To what extent can the chosen blood pressure measurement technique affect the outcomes of an observational survey?

Aim: We analyzed to what extent measurement protocol influenced individual blood pressure (BP) and achievement of treatment target in patients with coronary heart disease. Methods: In a subsample of Czech EUROASPIRE III-V survey participants (n = 913), we compared the per-protocol BP measurement (by automated oscillometric device OMRON at the beginning of survey procedure) with control auscultatory measurement (by physician during interview). Results: Per-protocol approach produced significantly (p < 0.0001) higher BP values (by 9/6 mmHg in median) than auscultatory measurements and led to markedly higher proportion of patients over target BP (less than 140/ 90 mmHg; 59.3 vs 34.9% [p < 0.0001], per-protocol vs auscultatory technique, respectively). Conclusion: Per-protocol oscillometric technique was not equivalent to conventional auscultatory measurement and seriously over-rated the real nonachievement of BP target in observational surveys.