Meeting Highlights


Determining Inter-arm Blood Pressure is Important in New Patients with Diabetesv

Presented by Christopher E. Clark, United Kingdom

Christopher E. Clark, PhD, University of Exeter Medical School, Devon, United Kingdom, presented results from a study of inter-arm differences (IAD) in systolic blood pressure (BP) in patients with diabetes. Simultaneous measurements, often impractical in a clinical setting, were obtained and compared with calculated sequential pairs. Associations between IAD and vascular disease and mortality were also explored.

Once they had provided informed consent, patients with diabetes and nondiabetic control patients underwent 4 pairs of bilateral simultaneous automated BP measurements. After 2 simultaneous measurements were conducted in a random order, cuffs were switched to the opposite arms and another pair of measurements was obtained. For the simultaneous measurements, IADs were calculated for each pair by subtracting the left BP from the right BP. Sequential pairs were modeled by subtracting the 2nd or 4th left BP from the 1st right BP, for best and worst case sequential pairs. Demographic information was collected from each participant. Patient records were flagged in the National Health Service Information Centre to acquire mortality data from death certificates.

A total of 727 patients with diabetes and 285 controls were enrolled. Of these, 514 (71%) of the patients with diabetes and 238 (84%) of the controls had 4 pairs of BP results (p<0.001). Prof. Clark attributed the smaller number of diabetes patients with complete results to the larger number of patients with atrial fibrillation in the diabetes group.

The control group was younger and two-thirds were hypertensive versus 90% of the patients with diabetes. In the diabetes population, 8.6% had a systolic IAD ≥10 mmHg compared with 2.9% of the controls. Prof. Clark stated that he and his colleagues could not attribute the reason for this difference in systolic IAD entirely to diabetes. Both the simultaneous and sequential single pair measurements were significant (p<0.001 for both) in a receiver operating characteristics curve, indicating that a sequential single pair is a useful way to determine IAD in place of simultaneous measurements.

A systolic IAD ≥10 mmHg was associated with peripheral artery disease (OR, 3.1; 95% CI, 1.2 to 8.0; p=0.03) and retinopathy (OR, 1.8; 95% CI, 1.0 to 3.4; p=0.056). A systolic IAD ≥15 mmHg was associated with retinopathy (OR, 6.5; 95% CI, 1.7 to 24.4; p=0.003) and chronic kidney disease (OR, 5.4; 95% CI, 1.4 to 21.1; p=0.033). Additionally, preliminary survival data showed a significant difference in cardiovascular mortality in patients with systolic IAD ≥10 mmHg (HR, 4.6; 95% CI 1.2 to 17.6; p=0.028) and systolic IAD ≥15 mmHg (HR, 10.9; 95% CI, 2.3 to 51.3; p=0.003).

Prof. Clark emphasized that “there [were] relatively few [adverse] events included in this [study and that they] intend to return to this in the future when a significant number of events have been collected.” He advised clinicians to measure BP in both arms when initially evaluating patients with diabetes as systolic IADs are associated with vascular disease and possibly related to increased cardiovascular mortality.