Table 3

Multivariate and univariate analysis for risk (HR, HR) of developing cervical intraepithelial neoplasia grade 3 (CIN3) or adenocarcinoma in situ (AIS) according to baseline Chlamydia trachomatis and high-risk human papillomavirus (hrHPV) DNA status

	N	C trachomatis positive at day 1 (N=354)			C trachomatis negative at day 1 (N=8087)			Multivariate model		Univariate model
	N	n	No of women with a CIN3/AIS lesion due to any HPV type	Rate^*	n	No of women with a CIN3/AIS lesion due to any HPV type	Rate^*	HR^† (95% CI)	p-value^‡	HR^† (95% CI)	p-value^‡
CIN3/AIS due to any HPV type
Total	8441	354	20	1.71	8087	267	0.96	1.31 (0.83 to 2.06)	0.253	1.74 (1.10 to 2.74)	0.017
Negative for HPV16 and 18	7382	268	10	1.09	7114	163	0.66	1.44 (0.76 to 2.73)	0.265	1.61 (0.85 to 3.05)	0.146
Positive for HPV16 and/or 18	965	81	10	4.3	884	103	3.71	1.19 (0.62 to 2.28)	0.601	1.15 (0.60 to 2.21)	0.666

	N	n	No of women with a CIN3/AIS lesion due to hrHPV type^§	Rate^*	n	No of women with a CIN3/AIS lesion due to hrHPV type^§	Rate^*	HR^† (95% CI)	p-value^‡	HR^† (95% CI)	p-value^‡
CIN3/AIS due to hrHPV^§ type
Total	8441	354	20	1.71	8087	256	0.92	1.10 (0.69 to 1.76)	0.693	1.82 (1.15 to 2.87)	0.010
Negative for all 12 tested^§ hrHPV types	5689	143	3	0.6	5546	77	0.39	1.43 (0.45 to 4.55)	0.540	1.50 (0.47 to 4.77)	0.488
Positive for ≥1 of 12 tested^§ hrHPV types	2629	204	16	2.48	2425	179	2.25	1.05 (0.63 to 1.75)	0.851	1.09 (0.65 to 1.81)	0.750

N: Total number of women with non-missing Chlamydia status and respective PCR status and at least one follow-up visit.
n: Number of women with positive/negative Chlamydia status and positive/negative PCR status and at least one follow-up visit.
↵* Number of women with a lesion per 100 person-years at risk.
↵† HR associated with being positive versus negative to Chlamydia at baseline for each model. For the ‘univariate—total’ estimates, HR is calculated using the full data. For the ‘univariate—negative/positive’ estimates, HR is calculated using data from each stratified HPV baseline status data. For the ‘multivariate—total’ estimates, HR is calculated after adjusting for HPV baseline status (positive or negative), age at study entry, number of lifetime sexual partners, and smoking status (current smoker, former smoker, never smoked). Interactions between baseline HPV status and Chlamydia status were tested and proven to be insignificant (P-values of interactions are 0.683 and 0.628 in the models of CIN3/AIS due to any HPV type and CIN3/AIS due to any hrHPV type, respectively). For the ‘multivariate—negative/positive’ estimates, HR is estimated within each HPV baseline status group after including the interaction term between baseline Chlamydia status and baseline HPV status and adjusting for age at study entry, number of lifetime sexual partners, and smoking status.
↵‡ p Value shows how significantly the estimated HRs differ from 1.
↵§ Includes HPV16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58 and 59.