Peptic ulcer disease case study

Observational cohort or case control designs have been used to determine ADR relationships with specific therapeutic classes. " Medical claims data are often used in these studies and caution should be warranted due to lack of definite confirmation of drug exposure and the potential for confounding variables. However, these studies have been beneficial in determining risk of ADRs with specific classes (e.g., NSAIDs and the risk of peptic ulcer disease). 

A meta-analysis has helped to clarify this issue (96). The aim was to assess the presence and magnitude of any possible interaction in peptic ulcer disease between these two susceptibility factors, with particular attention to bleeding peptic ulcer disease, the sites of ulceration, and the effect of H. pylori eradication. In all, 61 relevant studies were identified, 36 of which were excluded for various reasons. Thus, 25 studies were left for analysis, of which 16 observational studies (eight cross-sectional studies, seven case-control studies, and one cohort study) provided data on the prevalence of peptic ulcer disease in 1633 NSAID users, with data on H. pylori status for 1625 patients. The pooled frequency of peptic ulcer disease in NSAID users was 42% in those who were H. py/on-positive and 25% in those who were H. py/on-negative (OR = 2.12 95% Cl = 1.68, 2.67). 

The frequencies of uncomplicated peptic ulcer disease in NSAID users and non-users were compared in eight case-control studies however, the NSAID users and controls were not matched by age in three studies and so, because H. pylori infection is age-dependent, the prevalence of infection was analysed in only five studies. 

Case-control studies have been used extensively to assess the safety of pharmaceuticals. There are many examples of case-control studies that have identified important associations between drugs and adverse health events vaginal cancer and diethylstilbestrol, Reye s syndrome and aspirin, peptic ulcer disease and nonsteroidal antiinflammatory drugs, and venous thromboembolism and oral contraceptives. Data from case-control studies are used to calculate an odds ratio, which is the ratio of the odds of developing the disease for exposed patients to the odds of developing the disease for unexposed patients. 

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