Gender aspects suggestive of gastroparesis in patients with diabetes mellitus: a cross-sectional survey

BACKGROUND: It is suggested that symptoms related to gastroparesis are more common in female than in male patients with type 2 diabetes mellitus (T2DM). The association between sex and prevalence of symptoms suggestive of gastroparesis among patients with T2DM in Israel has not been reported. The aim of this study was to describe the associations between sex, clinical characteristics, type, severity and prevalence of dyspeptic symptoms in a large population of patients with T2DM in Israel. METHODS: All patients completed a demographic questionnaire and the Gastroparesis Cardinal Symptom Index (GCSI). Data regarding disease duration, medications, complications, recent blood glucose and HbA1c levels were also collected. In this nested case–control study, 173 female and 209 male patients were identified from within a cross-sectional survey of 382 patients with T2DM. Logistic and general linear modeling was used to assess associations between sex, clinical data, and the presence (type and number) of symptoms. RESULTS: Compared to males, female patients with T2DM had a higher body mass index (BMI) (31.9 vs. 29.2; P = 0.001) and HbA1c levels (7.9 vs. 7.5; P = 0.04). A larger proportion of males suffered from peripheral vascular disease (P = 0.02) and ischemic heart disease (P = 0.001). Other disease characteristics did not differ between the sexes. The prevalence of nausea (P = 0.001), early satiety (P = 0.005), loss of appetite (P = 0.002), or presence of any cardinal symptom (P = 0.001) was significantly higher among females. Severity of most cardinal symptoms was also higher in females. The presence of at least one cardinal symptom was more likely among obese females with longer disease duration and poor glycemic control. CONCLUSIONS: Prevalence and severity of symptoms suggestive of gastroparesis is particularly high among obese females with long standing and poorly controlled T2DM

Dyspepsia Symptoms and Helicobacter pylori Infection, Nakuru, Kenya

The prevalence of Helicobacter pylori infection was studied in 138 patients with dyspepsia in a hospital in Nakuru, Kenya, and in 138 asymptomatic sex- and age-matched controls from the same population. Anti–H. pylori immunoglobulin (Ig) G was more prevalent in dyspeptic than asymptomatic persons (71% vs. 51%), particularly those <30 years old (71% vs. 38%). H. pylori seropositivity was associated with dyspepsia after adjusting for age, sex, and residence (urban or rural). Among adults, the association between H. pylori infection and dyspepsia remained after adjusting for the above factors and for educational attainment, family size, and manual occupation. H. pylori infection in asymptomatic residents of Nakuru, Kenya, was more prevalent in older persons, with a rate of 68%, than in those 31–40 years of age. However, young persons with dyspepsia had an unexpectedly high prevalence of H. pylori infection. H. pylori test-and-treat strategy should be considered in Kenyan patients with dyspepsia, particularly in persons <30 years of age

Budget-Feasible Mechanism Design for Non-Monotone Submodular Objectives: Offline and Online

The framework of budget-feasible mechanism design studies procurement auctions where the auctioneer (buyer) aims to maximize his valuation function subject to a hard budget constraint. We study the problem of designing truthful mechanisms that have good approximation guarantees and never pay the participating agents (sellers) more than the budget. We focus on the case of general (non-monotone) submodular valuation functions and derive the first truthful, budget-feasible and $O(1)$-approximate mechanisms that run in polynomial time in the value query model, for both offline and online auctions. Prior to our work, the only $O(1)$-approximation mechanism known for non-monotone submodular objectives required an exponential number of value queries. At the heart of our approach lies a novel greedy algorithm for non-monotone submodular maximization under a knapsack constraint. Our algorithm builds two candidate solutions simultaneously (to achieve a good approximation), yet ensures that agents cannot jump from one solution to the other (to implicitly enforce truthfulness). Ours is the first mechanism for the problem where---crucially---the agents are not ordered with respect to their marginal value per cost. This allows us to appropriately adapt these ideas to the online setting as well. To further illustrate the applicability of our approach, we also consider the case where additional feasibility constraints are present. We obtain $O(p)$-approximation mechanisms for both monotone and non-monotone submodular objectives, when the feasible solutions are independent sets of a $p$-system. With the exception of additive valuation functions, no mechanisms were known for this setting prior to our work. Finally, we provide lower bounds suggesting that, when one cares about non-trivial approximation guarantees in polynomial time, our results are asymptotically best possible.Comment: Accepted to EC 201

Budget-feasible mechanism design for non-monotone submodular objectives: Offline and online

The framework of budget-feasible mechanism design studies procurement auctions where the auctioneer (buyer) aims to maximize his valuation function subject to a hard budget constraint. We study the problem of designing truthful mechanisms that have good approximation guarantees and never pay the participating agents (sellers) more than the budget. We focus on the case of general (non-monotone) submodular valuation functions and derive the first truthful, budget-feasible and O(1)-approximation mechanisms that run in polynomial time in the value query model, for both offline and online auctions. Since the introduction of the problem by Singer [40], obtaining efficient mechanisms for objectives that go beyond the class of monotone submodular functions has been elusive. Prior to our work, the only O(1)-approximation mechanism known for non-monotone submodular objectives required an exponential number of value queries. At the heart of our approach lies a novel greedy algorithm for non-monotone submodular maximization under a knapsack constraint. Our algorithm builds two candidate solutions simultaneously (to achieve a good approximation), yet ensures that agents cannot jump from one solution to the other (to implicitly enforce truthfulness). Ours is the first mechanism for the problem where-crucially-the agents are not ordered according to their marginal value per cost. This allows us to appropriately adapt these ideas to the online setting as well. To further illustrate the applicability of our approach, we also consider the case where additional feasibility constraints are present, e.g., at most k agents can be selected. We obtain O(p)-approximation mechanisms for both monotone and non-monotone submodular objectives, when the feasible solutions are independent sets of a p-system. With the exception of additive valuation functions, no mechanisms were known for this setting prior to our work. Finally, we provide lower bounds suggesting that, when one cares about non-trivial approximation guaran