David R. Chadwick

Dr. David R. Chadwick


Research Focus & Metrics

Academic Career Length

34Years (1993-Present)

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

Representative Publications

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1 August 2005 in Journal of Clinical Virology
Verified
Journal Article
Closed access
DCDavid R. Chadwick
David R. Chadwick
BABarbara Arch
Barbara Arch
AWAnnelies Wilder-Smith
Annelies Wilder-Smith
NPNicholas Paton
Nicholas Paton

1 January 2005 in British Medical Bulletin
Verified
Journal Article
Open access
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DCDavid R. Chadwick
David R. Chadwick
Viruses probably account for most cases of acute meningitis. Viral meningitis is often assumed to be a largely benign disease. For the commonest pathogens causing meningitis, enteroviruses, this is usually the case; however, for many of the other pathogens causing viral meningitis, and for common pathogens in the immunocompromised or infants, viral meningitis is frequently associated with substantial neurological complications and a significant mortality. Diagnostic methods for rapid and accurate identification of pathogens have improved over recent years, permitting more precise and earlier diagnoses. There have been fewer developments in therapies for viral meningitis, and there remain no effective therapies for most pathogens, emphasising the importance of prevention and early diagnosis. This review focuses on the presentation, diagnosis and management of viral meningitis and also covers the prevention of meningitis for pathogens where effective vaccines are available.

28 November 2017 in AIDS
Verified
Journal Article
Open access
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ATAlicia C. Thornton
Alicia C. Thornton
SJSophie Jose
Sophie Jose
SBSanjay Bhagani
Sanjay Bhagani
DCDavid R. Chadwick
David R. Chadwick
DDDavid Dunn
David Dunn
CSCaroline Anne Sabin
Caroline Anne Sabin
To compare rates of all-cause, liver-related, and AIDS-related mortality among individuals who are HIV-monoinfected with those coinfected with HIV and hepatitis B (HBV) and/or hepatitis C (HCV) viruses. An ongoing observational cohort study collating routinely collected clinical data on HIV-positive individuals attending for care at HIV treatment centres throughout the United Kingdom. Individuals were included if they had been seen for care from 2004 onwards and had tested for HBV and HCV. Crude mortality rates (all cause, liver related, and AIDS related) were calculated among HIV-monoinfected individuals and those coinfected with HIV, HBV, and/or HCV. Poisson regression was used to adjust for confounding factors, identify independent predictors of mortality, and estimate the impact of hepatitis coinfection on mortality in this cohort. Among 25 486 HIV-positive individuals, with a median follow-up 4.5 years, HBV coinfection was significantly associated with increased all-cause and liver-related mortality in multivariable analyses: adjusted rate ratios (ARR) [95% confidence intervals (95% CI)] were 1.60 (1.28–2.00) and 10.42 (5.78–18.80), respectively. HCV coinfection was significantly associated with increased all-cause (ARR 1.43, 95% CI 1.15–1.76) and liver-related mortality (ARR 6.20, 95% CI 3.31–11.60). Neither HBV nor HCV coinfection were associated with increased AIDS-related mortality: ARRs (95% CI) 1.07 (0.63–1.83) and 0.40 (0.20–0.81), respectively. The increased rate of all-cause and liver-related mortality among hepatitis-coinfected individuals in this HIV-positive cohort highlights the need for primary prevention and access to effective hepatitis treatment for HIV-positive individuals.

29 September 2013 in Journal of Antimicrobial Chemotherapy
Verified
Journal Article
Open access
PDF file
FSFred S. Sarfo
Fred S. Sarfo
YZYuan Zhang
Yuan Zhang
DEDeirdre Egan
Deirdre Egan
LTLambert A. Tetteh
Lambert A. Tetteh
RPRichard Odame Phillips
Richard Odame Phillips
DCDavid R. Chadwick
David R. Chadwick
Efavirenz is widely used in first-line antiretroviral therapy in sub-Saharan Africa. However, exposure to efavirenz shows marked interindividual variability that is genetically mediated with potential for important pharmacodynamic consequences. The aims of this study were to assess the frequencies of CYP2B6, CYP2A6, UGT2B7 and CAR single nucleotide polymorphisms (SNPs) and their impact on plasma efavirenz concentration and clinical/immunological responses in Ghanaian patients. Genomic DNA from 800 HIV-infected patients was genotyped for selected SNPs by real-time PCR-based allelic discrimination. Mid-dose plasma efavirenz concentrations were measured for 521 patients using HPLC with UV detection. Clinical outcomes in 299 patients on efavirenz were retrospectively assessed. Univariate and multivariate linear regression were performed using best subset selection. Time-to-event outcomes were analysed using a Cox proportional hazards regression model. The variant allele frequencies for CYP2B6 516G>T (rs3745274), CYP2B6 983T>C (rs28399499), CYP2A6 −48T>G (CYP2B6*9B; rs28399433), UGT2B7 802C>T (UGT2B7*2; rs7439366), UGT2B7 735A>G (UGT2B7*1c; rs28365062) and CAR 540C>T (rs2307424) were 48%, 4%, 3%, 23%, 15% and 7%, respectively. CYP2B6 516G>T, CYP2B6 983T>C and CYP2A6 −48T>G were associated with significantly elevated efavirenz concentrations. A trend towards association between plasma efavirenz concentration and CAR 540C>T was observed. CYP2B6 516G homozygosity was associated with immunological failure [adjusted hazards ratio compared with T homozygosity, 1.70 (1.04–2.76); P = 0.03]. CYP2B6 and CYP2A6 SNPs were associated with higher plasma efavirenz concentrations due to reduction in major and minor phase I routes of elimination, respectively. Further prospective studies are needed to validate the pharmacodynamic correlates of these polymorphisms in this population.

1 December 2015 in BMC Nephrology
Verified
Journal Article
Open access
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DCDavid R. Chadwick
David R. Chadwick
FSFred S. Sarfo
Fred S. Sarfo
EKElaine S. M. Kirk
Elaine S. M. Kirk
DODorcas Owusu
Dorcas Owusu
GBGeorge Bedu-Addo
George Bedu-Addo
RPRichard Odame Phillips
Richard Odame Phillips
HIV infection is associated with increased risk of renal dysfunction, including tubular dysfunction (TD) related to antiretroviral therapy (ART). Tenofovir disoproxil fumarate (TDF) is becoming available for ART in sub-Saharan Africa, although data on its long-term safety there is limited. We aimed to study the prevalence of HIV-associated renal dysfunction in Ghana and explore associations between proteinuria or TD and potential risk factors, including TDF use. A single-centre cross-sectional observational study of patients taking ART was undertaken. Creatinine clearance (CrCl) was calculated and proteinuria detected with dipsticks. Spot urinary albumin and protein:creatinine ratios (uACR/uPCR) were measured and further evidence of TD (defined as having two or more characteristic features) sought. Logistic regression analysis identified factors associated with proteinuria or TD. In 330 patients, of whom 101 were taking TDF (median 20 months), the prevalence of CrCl < 60ml/min/1.73m2, dipstick proteinuria and TD was 7 %, 37 % and 15 %. Factors associated with proteinuria were baseline CD4-count [aOR 0.86/100 cell increment (95 % CI, 0.74–0.99)] and TDF use [aOR 2.74 (95 % CI, 1.38–5.43)]. The only factor associated with TD was TDF use [aOR 3.43 (95 % CI, 1.10–10.69)]. In a subset with uPCR measurements, uPCRs were significantly higher in patients taking TDF than those on other drugs (10.8 vs. 5.7 mg/mmol, p < 0.001), and urinary albuin:protein ratios significantly lower (0.24 vs. 0.58, p < 0.001). Both proteinuria and TD are common and associated with TDF use in Ghana. Further longitudinal studies to determine whether proteinuria, TD or TDF use are linked to progressive decline in renal function or other adverse outcomes are needed in Africa.

3 September 2013 in Journal of Antimicrobial Chemotherapy
Verified
Journal Article
Open access
PDF file
FSFred S. Sarfo
Fred S. Sarfo
MSMaame Anima Sarfo
Maame Anima Sarfo
AKAdetayo Kasim
Adetayo Kasim
RPRichard Odame Phillips
Richard Odame Phillips
MBMark Booth
Mark Booth
DCDavid R. Chadwick
David R. Chadwick
Information on the long-term effectiveness and tolerability of efavirenz- or nevirapine-based antiretroviral therapy (ART) in Africa is lacking. The primary objective of this retrospective observational study was to compare the long-term clinical and immunological outcomes of efavirenz- versus nevirapine-based first-line ART in a large government clinic in Ghana. The main outcomes were AIDS, death, ART-related toxicity, discontinuation of ART and a composite endpoint of death, AIDS or ART discontinuation. These time-to-event outcomes were compared using a Cox proportional hazards regression model. CD4 counts on ART were compared using a mixed-effects model. A total of 3990 patients started non-nucleoside reverse transcriptase inhibitor (NNRTI)-based ART between 2004 and 2010, of which 2369 (59%) were on efavirenz. No significant differences were apparent between each NNRTI for subsequent risk of AIDS, death or the composite of treatment failure; however, stavudine use was independently associated with an increased risk of death [adjusted hazard ratio (HR) 1.60 (95% CI: 1.21–2.11)]. There was an increased risk of early toxicity with nevirapine leading to discontinuation [adjusted HR 1.53 (95% CI: 1.23–1.97)], mostly due to excess skin rashes in the first 2 months of treatment; however, overall discontinuation rates were low. There was no difference in the long-term effectiveness of efavirenz- and nevirapine-based ART in this population; however, patients initiating nevirapine were more likely to develop early toxicity and discontinue this drug. The excess mortality observed in patients taking stavudine is of concern and should prompt increased efforts to replace it with alternative antiretroviral drugs in developing countries.