Risk factors for diabetes mellitus in chronic pancreatitis

Background & Aims: The influence of disease progression and pancreatic surg ery on the appearance of diabetes mellitus in patients with chronic pancrea titis is unknown. Methods: A prospective cohort study of 500 consecutive pa tients with chronic pancreatitis (alcoholics, 85%) followed up over a mean period of 7.0 +/- 6.8 years in a medical-surgical institution between 1973 and 1996 was performed. Multivariate analysis of risk factors for diabetes mellitus was performed after exclusion of 47 patients. Patients who underwe nt elective pancreatic surgery (n = 231, 51%) were compared with patients w ho never underwent surgery (n = 222, 49%). Results: The cumulative rate of diabetes mellitus was 83% +/- 4% 25 years after the clinical onset of chron ic pancreatitis (insulin requirement, 54% +/- 6%), The prevalence of diabet es mellitus did not increase in the surgical group overall but was higher 5 years after distal pancreatectomy(57% +/- 8%) than after pancreaticoduoden ectomy (36% +/- 18%), pancreatic drainage (36% +/- 13%), or cystic, biliary , or digestive drainage (24% +/- 7%) (P = 0.005), without difference in the latter ones. Pancreatic drainage did not prevent the onset of diabetes mel litus. Distal pancreatectomy (risk ratio, 2.4; 95% confidence interval [CI] , 1.6-3.8; P < 0.0001) and early onset of pancreatic calcifications (risk r atio, 3.2; CI, 2.2-4.7; P < 0.0001) were the only independent risk factors for diabetes mellitus. Conclusions: The risk of diabetes mellitus is not in fluenced by elective pancreatic surgical procedures other than distal pancr eatectomy in patients with chronic pancreatitis. This risk seems to be larg ely caused by progression of the disease because it increased by more than 3-fold after the onset of pancreatic calcifications.