Magnitude of the white-coat effect in the community pharmacy setting: the MEPAFAR study.

BACKGROUND: There is little information regarding the community pharmacy blood pressure (CPBP) measurement method and their differences with home (HBP) or ambulatory BP (ABP). The aim of this study was to measure such differences and their variation over successive visits. METHOD: Cross-sectional study carried out in eight pharmacies in Gran Canaria (Spain). The study included 169 treated hypertensive patients. BP was measured at the pharmacy (four visits), at HBP (4 days) and 24-h ABP monitoring. We defined pharmacy white-coat effect (PWCE) as differences between CPBP and HBP (home PWCE) or daytime ABP (ambulatory PWCE). RESULTS: The overall (pooled values for all visits) ambulatory PWCE was not significantly different from zero for systolic BP (SBP) (-0.4 mm Hg (95% confidence interval (CI): -1.8 to 1.1)), but greater than zero for diastolic BP (DBP) (3.4 mm Hg (95% CI: 2.3 to 4.6)). The overall home PWCE was not significantly different from zero, both for SBP (1.2 mm Hg (95% CI: -0.1 to 2.6)) and DBP (0.1 mm Hg (95% CI: -0.7 to 1.0)). The ambulatory and home PWCE on the first visit were greater than zero (P < 0.001) (SBP/DBP): 3.5/4.8 and 1.9/1.5 mm Hg, respectively; but showed important reductions at the second visit and became not significantly different from zero, except the ambulatory PWCE in DBP, which persisted until the last visit. CONCLUSION: The trend in the PWCE decreased over the successive visits to the pharmacy. Only the ambulatory PWCE in DBP proved to be statistically greater than zero after the second visit. Repeated CPBP measurements could be a useful alternative to assess the response to antihypertensive treatment.

Clinical value of blood pressure measurement in the community pharmacy.

AIM OF THE STUDY: To investigate whether the measurement of blood pressure in the community pharmacy is a valuable method to diagnose hypertension, to assess the need and the effectiveness of anti-hypertensive treatments, or, in general, to make clinical decisions. METHOD: Information has been extracted from articles published in English and in Spanish, from January 1989 to December 2009, in indexed magazines in MEDLINE and EMBASE. To perform the search, multiple and specified terms related to the community pharmacy setting, to blood pressure measurement and to the comparison and agreement between blood pressure measurement methods were used. Selected articles were those that: (1) compared and/or measured the agreement (concordance) between community pharmacy blood pressure measurements obtained in repeated occasions, or (2) compared and/or measured the agreement between the community pharmacy blood pressure measurement method and other measurement methods used in clinical practice for decision-making purposes: blood pressure measurement by a physician, by a nurse and home or ambulatory blood pressure monitoring. Articles were included and analyzed by two investigators independently, who essentially extracted the main results of the manuscripts, emphasizing the assessment of the blood pressure measurement methods used and the completed statistical analysis. RESULTS: Only three studies comparing the community pharmacy blood pressure measurement method with other methods and one comparing repeated measurements of community pharmacy blood pressure were found. Moreover, these works present significant biases and limitations, both in terms of method and statistical analysis, which make difficult to draw consistent conclusions. CONCLUSION: Further research of high quality is needed, which results can guide the clinical decision-making based on the community pharmacy blood pressure measurement method.