Prevalence and cumulative incidence of abnormal cervical cytology among HIV-infected Thai women: a 5.5-year retrospective cohort study

To determine the appropriate interval of Pap smear screenings for HIV-infected Thai women and risk factors for subsequent abnormal cervical cytology, we assessed the prevalence, cumulative incidence and associated factors of cervical cell abnormalities (atypical squamous cell of undetermined significance or higher grades, ASCUS+) among this group of patients.The prevalence of ASCUS+ was 15.4% at the first visit, and the cumulative incidence of ASCUS+ gradually increased to 37% in the first 3.5 years of follow-up appointments (first 7 times), and tended to plateau in the last 2 years. For multivariate correlation analysis, women with a CD4 count <350 cells/μL had a significant correlation with ASCUS+ (P = 0.043). There were no associations of subsequent ASCUS+ with age, pregnancy, contraceptive method, highly active anti-retroviral treatment, assumed duration of infection, or the CD4 count nadir level.There are high prevalence and cumulative incidence of ASCUS+ in HIV-infected Thai women. With a high lost-to-follow-up rate, an appropriate interval of Pap smear screening cannot be concluded from the present study. Nevertheless, the HIV-infected Thai women may require more than two normal semi-annual Pap smears before shifting to routinely annual cytologic screening.Thailand is one of the world's endemic areas for HIV infection. In 2007, approximately 250,000 women were living with HIV infection[1]. Women living with HIV-AIDS clearly have an increased risk of cervical cancer. A recent study in HIV-infected women in Thailand found that cervical cancer was the most common AIDS-related malignancy[2]. Sufficient Papanicolaou (Pap) smear screening would render a high yield in early detection because of its affordability, availability and accessibility. Cervical squamous cell abnormalities in HIV-infected women, compared with women who are not infected, progress more rapidly to more significant cervical intraepithelial neoplasia (CIN) or even invasive cervical cancer[3].Our