RT Journal Article SR Electronic T1 Diagnosing hypertension in primary care: a retrospective cohort study to investigate the importance of night-time blood pressure assessment JF British Journal of General Practice JO Br J Gen Pract FD British Journal of General Practice SP e16 OP e23 DO 10.3399/BJGP.2022.0160 VO 73 IS 726 A1 Laura C Armitage A1 Shaun Davidson A1 Adam Mahdi A1 Mirae Harford A1 Richard McManus A1 Andrew Farmer A1 Peter Watkinson A1 Lionel Tarassenko YR 2023 UL http://bjgp.org/content/73/726/e16.abstract AB Background Ambulatory blood-pressure monitoring (ABPM) has become less frequent in primary care since the COVID-19 pandemic, with home blood-pressure monitoring (HBPM) often the preferred alternative; however, HBPM cannot measure night-time blood pressure (BP), and patients whose night-time BP does not dip, or rises (reverse dipping), have poorer cardiovascular outcomes.Aim To investigate the importance of measuring night-time BP when assessing individuals for hypertension.Design and setting Retrospective cohort study of two patient populations — namely, hospital patients admitted to four UK acute hospitals located in Oxfordshire, and participants of the BP in different ethnic groups (BP-Eth) study, who were recruited from 28 UK general practices in the West Midlands.Method Using BP data collected for the two cohorts, three systolic BP phenotypes (dipper, non-dipper, and reverse dipper) were studied.Results Among the hospital cohort, 48.9% (n = 10 610/21 716) patients were ‘reverse dippers’, with an average day–night systolic BP difference of +8.0 mmHg. Among the community (BP-Eth) cohort, 10.8% (n = 63/585) of patients were reverse dippers, with an average day–night systolic BP difference of +8.5 mmHg. Non-dipper and reverse-dipper phenotypes both had lower daytime systolic BP and higher night-time systolic BP than the dipper phenotype. Average daytime systolic BP was lowest in the reverse-dipping phenotype (this was 6.5 mmHg and 6.8 mmHg lower than for the dipper phenotype in the hospital and community cohorts, respectively), thereby placing them at risk of undiagnosed, or masked, hypertension.Conclusion Not measuring night-time BP puts all groups, other than dippers, at risk of failure to identify hypertension. As a result of this study, it is recommended that GPs should offer ABPM to all patients aged ≥60 years as a minimum when assessing for hypertension.