Serrano, Jose

Objectives: Participant retention is essential in prospective studies to minimize bias and maintain validity. This study aimed to estimate retention rates and identify factors influencing attrition in a multicenter cohort (PROCEED) of US adults with acute/recurrent acute pancreatitis (AP/RAP) and chronic pancreatitis (CP). Methods: Participants from the PROCEED study with AP/RAP or CP eligible for follow-up within the designated visit window were included. Retention was defined as completing at least one follow-up visit during the observation period. Retention was analyzed by follow-up mode (in-person and/or medical record review) and disease type (AP/RAP and CP). Retention factors were assessed using univariate analyses (Wilcoxon rank-sum for continuous variables, χ 2 /Fisher's exact for categorical) and multivariable logistic regression. Missing data were adjusted using multiple imputations in statistical modeling. Results: Among 1279 participants (AP/RAP: n=632, median age 47, 48.9% female; CP: n=647, median age 54, 46.5% female), we observed high cumulative and annualized retention rates, with improved retention when incorporating medical record reviews. In multivariable regression analyses, older age was statistically significantly associated with in-person retention in the AP/RAP group ( P =0.0001), while a higher self-reported physical health (assessed with PROMIS Global Health Physical Health T-score) was a key predictor of retention in CP ( P =0.034). Conclusions: Integrating medical records review substantially enhanced retention rates, enabling robust analyses of pancreatitis outcomes and disease progression. Older age and better self-reported physical health were key predictors of retention, highlighting the need for targeted strategies to enhance engagement among younger participants and those with poorer health in long-term studies.