Accuracy of Colposcopically Directed Biopsy: Results from an Online Quality Assurance Programme for Colposcopy in a Population-Based Cervical Screening Setting in Italy

Table 3

Factors associated with the odds ratio for incorrect selection of biopsy site (total number of observations 1829).

Factor^a	Number of; observations	Number (%) with; incorrect biopsy site		Univariate; odds ratio (95% CI)	Multivariate; odds ratio (95% CI)^b
Colposcopic impression
Negative	NA	NA	0.000
G1	472	46 (9.7)		1.00 (referent)	1.00 (referent)
G2	1121	85 (7.6)		0.76 (0.52–1.11)	0.46 (0.27–0.80)
Cancer	236	2 (0.8)		0.08 (0.02–0.33)	0.09 (0.02–0.42)
Squamocolumnar junction
Visible	1416	85 (6.0)	0.000	1.00 (referent)	1.00 (referent)
Not, or not entirely, visible	413	48 (11.6)		2.06 (1.42–2.99)	2.46 (1.62–3.73)
Original histological diagnosis
CIN1	413	35 (8.5)	0.001	1.00 (referent)	1.00 (referent)
CIN2	236	21 (8.9)		1.05 (0.60–1.86)	1.97 (1.01–3.85)
CIN3/AIS	944	75 (7.9)		0.93 (0.61–1.42)	2.52 (1.32–4.80)
Invasive carcinoma	236	2 (0.8)		0.09 (0.02–0.39)	0.29 (0.06–1.34)

G1: abnormal, grade 1; G2: abnormal, grade 2; Cancer: suspected invasive cancer; CIN: cervical intraepithelial neoplasia; AIS: adenocarcinoma in situ; CI: confidence interval; NA: not applicable.
^aPatient age, colposcopist age, and participation in previous local quality assurance initiatives were not associated with incorrect selection of biopsy site in univariate analysis ( > 0.05) and were not included in logistic regression analysis.
^bFrom a multiple logistic regression model with backward stepwise selection of variables. The level for removal of variables was set at = 0.10.