The Effect of the Body Mass Index and the Abdominal Circumference in the Diagnosis of Appendicitis using Ultrasonography

Roh,  Ki Sang; Oh,  Sung Chan; Kim,  Hye Jin; Cho,  Suk Jin; Lee,  Sang Lae; Ryu,  Seok Yong

J Korean Soc Emerg Med > Volume 20(2); 2009 > Article

Original Article

Journal of The Korean Society of Emergency Medicine 2009;20(2): 192-198.

The Effect of the Body Mass Index and the Abdominal Circumference in the Diagnosis of Appendicitis using Ultrasonography

Ki Sang Roh, Sung Chan Oh, Hye Jin Kim, Suk Jin Cho, Sang Lae Lee, Seok Yong Ryu

Department of Emergency Medicine, Sanggye Paik Hospital, College of Medicine, Inje University, Seoul, Korea. scoh@paik.ac.kr

ABSTRACT

PURPOSE:
This study was conducted to investigate the effect of body mass index (BMI) and abdominal circumference (AC) on the diagnosis of appendicitis using ultrasonography (US).
METHODS:
Between January 1, 2007, and June 30, 2007, we recruited 170 patients who complained about right lower-quadrant pain and who had an Alvarado score greater than 7 points. We recorded the height, weight, and AC for each patient and calculated a BMI. All patients received US investigation by emergency department residents. The cases were categorized according to whether the appendicitis was visible or non-visible. The sensitivity, specificity, and accuracy for each group were assessed and compared.
RESULTS:
A total of 170 patients was enrolled. Of those 94 patients had visible signs of appendicitis, and 76 patients had non-visible appendicitis. The mean BMI and AC of visible group were 22.09+/-3.12 and 77.47+/-9.32, as compared with 22.43+/-4.05 and 83.83+/-9.48 for the non-visible group, and the groups had significant differences in BMI and AC (p<0.001). The sensitivity, specificity and accuracy of US in patients with BMI under 25 were 58%, 60%, and 58%, respectively, and for those with BMI over 25 were 35%, 50%, and 36%. The sensitivity, specificity, and accuracy of US for male patients with AC under 90 cm were 55%, 75%, and 56%, and for those with AC over 90 cm the numbers were 35%, 50%, and 33%. The sensitivity, specificity, and accuracy of US in females with AC under 80 cm were 75%, 75%, and 74% and for those with AC over 80 cm, 45%, 50%, and 47%.
CONCLUSION:
Increasing BMI and AC negatively affect the US sensitivity, specificity, and accuracy in an appendicitis diagnosis.

Key words: Body mass index, Abdominal circumference, Appendicitis, Ultrasonography