Sonographic Evaluation of the Heel Pad Thickness in Diabetics in Nigeria.

Background: Diabetes mellitus is a chronic disease process affecting millions of people worldwide. Its prevalence is forecasted to reach a value of 7.7% by 2030. It carries severe morbidities and even mortality. Hyperglycemia and increased formation of advanced glycosylation end products causes the majority of soft tissue changes seen among diabetics. The effects are observed particularly in the heel pad and plantar fascia where thinning or thickening, fibre disorganization, calcification and hypoechoic foci are among the changes seen.

Methods: This cross-sectional descriptive study was carried out at the Department of Radiology, OAUTHC, Ile Ife, Osun state, Southwest Nigeria. 40 years old and above subjects with Type 2 diabetes mellitus were recruited from the diabetic clinic of the institution and Ultrasound evaluation of the heel fat pad and plantar fascia were subsequently performed for those who met the criteria using ultrasound machine equipped with a 7.5- 12.0 MHz high frequency linear array transducer.

Results: The mean heel pad thickness on the right feet was greater than that of the left in the study subjects. There was statistical significant difference in the heel fat pad thickness of diabetic subjects and the control group, in both feet. (=0.000). The heel pad thickness is higher in diabetic subject than in non-diabetic control subjects. However, there was no statistical significant difference in the right and left heel fat pad thickness of the participants of this study ( value 0.6062). Only HPT was a statistically significant predictor of foot ulcers among other variables after binary regression was computed. Using Spearman's rank correlation to test the relationship between the BMI of diabetic subjects and mean heel pad thickness, it revealed a moderate positive correlation, with good statistically significance (Spearman's rho = 0.4397, =0.0000). The relationship between the BMI of diabetic subjects and mean plantar fascia thickness showed a weak positive correlation, with good statistical significance (Spearman's rho = 0.2635, =0.0008).

Conclusion: The duration of diabetes mellitus did not determine the heel pad thickness and plantar fascia thickness. The findings in the study suggested that history of foot ulcer in the diabetic predispose them to have reduce HPT and further foot ulcers. Sonographic measurement of heel pad thickness can therefore be an additional imaging modality to evaluate and be used in the management of the diabetic patients' feet.