Browsing by Author "Cameron, D William"

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Open Access
CD4 enumeration technologies: a systematic review of test performance for determining eligibility for antiretroviral therapy.
(PLoS One, 2015) Peeling, Rosanna W; Sollis, Kimberly A; Glover, Sarah; Crowe, Suzanne M; Landay, Alan L; Cheng, Ben; Barnett, David; Denny, Thomas N; Spira, Thomas J; Stevens, Wendy S; Crowley, Siobhan; Essajee, Shaffiq; Vitoria, Marco; Ford, Nathan
BACKGROUND: Measurement of CD4+ T-lymphocytes (CD4) is a crucial parameter in the management of HIV patients, particularly in determining eligibility to initiate antiretroviral treatment (ART). A number of technologies exist for CD4 enumeration, with considerable variation in cost, complexity, and operational requirements. We conducted a systematic review of the performance of technologies for CD4 enumeration. METHODS AND FINDINGS: Studies were identified by searching electronic databases MEDLINE and EMBASE using a pre-defined search strategy. Data on test accuracy and precision included bias and limits of agreement with a reference standard, and misclassification probabilities around CD4 thresholds of 200 and 350 cells/μl over a clinically relevant range. The secondary outcome measure was test imprecision, expressed as % coefficient of variation. Thirty-two studies evaluating 15 CD4 technologies were included, of which less than half presented data on bias and misclassification compared to the same reference technology. At CD4 counts <350 cells/μl, bias ranged from -35.2 to +13.1 cells/μl while at counts >350 cells/μl, bias ranged from -70.7 to +47 cells/μl, compared to the BD FACSCount as a reference technology. Misclassification around the threshold of 350 cells/μl ranged from 1-29% for upward classification, resulting in under-treatment, and 7-68% for downward classification resulting in overtreatment. Less than half of these studies reported within laboratory precision or reproducibility of the CD4 values obtained. CONCLUSIONS: A wide range of bias and percent misclassification around treatment thresholds were reported on the CD4 enumeration technologies included in this review, with few studies reporting assay precision. The lack of standardised methodology on test evaluation, including the use of different reference standards, is a barrier to assessing relative assay performance and could hinder the introduction of new point-of-care assays in countries where they are most needed.
Open Access
Willingness to participate in clinical trials among patients of Chinese heritage: a meta-synthesis.
(PloS one, 2013-01-17) Limkakeng, Alexander; Phadtare, Amruta; Shah, Jatin; Vaghasia, Meenakshi; Wei, Ding Ying; Shah, Anand; Pietrobon, Ricardo
BACKGROUND: Subjects of Chinese heritage have been found to participate in clinical research at lower rates than other groups despite growing in numbers as a population. While much research has examined research participants' motivation, there has not been a comprehensive synthesis of this information with respect to participants of Chinese descent. We sought to identify the factors that promote and hinder participation in clinical research among participants of Chinese heritage. METHODOLOGY/PRINCIPAL FINDINGS: We conducted a systematic review of the literature in Pubmed, OpenJGATE, SCIRUS, and COCHRANE databases and performed a meta-synthesis of retrieved articles. We extracted qualitative data, such as quotes to identify emerging themes. We identified five studies that met our selection criteria. Of them, only one (1/5) was conducted in China while other studies involved Chinese emigrants in USA (3/5) and Singapore (1/5). Participants from China were similar to emigrants with regard to factors that either promoted or decreased research participation. Four studies reported data exclusively on Chinese subjects. Three of the five studies involved qualitative interviews while the others were conducted using a survey design. Six themes favoring research participation were identified: Personal Benefit to Participants, Financial Incentives, Participant Sense of Altruism, Family or Physician Recommendations, Advertisements, and Convenience to the Participant. Five factors were seen as a barrier to participation in clinical trials: Mistrust of Researchers, Language Barrier, Lack of Financial and Other Support, Cultural and Social Barriers, Lack of Knowledge about Clinical Trials. CONCLUSIONS/SIGNIFICANCE: Chinese heritage clinical research participants value personal benefit, financial incentives, the ability to help others, recommendations of others, advertisements, and convenience when considering clinical research participation. In addition, the establishment of trust and addressing knowledge deficits are important factors to them. Investigators seeking to optimize enrolment in these populations should incorporate these findings into their study design and subject handouts.