Estimated prevalence of hypertension and undiagnosed hypertension in a large inpatient population: A cross-sectional observational study.

Introduction Hypertension is a major cause of morbidity and mortality. In community populations the prevalence of hypertension, both in diagnosed and undiagnosed states, has been widely reported. However, estimates for the prevalence of hospitalised patients with average blood pressures that meet criteria for the diagnosis of hypertension are lacking. We aimed to estimate the prevalence of patients in a UK hospital setting, whose average blood pressures meet current international guidelines for hypertension diagnosis. Methods We performed a retrospective cross-sectional observational study of patients admitted to adult wards in four acute hospitals in Oxford, UK, between March 2014 and April 2018. Results We identified 41,455 eligible admitted patients with a total of 1.7 million blood pressure measurements recorded during their hospital admissions. According to European ESC/ESH diagnostic criteria for hypertension, 21.4% (respectively 47% according to American ACC/AHA diagnostic criteria) of patients had a mean blood pressure exceeding the diagnostic threshold for either Stage 1, 2 or 3 hypertension. Similarly, 5% had a mean blood pressure exceeding the ESC/ESH (respectively 13% had a mean blood pressure exceeding the ACC/AHA) diagnostic criteria for hypertension, but no pre-existing diagnostic code for hypertension or a prescribed antihypertensive medication during their hospital stay. Conclusion Large numbers of hospital inpatients have mean in-hospital blood pressures exceeding diagnostic thresholds for hypertension, with no evidence of diagnosis or treatment in the electronic record. Whether opportunistic screening for in -hospital high blood pressure is a useful way of detecting people with undiagnosed hypertension needs evaluation.