Clinical correlates of plantar pressure among diabetic veterans

Abstract

Objective: To assess the relationship between diabetes characteristics, medical history, foot deformity, sensory neuropathy, and plantar foot pressure.

Research design and methods: There were 517 subjects from a cohort of diabetic veterans enrolled in a prospective study of risk factors for foot complications who contributed 1,017 limbs for study. We interviewed subjects to collect data on demographics, diabetes characteristics, and medical history. A research nurse practitioner performed a directed physical exam of the lower extremities, assessing foot deformities and including quantitative sensory testing with a 5.07 monofilament. In-shoe foot-pressure measurements were obtained with F-scan insoles on subjects wearing their own footwear while walking 10 m at their usual pace.

Results: In univariate analyses, significant associations were seen between at least one measure of plantar pressure and body mass, sex, race, age, insulin use, certain foot deformities, plantar callus, and sensory neuropathy. Diabetes duration, HbA1c, and history of foot ulcer or amputation were unrelated to plantar pressure. In multiple regression analyses, body mass measured as log (weight), insulin use, white race, male sex, plantar callus, and diabetes duration were significantly related to certain pressures. Foot deformities were related primarily to forefoot pressures. With high pressure at two or more sites defined as the outcome, only body mass remained statistically significant as a predictor of this outcome in a backwards elimination logistic regression model.

Conclusions: High in-shoe plantar pressure in diabetic subjects can be predicted in part from readily available clinical characteristics. The mechanisms by which these characteristics may be related to plantar pressure require further study.