Can foot and ankle surgeons accurately estimate patient body mass index?

The body mass index (BMI) is an objective patient finding that has been established to have a negative effect on the development and outcomes of podiatric pathologic entities and interventions. The objective of the present investigation was to assess the ability of podiatric physicians to estimate the patient BMI from clinical and radiographic observation. For the clinical estimation of the patient BMI, podiatric specialists across 3 levels of experience (i.e., students, residents, and practicing clinicians) performed 294 estimations on 72 patients in 3 clinical situations (standing, sitting in a treatment chair, and lying in a hospital bed). It was more common to inaccurately estimate the patient BMI (77.9%) than it was to correctly estimate it (22.1%), with underestimations being the most common error (48.3%). The estimations were particularly inaccurate when the patients were in the common clinical situation of sitting in a treatment chair or lying in a hospital bed and with patients actually classified as obese. For the radiographic estimation of patient BMI, 150 consecutive lateral ankle radiographs were analyzed, with the ratio of the overlying soft tissue diameter to the underlying bone diameter calculated and compared. Positive, but weak, relationships were observed with these ratios. From these data, we have concluded that podiatric practitioners should perform an actual calculation of the patient BMI during the patient examination and medical decision-making process to fully appreciate the potential risks inherent to the treatment of obese patients.