Adherence to recommended follow-up in opportunistic versus non-opportunistic cervical screening: a registry-based cohort study from Denmark.

Aim: Organised cervical screening programmes often allow for opportunistic screening. Previous studies have shown that adherence to follow-up protocols after cervical screening is poor. This study aims to investigate if non-adherence to recommended screening intervals - that is, opportunistic screening, is associated with adherence to follow-up after non-negative cervical screening.

Methods: Using national registries we included 42,399 Danish women with a non-negative screening result from 2015 to 2017. Non-adherence was divided into insufficient and excessive follow-up. We calculated relative risks (RRs) of adherence to follow-up among different groups of opportunistically screened women, representing both too frequent and delayed screening participation, compared with non-opportunistically screened women.

Results: Compared with non-opportunistically screened women, opportunistically screened women who were delayed 1-3 years on their screening schedule had a higher risk of no follow-up (RR 1.99) and insufficient follow-up (RR 1.10). Women who were delayed 3-7 years on their screening also had a higher risk of no follow-up (RR 1.92). Women who attended screening up to 6 months too early had a higher risk of insufficient follow-up (RR 1.08) as well as excessive follow-up (RR 1.39). Finally, women screened more than 6 months too early had a higher risk of all deviations, but most pronounced was the risk of excessive follow-up (RR 1.67).

Conclusions: We found a higher risk of insufficient follow-up among women delayed in their screening schedule, and a higher risk of excessive follow-up among those with frequent screening. Screening participation behaviour seems to transfer to follow-up adherence. This underscores the important role of general practitioners in acting as gatekeepers in cervical screening follow-up.