Silke Walleser

University of Sydney, Sydney, New South Wales, Australia

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Publications (3)7.09 Total impact

  • Article: What is the value of computered tomography colonography in patients screening positive for fecal occult blood? A systematic review and economic evaluation.
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    ABSTRACT: Computerized tomography colonography (CTC) is a highly accurate test for the detection of colorectal polyps and cancers and has been proposed as a potential alternative to colonoscopy. Bowel cancer screening using fecal occult blood testing (FOBT) and follow-up diagnostic colonoscopy is an effective intervention that currently is being implemented in screening programs internationally. Because of high false-positive rates for FOBT, concerns have been raised about patient uptake and access to colonoscopy services. This study assessed the value of CTC as an alternative to colonoscopy in FOBT-positive individuals. A systematic review of studies comparing the accuracy of CTC and colonoscopy for the detection of lesions 10 mm or greater and cancers in nonscreening populations was conducted. A modeled economic analysis was undertaken to assess cost per life-year saved. Five eligible studies were identified. Pooled sensitivity and specificity for the detection of lesions 10 mm or greater were 63% (95% confidence interval [CI], 55%-71%) and 95% (95% CI, 94%-97%) for CTC, and 95% (95% CI, 90%-98%) and 99.8% (95% CI, 99.5%-100%) for colonoscopy, respectively (3 studies). Pooled sensitivity and specificity for the detection of cancer were 89% (95% CI, 70%-98%) and 97% (95% CI, 95%-98%) for CTC, and 96% (95% CI, 80%-100%) and 99.7% (95% CI, 99%-100%) for colonoscopy, respectively (3 studies). The base case economic analysis showed that CTC is less effective and more costly than colonoscopy. At a low prevalence of polyps, sensitivity analysis found CTC was less effective and less costly than colonoscopy; if CTC was more sensitive than colonoscopy, CTC was more effective, at higher cost. Overall, CTC appears less accurate, less effective, and potentially more costly than colonoscopy in individuals with a positive FOBT.
    Clinical gastroenterology and hepatology: the official clinical practice journal of the American Gastroenterological Association 12/2007; 5(12):1439-46; quiz 1368. · 5.64 Impact Factor
  • Article: The cost effectiveness of screening for genital Chlamydia trachomatis infection in Australia.
    Silke Walleser, Glenn Salkeld, Basil Donovan
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    ABSTRACT: In Australia, there is no published study on the cost effectiveness of screening for chlamydia. The aim of this study was to examine the cost effectiveness of a hypothetical screening programme for chlamydia based on annual opportunistic testing of all women 25 years of age or younger consulting a general practitioner, compared with no screening. A decision-analytic modelling approach was used to determine the incremental cost effectiveness ratio (ICER) of screening compared with no screening over 25 years. The analysis measured Australian health-care costs and benefits were assessed in terms of quality-adjusted life years (QALYs). The analysis resulted in a cost per QALY of 2968 dollars for screening. One-way sensitivity analyses on all variables, and multi-way sensitivity analyses on some variables, showed a wide range for the cost effectiveness, from dominance (where screening is effective and saves money overall) to an ICER of 67,715 dollars per QALY. The results indicate that annual opportunistic screening for chlamydia in women under 25 is a potentially worthwhile undertaking. However, the analysis also highlights uncertainties around the natural history of chlamydia and the effectiveness of chlamydia screening. Given these uncertainties, the need for further primary data collection in these areas becomes apparent.
    Sexual Health 01/2007; 3(4):225-34. · 1.45 Impact Factor
  • Article: Review: computed tomographic colonography is accurate for medium and large colorectal polyps and cancer.
    Michael J Solomon, Sarah J Lord, Silke Walleser
    Evidence-based medicine 11/2006; 11(5):153.