QJM vol. 97 no. 11 © Association of Physicians 2004; all rights reserved.
Hypertension in diabetes: is there a place for age-adjusted centile cut-offs in those aged <50 years?
From the Wolverhampton Diabetes Centre, New Cross Hospital, Wolverhampton, UK
Received 27 November 2004 and in revised form 24 June 2004
Background: Conventional cut-offs for hypertension are arbitrary, and vascular complications can occur below these values, particularly in diabetes.
Aim: To evaluate systolic blood pressure (SBP) distribution in diabetes and control populations, comparing hypertension prevalence using either conventional cut-offs (140 and 160 mmHg) or age-adjusted centile (75th and 90th) cut-offs derived from the control population.
Methods: We compared 2521 individuals with diabetes to 5809 controls, after excluding those on anti-hypertensives and with established vascular disease in both groups.
Results: Diabetic individuals were older (mean ± SD 56 ± 16 vs. 43 ± 16years, diabetes vs. controls), and had higher BMI (29 ± 5 vs. 24 ± 4 kg /cm2) and SBP (145 ± 23 vs. 131 ± 18 mmHg, all p < 0.001). These factors were adjusted for in subsequent analysis. SBP rose with age and was also significantly higher in the diabetes group. In diabetes, conventional cut-offs indicated less hypertension in those aged < 50 years, compared to age-adjusted centile cut-offs. In age bands 18–29, 30–39, 40–49, 50–59, 60–69 and >70 years of the diabetes group, 24%, 33%, 43%, 62%, 70% and 74%, respectively exceeded 140 mmHg, compared to 35%, 44%, 43%, 45%, 40% and 27% exceeding the control-derived 75th centile value.
Discussion: The use of control-derived age-adjusted cut-offs may provide an alternative approach to define hypertension in diabetes that may be of particular relevance to younger patients, although this would require validation against outcomes.
Address correspondence to Dr V. Baskar, 7 Coven Mill Close, Coven, Wolverhampton WV9 5HX. e-mail: baskar{at}doctors.org.uk