BACKGROUND
The most widely used topical agents for the field-based treatment of multiple actinic keratoses (AKs) are 5-fluorouracil and imiquimod, but their comparative effectiveness has not been assessed in a real-world setting.
OBJECTIVE
We compared the effectiveness of 5-fluorouracil and imiquimod in reducing risk of subsequent AKs in a large, integrated healthcare delivery system in Northern California.
METHODS
In this cohort study, we identified adult health plan members that had an AK diagnosed in 2007 and subsequently filled a prescription for 5-fluorouracil or imiquimod (n=5,700). We followed subjects for subsequent AKs identified by International Classification of Diseases codes and estimated the 2-year ("short-term") and 5-year ("long-term") differences in cumulative risk while controlling for potential confounding by pre-treatment variables.
RESULTS
5-Fluorouracil reduced the short-term incidence of subsequent AKs (cumulative risk difference -4.54% [95% CI: -7.91% to -1.17%]), but there was no statistically significant evidence of a long-term decreased risk (cumulative risk difference -1.43% [95% CI: -3.43% to 0.05%]) compared to imiquimod.
LIMITATIONS
This is a retrospective study. Generalizability to other healthcare settings may be limited.
CONCLUSION
We found that 5-fluorouracil appeared to be significantly more effective than imiquimod in the short-term, but not long-term, prevention of subsequent AKs.