To improve the quality of data
collected, patients’ medical records were
abstracted by reviewers blinded to the
Papanicolaou smear result and group
assignment. In addition, 20% of the
charts were randomly selected and
abstracted by a separate reviewer to
ensure accuracy of data extraction.
Furthermore, to determine HPV status,
we relied on the available Papanicolaou
smear data. Although HPV typing was
only available for women with ASCUS
Papanicolaou smears, we also included
in our exposed group women with LSIL
or HSIL Papanicolaou smear results and
assumed the infection with HR-HPV, as
these results are highly associated with
HR-HPV and current clinical guidelines
do not require HPV typing