The potential yield of ECG screening of hypertensive patients: The Utrecht Health Project
Objective: Several guidelines for hypertension and cardiovascular risk management recommend an ECG in hypertensive patients to improve risk prediction. We estimated the prevalence of clinically relevant ECG abnormalities and the number needed to screen (NNS) with a routine ECG to prevent the occurrence of one death in the next 10 years conditional on adequate treatment and follow-up. Methods: The study population consisted of 866 hypertensive participants recruited from the Utrecht Health Project (UHP), a dynamic population study in Utrecht. Baseline measurements included an ECG and the risk factors that enable a Systematic COronary Risk Evaluation (SCORE) risk estimation for each participant. ECGs were interpreted using Modular ECG Analysis System for computerized recognition of ECG abnormalities. NNS to prevent one death was computed by the reciprocal of the prevalence of the ECG abnormalities multiplied by number needed to treat to prevent one death when the ECG abnormality is managed according to the prevailing clinical guidelines. Results: The population consisted of 54.2% men with a mean age of 53.2 years (SD 11.5). The prevalence of ECG abnormalities was 17.6 [n = 95% confidence interval (CI) 15.0-20.1]. Prevalence of atrial fibrillation or prior myocardial infarction was 2.1% (95%CI 1.1-3.0) and of other ECG abnormalities related to increased cardiovascular disease risk 15.4% (95%CI 13.1-17.9). NNS to prevent one death from cardiovascular disease within 10 years was estimated at 260 (95%CI 220-308). Conclusion: Our findings support the existing recommendations to routinely record an ECG in unselected hypertensive patients as the prevalence of relevant abnormalities is considerable and NNS to prevent one death is lower than that in other widely accepted tests.