Age changes what a risk-factor count tells the referring physician: recorded cardiometabolic burden and obstructive coronary artery disease on CT angiography in a single-centre cross-sectional study

Abstract Background General practitioners considering coronary computed tomography angiography (CCTA) usually have only admission diagnoses and recent laboratory results. Whether the number of cardiometabolic risk factors in those records means the same at every age, and whether HbA1c and eGFR add discrimination, is untested. Methods Single-centre cross-sectional study of adult CCTA examinations from the general practice and cardiology pathways of a tertiary hospital, 2021 to 2025. The exposure was the number of hypertension, diabetes, dyslipidaemia and renal impairment recorded from diagnoses and laboratory results within 30 days before CCTA. Obstructive coronary artery disease (CAD) was read from reports by a validated text rule. After excluding prior revascularisation and incomplete laboratory data, 5,225 patients were analysed with patient-clustered logistic regression. Results Obstructive CAD was reported in 1,018 patients (19.5%), similarly in both pathways. Each additional risk factor carried an adjusted odds ratio of 1.70 (95% CI 1.57 to 1.84); adjusted prevalence rose from 9.2% with none to 43.9% with four. Age modified the association (interaction P < 0.001): the per-factor odds ratio was 2.20 under 55 years and 1.46 at 75 or older; obstructive CAD without recorded risk factors was 0.4% and 21.2%. Adjusted odds ratios were 4.41 for HbA1c of 8.0% or higher and 1.64 for eGFR below 60 mL/min/1.73 m². Conclusions The recorded risk-factor count shows a dose-response relationship with obstructive CAD that weakens with age. A clean record reassures in younger patients but much less in older ones. HbA1c and eGFR refine risk; risk-factor review before CCTA should be read by age.