Missed acute coronary syndrome during telephone triage at out-of-hours primary care: lessons from a case-control study

BACKGROUND: Serious adverse events (SAE) at out-of-hours services in primary care (OHS-PC) are rare. It most often concerns missed acute coronary syndromes (ACS). Root cause analyses highlighted errors in the triage process, but these analyses are hampered by hindsight bias. AIM: To compare triage calls at the OHS-PC of missed ACS with matched controls with chest discomfort but without a missed ACS; and to assess predictors of missed ACS. METHOD: A case-control study with triage recordings of calls of a missed ACS registered between 2013-2017. Controls were from the same period. Cases were matched 1:8 with controls based on age and gender. Clinical, patient and call characteristics were assessed, and 15 expert GPs rated the triage safety and quality, being blinded to the final diagnosis. We applied conditional logistic regression analysis. RESULTS: Fifteen missed ACS calls and 120 matched control calls were included. Cases used less cardiovascular medication (38.5% versus 64.1%, P = 0.05), and more often experienced retrosternal chest pain (63.3% versus 24.7%, P = 0.02) than controls. Consultation of the supervising GP (86.7% versus 49.2%, P = 0.02) occurred more often in cases than controls. Experts rated the triage of cases more often as 'poor' (33.3% versus 10.9%, P = 0.001), and 'unsafe' (73.3% versus 22.5%, P<0.001) than that of controls. CONCLUSION: It seems nearly impossible to differentiate missed ACS at the OHS-PC from others with chest discomfort based on symptom presentation.