Risk factors for squamous intraepithelial lesions in systemic lupus erythematosus: a prospective cohort study.

Objective: We undertook a prospective cohort study to ascertain the risk factors for the development of squamous intraepithelial lesions (SIL) in patients with systemic lupus erythematosus (SLE).

Methods: One hundred thirty-seven SLE patients with a normal Papanicolaou (Pap) smear at baseline were evaluated at 6-month intervals for up to 3 years. At each visit, a Pap smear, human papillomavirus (HPV) DNA test, and clinical assessment were performed.

Results: Among the 137 patients, there were 12 incident cases (8.8%) of SIL over a median followup duration of 30.7 months (interquartile range 25.5-31.7). Among the 30 patients with HPV infection detectable by DNA testing at baseline, 9 (30%) developed SIL. The independent risk factors for the incident SIL in this group of SLE patients included the use of cyclophosphamide (CYC) ever (odds ratio [OR] 5.6, 95% confidence interval [95% CI] 1.1-29.3; P=0.041) and persistent high-risk HPV infection (OR 26.9, 95% CI 3.2-222.3; P=0.002). The use of baseline HPV testing has a higher sensitivity than abnormal cytology (defined as atypical squamous cells of undetermined significance; 47.7% versus 33.3%) in predicting the development of SIL.

Conclusion: Independent risk factors associated with the development of SIL in SLE patients included persistent high-risk HPV infection and the use of CYC. Low-risk patients who receive negative test results on both cervical cytology screening and HPV DNA testing may not need to be rescreened within 3 years.