Abstract Disclosure: E.N. Haddad: None. M. Lansang: None. H. Xiao: None. R. Walsh: None. R. Simon: None. B.A. Hatipoglu: None. K. Zhou: None. Background: There is a lack of information regarding the immediate post-operative period as a predictor of early and long-term insulin independence after total pancreatectomy and islet auto-transplantation (TPIAT). This study examined the baseline and peri-operative variables that are associated with one-year and longer-term insulin independence following TPIAT. Methods: This was a retrospective study of 46 TPIAT patients in a single hospital system between 2010 and 2022. Perioperative variables were compared between short- (one year) and long-term (last follow up outside of year one) insulin-independent versus dependent patients. Multivariable models were used to adjust for clinically important variables. Results: The median age of the cohort at time of TPIAT was 38.5 years (IQR 30, 49). Patients were predominantly white (91%) and 50% were female. Nine (20%) and seven (15%) patients achieved short- and long-term insulin independence, respectively. The patients were followed for a median of 2.8 years (IQR 1.0, 4.7). There were no significant differences in patient demographics (age, sex, ethnicity), duration of pancreatitis, HbA1c, or mixed meal testing results (area under c-peptide curve from 0 to 4 hours) between those achieving insulin independence and those who did not. Short term insulin-independence was associated with higher median transplanted islet equivalents (IEQ)/kg (6,981 vs 4,493, p=0.02), lower units of basal insulin on discharge (7 vs 12, p=0.009), and lower rates of discharge from the hospital with an insulin regimen (67% vs 100%, p=0.006). Short-term insulin independence was also associated with decreased median insulin use in the immediate 24-hour post-operative period (14.3 vs 45.3 units, p=0.03), though this was not statistically significant when adjusting for patient weight (0.23 vs 0.56 units/kg, p=0.13). The odds of having short term insulin independence increased by 80% for every 1,000 increase in IEQ/kg (OR 1.80, CI 1.18 to 3.12, p=0.005) and decreased by 32% for every additional basal unit of insulin on discharge (OR 0.68, CI 0.42 to 0.91, p=0.003). This was no longer statistically significant after adjusting for sex, age, mixed meal testing area under c-peptide curve at 4 hours, and HbA1c. Long-term insulin independence was also associated with transplanted IEQ/kg and basal insulin units at discharge in univariable analysis. None of the patients on insulin or any other antihyperglycemic medication prior to surgery achieved short- or long-term insulin independence. Conclusion: Short- and long-term insulin independence after TPIAT is associated with a higher transplanted IEQ/kg and fewer units of basal insulin at discharge. Immediate post-operative variables can be used to inform the discussions clinicians have with their patients regarding glycemic prognosis following TPIAT. Presentation: 6/2/2024