95% bias corrected and accelerated CIs.
**Bootstrap mean difference with bias 95% bias corrected and accelerated CIs.
††Adjusted predicted mean cost difference (95% Confidence Intervals), generalised linear model (GLM) with a log link function and inverse gaussian family.
‡‡Data missing for 18 patients on the initial troponin result: 15 samples were haemolysed and three were lost.
§§Data were available to calculate primary and secondary care costs in 125/133 patients in the usual care arm 122/141 in the intervention. The unit cost template for this analysis is available in the online supplementary material.
Hs-cTn, high-sensitivity cardiac troponin; LoD, limit of detection; LoDED, limit of detection and ECG discharge; MACE, major adverse cardiac event.