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Patient-reported Weight Agrees With Clinic Data One Year After Metabolic/Bariatric Surgery

Key findings

  • This study compared national registry data with self-reports on weight and comorbidities from 1,130 patients from 53 centers who had undergone metabolic/bariatric surgery one year previously
  • In aggregate, patients underreported their weight by an average of only 2 lbs. compared with the registry, and 95% of patient-reported weights were within 13 lbs. of the registry-recorded weight
  • There was a sufficient agreement between patient and registry reports about the presence/absence of diabetes, hypertension, and hyperlipidemia, but not sleep apnea or gastroesophageal reflux disease
  • Patient reports on weight and certain comorbidities are reliable and could be valuable supplements to in-clinic visits and clinic reporting to registries

Patient-report questionnaires are normally used to measure subjective outcomes such as quality of life and satisfaction with medical care. However, they can also be constructed to gather objective clinical data directly from patients.

The Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) of the American College of Surgeons has determined that follow-up beyond 30 days after metabolic/bariatric surgery is poor. Patient reports of their postoperative body weight would be of interest if they could be shown to be reliable.

MBSAQIP is now partnering with the Patient-Centered Outcomes Research Institute to have patients across the U.S. report quality of life and obesity-related problems before and after metabolic/bariatric surgery.

Massachusetts General Hospital researchers determined that in this program, patient-reported data on weight and selected comorbidities show satisfactory agreement with data reported to MBSAQIP by clinics. Matthew M. Hutter, MD, MBA, MPH, medical director of the Codman Center for Clinical Effectiveness in Surgery, and colleagues present the evidence in Surgery for Obesity and Related Diseases.

Methods

At the time of data extraction (August 2021), 78 centers had enrolled in the patient-reported outcomes project. Via email, patients received a link to an online survey 21 days before their scheduled operation date and annually on the anniversary of the surgery.

All surveys included questionnaires from the Obesity and Weight-loss Quality of Life Instrument, the Obesity-related Problems Scale, and the Patient-Reported Outcomes Measurement Information System. The postoperative surveys included additional questions about current body weight and comorbidities.

This analysis compared patient reports with MBSAQIP registry records after one year of follow-up (the follow-up period could range from 9–18 months). The two sets of records had to be dated within 90 days of each other. Cases were restricted to adults ages 18 to 90 who had a single metabolic/bariatric operation between 2015 and 2020.

Weight

1,130 patients from 53 centers had matched data available on weight. In aggregate, patients underreported their weight by an average of only 2 lbs. compared with the registry.

The absolute differences from registry records were:

  • 50% of patient-reported weights were within 3 lbs.
  • 75% were within 5 lbs.
  • 95% were within 13 lbs.
  • 99% were within 23 lbs.

Comorbidities

1,059 patients answered questions about certain comorbidities (present or absent). The comparison with registry data was:

  • Diabetes—94% agreement; κ, 0.72 (substantial agreement)
  • Hypertension—88% agreement; κ, 0.70 (substantial agreement)
  • Hyperlipidemia—87% agreement; κ, 0.62 (substantial agreement)
  • Sleep apnea—81% agreement; κ, 0.53 (moderate agreement)
  • Gastroesophageal reflux disease—75% agreement; κ, 0.40 (fair agreement)

Commentary

Since weight fluctuates throughout the day, the average differences between patient- and registry-reported weights were remarkably small. In particular, the two-pound aggregate difference does not seem clinically meaningful. It's reasonable to conclude that patient-reported weights are reliable.

2lbs.
aggregate difference between patient-reported and clinic-reported body weight one year after metabolic/bariatric surgery

95%
of patients reported body weight within 13 lbs. of the clinic-reported body weight one year after metabolic/bariatric surgery

94%
agreement between patient and clinic reports one year after metabolic/bariatric surgery about whether the patient had diabetes

About the Codman Center for Clinical Effectiveness in Surgery

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Related

Matt Hutter, MD, MBA, MPH, is director of the Massachusetts General Hospital Weight Center, and medical director of the Codman Center. In this video, he discusses his research on measuring and improving the quality of care in metabolic and bariatric surgery.

Related

Matthew Hutter, MD, MBA, MPH, is director of the Massachusetts General Hospital Weight Center and medical director of the Codman Center. In this video, he discusses the Codman Center and how it achieves its mission to deliver the safest, highest value patient care through innovative research and education.