Dr Xin Hui S Chan MRCP

Research Area: Global Health
Technology Exchange: Bioinformatics and Medical statistics
Scientific Themes: Tropical Medicine & Global Health and Clinical Trials & Epidemiology
Keywords: Malaria, Elimination, Epidemiology, Policy, Health systems, Artemisinin-combination therapies, Drug Safety / Pharmacovigilance, Antimalarial cardiotoxicity, Clinical Trials, Antimalarial drug resistance and Genomics
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Dr Xin Hui Chan is research physician and NDM Prize Studentship-MRC Doctoral Training Partnership research fellow in the Mahidol-Oxford Tropical Medicine Research Unit (MORU), specialty registrar in infectious diseases and general internal medicine at Oxford University Hospitals, and lecturer in medicine at Worcester College, University of Oxford.

Xin Hui is interested in the translation of scientific research into actionable interventions. Her research focuses on optimising interventions for malaria elimination and containment of antimalarial resistance. Her work combines clinical trial, field surveillance, drug safety / pharmacovigilance, pharmacoepidemiology, and genomic studies. She is currently the WHO technical resource person and rapporteur of the WHO Evidence Review Group on the cardiotoxicity of antimalarials.

Xin Hui's previous experience has been with the University of Oxford, the London School of Hygiene and Tropical Medicine, the MRC Unit in the Gambia, the US National Institutes of Health, and the UK Faculty of Medical Leadership and Management.

Name Department Institution Country
Professor Sir Nicholas J White FRS Tropical Medicine Oxford University, Bangkok Thailand
Professor Nicholas PJ Day FMedSci FRCP Tropical Medicine Oxford University, Bangkok Thailand
Professor Adrianus Dondorp Tropical Medicine Oxford University, Bangkok Thailand
Professor François H Nosten Tropical Medicine Oxford University, Mae Sot Thailand
Professor Joel Tarning Tropical Medicine Oxford University, Bangkok Thailand
Professor Olivo Miotto Tropical Medicine Oxford University, Bangkok Thailand
Tun STT, Lubell Y, Dondorp AM, Fieldman T, Tun KM, Celhay O, Chan XH, Saralamba S, White LJ. 2017. Identifying artemisinin resistance from parasite clearance half-life data with a simple Shiny web application. PLoS One, 12 (5), pp. e0177840. | Show Abstract | Read more

The emergence of artemisinin-resistant Plasmodium falciparum malaria is a major threat to malaria elimination. New tools for supporting the surveillance of artemisinin resistance are critical for current and future malaria control and elimination strategies. We have developed an open-access, user-friendly, web-based tool to analyse parasite clearance half-life data of P. falciparum infected patients after treatment with artemisinin derivatives, so that resistance to artemisinin can be identified. The tool can be accessed at bit.ly/id_artemisinin_resistance.

Chan XHS, Onen BL, Raza MM, Mital D, Smith RW. 2016. HIV - lessons from a late diagnosis. Acute Med, 15 (2), pp. 84-87. | Show Abstract

Late HIV diagnosis is the most important predictor of HIV-related morbidity and mortality in the UK and often results from missed testing opportunities during earlier contact with health services. The HPA now recommends routine HIV testing be commissioned as a priority for all general medical admissions in high prevalence areas, such as Milton Keynes. We present the case of a patient admitted to our Medical Admissions Unit (MAU) managed initially for presumed septic complications of metastatic disease who was later found to have terminal HIV disease. In keeping with UK-wide experience which we review, a local audit following this case found MAU HIV test coverage increased after routine testing but not after staff education alone, and resulted in implementation of routine HIV testing in our MAU.

Chan XHS, Koh CE, Glover M, Bryson P, Travis SPL, Mortensen NJ. 2014. Healing under pressure: hyperbaric oxygen and myocutaneous flap repair for extreme persistent perineal sinus after proctectomy for inflammatory bowel disease. Colorectal Dis, 16 (3), pp. 186-190. | Show Abstract | Read more

AIM: Persistent perineal sinus (PPS) following proctectomy for inflammatory bowel disease affects about 50% of patients. Up to 33% of cases of PPS remain unhealed at 12 months and the most refractory cases are unhealed at 24 months despite optimal conventional therapy. Reports of hyperbaric oxygen therapy (HBOT) for chronic wounds and Crohn's perianal disease led us to explore perioperative HBOT with rectus abdominis myocutaneous (RAM) flap repair in a highly selected group of patients with extreme PPS who had failed all other interventions. METHOD: Patients with extreme PPS received preoperative HBOT (a 90-min session at 2.2-2.4 atmospheres, five times per week for 5-6 weeks, for a total of up to 30 sessions), before abdominoperineal PPS excision and perineal reconstruction with vertical or transverse RAM flap repair within 2-4 weeks of completing HBOT. Postoperative HBOT (10 further 90-min sessions) was administered within 2 weeks where practicable. RESULTS: Between 2007 and 2011, four patients with extreme PPS underwent RAM flap repair with preoperative HBOT; two also received postoperative HBOT. The median (range) duration of PPS before HBOT was 88.5 (23-156) months. All patients had previously failed multiple (5 to > 35) surgical procedures. Complete healing occurred in all patients at a median (range) follow-up of 2.5 (2-3) months. There were no further hospital admissions for PPS at a median (range) follow-up of 35 (8-64) months. CONCLUSION: Hyperbaric oxygen therapy combined with PPS excision and perineal reconstruction with a RAM flap led to complete perineal healing in four patients with extreme PPS and appears a safe and effective extension to the therapeutic pathway for exceptionally treatment-refractory PPS.

Mayo-Wilson E, Junior JA, Imdad A, Dean S, Chan XHS, Chan ES, Jaswal A, Bhutta ZA. 2014. Zinc supplementation for preventing mortality, morbidity, and growth failure in children aged 6 months to 12 years of age. Cochrane Database Syst Rev, 5 (5), pp. CD009384. | Show Abstract | Read more

BACKGROUND: Zinc deficiency is prevalent in low- and middle-income countries, and contributes to significant diarrhoea-, pneumonia-, and malaria-related morbidity and mortality among young children. Zinc deficiency also impairs growth. OBJECTIVES: To assess the effects of zinc supplementation for preventing mortality and morbidity, and for promoting growth, in children aged six months to 12 years of age. SEARCH METHODS: Between December 2012 and January 2013, we searched CENTRAL, MEDLINE, MEDLINE In-Process and Other Non-Indexed Citations, Embase, African Index Medicus, Conference Proceedings Citation Index, Dissertation Abstracts, Global Health, IndMED, LILACS, WHOLIS, metaRegister of Controlled Trials, and WHO ICTRP. SELECTION CRITERIA: Randomised controlled trials of preventive zinc supplementation in children aged six months to 12 years compared with no intervention, a placebo, or a waiting list control. We excluded hospitalised children and children with chronic diseases or conditions. We excluded food fortification or intake, sprinkles, and therapeutic interventions. DATA COLLECTION AND ANALYSIS: Two authors screened studies, extracted data, and assessed risk of bias. We contacted trial authors for missing information. MAIN RESULTS: We included 80 randomised controlled trials with 205,401 eligible participants. We did not consider that the evidence for the key analyses of morbidity and mortality outcomes were affected by risk of bias. The risk ratio (RR) for all-cause mortality was compatible with a reduction and a small increased risk of death with zinc supplementation (RR 0.95, 95% confidence interval (CI) 0.86 to 1.05, 14 studies, high-quality evidence), and also for cause-specific mortality due to diarrhoea (RR 0.95, 95% CI 0.69 to 1.31, four studies, moderate-quality evidence), lower respiratory tract infection (LRTI) (RR 0.86, 95% CI 0.64 to 1.15, three studies, moderate-quality evidence), or malaria (RR 0.90, 95% CI 0.77 to 1.06, two studies, moderate-quality evidence).Supplementation reduced diarrhoea morbidity, including the incidence of all-cause diarrhoea (RR 0.87, 95% CI 0.85 to 0.89, 26 studies, moderate-quality evidence), but the results for LRTI and malaria were imprecise: LRTI (RR 1, 95% CI 0.94 to 1.07, 12 studies, moderate-quality evidence); malaria (RR 1.05, 95% 0.95 to 1.15, four studies, moderate-quality evidence).There was moderate-quality evidence of a very small improvement in height with supplementation (standardised mean difference (SMD) -0.09, 95% CI -0.13 to -0.06; 50 studies), but the size of this effect might not be clinically important. There was a medium to large positive effect on zinc status.Supplementation was associated with an increase in the number of participants with at least one vomiting episode (RR 1.29, 95% CI 1.14 to 1.46, five studies, high-quality evidence). We found no clear evidence of benefit or harm of supplementation with regard to haemoglobin or iron status. Supplementation had a negative effect on copper status. AUTHORS' CONCLUSIONS: In our opinion, the benefits of preventive zinc supplementation outweigh the harms in areas where the risk of zinc deficiency is relatively high. Further research should determine optimal intervention characteristics such as supplement dose.

Chan XH, Wynn-Jones W, Lobban C. 2012. Time for an open access secure online data collection tool. BMJ, 345 (jul16 2), pp. e4805. | Read more

Tun STT, Lubell Y, Dondorp AM, Fieldman T, Tun KM, Celhay O, Chan XH, Saralamba S, White LJ. 2017. Identifying artemisinin resistance from parasite clearance half-life data with a simple Shiny web application. PLoS One, 12 (5), pp. e0177840. | Show Abstract | Read more

The emergence of artemisinin-resistant Plasmodium falciparum malaria is a major threat to malaria elimination. New tools for supporting the surveillance of artemisinin resistance are critical for current and future malaria control and elimination strategies. We have developed an open-access, user-friendly, web-based tool to analyse parasite clearance half-life data of P. falciparum infected patients after treatment with artemisinin derivatives, so that resistance to artemisinin can be identified. The tool can be accessed at bit.ly/id_artemisinin_resistance.

Chan XHS, Onen BL, Raza MM, Mital D, Smith RW. 2016. HIV - lessons from a late diagnosis. Acute Med, 15 (2), pp. 84-87. | Show Abstract

Late HIV diagnosis is the most important predictor of HIV-related morbidity and mortality in the UK and often results from missed testing opportunities during earlier contact with health services. The HPA now recommends routine HIV testing be commissioned as a priority for all general medical admissions in high prevalence areas, such as Milton Keynes. We present the case of a patient admitted to our Medical Admissions Unit (MAU) managed initially for presumed septic complications of metastatic disease who was later found to have terminal HIV disease. In keeping with UK-wide experience which we review, a local audit following this case found MAU HIV test coverage increased after routine testing but not after staff education alone, and resulted in implementation of routine HIV testing in our MAU.

Mayo-Wilson E, Junior JA, Imdad A, Dean S, Chan XHS, Chan ES, Jaswal A, Bhutta ZA. 2014. Zinc supplementation for preventing mortality, morbidity, and growth failure in children aged 6 months to 12 years of age. Cochrane Database Syst Rev, 5 (5), pp. CD009384. | Show Abstract | Read more

BACKGROUND: Zinc deficiency is prevalent in low- and middle-income countries, and contributes to significant diarrhoea-, pneumonia-, and malaria-related morbidity and mortality among young children. Zinc deficiency also impairs growth. OBJECTIVES: To assess the effects of zinc supplementation for preventing mortality and morbidity, and for promoting growth, in children aged six months to 12 years of age. SEARCH METHODS: Between December 2012 and January 2013, we searched CENTRAL, MEDLINE, MEDLINE In-Process and Other Non-Indexed Citations, Embase, African Index Medicus, Conference Proceedings Citation Index, Dissertation Abstracts, Global Health, IndMED, LILACS, WHOLIS, metaRegister of Controlled Trials, and WHO ICTRP. SELECTION CRITERIA: Randomised controlled trials of preventive zinc supplementation in children aged six months to 12 years compared with no intervention, a placebo, or a waiting list control. We excluded hospitalised children and children with chronic diseases or conditions. We excluded food fortification or intake, sprinkles, and therapeutic interventions. DATA COLLECTION AND ANALYSIS: Two authors screened studies, extracted data, and assessed risk of bias. We contacted trial authors for missing information. MAIN RESULTS: We included 80 randomised controlled trials with 205,401 eligible participants. We did not consider that the evidence for the key analyses of morbidity and mortality outcomes were affected by risk of bias. The risk ratio (RR) for all-cause mortality was compatible with a reduction and a small increased risk of death with zinc supplementation (RR 0.95, 95% confidence interval (CI) 0.86 to 1.05, 14 studies, high-quality evidence), and also for cause-specific mortality due to diarrhoea (RR 0.95, 95% CI 0.69 to 1.31, four studies, moderate-quality evidence), lower respiratory tract infection (LRTI) (RR 0.86, 95% CI 0.64 to 1.15, three studies, moderate-quality evidence), or malaria (RR 0.90, 95% CI 0.77 to 1.06, two studies, moderate-quality evidence).Supplementation reduced diarrhoea morbidity, including the incidence of all-cause diarrhoea (RR 0.87, 95% CI 0.85 to 0.89, 26 studies, moderate-quality evidence), but the results for LRTI and malaria were imprecise: LRTI (RR 1, 95% CI 0.94 to 1.07, 12 studies, moderate-quality evidence); malaria (RR 1.05, 95% 0.95 to 1.15, four studies, moderate-quality evidence).There was moderate-quality evidence of a very small improvement in height with supplementation (standardised mean difference (SMD) -0.09, 95% CI -0.13 to -0.06; 50 studies), but the size of this effect might not be clinically important. There was a medium to large positive effect on zinc status.Supplementation was associated with an increase in the number of participants with at least one vomiting episode (RR 1.29, 95% CI 1.14 to 1.46, five studies, high-quality evidence). We found no clear evidence of benefit or harm of supplementation with regard to haemoglobin or iron status. Supplementation had a negative effect on copper status. AUTHORS' CONCLUSIONS: In our opinion, the benefits of preventive zinc supplementation outweigh the harms in areas where the risk of zinc deficiency is relatively high. Further research should determine optimal intervention characteristics such as supplement dose.

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