Even among patients who achieve moderate weight loss before surgery

Loosing 10% or more of body weight prior to bariatric surgery was associated with a 42% lower risk of 30-day mortality, researchers found. And, even moderate weight loss — less than 5% — lessened 30-day mortality following the procedure.

While bariatric surgery has been shown to be the most effective — and durable — treatment for clinically morbid obesity, “there has been long-standing uncertainty and debate regarding the value of preoperative weight loss as a requirement for bariatric surgery,” wrote Yangbo Sun, MD, PhD, Department of Epidemiology, University of Iowa College of Public Health, and colleagues was published in JAMA Network Open.

In fact, perceptions regarding the value of pre-operative weight loss vary among physicians, hospitals, patients, and payers, and current clinical guidelines do not recommend pre-operative weight loss because there is a lack of scientific evidence showing its benefits.

Therefore, “there is an urgent and critical need to clarify the potential influence of pre-operative weight loss on postoperative outcomes after bariatric surgery,” Sun and colleagues observed.

Considering the importance of 30-day mortality as an indicator of surgical outcomes after bariatric surgery, the authors wanted to evaluate the association of preoperative BMI and weight loss with 30-day mortality after the procedure.

In this study, the authors used data from the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) Participant Use Data File, which included 480,075 cases performed in all 832 MBSAQIP centers during the period from 2015 to 2017.

The mean percentage reduction in body weight in these patients before surgery was 4.0% (SD, 4.4%; range, 0%-70.2%).

Compared with patients without weight loss before surgery, patients with greater weight loss before bariatric surgery were:

  • More likely to be slightly older (mean [SD] age, 44.7 years versus 47.1 years).
  • More likely to be male and non-Hispanic white.
  • More likely to undergo Roux-en-Y gastric bypass.
  • More likely to have higher highest recorded preoperative BMI and lower preoperative BMI closest to the day of surgery.
  • Less likely to have smoked tobacco during the past year.
  • More likely to have 2 or more comorbid conditions at baseline.

Of the patients in the study, 511 deaths (0.1%) occurred within 30 days of surgery. Greater weight loss before bariatric surgery was associated with lower risk of 30-day mortality. Furthermore, compared with patients with no preoperative weight loss, the multivariable-adjusted odds ratio for 30-day mortality for patients was 0.76 (95% CI, 0.60-0.96) for patients with percentage body weight reduction of more than 0% to less than 5.0%, and 0.69 (95% CI, 0.53-0.90) for patients with a percentage body weight reduction of between 5.0% and 9.9%. Those patients with the highest percentage body weight reduction (10% and higher) had an adjusted odds ratio of 0.58 (95% CI, 0.41-0.82) – a 42% lower risk of 30-day mortality.

They also found that compared with patients with a preoperative BMI of 35.0 to 39.9, the multivariable-adjusted odds ratios for 30-day mortality increased as preoperative BMI increased.

In a commentary accompanying the study, Micaela M. Esquivel, MD, and Dan Azagury, MD, both of the Division of General Surgery, Department of Surgery, Stanford University School of Medicine, highlighted that last finding in suggesting that the answer to improving mortality after bariatric surgery “is not really about maximizing preoperative weight loss.”

Instead, “perhaps the answer is treating patients in the earliest possible stage of their disease to negate the increased morbidity and mortality that is associated with more advanced disease and higher BMI,” wrote Esquivel and Azagury. “Patients should be provided early and rapid access to the care they need; in this case, that means access to a life-saving procedure without artificial insurance barriers, such as duration-based mandatory weight loss.”

Sun and colleagues pointed out that their study has important clinical implications considering the considerable number of patients who die after undergoing bariatric surgery. “Although current clinical guidelines do not require preoperative weight loss and a decision to perform bariatric surgery should not be based on whether and how much preoperative weight loss is achieved, it may be beneficial for patients with obesity to be referred to an established weight loss program before surgery to reduce the risk of mortality,” they concluded.

  1. Preoperative weight loss in patients undergoing bariatric surgery is associated with reduced 30-day mortality.

  2. This was true even among patients who achieved moderate weight loss of less than 5% reduction in body weight.

Michael Bassett, Contributing Writer, BreakingMED™

None of the authors quoted in this article had any industry relationships to disclose.

Cat ID: 51

Topic ID: 86,51,730,51,518,917,159