Table 3.
Factors associated with the odds ratio for incorrect selection of biopsy site (total number of observations 1829).
| Factora | Number of observations |
Number (%) with incorrect biopsy site |
P | 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 (P > 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 P = 0.10.