Terminal Digit Preference and Blood Pressure Control in VA Medical Centers

Abstract Background Few studies have examined terminal digit preference (TDP) and blood pressure (BP) measurement in Veterans Affairs (VA) medical centers. Methods This mixed methods study examined TDP for BP measured in Veterans age 18 to 85 years with a hypertension diagnosis during a primary care visit within 8 Midwest VA medical centers from January 1, 2019, through March 1, 2020. TDP for both systolic (SBP) and diastolic blood pressures (DBP) was examined using a goodness of fit test assuming10% frequency for digits 0 through 9. Interviews were conducted with primary care clinicians from 3 VA centers to assess perceptions of BP measurement protocols. Results The mean age of the 98,433 Veterans (93% male) was 68.5 years (SD 12.7). Frequency of terminal digits 0 through 9 differed significantly from 10% for both SBP and DBP overall and within each VA center (P < 0.001). The most common terminal digits recorded were 0 and 8 for SBP (14.9% and 14.3%, respectively) and for DBP (17.5% and 14.3%, respectively). Interviews were conducted with 6 LPNs, 1 nurse manager and 6 primary care physicians. Most interviewees reported their clinic BP measurements were performed using semi-automated oscillometric devices but elevated readings were often confirmed by auscultatory methods. Only 5 of the 13 interviewees were aware of a clinic policy for BP measurement for their VA center. Conclusions Significant TDP exists for BP measurement in these eight VA centers indicating measurement bias. Future studies should examine strategies for improving BP measurement accuracyto optimize diagnosis and treatment.