Agreement between community pharmacy, physician's office, and home blood pressure measurement methods: the PALMERA Study

Background: The usefulness of the community pharmacy blood pressure (BP) (CPBP) method in assessing the effectiveness of antihypertensive treatment has not been adequately studied. The aim of this study was to assess the agreement between community pharmacy, home, and physician office BP (POBP) measurement methods in treated hypertensive patients.

Methods: BP was measured at the pharmacy (three visits), at home (4 days) and at the physician office (three visits). The Lin correlation-concordance coefficient (CCC) was used to evaluate the quantitative agreement. The qualitative agreement between methods to establish the patient's hypertensive state was evaluated using the κ-coefficient. Using home BP (HBP) monitoring as the reference method, the sensitivity, specificity, positive and negative likelihood ratios of the CPBP and POBP measurement methods were calculated.

Results: The study included 70 patients. Agreements were acceptable-moderate between CPBP and HBP (CCC (systolic BP (SBP)/diastolic BP (DBP)) = 0.79/0.66; κ = 0.56), moderate between CPBP and POBP (CCC = 0.57/0.61; κ = 0.35), and moderate-poor (CCC = 0.56/0.49; κ = 0.28) between POBP and HBP. The sensitivity, specificity, positive and negative likelihood ratio for the CPBP and the POBP measurement methods were: 60.7%, 92.9%, 8.5, 0.4 and 75.0%, 54.8%, 1.7, 0.5, respectively.

Conclusions: In this sample of treated hypertensive patients, the agreement between the community pharmacy and HBP measurement methods was acceptable-moderate and greater than other agreements. The CPBP measurement method was more reliable than the POBP measurement method for detecting the presence of both uncontrolled and controlled BP and could be a good alternative to HBP monitoring when the latter lacks suitability.