Accuracy of Self-Estimated BMI in the Context of Telephone Assessment Before Elective General Surgery

Background This study aimed to determine if self-estimated body mass index (BMI) from telephone consultation was accurate and useful for surgical planning prior to elective general surgery. Methods A prospective cohort study was performed under a single surgeon at a district general hospital in the United Kingdom. Estimated BMI was collected from consecutive patients attending a pre-operative telephone consultation. Actual BMI was measured on the day of surgery and compared. Patient age and gender were also collected. Results Data were collected from 124 participants (median age 59 years, 49.2% male). A total of 33 participants under-estimated, 53 over-estimated, and 38 accurately estimated their BMIs. The median change in BMI was 0.0 (IQR -0.1, 0.3, p = 0.003). The median change in males was 0.0 (-0.1, 0.2, p = 0.479) compared to 0.1 (0.0, 0.7, p = 0.002) in females. Those with an actual BMI > 29.9 had a significantly higher median change (0.2 {0.0, 1.1}) compared to those with BMI ≤ 29.9 (0.0 {-0.2, 0.1}; p <0.001). Only two patients could have required a change in surgeon on the day of the procedure and this was not statistically significant (p = 0.500). Conclusions Self-estimated BMI, collected via telephone consultation, is a suitable method for assessing patients for surgical planning ahead of elective general surgery procedures, particularly for males. However, it is important to be aware that those with higher BMIs, particularly females, may underestimate their BMIs.