Association of Patient Belief About Success of Antibiotics for Appendicitis and Outcomes
Authors:   Writing Group for the CODA Collaborative, Abouzeid Mohamad , Alam Hasan B. , Arif Hikmatullah , Ballman Karla , Bennion Robert , Bernardi Karla , Burris Debra , Carter Damien , Chee Patricia , Chen Formosa , Chung Bruce , Clark Sunday , Cooper Randall , Cuschieri Joseph , Deeney Kimberly , Dhanani Naila , Diflo Thomas , Drake F. Thurston , Fairfield Cathy , Farjah Farhood , Ferrigno Lisa , Fischkoff Katherine , Fleischman Ross , Foster Careen , Gerry Terilee , Gibbons Melinda , Guiden Mary , Haas Nathan , Hayes Lillian Adrianna , Hayward Alyssa , Hennessey Laura , Hernandez Miriam , Horvath Karen F. , Howell Erin C. , Hsu Cindy , Johnson Jeffrey , Johnsson Billie , Kim Dennis , Kim Daniel , Ko Tien C. , Lavallee Danielle C. , Lew Debbie , Mack Joseph , MacKenzie David , Maggi Jason , Marquez Stephanie , Martinez Ryan , McGrane Karen , Melis Marcovalerio , Miller Karen , Mireles Debbie , Moran Gregory J. , Morgan Dayna , Morris Arden , Moser Kelly M. , Mount Lauren , O'Connor Kathleen , Odom Stephen R. , Olavarria Oscar , Olbrich Norman , Osborn Scott , Owens Olga , Park Pauline , Parr Zoe , Parsons Charles S. , Pathmarajah Kavitha , Patki Deepti , Patton Joe H. , Peacock Rebekah K. , Pierce Kristyn , Pullar Kelsey , Putnam Brant , Rushing Amy , Sabbatini Amber , Saltzman Darin , Salzberg Matthew , Schaetzel Shaina , Schmidt Paul J , Shah Paresh , Shapiro Nathan I. , Sinha Prashant , Skeete Dionne , Skopin Elliott , Sohn Vance , Spence Lara H. , Steinberg Steven , Tichter Aleksandr , Tschirhart John , Tudor Brandon , Uribe Lisandra , VanDusen Heather , Wallick Julie , Weiss Meridith , Wells Sean , Wiebusch Abigail , Williams Estell J. , Winchell Robert J. , Wisler Jon , Wolfe Bruce , Wolff Erika , Yealy Donald M. , Yu Julianna , Zhang Irene Y. , Voldal Emily C. , Davidson Giana H. , Liao Joshua M. , Thompson Callie M. , Self Wesley H. , Kao Lillian S. , Cherry-Bukowiec Jill , Raghavendran Krishnan , Kaji Amy H. , DeUgarte Daniel A. , Gonzalez Eva , Mandell Katherine A. , Ohe Kristen , Siparsky Nicole , Price Thea P. , Evans David C. , Victory Jesse , Chiang William , Jones Alan , Kutcher Matthew E. , Ciomperlik Hailie , Liang Mike K. , Evans Heather L. , Faine Brett A. , Neufeld Miriam , Sanchez Sabrina E. , Krishnadasan Anusha , Comstock Bryan A. , Heagerty Patrick J. , Lawrence Sarah O. , Monsell Sarah E. , Fannon Erin E. C. , Kessler Larry G. , Talan David A. , Flum David R. 
Published: October 2022

Importance

A patient’s belief in the likely success of a treatment may influence outcomes, but this has been understudied in surgical trials.

Objective

To examine the association between patients’ baseline beliefs about the likelihood of treatment success with outcomes of antibiotics for appendicitis in the Comparison of Outcomes of Antibiotic Drugs and Appendectomy (CODA) trial.

Design, Setting, and Participants

This was a secondary analysis of the CODA randomized clinical trial. Participants from 25 US medical centers were enrolled between May 3, 2016, and February 5, 2020. Included in the analysis were participants with appendicitis who were randomly assigned to receive antibiotics in the CODA trial. After informed consent but before randomization, participants who were assigned to receive antibiotics responded to a baseline survey including a question about how successful they believed antibiotics could be in treating their appendicitis.

Interventions

Participants were categorized based on baseline survey responses into 1 of 3 belief groups: unsuccessful/unsure, intermediate, and completely successful.

Main Outcomes and Measures

Three outcomes were assigned at 30 days: (1) appendectomy, (2) high decisional regret or dissatisfaction with treatment, and (3) persistent signs and symptoms (abdominal pain, tenderness, fever, or chills). Outcomes were compared across groups using adjusted risk differences (aRDs), with propensity score adjustment for sociodemographic and clinical factors.

Results

Of the 776 study participants who were assigned antibiotic treatment in CODA, a total of 425 (mean [SD] age, 38.5 [13.6] years; 277 male [65%]) completed the baseline belief survey before knowing their treatment assignment. Baseline beliefs were as follows: 22% of participants (92 of 415) had an unsuccessful/unsure response, 51% (212 of 415) had an intermediate response, and 27% (111 of 415) had a completely successful response. Compared with the unsuccessful/unsure group, those who believed antibiotics could be completely successful had a 13–percentage point lower risk of appendectomy (aRD, −13.49; 95% CI, −24.57 to −2.40). The aRD between those with intermediate vs unsuccessful/unsure beliefs was −5.68 (95% CI, −16.57 to 5.20). Compared with the unsuccessful/unsure group, those with intermediate beliefs had a lower risk of persistent signs and symptoms (aRD, −15.72; 95% CI, −29.71 to −1.72), with directionally similar results for the completely successful group (aRD, −15.14; 95% CI, −30.56 to 0.28).

Conclusions and Relevance

Positive patient beliefs about the likely success of antibiotics for appendicitis were associated with a lower risk of appendectomy and with resolution of signs and symptoms by 30 days. Pathways relating beliefs to outcomes and the potential modifiability of beliefs to improve outcomes merit further investigation.

Trial Registration

ClinicalTrials.gov Identifier: NCT02800785