Objective: This study was conducted to define an evaluation model to estimate changes in the co-prescription of gastroprotective agents (GPAs) induced by rofecoxib in the treatment of osteoarthritis (OA).
Methods: On the basis of a cross-linking information, which were stored in different administrative and clinical databases, a multivariate regression analysis was used to develop the model. Data were collected by 30 general practitioners of the Local Health Unit of Ravenna (middle-north of Italy).
Results: The study population consisted of 2,944 patients treated with non-steroidal anti-inflammatory drugs (NSAIDs) and 487 treated with rofecoxib. Patients treated with rofecoxib generally presented a higher number of gastrointestinal damage risk factors and also a lower level of GPAs co-prescription compared to those treated with NSAIDs. Including in the model variables such as type of anti-inflammatory treatment (NSAIDs or rofecoxib), gender, age by class, previous hospital admissions due to gastrointestinal complications, number of different NSAIDs used, and prescription of corticosteroids, the regression equation and its coefficients were identified. A non-linear relationship between the percentage of patients treated with rofecoxib and the relative reduction of GPAs co-prescription was found. It has been estimated the basis of the registered percentage of patients treated with rofecoxib (17,6%) adjusting for gastrointestinal damage risk factors, and on a 63% (CI95%: 55%-70%) relative reduction of GPA use with rofecoxib with respect to NSAIDs was estimated.
Conclusions: Based on data collected in the clinical practice after the introduction of rofecoxib, a model evaluating the relationship between the frequency of its use in the OA population and the expected reduction of GPAs, has been developed.