Anal intraepithelial neoplasia screening in women from the largest center for lower genital tract disease in China.

This study aimed to provide comprehensive clinical screening data for anal intraepithelial neoplasia (AIN). This study included 312 patients who underwent high-resolution anoscopy (HRA) examinations between January 1, 2020 and April 15, 2024. Clinical data, including demographic information, clinical history, cytology/high-risk human papilloma virus (hrHPV) results, and HRA records, were analyzed. The median age of all patients was 42 years (interquartile range: 33-52 years). Approximately 26.3% reported a history of VIN2/3+, 13.5% had a history of VaIN2/3+, 29.8% had a history of CIN2/3+, 44.6% had persistent cervical HPV16 infection, and 12.5% had immune suppression. Among the 312 patients, 14.4% were diagnosed with AIN2/3, 25.0% with AIN1 and 60.6% were normal. Anal cytological abnormalities were found in 41.3% of all patients, with a significantly higher rate in AIN2/3 patients than in ≤AIN1, 71.1% versus 36.3%, p < 0.001. The hrHPV positivity rate was 89.7%, with HPV16 being the most prevalent. The complete agreement rate for HRA impressions was 79.5%. Multi-variable analysis revealed immune suppression (odds ratio [OR]: 3.47, 95% confidence interval [CI]: 1.42-8.5) and VIN2/3+ (OR: 2.82, 95% CI: 1.27-6.28) were independent risk factors for AIN2/3. Abnormal cytology results (OR: 3.3, 95% CI: 1.52-7.17) and anal HPV16 infection (OR: 3.2, 95% CI: 1.26-8.12) demonstrated similar ORs for AIN2/3. Early screening for AIN2/3+ is crucial in Chinese women with lower genital tract precancerous and cancerous lesions, particularly in those with VIN2/3+ and immune suppression.