P1384 - Development and Validation of an Administrative Codes Algorithm to Identify Abdominal Surgery and Bowel Obstruction in Patients With Inflammatory Bowel Disease

Presenting Author(s)

• CG

  Cassandra Gandle, MD

  Houston, Texas

Cassandra Gandle, MD¹, Frank Scott, MD, MSCE², Akbar Waljee, MD, MSc³, Jason Hou, MD, MS¹

¹Baylor College of Medicine, Houston, TX; ²University of Colorado, Aurora, CO; ³University of Michigan, Ann Arbor, MI

Introduction: International Classification of Diseases (ICD) codes are utilized in reporting patient diagnoses while current procedural terminology (CPT) codes identify medical, surgical, and diagnostic procedures. Use of administrative codes may be used to efficiently identify patients with inflammatory bowel disease and related outcomes, but require validation due to variability of coding patterns. The aim of this study was to determine the accuracy of ICD and CPT codes for surgery and post-operative obstructive complications in a cohort of IBD patients at the VA.

Methods: We performed a retrospective study of patients with IBD at the Michael E. DeBakey VA Medical Center in Houston, Texas between February 1, 2000 and August 30, 2015. IBD patients with with administrative codes for abdominal surgery and post-operative complications were reviewed by manual chart review to confirm type and date of surgery and type and date of post-operative complication. A total of 710 abdominal surgery ICD-9 and CPT codes and 3 post-operative obstruction related ICD-codes (560.81, 560.89, and 560.9) were evaluated. Analyses were performed on a per encounter basis. Codes were considered accurate if the procedure or complication occurred within 3 months of the coded date. Sensitivity analyses were performed, broadening the time window to 6 months. Positive predictive values (PPV) and negative predictive value (NPV)  were calculated for each code and overall.

Results: A total of 77 IBD patients had at least one encounter with ICD-9 or CPT codes for abdominal surgery. The PPV for abdominal surgery codes overall was 96.4%, which remained unchanged on sensitivity analyses extending time window to 6 months. Evaluating the accuracy of post-operative obstructive-type complications, 39 patients were identified utilizing 3 ICD-9 codes for obstructive complications in 67 individual encounters. The PPV of any obstruction-type ICD-9 code for confirmed bowel obstruction was 80.5%. The NPV for obstructive complications in patient encounters without a corresponding obstruction-related code was 96%. On sensitivity analyses extending window to 6 months prior to date of code, the PPV for obstructive ICD-9 codes increased to 82.1%.

Discussion: ICD-9 and CPT codes for abdominal surgery and post-operative obstructive-type complications can be accurately utilized in IBD patients at the VA.

Citation: Cassandra Gandle, MD; Frank Scott, MD, MSCE; Akbar Waljee, MD, MSc; Jason Hou, MD, MS. P1384 - DEVELOPMENT AND VALIDATION OF AN ADMINISTRATIVE CODES ALGORITHM TO IDENTIFY ABDOMINAL SURGERY AND BOWEL OBSTRUCTION IN PATIENTS WITH INFLAMMATORY BOWEL DISEASE. Program No. P1384. ACG 2019 Annual Scientific Meeting Abstracts. San Antonio, Texas: American College of Gastroenterology.