Association of outpatient utilisation of non-steroidal anti-inflammatory drugs and hospitalised heart failure in the entire Swedish population

Abstract.

Objective: Individual-based studies on restricted geographical settings have suggested that non-steroidal anti-inflammatory drugs (NSAIDs) may precipitate congestive heart failure. As NSAID use is very extensive, it might increase the occurrence of symptomatic heart failure in the general population. Therefore, in order to study the impact of NSAID utilisation (prescribed and over the counter) on hospitalised heart failure in an entire country (Sweden), we performed an ecological analysis, a design appropriate for studying large geographical areas. Methods: We employed weighted (population size) ecological linear regression to study the association between outpatient utilisation of NSAIDs during 1989–1993 and hospitalised heart failure in 1993 in 283 of Sweden's 288 municipalities. Data were adjusted for age and gender proportions, socio-economic factors, latitude and utilisation of cardiovascular drugs, aspirin, low-dose aspirin and paracetamol. Results: The unadjusted relative risk of hospitalised heart failure for each increase of one standard deviation of NSAID utilisation (5.8 defined daily doses/1000 inhabitants/day) was 1.23 [95% confidence interval (CI) 1.18, 1.27]. After adjustments, the relative risk was 1.08 (95% CI 1.04, 1.12); the corresponding values if aspirin (non-low-dose) was included as an NSAID were 1.26 (95% CI 1.23, 1.28) and 1.07 (95% CI 1.04, 1.10). There was no such adjusted association with the utilisation of paracetamol – 0.95 (95% CI 0.92, 0.98). Conclusion: The NSAID–heart failure association already established by individual-based studies on restricted geographical settings was corroborated in the present ecological study based on the whole population of an entire country (Sweden). Efforts should be made to promote a rational use of NSAIDs in the general population.