Impact of preexisting health conditions on the outcome of an adverse drug reaction alerting program: gastrointestinal disorders before piroxicam and sulindac therapy.

OBJECTIVE

To assess the impact of data concerning preexisting serious gastrointestinal (GI) disorders before piroxicam and sulindac therapy in an acute adverse drug reaction alerting program.

DESIGN

Cohort study.

SETTING

Saskatchewan province's prescription drug and healthcare insurance system covering a population of approximately 1 million.

PARTICIPANTS

The first 20,000 new patients who were dispensed piroxicam in 1982 and the first 20,000 patients who were dispensed sulindac in 1979-1981 through the Saskatchewan drug plan.

MAIN OUTCOME MEASURES

Physician services and hospitalizations with a diagnosis of peptic ulceration or GI hemorrhage within 30 days of the first piroxicam or sulindac prescription.

RESULTS

Rates of physician services for peptic ulceration or GI hemorrhage in the 30 days after starting piroxicam or sulindac therapy for patients who had services or hospitalizations for serious stomach or duodenum disorders in the 90 days before their prescriptions were significantly greater than the corresponding rates for patients without a recent history of these conditions (piroxicam: odds ratio [OR] = 7.89; 95% confidence interval [CI] = 5.71 to 10.91; p < 0.001; sulindac: OR = 24.08; 95% CI = 18.99 to 30.54; p < 0.001). Also, the rate of hospitalizations for peptic ulceration or GI hemorrhage in the 30 days after starting sulindac therapy for patients who had services for the conditions in the previous 90 days was significantly greater than the rate for patients who did not (OR = 10.91; 95% CI = 5.70 to 20.87; p < 0.001).

CONCLUSIONS

Rates of serious GI disorders in patients taking piroxicam and sulindac with a recent history of such disorders were larger than those in the other patients. However, because the proportion of individuals with recent serious GI disorders is small, these differences are lost in an overall assessment of patients taking these drugs. Data regarding preexisting health conditions are essential in adverse drug reaction alerting program and, indeed, in all evaluations of adverse reactions.