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Rating centres

Objective scale published to rate bariatric centres

Study ompared with using individual characteristics at surgical centres to measure site quality
Justin Dimick

An objective measure that includes procedure complications, patient and surgeon volume, and other outcomes provided a more suitable scale when rating centres that perform bariatric surgery, according to researchers from the University of Michigan.

Published online in JAMA Surgery, the paper compares with using individual characteristics at surgical centres to measure site quality, which did not achieve significance, the composite scale was able to differentiate risk of complications between low-scoring and high-scoring centres (OR 1.99, 95% CI 1.14-3.47).

The researchers stated that the optimal approach for profiling hospital performance with bariatric surgery is unclear, so they set out to develop a novel composite measure for profiling hospital performance with bariatric surgery.

The objective rating scale for surgical centres was published shortly after an announcement from the Centers for Medicare and Medicaid Services saying they would eliminate certification requirements for facilities that offer bariatric procedures, citing that certification was not associated with improved outcomes at bariatric surgery centres.

The new measure was developed through data acquired from the Michigan Bariatric Surgical Collaborative clinical registry on 2,942 patients who underwent bariatric surgery in Michigan from 2008 to 2010.

The registry includes 29 hospitals and 75 surgeons, and collects information on patient characteristics, procedure type, processes of care, and postoperative outcomes. The procedures included in the study were open and laparoscopic gastric bypass, adjustable gastric banding, sleeve gastrectomy, and biliopancreatic diversion with duodenal switch.

The scale included scores for hospital volume, risk-adjusted complication rates, risk- and reliability-adjusted complication rates. Hospitals were scored on each of these categories individually and as a composite scale.


The authors, led by according to Dr Justin Dimick of the Center for Healthcare Outcomes and Policy at the University of Michigan in Ann Arbor, limited complications used in the scale to those considered potentially life threatening, grade II, or worse. These included abdominal abscess, bowel obstruction, leak, bleeding, wound infection or dehiscence, respiratory failure, venous thromboembolism, band-related problems that required reoperation, myocardial infarction, cardiac arrest, renal failure requiring long-term dialysis, and death.

Adjustments were made based on patients' BMI, mobility limitations, smoking status and comorbid conditions. These comorbidities included pulmonary disease, cardiovascular disease, sleep apnoea, psychological disorders, prior venous thromboembolism, diabetes, chronic renal failure, urinary incontinence, gastro-oesophageal reflux disease, peptic ulcer disease, cholelithiasis, previous ventral hernia repair, and musculoskeletal disorders.

Risk and reliability measures were based on centre size-adjusted complication rates, such as mortality, incidence of other complications, reoperation, readmission, and length of stay. Quality measures were given weighted scores.

Patients were well matched across hospitals when scored through the composite measure.

Centers were scored on a three-star rating scale; 3-star (top 20%), 2-star (middle 60%), and 1-star (bottom 20%). They assessed how well these ratings predicted outcomes in the next year (2010) compared with other widely used measures.


The results showed that composite measures explained a larger proportion of hospital-level variation in serious complication rates with laparoscopic gastric bypass than other measures. For example, the composite measure explained 89% of the variation compared with only 28% for risk-adjusted complication rates alone.

Composite measures also appeared better at predicting future performance compared with individual measures. When ranked on the composite measure, 1-star hospitals had 2-fold higher serious complication rates (4.6% vs 2.4%; odds ratio, 2.0; 95% CI, 1.1-3.5) compared with 3-star hospitals.

Differences in serious complication rates between 1- and 3-star hospitals were much smaller when hospitals were ranked using serious complications (4.0% vs 2.7%; odds ratio, 1.6; 95% CI, 0.8-2.9) and hospital volume (3.3% vs 3.2%; odds ratio, 0.85; 95% CI, 0.4-1.7).

“Composite measures are much better at explaining hospital-level variation in serious complications and predicting future performance than other approaches,” the authors conclude. “In this preliminary study, it appears that such composite measures may be better than existing alternatives for profiling hospital
performance with bariatric surgery.”

The study was supported by the Agency for Healthcare Research and Quality and the National Institute of Diabetes and Digestive and Kidney Diseases.

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