Browsing by Author "Ross, Jonathan"

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    Achieving consistency in measures of HIV-1 viral suppression across countries: derivation of an adjustment based on international antiretroviral treatment cohort data
    (Wiley, 2021) Johnson, Leigh F.; Kariminia, Azar; Trickey, Adam; Yiannoutsos, Constantin T.; Ekouevi, Didier K.; Minga, Albert K.; Pascom, Ana Roberta Pati; Han, Win Min; Zhang, Lei; Althoff, Keri N.; Rebeiro, Peter F.; Murenzi, Gad; Ross, Jonathan; Hsiao, Nei-Yuan; Marsh, Kimberly; Biostatistics and Health Data Science, Richard M. Fairbanks School of Public Health
    Introduction: The third of the Joint United Nations Programme on HIV/AIDS (UNAIDS) 90-90-90 targets is to achieve a 90% rate of viral suppression (HIV viral load <1000 HIV-1 RNA copies/ml) in patients on antiretroviral treatment (ART) by 2020. However, some countries use different thresholds when reporting viral suppression, and there is thus a need for an adjustment to standardize estimates to the <1000 threshold. We aim to propose such an adjustment, to support consistent monitoring of progress towards the "third 90" target. Methods: We considered three possible distributions for viral loads in ART patients: Weibull, Pareto and reverse Weibull (imposing an upper limit but no lower limit on the log scale). The models were fitted to data on viral load distributions in ART patients in the International epidemiology Databases to Evaluate AIDS (IeDEA) collaboration (representing seven global regions) and the ART Cohort Collaboration (representing Europe), using separate random effects models for adults and children. The models were validated using data from the World Health Organization (WHO) HIV drug resistance report and the Brazilian national ART programme. Results: Models were calibrated using 921,157 adult and 37,431 paediatric viral load measurements, over 2010-2019. The Pareto and reverse Weibull models provided the best fits to the data, but for all models, the "shape" parameters for the viral load distributions differed significantly between regions. The Weibull model performed best in the validation against the WHO drug resistance survey data, while the Pareto model produced uncertainty ranges that were too narrow, relative to the validation data. Based on these analyses, we recommend using the reverse Weibull model. For example, if a country reports an 80% rate of viral suppression at <200 copies/ml, this model estimates the proportion virally suppressed at <1000 copies/ml is 88.3% (0.800.56 ), with uncertainty range 85.5-90.6% (0.800.70 -0.800.44 ). Conclusions: Estimates of viral suppression can change substantially depending on the threshold used in defining viral suppression. It is, therefore, important that viral suppression rates are standardized to the same threshold for the purpose of assessing progress towards UNAIDS targets. We have proposed a simple adjustment that allows this, and this has been incorporated into UNAIDS modelling software.
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    Imaging Appearance of Nongerminoma Pediatric Ovarian Germ Cell Tumors Does Not Discriminate Benign from Malignant Histology
    (Elsevier, 2020) Billmire, Deborah; Dicken, Bryan; Rescorla, Frederick; Ross, Jonathan; Piao, Jin; Huang, Li; Krailo, Mark; Pashankar, Farzana; Frazier, Lindsay; Surgery, School of Medicine
    Study Objective Pediatric ovarian neoplasms with imaging appearance suggestive of teratoma are often presumed to have low risk of malignancy. We assessed the pre-operative imaging appearance of pediatric malignant ovarian germ cell tumors (MOGCT) and the presence of associated teratoma in a series of MOGCT. Design Retrospective review of clinical and pathology data. Setting Multicenter trial for extracranial malignant germ cell tumors in young female individuals by the Children's Oncology Group (COG study AGCT0132) that included yolk sac tumor, embryonal carcinoma and choriocarcinoma. Participants Female individuals 0-20 years of age at enrollment with ovarian primary nonseminomatous malignant germ cell tumors. Interventions Review of data forms, including prospectively collected surgical checklist documenting imaging characteristics of the tumor, and review of pathology reports. Main Outcome Measures Description of imaging appearance and frequency of mixed histology with benign teratoma elements. Results A total of 138 female individuals (11 months to 20 years of age) had primary ovarian tumors. Imaging appearance and pathology information were available for 133 patients. Among the 133 patients, tumor appearance was solid (10.5%), solid with calcification (3.0%), mixed cystic and solid (58.7%), mixed cystic and solid with calcification (24.8%), and unknown (3.0%). In all, 54% had elements of teratoma in addition to malignant histology. Conclusion Mixed cystic and solid appearance with or without calcification was seen in 83.5% of pediatric ovarian malignant germ cell tumors. Associated benign teratoma was common. The presence of a mixed cystic and solid appearance on preoperative imaging should not dissuade the surgeon from obtaining preoperative serum markers and undertaking complete surgical staging.