A Meta-analysis to Determine the Validity of Taking Blood Pressure Using the Indirect Cuff Method

The purpose of this meta-analysis was to compare the magnitude of systematic bias (mean difference) and random error (standard deviation of mean difference) between the cuff method of indirect blood pressure and directly measured intra-arterial pressure.

Blood pressure is almost exclusively assessed using the indirect cuff method; however, numerous individual studies have questioned the validity relative to directly measured intra-arterial blood pressure. PubMed, SportsDiscus, and Scopus were searched through February 2018. Data were analyzed using a random effects model. A total of 62 studies met the inclusion criteria for quantitative analysis including 103 effect sizes for systolic and 114 effect sizes for diastolic blood pressure. Indirect measures of systolic blood pressure were underestimated (- 4.55 (95% CI = - 5.58 to - 3.53) mmHg), while diastolic blood pressure was overestimated (6.20 (95% CI = 5.09 to 7.31) mmHg). The random error (SD units) was 10.32 (95% CI = 9.29 to 11.36) for systolic and 7.92 (95% CI = 7.35 to 8.50) for diastolic blood pressure which corresponds to an estimation accuracy (95% confidence) of ± 20.2 mmHg for systolic blood pressure and ± 15.5 mmHg for diastolic blood pressure. These data indicate that it may be difficult to accurately estimate intra-arterial blood pressure using the cuff method. These results not only have implications for clinicians in diagnosing hypertension, but also may detail a potential underestimation of the association between blood pressure and numerous other health outcomes found in epidemiological studies.