A community laboratory drop-off option for bowel screening test kits increases participation rates: results from an interrupted time series analysis.

Background: Countries with population-based colorectal cancer screening using faecal occult blood test kits performed in the home and posted to the laboratory struggle to achieve higher than 60% uptake. We measured the impact on participation of offering a community laboratory drop-off (CLD) alternative to postal return in New Zealand's Bowel Screening Pilot.
Methods: From May to September, 2015, a flyer added to the bowel screening test kit offered CLD as an alternative to returning the kit by post. Participation rates for equal-length periods before and after were measured. Interrupted time series and logistic regression models measured CLD-attributable the changes in screening participation.
Results: Overall, 26% of invitees used the CLD option. The effect of the CLD option on participation varied significantly by age, gender and ethnicity. There was a significant increase in participation among males (+1.75%; P = 0.002); patients under 60 (+1.65%; P = 0.006); Māori and Pacific (+2.88%; P = 0.029); and in the European/other ethnic group (+1.04%; P = 0.045) but not in Asians.
Conclusions: Both analyses showed that at little or no additional cost, the CLD option produced small but significant increases in participation for non-Asian men and younger invitees. A CLD kit return option may have benefits for other bowel screening programmes.