Table 4:
Associations between Inconclusive Test Results and Process of Care and Outcomes by Test Type
| Frequency of Event (# Events/Sample Size) | Unadjusted | Adjusted* | ||||
|---|---|---|---|---|---|---|
| Process of Care | Conclusive Positive or Inconclusive | Conclusive Negative | Odds Ratio (95% CI) | P-value | Odds Ratio (95% CI) | P-value |
| Overall Stress | ||||||
| Referral to second NIT within 90 days of first NIT | ||||||
| Conclusive Positive vs. Conclusive Negative | 145/564 (25.71%) | 299/3531 (8.47%) | 3.74 (2.99–4.68) | <0.001 | 3.59 (2.85–4.53) | <0.001 |
| Inconclusive vs. Conclusive Negative | 64/438 (14.61%) | 299/3531 (8.47%) | 1.85 (1.38–2.47) | <0.001 | 1.91 (1.42–2.56) | <0.001 |
| Referral to ICA within 90 days of Randomization | ||||||
| Conclusive Positive vs. Conclusive Negative | 263/564 (46.63%) | 85/3531 (2.41%) | 35.43 (27.00–46.47) | <0.001 | 34.62 (26.08–45.98) | <0.001 |
| Inconclusive vs. Conclusive Negative | 24/438 (5.48%) | 85/3531 (2.41%) | 2.35 (1.48–3.74) | <0.001 | 2.36 (1.47–3.78) | <0.001 |
| CTA | ||||||
| Referral to second NIT within 90 days of first NIT | ||||||
| Conclusive Positive vs. Conclusive Negative | 124/534 (23.22%) | 324/3844 (8.43%) | 3.29 (2.61–4.14) | <0.001 | 2.97 (2.32–3.78) | <0.001 |
| Inconclusive vs. Conclusive Negative | 109/299 (36.45%) | 324/3844 (8.43%) | 6.23 (4.80–8.10) | <0.001 | 5.95 (4.52–7.85) | <0.001 |
| Referral to ICA within 90 days of Randomization | ||||||
| Conclusive Positive vs. Conclusive Negative | 354/534 (66.29%) | 159/3844 (4.14%) | 45.57 (35.87–57.91) | <0.001 | 42.81 (33.18–55.24) | <0.001 |
| Inconclusive vs. Conclusive Negative | 70/299 (23.41%) | 159/3844 (4.14%) | 7.08 (5.19–9.67) | <0.001 | 6.49 (4.67–9.02) | <0.001 |
| Outcome | Hazard Ratio (95% CI) | P-value | Hazard Ratio (95% CI) | P-value | ||
| Overall Stress | ||||||
| All-cause death/MI/UAH | ||||||
| Conclusive Positive vs. Conclusive Negative | 47/564 (8.33%) | 69/3531 (1.95%) | 4.45 (3.07–6.45) | <0.001 | 3.50 (2.38–5.15) | <0.001 |
| Inconclusive vs. Conclusive Negative | 16/438 (3.65%) | 69/3531 (1.95%) | 1.90 (1.10–3.28) | 0.021 | 1.81 (1.05–3.13) | 0.034 |
| CV Death/MI | ||||||
| Conclusive Positive vs. Conclusive Negative | 19/564 (3.37%) | 43/3531 (1.22%) | 2.74 (1.60–4.71) | <0.001 | 1.96 (1.11–3.46) | 0.019 |
| Inconclusive vs. Conclusive Negative | 11/438 (2.51%) | 43/3531 (1.22%) | 2.09 (1.08–4.06) | 0.029 | 2.04 (1.05–3.97) | 0.037 |
| CTA | ||||||
| All-cause death/MI/UAH | ||||||
| Conclusive Positive vs. Conclusive Negative | 49/534 (9.18%) | 83/3844 (2.16%) | 4.48 (3.15–6.38) | <0.001 | 3.66 (2.51–5.35) | <0.001 |
| Inconclusive vs. Conclusive Negative | 15/299 (5.02%) | 83/3844 (2.16%) | 2.43 (1.40–4.20) | 0.002 | 1.85 (1.02–3.36) | 0.044 |
| CV Death/MI | ||||||
| Conclusive Positive vs. Conclusive Negative | 14/534 (2.62%) | 45/3844 (1.17%) | 2.26 (1.24–4.12) | 0.008 | 1.66 (0.88–3.15) | 0.120 |
| Inconclusive vs. Conclusive Negative | 4/299 (1.34%) | 45/3844 (1.17%) | 1.18 (0.43–3.29) | 0.746 | 0.74 (0.23–2.43) | 0.623 |
ICA = invasive coronary angiography, MI = myocardial infarction, UAH = unstable angina hospitalization.
*
Adjusted model controls for NIT modality (stress test vs. CTA), age, sex, BMI, diabetes, smoker (ever), CAD equivalent, site characterization of chest pain, provider estimation of likelihood of obstructive epicardial disease (high or very high), hypertension, dyslipidemia, family history of premature CAD, participate in physical activity, Framingham Risk Score (2008), and Diamond-Forrester (2011).