Application of a propensity score to adjust for channelling bias with NSAIDs

Steve V. Morant (Lead / Corresponding author), D. Pettitt, T. M. MacDonald, T. A. Burke, J. L. Goldstein

    Research output: Contribution to journalArticlepeer-review

    15 Citations (Scopus)


    Purpose. To compare the relative risks of upper GI haemorrhage (UGIH) in users of Newer versus Older, non-specific NSAIDs when adjusted for channelling bias by regression on individual covariates, a propensity score and both. Methods. Cohort study of patients prescribed NSAIDs between June 1987 and January 2000. Exposure to Newer and Older non-specific NSAIDs was identified, and risk factors evaluated for each patient. Results of multiple covariate analyses and the propensity scoring technique to assess potential channelling bias in comparisons between Newer and Older non-specific NSAIDs were compared. Results. This study included 7.1 thousand patient years (tpy) exposure to meloxicam, 1.6 tpy exposure to coxibs, and 628 tpy exposure to Older non-specific NSAIDs. Patients receiving Newer NSAIDs were older, more likely to have a history of GI symptoms, and at higher risk for GI complications. Adjusting for these risk factors reduced the relative risks of UGIH on meloxicam and coxibs versus Older non-specific NSAIDs to 0.84 (95%CI 0.60, 1.17) and 0.36 (0.14, 0.97) respectively. Conclusions. Channelling towards high GI risk patients occurred in the prescribing of Newer NSAIDs. Propensity scores highlighted the markedly different risk profiles of users of Newer and Older non-specific NSAID. Correcting for channelling bias, coxib exposure, but not meloxicam exposure, was associated with less UGIH than Older non-specific NSAID exposure. In the present study, corrections made by regression on a propensity score and on individual covariates were similar.

    Original languageEnglish
    Pages (from-to)345-353
    Number of pages9
    JournalPharmacoepidemiology and Drug Safety
    Issue number6
    Publication statusPublished - Jun 2004


    • Coxibs
    • Gastrointestinal haemorrhage
    • General practice research database
    • Nonsteroidal anti-inflammatory drugs
    • Propensity score

    ASJC Scopus subject areas

    • Pharmacology (medical)
    • Pharmacology, Toxicology and Pharmaceutics(all)


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