Effects of surgically induced weight loss on urinary bladder pressure, sagittal abdominal diameter and obesity co-morbidity H Sugerman, A Windsor, M Bessos, J Kellum, H Reines and E DeMaria Division of General and Trauma Surgery, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, USA OBJECTIVE: Evaluate the effects of surgically induced weight loss on intra-abdominal pressure at one year, re¯ected in urinary bladder pressure, central obesity, measured by sagittal abdominal diameter and obesity co-morbidity. DESIGN: Prospective, non-randomized trial. SETTING: University Hospital, Operating Room, In-patient, Outpatient Clinics. SUBJECTS: Gastric bypass in 15 severely obese patients. MEASUREMENTS: Patients underwent pre-operative assessment of weight, body mass index (BMI), co-morbid history, urinary bladder pressure and sagittal abdominal diameter. Patients were reassessed one year after gastric bypass with repeat measurement of weight, bladder pressure, and sagittal abdominal diameter and assessment of co-morbidity. RESULTS: There were signi®cant (P < 0.001) decreases in weight (140  8±87  6 kg), BMI (52  3±33  2 kg/m 2 ), sagittal abdominal diameter (32  1±20  2 cm), urinary bladder pressure (17  2±10  1 cm H 2 O) and obesity related problems per patient (2.9  0.4±1  0.2) one year after gastric bypass, with 69  4% loss of excess weight. CONCLUSIONS: Increased sagittal abdominal diameter is associated with increased intra-abdominal pressure which contributes to obesity related co-morbidity. Weight loss following gastric bypass decreases abdominal pressure, sagittal abdominal diameter and obesity co-morbidity. Keywords: central obesity; gastric bypass; surgery; sagittal abdominal diameter; urinary bladder pressure; obesity co-morbidity Introduction There is general agreement that obesity is associated with increased morbidity and mortality 1,2 and that this increased health risk is positively correlated with regional fat distribution and not simply the degree of obesity. 3±5 The metabolic activity of visceral adi- pose tissue appears responsible for risk factors, col- lectively known as `syndrome X', such as insulin resistance, hyperinsulinemia and diabetes, hyperten- sion, and altered lipid metabolism. 6±8 In a previous study, we found that central obesity is also associated with increased intra-abdominal pressure, as measured by urinary bladder pressure, and this is associated with a number of co-morbid problems. We hypothesized that several of these are probably due to increased intra-abdominal pressure and include hypoventilation, urinary incontinence, venous stasis, gastroesophageal re¯ux and incisional hernia, and hypertension. 9 This study also supported data from other reports 10±12 that sagittal abdominal diameter is a more reliable indica- tor of central obesity than waist to hip ratio (WHR). The current study was designed to evaluate the effects of surgically induced weight loss on sagittal abdom- inal diameter, abdominal pressure as estimated from urinary bladder pressure and obesity co-morbidity. Methods Patient population 15 morbidly obese patients (body mass index (BMI)  35 kg/m 2 ) of 84 previously reported patients 9 undergoing surgery for morbid obesity at the Medical College of Virginia, Virginia Commonwealth Univer- sity, were entered into the study. The study was approved by the Committee on the Conduct of Human Research. Patient weight, height, BMI and ideal body weight according to the 1983 Metropolitan Life Insurance Company actuarial tables 13 were deter- mined pre-operatively and informed consent obtained. Abdominal diameter and bladder pressure At the time of surgery, patients were placed supine on the operating table, which was leveled with a spirit level. Following induction of anesthesia, the patient was paralyzed and intubated. The sagittal abdominal Correspondence: Harvey J Sugerman, David Hume Professor of Surgery, Box 980519, MCV Station, Richmond VA 23298-0519, USA. Received 4 October 1996; revised 15 April 1997, 23 July 1997; accepted 3 November 1997 International Journal of Obesity (1998) 22, 230±235 ß 1998 Stockton Press All rights reserved 0307±0565/98 $12.00