Key publications
Rodgers LR, Streeter AJ, Lin N, Hamilton W, Henley WE (2021). Impact of influenza vaccination on amoxicillin prescriptions in older adults: a retrospective cohort study using primary care data.
PLOS ONE,
16(1), e0246156-e0246156.
Abstract:
Impact of influenza vaccination on amoxicillin prescriptions in older adults: a retrospective cohort study using primary care data
Background
Bacterial infections of the upper and lower respiratory tract are a frequent complication of influenza and contribute to the widespread use of antibiotics. Influenza vaccination may help reduce both appropriate and inappropriate prescribing of antibiotics. Electronic health records provide a rich source of information for assessing secondary effects of influenza vaccination.
Methods
We conducted a retrospective study to estimate effects of influenza vaccine on antibiotic (amoxicillin) prescription in the elderly based on data from the Clinical Practice Research Datalink. The introduction of UK policy to recommend the influenza vaccine to older adults in 2000 led to a substantial increase in uptake, creating a natural experiment. of 259,753 eligible patients that were unvaccinated in 1999 and aged≥65y by January 2000, 88,519 patients received influenza vaccination in 2000. These were propensity score matched 1:1 to unvaccinated patients. Time-to-amoxicillin was analysed using the Prior Event Rate Ratio (PERR) Pairwise method to address bias from time-invariant measured and unmeasured confounders. A simulation study and negative control outcome were used to help strengthen the validity of results.
Results
Compared to unvaccinated patients, those from the vaccinated group were more likely to be prescribed amoxicillin in the year prior to vaccination: hazard ratio (HR) 1.90 (95% confidence interval 1.83, 1.98). Following vaccination, the vaccinated group were again more likely to be prescribed amoxicillin, HR 1.64 (1.58,1.71). After adjusting for prior differences between the two groups using PERR Pairwise, overall vaccine effectiveness was 0.86 (0.81, 0.92). Additional analyses suggested that provided data meet the PERR assumptions, these estimates were robust.
Conclusions
Once differences between groups were taken into account, influenza vaccine had a beneficial effect, lowering the frequency of amoxicillin prescribing in the vaccinated group. Ensuring successful implementation of national programmes of vaccinating older adults against influenza may help contribute to reducing antibiotic resistance.
Abstract.
Full text.
Greiner RS, Hill A, Knight BA, McDonald T, Shields B, Jones AG, Rodgers LR (2020). HbA(1c) thresholds have substantial impact in screening procedures for those at risk of developing type 2 diabetes.
Author URL.
Rodgers LR, Dennis JM, Shields BM, Mounce L, Fisher I, Hattersley AT, Henley WE (2020). Prior event rate ratio adjustment produced estimates consistent with randomized trial: a diabetes case study.
Journal of Clinical Epidemiology,
122, 78-86.
Full text.
Farmer AJ, Rodgers LR, Lonergan M, Shields B, Weedon MN, Donnelly L, Holman RR, Pearson ER, Hattersley AT (2016). Adherence to Oral Glucose-Lowering Therapies and Associations with 1-Year HbA1c: a Retrospective Cohort Analysis in a Large Primary Care Database.
Diabetes Care,
39(2), 258-263.
Abstract:
Adherence to Oral Glucose-Lowering Therapies and Associations with 1-Year HbA1c: a Retrospective Cohort Analysis in a Large Primary Care Database.
OBJECTIVE: the impact of taking oral glucose-lowering medicines intermittently, rather than as recommended, is unclear. We conducted a retrospective cohort study using community-acquired U.K. clinical data (Clinical Practice Research Database [CPRD] and GoDARTS database) to examine the prevalence of nonadherence to treatment for type 2 diabetes and investigate its potential impact on HbA1c reduction stratified by type of glucose-lowering medication. RESEARCH DESIGN AND METHODS: Data were extracted for patients treated between 2004 and 2014 who were newly prescribed metformin, sulfonylurea, thiazolidinedione, or dipeptidyl peptidase 4 inhibitors and who continued to obtain prescriptions over 1 year. Cohorts were defined by prescribed medication type, and good adherence was defined as a medication possession ratio ≥0.8. Linear regression was used to determine potential associations between adherence and 1-year baseline-adjusted HbA1c reduction. RESULTS: in CPRD and GoDARTS, 13% and 15% of patients, respectively, were nonadherent. Proportions of nonadherent patients varied by the oral glucose-lowering treatment prescribed (range 8.6% [thiazolidinedione] to 18.8% [metformin]). Nonadherent, compared with adherent, patients had a smaller HbA1c reduction (0.4% [4.4 mmol/mol] and 0.46% [5.0 mmol/mol] for CPRD and GoDARTs, respectively). Difference in HbA1c response for adherent compared with nonadherent patients varied by drug (range 0.38% [4.1 mmol/mol] to 0.75% [8.2 mmol/mol] lower in adherent group). Decreasing levels of adherence were consistently associated with a smaller reduction in HbA1c. CONCLUSIONS: Reduced medication adherence for commonly used glucose-lowering therapies among patients persisting with treatment is associated with smaller HbA1c reductions compared with those taking treatment as recommended. Differences observed in HbA1c responses to glucose-lowering treatments may be explained in part by their intermittent use.
Abstract.
Author URL.
Full text.
Matthews JNS, Henderson R, Farewell DM, Ho W-K, Rodgers LR (2014). Dropout in crossover and longitudinal studies: is complete case so bad?.
Stat Methods Med Res,
23(1), 60-73.
Abstract:
Dropout in crossover and longitudinal studies: is complete case so bad?
We discuss inference for longitudinal clinical trials subject to possibly informative dropout. A selection of available methods is reviewed for the simple case of trials with two timepoints. Using data from two such clinical trials, each with two treatments, we demonstrate that different analysis methods can at times lead to quite different conclusions from the same data. We investigate properties of complete-case estimators for the type of trials considered, with emphasis on interpretation and meaning of parameters. We contrast longitudinal and crossover designs and argue that for crossover studies there are often good reasons to prefer a complete case analysis. More generally, we suggest that there is merit in an approach in which no untestable assumptions are made. Such an approach would combine a dropout analysis, an analysis of complete-case data only, and a careful statement of justified conclusions.
Abstract.
Author URL.
Rotheray S, Racey D, Rodgers L, Mcgilloway S, Berry V, Ford T (2014). Innovations in Practice: Further evidence on the effectiveness of the strengths and difficulties added value score as an outcome measure for child and adolescent services. Child and Adolescent Mental Health
Publications by year
In Press
Rodgers LR, weedon MN, Henley WE, Hattersley AT, Shields BM (In Press). Cohort profile for the MASTERMIND study: Using the Clinical Practice Research Datalink (CPRD) to investigate stratification of response to treatment in patients with Type 2 diabetes.
BMJ Open Full text.
Dennis J, Henley W, Weedon M, Lonergan M, Rodgers L, Jones A, Hamilton W, Sattar N, Janmohamed S, Holman R, et al (In Press). Sex and BMI alter the benefits and risks of sulfonylureas and thiazolidinediones in type 2 diabetes: a framework for evaluating stratification using routine clinical and individual trial data.
Diabetes Care Full text.
McGovern A, Shields B, Hattersley A, Pearson E, Jones AG (In Press). What to do with diabetes therapies when HbA1c lowering is inadequate: add, switch, or continue? a MASTERMIND study.
BMC Medicine Full text.
2021
Rodgers LR, Streeter AJ, Lin N, Hamilton W, Henley WE (2021). Impact of influenza vaccination on amoxicillin prescriptions in older adults: a retrospective cohort study using primary care data.
PLOS ONE,
16(1), e0246156-e0246156.
Abstract:
Impact of influenza vaccination on amoxicillin prescriptions in older adults: a retrospective cohort study using primary care data
Background
Bacterial infections of the upper and lower respiratory tract are a frequent complication of influenza and contribute to the widespread use of antibiotics. Influenza vaccination may help reduce both appropriate and inappropriate prescribing of antibiotics. Electronic health records provide a rich source of information for assessing secondary effects of influenza vaccination.
Methods
We conducted a retrospective study to estimate effects of influenza vaccine on antibiotic (amoxicillin) prescription in the elderly based on data from the Clinical Practice Research Datalink. The introduction of UK policy to recommend the influenza vaccine to older adults in 2000 led to a substantial increase in uptake, creating a natural experiment. of 259,753 eligible patients that were unvaccinated in 1999 and aged≥65y by January 2000, 88,519 patients received influenza vaccination in 2000. These were propensity score matched 1:1 to unvaccinated patients. Time-to-amoxicillin was analysed using the Prior Event Rate Ratio (PERR) Pairwise method to address bias from time-invariant measured and unmeasured confounders. A simulation study and negative control outcome were used to help strengthen the validity of results.
Results
Compared to unvaccinated patients, those from the vaccinated group were more likely to be prescribed amoxicillin in the year prior to vaccination: hazard ratio (HR) 1.90 (95% confidence interval 1.83, 1.98). Following vaccination, the vaccinated group were again more likely to be prescribed amoxicillin, HR 1.64 (1.58,1.71). After adjusting for prior differences between the two groups using PERR Pairwise, overall vaccine effectiveness was 0.86 (0.81, 0.92). Additional analyses suggested that provided data meet the PERR assumptions, these estimates were robust.
Conclusions
Once differences between groups were taken into account, influenza vaccine had a beneficial effect, lowering the frequency of amoxicillin prescribing in the vaccinated group. Ensuring successful implementation of national programmes of vaccinating older adults against influenza may help contribute to reducing antibiotic resistance.
Abstract.
Full text.
2020
Greiner RS, Hill A, Knight BA, McDonald T, Shields B, Jones AG, Rodgers LR (2020). HbA(1c) thresholds have substantial impact in screening procedures for those at risk of developing type 2 diabetes.
Author URL.
Rodgers LR, Dennis JM, Shields BM, Mounce L, Fisher I, Hattersley AT, Henley WE (2020). Prior event rate ratio adjustment produced estimates consistent with randomized trial: a diabetes case study.
Journal of Clinical Epidemiology,
122, 78-86.
Full text.
2019
Rodgers LR, Hill AV, Hattersley AT, McDonald TJ, Jones A, Shields BM (2019). Time to revise HbA(1c) thresholds for diabetes risk? Evidence from a prospective study of 4010 participants.
Author URL.
2018
Dennis JM, Henley WE, Weedon MN, Rodgers LR, Jones AG, Pearson ER, Hattersley AT, Shields BM (2018). Are the new drugs better? Changing UK prescribing of Type 2 diabetes medications and effects on HbA1c and weight, 2010 to 2016.
Author URL.
Full text.
Kimmitt RA, Dennis JM, Weedon M, Rodgers LR, Jones AG, Pearson ER, Hattersley AT, Oram RA, Shields BM (2018). Higher estimated glomerular filtration rate (eGFR) is associated with improved glycaemic response to sodium-glucose co-transporter-2 (SGLT2) inhibitors in patients with Type 2 diabetes and normal renal function: a MASTERMIND study.
Author URL.
Dennis J, Shields B, Hill A, Knight B, McDonald T, Rodgers L, Weedon M, Henley W, Sattar N, Holman R, et al (2018). Precision medicine in Type 2 diabetes: Clinical markers of insulin resistance are associated with altered short- and long-term glycemic response to DPP-4 inhibitor therapy.
Diabetes Care Full text.
Shakweh EY, Shields BM, Angwin CD, Rodgers LR, McDonald TJ, Pearson ER, Hattersley AT, Jones AG, Consortium M (2018). Precision medicine in Type 2 diabetes: is variation in response to sitagliptin and gliclazide therapy related to drug levels?.
Author URL.
2017
Dennis JM, Henley WE, Weedon MN, Lonergan M, Rodgers LR, Jones AG, Sattar NA, Holman RR, Pearson ER, Hattersley AT, et al (2017). A calculator to predict durability of HbA(1c) response with DPP4 inhibitors, sulfonylureas and thiazolidinediones: a MASTERMIND precision medicine study.
Author URL.
Dennis JM, Shields BM, Henley WE, Knight BA, McDonald TJ, Hill AV, Weedon MN, Rodgers LR, Hattersley AT, Jones AG, et al (2017). Clinical markers of insulin resistance predict reduced glycaemic response with DPP4-inhibitors: a MASTERMIND stratified medicine study.
Author URL.
Dennis JM, Henley WE, Weedon M, Lonergan M, Jones AG, Sattar N, Holman RR, Pearson ER, Hattersley AT, Shields BM, et al (2017). Development of an online risk calculator to predict durability of good glycaemic control with sulfonylurea and thiazolidinedione therapy: a MASTERMIND stratified medicine study.
Author URL.
Allen K, Marlow R, Edwards V, Parker C, Rodgers L, Ukoumunne O, Chan Seem E, Hayes R, Price A, Ford T, et al (2017). ‘How I feel About My School’: the construction and validation of a measure of wellbeing at school for primary school children.
Clinical Child Psychology and Psychiatry,
55 Full text.
2016
Farmer AJ, Rodgers LR, Lonergan M, Shields B, Weedon MN, Donnelly L, Holman RR, Pearson ER, Hattersley AT (2016). Adherence to Oral Glucose-Lowering Therapies and Associations with 1-Year HbA1c: a Retrospective Cohort Analysis in a Large Primary Care Database.
Diabetes Care,
39(2), 258-263.
Abstract:
Adherence to Oral Glucose-Lowering Therapies and Associations with 1-Year HbA1c: a Retrospective Cohort Analysis in a Large Primary Care Database.
OBJECTIVE: the impact of taking oral glucose-lowering medicines intermittently, rather than as recommended, is unclear. We conducted a retrospective cohort study using community-acquired U.K. clinical data (Clinical Practice Research Database [CPRD] and GoDARTS database) to examine the prevalence of nonadherence to treatment for type 2 diabetes and investigate its potential impact on HbA1c reduction stratified by type of glucose-lowering medication. RESEARCH DESIGN AND METHODS: Data were extracted for patients treated between 2004 and 2014 who were newly prescribed metformin, sulfonylurea, thiazolidinedione, or dipeptidyl peptidase 4 inhibitors and who continued to obtain prescriptions over 1 year. Cohorts were defined by prescribed medication type, and good adherence was defined as a medication possession ratio ≥0.8. Linear regression was used to determine potential associations between adherence and 1-year baseline-adjusted HbA1c reduction. RESULTS: in CPRD and GoDARTS, 13% and 15% of patients, respectively, were nonadherent. Proportions of nonadherent patients varied by the oral glucose-lowering treatment prescribed (range 8.6% [thiazolidinedione] to 18.8% [metformin]). Nonadherent, compared with adherent, patients had a smaller HbA1c reduction (0.4% [4.4 mmol/mol] and 0.46% [5.0 mmol/mol] for CPRD and GoDARTs, respectively). Difference in HbA1c response for adherent compared with nonadherent patients varied by drug (range 0.38% [4.1 mmol/mol] to 0.75% [8.2 mmol/mol] lower in adherent group). Decreasing levels of adherence were consistently associated with a smaller reduction in HbA1c. CONCLUSIONS: Reduced medication adherence for commonly used glucose-lowering therapies among patients persisting with treatment is associated with smaller HbA1c reductions compared with those taking treatment as recommended. Differences observed in HbA1c responses to glucose-lowering treatments may be explained in part by their intermittent use.
Abstract.
Author URL.
Full text.
Shields BM, Dennis JM, Henley W, Weedon M, Lonergan M, Rodgers L, Jones AG, Holman RR, Pearson ER, Hattersley AT, et al (2016). Personalising therapy in type 2 diabetes: the effect of BMI and sex on glycaemic response and side effects to sulphonylureas and thiazolidinediones.
Author URL.
Dennis JM, Henley WE, Weedon MN, Lonergan M, Rodgers LR, Jones AG, Holman RR, Pearson ER, Hattersley AT, Shields BM, et al (2016). Personalizing Therapy in Type 2 Diabetes: the Effect of BMI and Gender on Response and Side Effects to Sulfonylureas and Thiazolidinediones.
Author URL.
2015
Dennis JM, Hattersley AT, Weedon M, Angwin C, Rodgers L, Pearson ER, Henley WE, Shields BM (2015). Development of oedema is associated with an improved glycaemic response in patients initiating thiazolidinediones: a MASTERMIND study.
Author URL.
Full text.
Rodgers LR, Pearson ER, Hammersley S, Angwin CD, JMcDonald T, Shields BM, Hattersley AT, Jones AG, Consortium MASTERMIND (2015). Patients with a high fasting glucose respond better to sulphonylureas than dipeptidyl peptidase IV (DPP-IV) inhibitors: a MASTERMIND study.
Author URL.
Rodgers LR, Pearson ER, Angwin CD, Hammersley S, McDonald TJ, Shields BM, Hattersley AT, Jones AG, Consortium M (2015). Response to glucose lowering therapy can be assessed by a brief period of treatment withdrawal: a MASTERMIND study.
Author URL.
Jones AG, Lonergan M, Rodgers LR, Henley WE, Pearson EW, Hattersley AT, Shields BM, Consortium M (2015). Studies of diabetes treatment stratification should correct for baseline HbA1c: a MASTERMIND study.
Author URL.
Farmer AJ, Rodgers LR, Lonergan M, Weedon MN, Shields B, Donnelly L, Holman RR, Pearson ER, Hattersley AT, Consortium M, et al (2015). Taking Less Oral Glucose-Lowering Treatment than Prescribed is Associated with a Reduced Improvement in 12-Month HbA1c: a Retrospective MASTERMIND Cohort Analysis Stratified by Type of Treatment.
Author URL.
2014
Matthews JNS, Henderson R, Farewell DM, Ho W-K, Rodgers LR (2014). Dropout in crossover and longitudinal studies: is complete case so bad?.
Stat Methods Med Res,
23(1), 60-73.
Abstract:
Dropout in crossover and longitudinal studies: is complete case so bad?
We discuss inference for longitudinal clinical trials subject to possibly informative dropout. A selection of available methods is reviewed for the simple case of trials with two timepoints. Using data from two such clinical trials, each with two treatments, we demonstrate that different analysis methods can at times lead to quite different conclusions from the same data. We investigate properties of complete-case estimators for the type of trials considered, with emphasis on interpretation and meaning of parameters. We contrast longitudinal and crossover designs and argue that for crossover studies there are often good reasons to prefer a complete case analysis. More generally, we suggest that there is merit in an approach in which no untestable assumptions are made. Such an approach would combine a dropout analysis, an analysis of complete-case data only, and a careful statement of justified conclusions.
Abstract.
Author URL.
Abbott RA, Whear R, Rodgers LR, Bethel A, Thompson Coon J, Kuyken W, Stein K, Dickens C (2014). Effectiveness of mindfulness-based stress reduction and mindfulness based cognitive therapy in vascular disease: a systematic review and meta-analysis of randomised controlled trials.
Journal of Psychosomatic Research,
76(5), 341-351.
Abstract:
Effectiveness of mindfulness-based stress reduction and mindfulness based cognitive therapy in vascular disease: a systematic review and meta-analysis of randomised controlled trials
Objective: to determine the effectiveness of mindfulness-based stress reduction (MBSR) and mindfulness-based cognitive therapy (MBCT) on psychological and physical outcomes for people with vascular disease. Design: Systematic review and meta-analysis of randomised controlled trials. Data sources: AMED, CINAHL, EMBASE, British Nursing Index, Medline, Web of Science, PsycINFO, Cochrane Database of Systematic Reviews, Central, Social Sciences Citation Index, Social Policy and Practice, and HMIC from inception to January 2013. Review methods: Articles were screened for inclusion independently by two reviewers. Data extraction and quality appraisal were performed by one reviewer and checked by a second with discrepancies resolved by discussion with a third if necessary. Random-effects meta-analyses were performed. Results: Nine articles (from eight original randomised controlled trials) met eligibility criteria and were included in the final review. In total, 578 participants were enrolled across the trials, with participants presenting with prehypertension/hypertension (n. = 3 trials), type 1 or 2 diabetes (n. = 2), heart disease (n. = 2) and stroke (n. = 1). Meta-analyses, using standardised mean differences, showed evidence of reductions in stress (- 0.36; 95% CI - 0.67 to - 0.09; p. = 0.01), depression (- 0.35; 95% CI - 0.53 to - 0.16; p. = 0.003) and anxiety (- 0.50; 95% CI - 0.70 to - 0.29; p. < 0.001). Effects on physical outcomes (blood pressure, albuminuria, stress hormones) were mixed. Conclusion: Whilst populations with vascular disease appear to derive a range of psychological benefits from MBSR/MBCT intervention, the effects on physical parameters of disease are not yet established. More robust studies, with longer term follow-up, are required to ascertain full effectiveness of such intervention. © 2014.
Abstract.
Rotheray S, Racey D, Rodgers L, Mcgilloway S, Berry V, Ford T (2014). Innovations in Practice: Further evidence on the effectiveness of the strengths and difficulties added value score as an outcome measure for child and adolescent services. Child and Adolescent Mental Health
Rotheray S, Racey D, Rodgers L, Mcgilloway S, Berry V, Ford T (2014). Innovations in Practice: Further evidence on the effectiveness of the strengths and difficulties added value score as an outcome measure for child and adolescent services.
Child and Adolescent Mental Health,
19(4), 270-273.
Abstract:
Innovations in Practice: Further evidence on the effectiveness of the strengths and difficulties added value score as an outcome measure for child and adolescent services
Background: the Strengths and Difficulties Added Value Score (SDQ AVS) uses a large epidemiological study to predict follow-up parental SDQ scores for the evaluation of routine outcomes. Method: We tested the prediction of the SDQ AVS derived from a national population survey separately on scores for the waiting list control and intervention groups in a randomised controlled trial. If the SDQ AVS is to be clinically useful, it needs to function as expected across different populations. Results: in the control arm, the SDQ AVS predicted an effect size of 0.15 (95% CI -0.01-0.30) compared to an expected effect size of 0, as the children in this arm received no treatment. In the experimental arm, the SDQ AVS predicted an effect size of 0.62 (95% CI 0.42-0.83) compared to the study effect size of 0.53. Change scores overestimated the effect size in both arms (control 0.50 95% CI 0.34-0.66, intervention 0.85 95% CI 0.66-1.04). Conclusion: Our findings suggest that the SDQ AVS adjusts for spontaneous improvement, regression to the mean and attenuation.
Abstract.
Russell G, Rodgers LR, Ukoumunne OC, Ford T (2014). Prevalence of parent-reported ASD and ADHD in the UK: findings from the Millennium Cohort Study.
J Autism Dev Disord,
44(1), 31-40.
Abstract:
Prevalence of parent-reported ASD and ADHD in the UK: findings from the Millennium Cohort Study.
The UK prevalence of parent-reported autism spectrum disorder (ASD) and attention deficit/hyperactivity disorder (ADHD) were estimated from the Millennium Cohort Study. Case definition was if a doctor or health care professional had ever told parents that their child had ASD and/or ADHD. Data were collected in 2008/2009 for 14,043 children. 1.7 % of children were reported as having ASD (95 % CI 1.4-2.0) at mean age 7.2 years (SD = 0.2; range = 6.3-8.2). 1.4 % reportedly had ADHD (95 % CI 1.2-1.7), and 0.3 % had both ASD and ADHD (95 % CI 0.2-0.5). After adjusting for socio-economic disadvantage, only male sex (p
Abstract.
Author URL.
Thompson H, Reville MC, Price A, Reynolds L, Rodgers LR, Ford T (2014). The Quality of Life scale for Children (QoL-C).
Journal of Children's Services: research informing policy and practice,
9, 4-17.
Full text.
2013
Puch-Solis R, Rodgers L, Mazumder A, Pope S, Evett I, Curran J, Balding D (2013). Evaluating forensic DNA profiles using peak heights, allowing for multiple donors, allelic dropout and stutters.
Forensic Science International: Genetics,
7(5), 555-563.
Abstract:
Evaluating forensic DNA profiles using peak heights, allowing for multiple donors, allelic dropout and stutters
Increases in the sensitivity of DNA profiling technology now allow profiles to be obtained from smaller and more degraded DNA samples than was previously possible. The resulting profiles can be highly informative, but the subjective elements in the interpretation make it problematic to achieve the valid and efficient evaluation of evidential strength required in criminal cases. The problems arise from stochastic phenomena such as "dropout" (absence of an allele in the profile that is present in the underlying DNA) and experimental artefacts such as "stutter" that can generate peaks of ambiguous allelic status. Currently in the UK, evidential strength evaluation uses an approach in which the complex signals in the DNA profiles are interpreted in a semi-manual fashion by trained experts aided by a set of guidelines, but also relying substantially on professional judgment. We introduce a statistical model to calculate likelihood ratios for evaluating DNA evidence arising from multiple known and unknown contributors that allows for such stochastic phenomena by incorporating peak heights. Efficient use of peak heights allows for more crime scene profiles to be reported to courts than is currently possible. The model parameters are estimated from experimental data incorporating multiple sources of variability in the profiling system. We report and analyse experimental results from the SGMPlus system, run at 28 amplification cycles with no enhancements, currently used in the UK. Our methods are readily adapted to other DNA profiling systems provided that the experimental data for the parameter estimation is available. © 2013 Elsevier Ireland Ltd. All rights reserved.
Abstract.
Russell G, Rodgers LR, Ford T (2013). The Strengths and Difficulties Questionnaire as a predictor of parent-reported diagnosis of Autism Spectrum Disorder and Attention Deficit Hyperactivity Disorder.
PLOS ONE Full text.
2012
Ho WK, Matthews JNS, Henderson R, Farewell D, Rodgers LR (2012). Dropouts in the AB/BA crossover design.
Stat Med,
31(16), 1675-1687.
Abstract:
Dropouts in the AB/BA crossover design.
Missing data arise in crossover trials, as they do in any form of clinical trial. Several papers have addressed the problems that missing data create, although almost all of these assume that the probability that a planned observation is missing does not depend on the value that would have been observed; that is, the data are missing at random (MAR). In many applications, this assumption is likely to be untenable; in which case, the data are missing not at random (MNAR). We investigate the effect on estimates of the treatment effect that assume data are MAR when data are actually MNAR. We also propose using the assumption of no carryover treatment effect, which is usually required for this design, to permit the estimation of a treatment effect when data are MNAR. The results are applied to a trial comparing two treatments for neuropathic pain and show that the estimate of treatment effect is sensitive to the assumption of MAR.
Abstract.
Author URL.
Puch-Solis R, Rodgers LR (2012). Improvements in and relating to the consideration of evidence [Patent: PCT/GB2011/050470, CA2796023A1, EP2545480A1, US20130173172].
2009
Puch-Solis R, Rodgers L, Pope S, Evett I (2009). Assigning weight of DNA evidence using a continuous model that takes into account stutter and dropout.
Forensic Science International: Genetics Supplement Series,
2(1), 460-461.
Abstract:
Assigning weight of DNA evidence using a continuous model that takes into account stutter and dropout
Currently practitioners use a binary approach to DNA profile interpretation. However it is recognised that methods considering peak heights/areas are preferable. In this paper we give an example that shows how peaks in stutter position and preferential amplification can be included in a calculation of likelihood ratios using a model that takes into account peak heights. © 2009 Elsevier Ireland Ltd.
Abstract.
Cooke NJ, Rodgers L, Rawlings D, McCaskie AW, Holland JP (2009). Bone density of the femoral neck following Birmingham hip resurfacing a 2-year prospective study in 27 hips.
Acta Orthopaedica,
80(6), 660-665.
Abstract:
Bone density of the femoral neck following Birmingham hip resurfacing a 2-year prospective study in 27 hips
Background Resurfacing is a popular alternative to a standard hip replacement in young arthritic patients. Despite bone preservation around the femoral component, there is little information regarding the bone quality. Patients and methods 32 patients underwent consecutive Birmingham hip resurfacing. The bone density of the femoral neck was measured preoperatively and then at 6 weeks, 3 months, 1 year, and 2 years. The femoral neck was divided into regions of interest. Results were available for 27 hips in 26 patients. Results the overall femoral neck bone density showed a trend towards a decrease at 6 weeks and 3 months but returned to the preoperative level at 1 year, and was maintained at 2 years. The combined superior regions of the neck showed a statistically significant decrease in bone density at 6 weeks and 3 months. This returned to preoperative levels at 1 year and was maintained at 2 years. Interpretation Bone density appears to decrease at 6 weeks and 3 months, suggesting that care is necessary until bone density begins to recover. © Nordic Orthopedic Federation.
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2008
Rodgers LR (2008). Analysis of treatment effect in crossover designs with missing data [PhD Thesis].