Peptic ulceration
Gastric ulcer (GU) and duodenal ulcer (DU) have been diagnosed throughout this period, but differ in their secular trends, with GU rising over time and DU decreasing (Fig. 3). Using logistic regression to model the effects of time on DU in 15,467 records, there has been a 14 % reduction in DU diagnosis per decade (OR 0.86; 95 % CI 0.82, 0.90; P < 0.0001). Female sex was associated with a lower risk of DU (OR 0.64; 95 % CI 0.57, 0.71; P < 0.0001). In contrast, in 15,076 records there has been a steady rise in diagnosis of GU of 22 % per decade (OR 1.22; 95 % CI 1.15, 1.30; P < 0.0001), and again women were less likely to have a GU detected (OR 0.73; 95 % CI 0.64, 0.82; P < 0.0001). When surgical specialty or individual doctors were included in the regression models, these changes per decade remained highly significant, with little effect on odds ratio. In these models no individual doctor was specifically less or more likely to diagnose GU, but doctors 5 (a physician) and 12 (a surgeon) were significantly less likely to diagnose DU. DU, but not GU, was seasonal (P < 0.0001), with lower incidence (481, 8 %) in the hot season (October-December) than during the rainy or cool seasons (1023, 9.7 %).
Fig. 3 Gastric ulcer (GU) and duodenal ulcer (DU) diagnosis as percentage of peptic ulcer diagnoses over time