Tan Doan

Tan Doan


Research Focus & Metrics

Academic Career Length

14Years (2013-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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17 January 2018 in Epidemiology and Infection
Verified
Journal Article
Open access
PDF file
YMY.A. Melsew
Y.A. Melsew
TDTan Doan
Tan Doan
MGM. Gambhir
M. Gambhir
ACA.C. Cheng
A.C. Cheng
EMEmma McBryde
Emma McBryde
JTJ.M. Trauer
J.M. Trauer
We performed a systematic review and meta-analyses of studies assessing tuberculosis (TB) patient-related risk factors for transmission of Mycobacterium tuberculosis infection. Meta-analyses were conducted for sputum smear-positivity, lung cavitation and HIV seropositivity of index patients with both crude and adjusted odds ratios (AORs) pooled using random effect models. Thirty-seven studies were included in the review. We found that demographic characteristics such as age and sex were not significant risk factors, while behaviours such as smoking and alcohol intake were associated with infectiousness although inconsistently. Treatment delay of >28 days was a significant predictor of greater infectiousness. Contacts of sputum smear-positive index patients were found to be more likely to be infected than contacts of sputum smear-negative patients, with a pooled AOR of 2.15 (95% confidence interval (CI) 1.47–3.17, I2 = 38%). Similarly, contacts of patients with the cavitary disease were around twice as likely to be infected as contacts of patients without cavitation (pooled AOR 1.9, 95% CI 1.26–2.84, I2 = 63%). In contrast, HIV seropositive patients were associated with few contact infections than HIV seronegative patients (AOR 0.45, 95% CI 0.26–0.80, I2 = 52%). In conclusion, behavioural and clinical characteristics of TB patients can be used to identify highly infectious patients for targeted interventions.

3 April 2013 in Journal of Intellectual & Developmental Disability
Verified
Journal Article
Closed access
TDTan Doan
Tan Doan
NLNicholas G. Lennox
Nicholas G. Lennox
MTMiriam Taylor-Gomez
Miriam Taylor-Gomez
Robert WareRobert Ware
Robert Ware
There is concern about widespread medication use by people with intellectual disability (ID), especially psychotropic and anticonvulsant agents. However, there is sparse information on prescribing patterns in Australia. This cross-sectional study was conducted between 2000 and 2002 among adults with ID who live in the community in Brisbane, Australia. Medication data were extracted from a health screening tool. Demographic and medical data were collected from telephone interviews and medical records. Of 117 participants, 35% were prescribed psychotropic medications, most commonly antipsychotics, and 26% anticonvulsants. Complementary medications (vitamins, minerals, amino acids, fish oil, and herbal products) were used by 29% of participants. After adjusting for potentially confounding variables, psychotropic medication use was significantly associated with having a psychiatric illness (adjusted odds ratio = 4.6, 95% CI [1.0, 20.6]) and challenging behaviours (4.4, [1.1, 17.3]). People with ID use a broad range of medications. Psychotropic medications continue to be the most predominant agents prescribed for this population. Psychotropic medication use is positively associated with having a psychiatric illness and challenging behaviours.

1 March 2017 in International Journal of Infectious Diseases
Verified
Journal Article
Open access
EMEmma McBryde
Emma McBryde
MMMichael T. Meehan
Michael T. Meehan
TDTan Doan
Tan Doan
RRRomain Ragonnet
Romain Ragonnet
BMBen J. Marais
Ben J. Marais
JTJames M. Trauer
James M. Trauer
Multidrug-resistant tuberculosis (MDR-TB) is a threat to tuberculosis (TB) control. To guide TB control, it is essential to understand the extent to which and the circumstances in which MDR-TB will replace drug-susceptible TB (DS-TB) as the dominant phenotype. The issue was examined by assessing evidence from genomics, pharmacokinetics, and epidemiology studies. This evidence was then synthesized into a mathematical model. This model considers two TB strains, one with and one without an MDR phenotype. It was considered that intrinsic transmissibility may be different between the two strains, as may the control response including the detection, treatment failure, and default rates. The outcomes were explored in terms of the incidence of MDR-TB and time until MDR-TB surpasses DS-TB as the dominant strain. The ability of MDR-TB to dominate DS-TB was highly sensitive to the relative transmissibility of the resistant strain; however, MDR-TB could dominate even when its transmissibility was modestly reduced (to between 50% and 100% as transmissible as the DS-TB strain). This model suggests that it may take decades or more for strain replacement to occur. It was also found that while the amplification of resistance is the early cause of MDR-TB, this will rapidly give way to person-to-person transmission.

28 November 2017 in PLOS ONE
Verified
Journal Article
Open access
PDF file
TDTan Doan
Tan Doan
DEdamon eisen
damon eisen
MRMorgan T Rose
Morgan T Rose
ASAndrew Slack
Andrew Slack
GSGrace Stearnes
Grace Stearnes
EMEmma McBryde
Emma McBryde
Accurate diagnosis and subsequent treatment of latent tuberculosis infection (LTBI) is essential for TB elimination. However, the absence of a gold standard test for diagnosing LTBI makes assessment of the true prevalence of LTBI and the accuracy of diagnostic tests challenging. Bayesian latent class models can be used to make inferences about disease prevalence and the sensitivity and specificity of diagnostic tests using data on the concordance between tests. We performed the largest meta-analysis to date aiming to evaluate the performance of tuberculin skin test (TST) and interferon-gamma release assays (IGRAs) for LTBI diagnosis in various patient populations using Bayesian latent class modelling. Systematic search of PubMeb, Embase and African Index Medicus was conducted without date and language restrictions on September 11, 2017 to identify studies that compared the performance of TST and IGRAs for LTBI diagnosis. Two IGRA methods were considered: QuantiFERON-TB Gold In Tube (QFT-GIT) and T-SPOT.TB. Studies were included if they reported 2x2 agreement data between TST and QFT-GIT or T-SPOT.TB. A Bayesian latent class model was developed to estimate the sensitivity and specificity of TST and IGRAs in various populations, including immune-competent adults, immune-compromised adults and children. A TST cut-off value of 10 mm was used for immune-competent subjects and 5 mm for immune-compromised individuals. A total of 157 studies were included in the analysis. In immune-competent adults, the sensitivity of TST and QFT-GIT were estimated to be 84% (95% credible interval [CrI] 82–85%) and 52% (50–53%), respectively. The specificity of QFT-GIT was 97% (96–97%) in non-BCG-vaccinated and 93% (92–94%) in BCG-vaccinated immune-competent adults. The estimated figures for TST were 100% (99–100%) and 79% (76–82%), respectively. T-SPOT.TB has comparable specificity (97% for both tests) and better sensitivity (68% versus 52%) than QFT-GIT in immune-competent adults. In immune-compromised adults, both TST and QFT-GIT display low sensitivity but high specificity. QFT-GIT and TST are equally specific (98% for both tests) in non-BCG-vaccinated children; however, QFT-GIT is more specific than TST (98% versus 82%) in BCG-vaccinated group. TST is more sensitive than QFT-GIT (82% versus 73%) in children. This study is the first to assess the utility of TST and IGRAs for LTBI diagnosis in different population groups using all available data with Bayesian latent class modelling. Our results challenge the current beliefs about the performance of LTBI screening tests, and have important implications for LTBI screening policy and practice. We estimated that the performance of IGRAs is not as reliable as previously measured in the general population. However, IGRAs are not or minimally affected by BCG and should be the preferred tests in this setting. Adoption of IGRAs in settings where BCG is widely administered will allow for a more accurate identification and treatment of LTBI.

5 October 2018 in Journal of Antimicrobial Chemotherapy
Verified
Journal Article
Closed access
TDTan Doan
Tan Doan
GFGreg J Fox
Greg J Fox
MMMichael T Meehan
Michael T Meehan
NSNick Scott
Nick Scott
Romain RagonnetRomain Ragonnet
Romain Ragonnet
EMEmma McBryde
Emma McBryde
Latent tuberculosis infection (LTBI) is a critical driver of the global burden of active TB, and therefore LTBI treatment is key for TB elimination. Treatment regimens for LTBI include self-administered daily isoniazid for 6 (6H) or 9 (9H) months, self-administered daily rifampicin plus isoniazid for 3 months (3RH), self-administered daily rifampicin for 4 months (4R) and weekly rifapentine plus isoniazid for 3 months self-administered (3HP-SAT) or administered by a healthcare worker as directly observed therapy (3HP-DOT). Data on the relative cost-effectiveness of these regimens are needed to assist policymakers and clinicians in selecting an LTBI regimen. To evaluate the cost-effectiveness of all regimens for treating LTBI. We developed a Markov model to investigate the cost-effectiveness of 3HP-DOT, 3HP-SAT, 4R, 3RH, 9H and 6H for LTBI treatment in a cohort of 10000 adults with LTBI. Cost-effectiveness was evaluated from a health system perspective over a 20 year time horizon. Compared with no preventive treatment, 3HP-DOT, 3HP-SAT, 4R, 3RH, 9H and 6H prevented 496, 470, 442, 418, 370 and 276 additional cases of active TB per 10000 patients, respectively. All regimens reduced costs and increased QALYs compared with no preventive treatment. 3HP was more cost-effective under DOT than under SAT at a cost of US$27948 per QALY gained. Three months of weekly rifapentine plus isoniazid is more cost-effective than other regimens. Greater recognition of the benefits of short-course regimens can contribute to the scale-up of prevention and achieving the 'End TB' targets.

30 October 2015 in Journal of Antimicrobial Chemotherapy
Verified
Journal Article
Closed access
PDF file
TDTan Doan
Tan Doan
CKCarl Michael James Kirkpatrick
Carl Michael James Kirkpatrick
PWPatricia Walker
Patricia Walker
Monica SlavinMonica Slavin
Monica Slavin
MAMichelle R. Ananda-Rajah
Michelle R. Ananda-Rajah
DKDavid C. M. Kong
David C. M. Kong
Objectives The primary objectives were to investigate the prescribing practices of primary antifungal prophylaxis (PAP) and incidence of invasive fungal disease (IFD) in adult patients with ALL receiving induction-consolidation chemotherapy. Secondary objectives were to determine risk factors for IFD and resource utilization associated with IFD. Methods A retrospective chart review of adult patients with ALL from commencement of induction until completion of consolidation chemotherapy was undertaken from January 2008 to June 2013 in four hospitals in Melbourne, Australia. IFD was classified according to the revised European Organisation for Research and Treatment of Cancer criteria. Cost analysis was performed from an Australian public hospital perspective. Results Ninety-eight patients were included in the audit; 83 (85%) received PAP. Most patients (49/83, 59%) switched between two different antifungal agents, predominantly between liposomal amphotericin B and an azole. Five proven/probable and six possible IFD cases were identified. Proven/probable IFD was most common in patients receiving the BFM95 chemotherapy protocol. The incidence of proven/probable IFD was significantly lower in patients receiving PAP compared with those who did not (2/78, 2.6% versus 3/14, 21.4%; P = 0.024). For every five patients receiving PAP, one proven/probable IFD case would be prevented. Proven/probable IFD was associated with an additional median cost of 121 520 Australian dollars (95% CI: 90 781–180 141 Australian dollars; P < 0.001) compared with patients without IFD. Conclusions This is the first multicentre study evaluating PAP use in patients with ALL. With the caveats of interpretation of retrospective, non-randomized data, PAP was associated with a reduced IFD risk.