Beta-cell function and insulin sensitivity in tropical calcific pancreatitis from north India

Abstract

Tropical calcific pancreatitis (TCP) is a variant of chronic pancreatitis, occurring only in developing countries. It frequently leads to diabetes at a young age. To determine the pathogenesis of glucose intolerance, beta-cell function and insulin sensitivity were measured in 11 TCP patients with normal glucose tolerance (TCP-NGT), six TCP patients with mild hyperglycemia [TCP-DM] median fasting plasma glucose, 6.1 mmol/L), and 16 healthy control subjects. The technique of continuous infusion of glucose with model assessment (CIGMA) was used to calculate beta-cell function (%B) and insulin sensitivity (%S), based on plasma glucose and insulin levels achieved after an intravenous infusion of glucose. %S was similar in both groups of TCP patients and controls. In contrast, %B was significantly lower in TCP-DM patients (median, 53; interquartile range, 41 to 62) compared with controls (90; 65 to 143; P < .01) and with TCP-NGT patients (119; 91 to 159; P < .01). TCP-NGT and control subjects had similar beta-cell function. Among patients with TCP, %B negatively correlated with the duration of pancreatitis (r = -.63, P < .05). Our results suggest that patients with TCP develop diabetes due to a diminution in beta-cell function, and that insulin resistance does not play a significant role in its pathogenesis.