Influence of Siesta in the Estimation of Blood Pressure Control in Patients With Hypertension
To the Editor
Banegas et al1 in their article have compared the measurements of blood pressure (BP) in the office and in ambulatory monitoring to assess the BP control in treated patients with hypertension in primary care centers. Ben-Dov and Busztyn,2 in their letter, have suggested that the influence of the nap in the BP diurnal average perhaps can present erroneously higher rates of daytime BP control than real.
In our department, for 2 years we have studied the influence of siesta in several variables of ambulatory BP monitoring (ABPM). A prospective evaluation of 1056 consecutive ABPMs in our hypertension unit over a 2-year period revealed that siesta was reported by 305 patients, ≈29% of the total ABPM recordings. At last, considering quality standards and exclusion criteria, 115 treated patients with hypertension were analyzed. There are a few points that we would like to make about these articles1,2 and in this way to contribute to this interesting area.
In our study, the rate of office BP control (<140/ 90 mm Hg) was 15%, and according to daytime ABPM (<135/85 mm Hg), 36% of patients were controlled. However, if we consider the daytime average and exclude the napping time BP measurements from the analysis, the control rate was 30%.
We agree with the main conclusion exposed by Banegas et al1 and general practitioners in primary care centers: the real management of hypertension is much better than it looks based on office measurements. However, we dissent with the appraisal that the influence of removing siesta BP measurements on daytime ambulatory BP is small. The fact is that the differences between both BP daytime averages (with and without nap measurements) exist and are statistically significant. In our experience, ignoring siesta, we overestimate the rate of control by ≈6%. If we are seeking an improvement in the assessment of BP control, it does not seem to us suitable to ignore the nap as a potential distortion factor, as Ben-Dov and Bursztyn2 suggest.
Although Banegas et al3 state that most siestas take <1 hour in Spain, according to the only Sleep National Report in Spain,4 the average for daytime napping (namely, siesta) in the Spanish general population is ≈60 to 65 minutes. In some subgroups, for example, students or the unemployed population, the nap time rank increases considerably (60 to 88 minutes). In other countries, reviewing the references about ABPM and siesta, the average nap times are even higher.5
Overall, we emphasize the importance of siesta as a real distortion factor in the daytime BP average and, thus, a distortion factor in the assessment in control rate of hypertension. From our experience in a hypertension unit, we endorse the main conclusion of Banegas et al1 in primary care centers: the management of hypertension is better than it looks based on office surveys.
Banegas JR, Segura J, Sobrino J, Rodriguez-Artalejo F, Sierra A, Cruz JJ, Gorostidi M, Sarria A, Ruilope LM; Spanish Society of Hypertension Ambulatory Blood Pressure Monitoring Registry Investigators. Effectiveness of blood pressure control outside the medical setting. Hypertension. 2007; 49: 62–68.
Ben-Dov IZ, Bursztyn M. Is siesta masking masked hypertension? Hypertension. 2007; 49: e25.
Banegas JR, de la Sierra A, Segura J, Sobrino J, Ruilope LM. Response to is siesta masking masked hypertension? Hypertension. 2007; 49: e26.
Informe Nacional del Sueño Pikolin. Pikolin, Spain: 1998.
Bursztyn M, Mekler J, Watchel N, Ben-Ishay D. Siesta and ambulatory blood pressure monitoring. Comparability of the afternoon nap and night sleep. Am J Hypertens. 1994; 7: 217–221.