NSAID use and risk of leukaemia: a population-based case-control study.

Purpose: The use of non-steroidal anti-inflammatory drugs (NSAIDs) is associated with a reduced risk of developing colorectal and lung cancer. Studies suggesting similar associations in leukaemia have been small and underpowered. We have conducted a large population-based case-control study to determine whether the use of NSAIDs is associated with a reduced risk of acute and chronic leukaemias, and whether their use has any impact on survival in these patients.

Methods: We identified all the incident cases of leukaemia in 'The Health Improvement Network' (THIN) general practice dataset, along with at least four matched controls per case. We used conditional logistic regression to determine odds ratios for NSAID prescription rates and the risk of developing several leukaemia sub-types. We then used Cox regression to determine the association between NSAID prescription rate and risk of death in leukaemia. Hazard ratios were adjusted for gender, age at diagnosis, smoking status and Townsend Score.

Results: The risk of leukaemia overall appears to increase marginally with increased use of NSAIDs prior to diagnosis. This is not seen when individual leukaemia sub-types are examined, however, except perhaps in CLL where patients who had received 2-5 prescriptions/year are 34% more likely to be diagnosed with CLL than those who had not had any NSAID prescriptions (O.R. 1.34, p = 0.03, 95% C.I. 1.02-1.74). There was no statistically significant association between exposure to NSAIDs prior to leukaemia diagnosis and survival.

Conclusion: The use of NSAIDs does not reduce the risk of developing leukaemia, nor do they improve survival.