Biliopancreatic Diversion for Severe Obesity: A 50-Year Cohort Study on Survival, Weight Loss, Control of Metabolic Comorbidities, Nutritional Morbidity, and Late Revisions.

OBJECTIVE: To document the 50-year outcomes of the original biliopancreatic diversion (BPD) cohort, providing the longest-ever reported follow-up for any bariatric procedure. SUMMARY BACKGROUND DATA: Lifelong data on the consequences of surgically altering human physiology are essential. While the mid-term efficacy of hypoabsorptive procedures is established, their long-term safety profile, particularly beyond the second decade, remains critically under-explored. METHODS: A retrospective analysis of a prospectively maintained database of the first 85 consecutive patients submitted to BPD (1976-1979). All-cause mortality was compared with the Italian general population (ISTAT life tables) using standardized mortality ratios (SMR) and descriptively with a historical cohort of non-operated severely obese Italians. RESULTS: The cohort (70 F, 15 M) had a mean preoperative age of 35 years and BMI of 42.2 kg/m². All-cause mortality was 29.4% (25/85). Kaplan-Meier survival estimates were 98.8% at 1 year, 89.1% at 10 years, 80.7% at 20 years, 67.8% at 30 years, and 53.7% at 40 years. Mortality was significantly elevated compared to the age-matched Italian population (SMR 2.62, 95% CI 1.71-3.86), similar to that of non-operated severely obese Italians. Percent total weight loss (%TWL) increased from 31% at 1 year to 39% at >40 years. Remission of type 2 diabetes was universal and durable. The revision rate for malnutrition or diarrhea was 20% (17/85), with procedures occurring up to 26 years postoperatively. The prevalence of any nutritional complication increased from 13% at 1 year to 86% at >40 years. CONCLUSIONS: Over five decades, BPD provided sustained weight loss and metabolic control but was associated with elevated long-term mortality and a high, persistent risk of severe, life-altering nutritional complications requiring surgical revision decades after the initial procedure.