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

Objective: Individual-based studies on restricted geographical settings hav e suggested that nonsteroidal anti-inflammatory drugs (NSAIDs) may precipit ate congestive heart failure. As NSAID use is very extensive, it might incr ease the occurrence of symptomatic heart failure in the general population. Therefore, in order to study the impact of NSAID utilisation (prescribed a nd over the counter) on hospitalised heart failure in an entire country (Sw eden), we performed an ecological analysis, a design appropriate for studyi ng large geographical areas. Methods: We employed weighted (population size) ecological linear regressio n to study the association between outpatient utilisation of NSAIDs during 1989-1993 and hospitalised heart failure in 1993 in 283 of Sweden's 288 mun icipalities. Data were adjusted for age and ender proportions, socio-econom ic factors, latitude and utilisation of cardiovascular drugs, aspirin, low- dose aspirin and paracetamol. Results: The unadjusted relative risk of hospitalised heart failure for eac h increase of one standard deviation of NSAID utilisation (5.8 defined dail y 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); t he 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 su ch adjusted association with the utilisation of paracetamol - 0.95 (95% CI 0.92, 0.98). Conclusion: The NSAID-heart failure association already established by indi vidual-based studies on restricted geographical settings was corroborated i n the present ecological study based on the whole population of an entire c ountry (Sweden). Efforts should be made to promote a rational use of NSAIDs in the general population.