Systolic blood pressure variability and lower extremity amputation in a non-elderly population with diabetes

- Excessive systolic blood pressure variability was a significant and strong predictor of major amputations in the lower extremities.
- Significant graded relationship between SBP variability and major amputation was found in both normotensive and hypertensive groups.
- Persons with existing peripheral vascular disease may not be subject to this graded relationship.

ObjectiveSystolic blood pressure (SBP) variability is emerging as a new risk factor for cardiovascular diseases, diabetic nephropathy, and other atherosclerotic conditions. Our objective is to examine whether it has any prognostic value for lower-extremity amputations.Research design and methodsThis is a nested case-control study of a cohort of patients with diabetes aged < 60 years and treated in the US Department of Veterans Healthcare system in 2003. They were followed over five years for any above-ankle (major) amputations. For each case with a major amputation (event), we randomly selected up to five matched controls based on age, sex, race/ethnicity, and calendar time. SBP variability was computed using three or more blood pressure measures taken during the one-year period before the event. Patients were classified into quartiles according to their SBP variability.ResultsThe study sample included 1038 cases and 2932 controls. Compared to Quartile 1 (lowest variability), Quartile 2 had 1.4 times (OR = 1.44, 95% CI = 1.00-2.07) and Quartiles 3 and 4 (highest) had 2.5 times (OR for Quartile 3 = 2.62, 95% CI = 1.85-3.72; OR for Quartile 4 = 2.50, 95% CI = 1.74-3.59) higher risk of major amputation (P for trend < 0.001). This gradient relationship held in both normotensive and hypertensive groups as well as for individuals without prior peripheral vascular disease.ConclusionsThis is the first study to show a significant graded relationship between SBP variability and risk of major amputation among non-elderly persons with diabetes.