Interaction between nonsteroidal anti-inflammatory drug intake and calcium-channel blocker-based antihypertensive treatment in the Syst-Eur trial

Objective: To assess the relationship between chronic intake of nonsteroidal anti-inflammatory drugs (NSAID) and outcome, in particular (gastrointestinal) bleeding and to investigate whether the effect of chronic NSAID intake was similar in untreated and treated elderly hypertensives. Methods. Eligible patients (greater than or equal to 60 years, with systolic blood pressure 160-219 mm Hg and diastolic blood pressure <95 mm Hg) were randomised to active treatment or placebo. Active treatment consisted of nitrendipine, with the possible addition of enalapril, hydrochlorothiazide, or both, titrated or combined to reduce the sitting systolic blood pressure by at least 20 mm Hg to below 150 mm Hg. Patients never taking NSAIDs (n=2882) were compared with patients on chronic NSAID intake (n=861), defined as reporting NSAID intake on at least 50% of the patient forms. Results: There was a tendency towards lower mortality (relative hazard rate (95% confidence interval (CI), 0.77 (0.56-1.06)) and higher incidence of bleeding (1.13 (0.63-2.05) with chronic NSAID intake. Although there was no significant interaction between calcium-channel blocker (CCB)-based treatment and chronic NSAID intake for any of the end points, chronic NSAID intake tended to be associated with a lower incidence of bleeding on active treatment as compared to placebo (P-value of the interaction term = 0.07). Conclusion: The effect of chronic NSAID intake on outcome was similar in patients on active treatment based on a dihydropyridine CCB or on placebo. However, chronic NSAID intake might have a less deleterious effect on bleeding on active treatment as compared to placebo.