Routine Errors Matter: The Effect of Non-Standardized Blood Pressure Measurement

BackgroundBlood pressure (BP) is routinely measured during healthcare visits. A standardized measurement is essential to ensure accurate values, particularly in outpatient settings, where patient preparation, environment, and technique can significantly influence results. MethodsA quasi-experimental study was conducted in adult outpatients. Demographic, anthropometric, and clinical data were collected through interviews and physical examination. BP was measured using a validated automated oscillometric device under four non-randomized predefined sequences. The standardized method followed international guideline recommendations, whereas the other three incorporated common errors observed in clinical practice (unsupported body position on the examination table, patient speaking, or legs crossed). Systolic and diastolic BP values were compared using the Friedman test and paired Wilcoxon tests with Holm adjustment. Effect sizes were expressed as median paired differences with interquartile ranges. Analyses were performed using R and Stata. ResultsA total of 295 participants were included (61% women; median age 56 years), with hypertension as the most frequent comorbidity (33%). Significant differences were observed across the four measurement models (p < 0.001). Compared with the standardized method, systolic BP was higher by +8 mmHg (M2), +2.5 mmHg (M3), and +4 mmHg (M4), while diastolic BP increased by +7 mmHg, +2 mmHg, and +2 mmHg, respectively. Clinically relevant differences (|{Delta}| [&ge;] 5 mmHg) occurred in up to 81% of systolic and 79% of diastolic measurements with M2. ConclusionsNon-adherence to guideline-recommended BP measurement protocols leads to BP overestimation and misclassification of hypertension status, which may affect therapeutic decision-making and the use of pharmacological treatments.