Reduction in colposcopy workload and associated clinical activity following HPV catch-up vaccination programme in Scotland: an ecological study

Objective: To measure patterns of clinical activity at colposcopy before and after vaccinated women entered the Scottish Cervical Screening Programme (SCSP). Design: Population-based observational study using nationally collected data. Setting: Scottish colposcopy clinics. Sample: All women with a date of birth on or after 1 January 1985 who attended colposcopy in Scotland between 2008-2014. Methods: Routinely collected data from the Scottish National Colposcopy Clinical Information Audit System (NCCIAS) was extracted, including: referral criteria, referral cervical cytology, colposcopic findings, clinical procedures and histology results. Analysis was restricted to those referred to colposcopy at age 20 or 21 years. Main outcome measures: Referral criteria, positive predictive value of colposcopy, default rates and rates of cervical biopsies and treatments. Results: 7372 women referred for colposcopy at age 20/ 21 years were identified. There was a downward trend in the proportion of those referred with abnormal cytology (2008/9: 91.0%, 2013/14: 90.3%, linear trend p value = 0.03). Women were less likely to have diagnostic or therapeutic interventions. The proportion with no biopsy (2008/9: 19.5%, 2013/14: 26.9%, linear trend p value < 0.0001) and no treatment (2008/9: 74.9%, 2013/14: 91.8%, linear trend p value < 0.0001) increased over the period of observation. Conclusions: A reduction in clinical activity related to abnormal screening referrals is likely to be associated with the HPV catch-up immunisation programme. Referral criteria and service provision of colposcopy needs to be planned carefully taking account of the increasing number of HPV- immunised women that will be entering cervical screening programmes worldwide.