Table 4.
Univariable and multivariable associations between a positive decision to order a CA and factors using Generalised Linear Mixed Models (GLMM)
| Factor | GROUP 1 (n=57 cardiologists) |
GROUP 2 (n=54 cardiologists) |
||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Univariable analysis |
Multivariable analysis |
Univariable analysis |
Multivariable analysis |
|||||||||
| Raw % CA=yes‡ | OR | 95% CI LL-UL | OR | 95% CI LL–UL | p Value* | Raw % CA=yes‡ | OR | 95% CI LL–UL | OR | 95% CI LL–UL | p Value* | |
| Troponin levels | ||||||||||||
| Elevated | 80.6 | 13.7 | 8.25 to 22.69 | 66.90 | 26.29 to 170.25 | ≤0.001 | 84.9 | 11.57 | 7.14 to 18.76 | 55.80 | 22.50 to 138.36 | ≤0.001 |
| Normal | 26.9 | 1.0 | 1.0 | 33.9 | 1.0 | 1.0 | ||||||
| ECG changes† | ≤0.001 | ≤0.001 | ||||||||||
| Aspecific | 43.0 | 1.04 | 0.66 to 1.65 | 1.13 | 0.54 to 2.39 | 0.74 | 49.3 | 1.13 | 0.71 to 1.82 | 2.00 | 0.88 to 4.56 | 0.10 |
| Typical ischaemic | 74.7 | 4.17 | 2.51 to 6.92 | 15.39 | 6.37 to 37.17 | ≤0.001 | 77.7 | 4.05 | 2.41 to 6.79 | 16.40 | 4.80 to 56.05 | ≤0.001 |
| Normal | 42.8 | 1.0 | 1.0 | 46.4 | 1.0 | 1.0 | ||||||
| Age† | ≤0.001 | 0.50 | ||||||||||
| 70–80 years | 65.0 | 1.81 | 1.13 to 2.89 | 1.21 | 0.58 to 2.49 | 0.61 | 72.8 | 2.58 | 1.56 to 4.26 | 1.08 | 0.28 to 4.18 | 0.91 |
| >80 years | 42.0 | 0.72 | 0.45 to 1.14 | 0.14 | 0.05 to 0.34 | ≤0.001 | 49.7 | 0.97 | 0.60 to 1.55 | 0.58 | 0.10 to 3.48 | 0.55 |
| <70 years | 51.7 | 1.0 | 1.0 | 51.4 | 1.0 | 1.0 | ||||||
| Presence of risk factors† | 0.43 | 0.45 | ||||||||||
| 1 risk factor | 51.0 | 1.01 | 0.64 to 1.61 | 0.82 | 0.35 to 1.91 | 0.65 | 59.3 | 1.07 | 0.66 to 1.74 | 0.69 | 0.30 to 1.59 | 0.38 |
| >1 risk factor | 58.2 | 1.40 | 0.88 to 2.22 | 1.32 | 0.61 to 2.85 | 0.48 | 59.0 | 1.08 | 0.68 to 1.72 | 1.09 | 0.50 to 2.39 | 0.83 |
| No risk factors | 49.7 | 1.0 | 1.0 | 56.0 | 1.0 | 1.0 | ||||||
| Renal dysfunction† | ≤0.001 | ≤0.001 | ||||||||||
| Mild to moderate | 54.1 | 0.62 | 0.38 to 0.99 | 0.52 | 0.23 to 1.18 | 0.12 | 64.3 | 1.36 | 0.84 to 2.21 | 2.17 | 0.84 to 5.60 | 0.11 |
| Severe | 39.4 | 0.33 | 0.21 to 0.54 | 0.09 | 0.04 to 0.21 | ≤0.001 | 51.4 | 0.76 | 0.47 to 1.21 | 0.25 | 0.10 to 0.63 | ≤0.001 |
| No | 66.0 | 1.0 | 1.0 | 58.7 | 1.0 | 1.0 | ||||||
| Previous CAD | ||||||||||||
| Yes | 61.4 | 2.08 | 1.42 to 3.04 | 2.80 | 1.45 to 5.42 | ≤0.01 | 57.3 | 0.93 | 0.63 to 1.37 | 0.94 | 0.50 to 1.78 | 0.75 |
| No | 44.1 | 1.0 | 1.0 | 59.0 | 1.0 | 1.0 | ||||||
| Persistent chest pain | ||||||||||||
| Yes | 63.2 | 2.29 | 1.57 to 3.36 | 4.90 | 2.36 to 10.16 | 0.000 | 68.4 | 2.36 | 1.56 to 3.51 | 3.79 | 1.92 to 7.51 | 0.000 |
| No | 43.6 | 1.0 | 1.0 | 48.2 | 1.0 | 1.0 | ||||||
| Risk score outcome† | NA | 0.02 | ||||||||||
| Intermediate | NA | NA | NA | NA | NA | 63.7 | 4.41 | 2.60 to 7.49 | 4.40 | 0.84 to 22.93 | 0.08 | |
| High | NA. | NA | NA | NA | NA | 71.8 | 6.32 | 3.21 to 12.42 | 1.27 | 0.09 to 18.20 | 0.86 | |
| Low | NA | NA | NA | NA | NA | 32.7 | 1.0 | 1.0 | ||||
Associations comparing level 2 vs 3 for the different factors were.
▪ ECG changes: typical ischaemic versus aspecific (GROUP 1: p 0.000, OR 13.57, CI 95% 5.65 to 32.60)/(GROUP 2: p 0.000, OR 8.20, CI 95% 2.87 to 23.46).
▪ Age: >80 years versus 70–80 years (GROUP 1: p 0.000, OR 0.11, CI 95% 0.05 to 0.27)/(GROUP 2: p 0.25, OR 0.53, CI 95% 0.18 to 1.55).
▪ Presence of risk factors: >1 risk factor versus 1 risk factor (GROUP 1: p 0.21, OR 1.61, CI 95% 0.77 to 3.36)/(GROUP 2: p 0.22, OR 1.56, CI 95% 0.76 to 3.32).
▪ Renal dysfunction: severe versus mild to moderate (GROUP 1: p 0.000, OR 0.17, CI 95% 0.07 to 0.39)/(GROUP 2: p 0.000, OR 0.12, CI 95% 0.05 to 0.26).
▪ Risk score outcome: high versus intermediate (GROUP 2: p 0.14, OR 0.29, CI 95% 0.06 to 1.50).
*Significance tests for independent factors were based on the loglikelihood ratio test (in bold).
†Significance tests for independent factors with three levels of pairwise comparisons, that is, level 1 vs 2, level 1 vs 3, and level 2 vs 3, were based on the Wald test (in italic).
‡ Raw percentages of patients receiving CA for each level of a factor are presented. Eg, in group 1, for factor Troponin, 222 vignettes are in the category ‘elevated’ and 179 of these received CA, leading to 179/222×100=80.6%.
CAD, coronary artery disease; LL, lower limit; LRT, loglikelihood ratio test; NA, not applicable; UL, upper limit.