Differences in patient outcomes after outpatient GI endoscopy across settings: a statewide matched cohort study

Post written by Meng-Yun Lin, PhD, MPH, from the Department of Social Sciences and Health Policy, Wake Forest School of Medicine, Winston-Salem, North Carolina, and the Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, USA.


Using the Massachusetts All-Payer Claims Database and Medicare data, our study compares patient outcomes of outpatient GI endoscopy between hospital outpatient departments and ambulatory surgery centers (ASCs) at the population level.

More outpatient procedures are performed in nonhospital settings, specifically ASCs, which are facilities that specialize in surgical and diagnostic procedures that do not require an overnight stay. Unlike hospitals, ASCs are loosely regulated. For example, ASCs are not required to report cost and quality data to the Centers for Medicare & Medicaid Services.

GI endoscopies are the most common procedures performed in ASCs, accounting for roughly 25% of total surgical procedures performed. However, evidence on whether patient outcomes are comparable between ASCs and hospital outpatient departments is scarce. Most prior studies were either limited to experiences at a single facility or focused on provider self-reporting data.

Therefore, we felt an urgent need for a comprehensive evaluation of patient outcomes at the population level. Our study concluded that GI endoscopies could be performed safely on select patients in ASC settings. During the study period, physicians seemed to be prudent in selecting low-risk patients for receiving procedures in ASCs. For example, fewer patients were selected to receive complex procedures involving biopsies or removal of tumor polyps in ASCs.

However, as procedure volume in ASCs continues to grow, ASCs may start to perform procedures on patients at higher risk for adverse events. Future studies should re-examine patient outcomes across settings and extend investigations to broader quality metrics, such as polyp detection and colon cancer diagnosis rate.

Also, as scrutiny of quality in ASCs increases, state and federal regulatory agencies should consider proactively developing surveillance programs.

Medical record abstraction may be the “gold standard” to determine procedure-related adverse events. However, it is not feasible, both economically and technically, to perform chart reviews at the population level. Federal efforts have so far been unsuccessful in designing an effective system of monitoring patient safety in ASCs.

Although claims-based studies might not tell the whole story, population-level estimates provide valuable information to regulatory agencies to refine and redesign programs aiming to safeguard patient safety.


Relative odds of unplanned hospital visits after GI endoscopies performed in ambulatory surgery centers. Adjusted odds ratios (95% confidence intervals) were calculated from multivariable models using the matched sample and adjusting for patient, procedure, and facility characteristics.

Read the full article online.

The information presented in Endoscopedia reflects the opinions of the authors and does not represent the position of the American Society for Gastrointestinal Endoscopy (ASGE). ASGE expressly disclaims any warranties or guarantees, expressed or implied, and is not liable for damages of any kind in connection with the material, information, or procedures set forth.

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