Evaluating agreement between clinic- and patient-reported outcomes for weight and co-morbidities at 1 year after bariatric surgery

Background: Development of patient-reported outcomes (PROs) to include traditionally clinic-reported data has the potential to decrease the data-collection burden for patients and clinicians and increase follow-up rates. However, replacing clinic report by patient report requires that the data reasonably agree. Objective: To assess agreement between PROs and clinical registry data at 1 year after bariatric surgery. Setting: Not-for-profit organization, bariatric surgery data registry, PROs platform. Methods: Patient- and clinic-reported 1-year postoperative weight and co-morbidities were compared for matched PROs and registry records. The co-morbidities evaluated were diabetes, sleep apnea, hypertension, gastroesophageal reflux disease, and hyperlipidemia. Weight difference in pounds and nominal groupings (binary, 4-level) for co-morbidities were assessed for agreement between data sources using descriptive statistics, Bland–Altman plots, multiple regression, and kappa coefficients. Sensitivity analyses and follow-up by response method were examined. Results: Among 1130 patients with both 1-year PROs and registry weights, 95% of patient-reported weights were within 13 lb of the registry-recorded weight, and patients underreported their weight by ∼2 lb, on average. Percent agreement and kappa coefficients were highest for diabetes (n = 999; binary: 94%, κ =.72; 4-level: 86%, κ =.71) and lowest for gastroesophageal reflux disease (n = 1032; binary: 75%, κ =.40; 4-level: 57%, κ =.35). Of patients eligible for both PROs and registry 1-year follow-up, 21% had PROs only. Conclusions: One-year patient- and clinic-reported weights and disease status for patients with diabetes and hypertension showed high agreement. The degree of bias from patient report was low. Patient report is a viable alternative to clinic report for certain objective measurements and may increase follow-up.