Difference in Blood Pressure between Arms of Normotensive Female Farmers in the Semi-arid Midlands of Kenya

Introduction: Hypertension has been identified as the leading risk factor for mortality worldwide. The common clinical practice of one arm blood pressure measure and the presence of a difference between arm measurements is likely to lead to delayed diagnosis of hypertension and is associated with a higher prevalence of poor control of hypertension. Objective: To examine inter-arm differences that could give rise to undetected hypertension. Methods: A household cross-sectional survey was undertaken amongst 293 females who were participating in agricultural farm activities in lower Eastern Kenya. Six alternating arm blood pressure readings were taken, three on each arm with 3 minutes rest between each session. Results: Marginal but statistically significant inter-arm differences were observed in mean systolic blood pressure (right-arm 124.4 ± 12.5 mmHg; left-arm 123.3 ± 13.2 mmHg) and diastolic blood pressure (right-arm 75.4 ± 8.9 mmHg; left-arm 76.2 ± 9.1 mmHg). Right arm blood pressure readings indicated a higher prevalence of prehypertension and hypertension (51.2% and 12.3%) than left-arm (47.8 and 10.6%; p=0.001) readings. Statistically significant intra-arm differences (p=0.001) were observed between the 1st vs. 2nd and the 1st vs. 3rd right and left arm systolic blood pressure and diastolic blood pressure readings respectively. Conclusion and recommendation: Repeated blood pressure readings when measured on both arms can assist in more accurate identification of elevated blood pressure and timely diagnosis of hypertension. Population-wide studies are needed to examine the long term significance of blood pressure differences between arms.