OBJECTIVETo investigate the natural outcome of genital tract high risk human papillomavirus (HR-HPV) infection and associated factors among women in Xi'an region.

METHODSTotally 760 women with primary genital tract HR-HPV infection were enrolled and followed up by HPV-DNA genotyping technology. The cervical cytological techniques and/or colposcopy were used when necessary.

RESULTSAmong these subjects,the natural clearance rate of HR-HPV infection was 71.58%,with the median time of 8.10 months. The rate of HPV persistent infection was 22.63%, with the median time of 17.23 months. The rate of progression to cervical intraepithelial neoplasia (CIN)/cervical cancer (CC) was 5.79%, with the median time of 29.34 months. The natural clearance rate (P=0.000), persistent infection rate (P=0.000) and progression rate (P=0.040) in women older than 50 years were statistically difference from other age groups. The persistent infection rate in multiple infections group was significantly lower than that in single infection group (P=0.010), with the median time statistically longer than that in single infection group (P=0.018). The most easily progressive genotypes were HPV-16,HPV-33, HPV-58,HPV-18,HPV-52, and HPV-68, among which HPV-16 was the most common genotype in CIN 3/CC cases, accounting for 85.00%.

CONCLUSIONSMost of HR-HPV infections are naturally cleared within 2 years, and only a few cases progresses to CIN/CC. Women older than 50 years have a lower natural clearance rate and higher persistent and progressive rates. Multiple infections can affect the persistent infection. HPV-16 is the most common carcinogenic genotype in Xi'an region.