Visual diagnosis of female genital schistosomiasis in Zambian women from hand-held colposcopy: agreement of expert image review and association with clinical symptoms
Amy Sturt, Henrietta Bristowe, Emily L. Webb, Isaiah Hansingo, Comfort R Phiri, Maina Mudenda, Joyce Mapani, Tobias Mweene, Bruno Levecke, Piet Cools, Govert J. van Dam, Paul L. A. M. Corstjens, Helen Ayles, Richard Hayes, Suzanna C. Francis, Lisette van Lieshout, Bellington Vwalika, Eyrun Floerecke Kjetland, Amaya L. Bustinduy
Abstract
<ns4:p> <ns4:bold>Background: </ns4:bold> Female genital schistosomiasis (FGS) can occur in <ns4:italic>S. haematobium</ns4:italic> infection and is caused by egg deposition in the genital tract. Confirming a diagnosis of FGS is challenging due to the lack of a diagnostic reference standard. A 2010 expert-led consensus meeting proposed visual inspection of the cervicovaginal mucosa as an adequate reference standard for FGS diagnosis. The agreement of expert human reviewers for visual-FGS has not been previously described. </ns4:p> <ns4:p> <ns4:bold>Methods:</ns4:bold> In two Zambian communities, non-menstruating, non-pregnant, sexually-active women aged 18-31 years participating in the HPTN 071 (PopART) Population-Cohort were enrolled in a cross-sectional study. Self-collected genital swabs and a urine specimen were collected at a home visit; trained midwives performed cervicovaginal lavage (CVL) and hand-held colposcopy at a clinic visit. <ns4:italic>S. haematobium</ns4:italic> eggs and circulating anodic antigen (CAA) were detected from urine. Two senior physicians served as expert reviewers and independently diagnosed visual-FGS as the presence of sandy patches, rubbery papules or abnormal blood vessels in cervicovaginal images obtained by hand-held colposcopy. PCR-FGS was defined as <ns4:italic>Schistosoma </ns4:italic> DNA detected by real-time PCR in any genital specimen (CVL or genital swab). </ns4:p> <ns4:p> <ns4:bold>Results:</ns4:bold> Of 527 women with cervicovaginal colposcopic images, 468/527 (88.8%) were deemed interpretable by Reviewer 1 and 417/527 (79.1%) by Reviewer 2. Visual-FGS was detected in 35.3% (165/468) of participants by expert review of colposcopic images by Reviewer 1 and in 63.6% (265/417) by Reviewer 2. Cohen’s kappa statistic for agreement between the two reviewers was 0.16, corresponding to "slight" agreement. The reviewers made concordant diagnoses in 38.7% (204/527) participants (100 negative, 104 positive) and discordant diagnoses in 31.8% (168/527) participants. </ns4:p> <ns4:p> <ns4:bold>Conclusions:</ns4:bold> The unexpectedly low level of correlation between expert reviewers highlights the imperfect nature of visual diagnosis for FGS based on cervicovaginal images. This finding is a call to action for improved point-of-care diagnostics for female genital schistosomiasis. </ns4:p>