Cardiac troponin blood assay by median age*: multivariable binomial regressions† using the GEE approach
| Covariates | Ages 18–54 n=37 307 presentations | Ages 55+ n=38 909 presentations | ||
| OR (95% CI) | P value | OR (95% CI) | P value | |
| Age categories | ||||
| First tertile (youngest category) (reference) | 1.00 | 1.00 | ||
| Second tertile | 2.41 (2.28 to 2.54) | <0.001 | 1.15 (1.08 to 1.23) | <0.001 |
| Third tertile (oldest category) | 3.07 (2.88 to 3.26) | <0.001 | 1.23 (1.15 to 1.32) | <0.001 |
| Female sex | 0.73 (0.70 to 0.77) | <0.001 | 0.91 (0.87 to 0.97) | 0.001 |
| Arrival by ambulance | 1.60 (1.52 to 1.69) | <0.001 | 1.30 (1.23 to 1.38) | <0.001 |
| Main presenting sign or symptom | ||||
| Musculoskeletal pain (reference) | 1.00 | 1.00 | ||
| Chest pain | 1.22 (1.05 to 1.39) | 0.008 | 1.30 (1.12 to 1.50) | <0.001 |
| Arrhythmia/altered consciousness | 0.56 (0.48 to 0.66) | <0.001 | 0.41 (0.35 to 0.48) | <0.001 |
| Shortness of breath | 1.14 (0.91 to 1.43) | 0.263 | 1.32 (1.04 to 1.66) | 0.020 |
| Urgency ATS score allocation of 1 ‘immediate review’ or 2 ‘review within 10 min’ | 2.49 (2.37 to 2.62) | <0.001 | 1.60 (1.51 to 1.69) | <0.001 |
| AMI | ||||
| No (reference) | 1.00 | 1.00 | ||
| Yes, non-ST segment elevation AMI | 2.46 (2.02 to 3.01) | <0.001 | 2.30 (2.03 to 2.60) | <0.001 |
| Yes, ST segment elevation AMI | 0.73 (0.57 to 0.92) | 0.009 | 0.54 (0.46 to 0.63) | <0.001 |
| QIC for model adjusting for age | 50 678.7 | 39 921.1 | ||
| QIC for full model | 37 879.9 | 26 712.3 | ||
*The median age of study participants on their first encounter was chosen as it approximately differentiated between premenopausal and postmenopausal women in the study sample.
†Models were also adjusted for comorbidities: angina pectoris, chronic heart disease and chronic respiratory disease; acute conditions associated with chest pain: cardiopulmonary arrest, acute respiratory, gastrointestinal and neurological conditions, and emotional and mental disorders; hospital; and day during week and hour of presentation.
AMI, acute myocardial infarction; ATS, Australasian Triage; GEE, generalised estimating equations; QIC, quasi-likelihood under independence model criterion.