Item Type Article Authors Stevens, S.L.; Stevens, R.J.; de Leeuw, P.; Kroon, A.A.; Greenfield, S.; Mohammed, Mohammed A.; Gill, P.; Verberk, W.J.; McManus, R.J. Citation Stevens SL, Stevens RJ, de Leeuw P et al (2019) Using outof-office blood pressure measurements in established cardiovascular risk scores: implications for practice. British Journal of General Practice. 69(683): e381-e388.
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AbstractBackground: Blood pressure (BP) measurement is increasingly carried out through home or ambulatory monitoring, yet existing cardiovascular risk scores were developed for use with measurements obtained in clinic.Aim: To describe differences in cardiovascular risk estimates obtained using ambulatory or home BP measurements instead of clinic readings.Design and setting: Secondary analysis of data from adults aged 30-84 without prior history of cardiovascular disease (CVD) in two BP monitoring studies (BP-Eth and HOMERUS).
Method:The primary comparison was Framingham risk calculated using BP measured as in the Framingham study or daytime ambulatory BP measurements. The QRISK2 and SCORE risk equations were also studied. Statistical and clinical significance were determined using the Wilcoxon signedrank test and scatter plots respectively.
Results:In 442 BP-Eth patients (mean age = 58 years, 50% female) the median absolute difference in 10-year Framingham cardiovascular risk calculated using BP measured as in the Framingham study or daytime ambulatory BP measurements was 1.84% (interquartile range 0.65 to 3.63, p=0.67). Only 31/ 442 (7.0%) of patients were reclassified across the 10% risk treatment threshold. In 165 HOMERUS patients (mean age = 56 years, 46% female) the median difference in 10-year risk was 2.76% (IQR 1.19 to 6.39, p<0.001) and only 8/165 (4.8%) of patient were reclassified.Conclusion: Estimates of cardiovascular risk are similar when calculated using BP measurements obtained as in the risk score derivation study or through ambulatory monitoring. Further research is required to determine if differences in estimated risk would meaningfully influence risk score accuracy.
How this fits in:Out-of-office blood pressure (BP) measurement is increasingly common but cardiovascular risk scores were developed using clinic BP measurements. It is unclear how estimates of cardiovascular risk may be affected by the use of out-of-office measurements in risk prediction algorithms. We have shown that differences in risk are generally small and few patients are reclassified across treatment thresholds when using different BP measurements. Extra care on the part of clinicians may be warranted in subgroups with large BP differences or those with risk estimates close to risk thresholds.