Publications
288 results found
Fletcher JN, Smyth RL, Thomas HM, et al., 1997, Respiratory syncytial virus genotypes and disease severity among children in hospital, ARCHIVES OF DISEASE IN CHILDHOOD, Vol: 77, Pages: 508-511, ISSN: 0003-9888
- Author Web Link
- Cite
- Citations: 30
Fayers PM, Ashby D, Parmar MKB, 1997, Tutorial in biostatistics Bayesian data monitoring in clinical trials, STATISTICS IN MEDICINE, Vol: 16, Pages: 1413-1430, ISSN: 0277-6715
- Author Web Link
- Cite
- Citations: 85
Fayers PM, Ashby D, Parmar MKB, 1997, Bayesian data monitoring in clinical trials, Statistics in Medicine, Vol: 16, Pages: 1413-1430, ISSN: 0277-6715
Many clinical trials organizations use regular interim analyses to monitor the accruing results in large clinical trials. In disease areas such as cancer, where survival is usually a major outcome variable, ethical considerations may lead to a stipulated requirement for data monitoring of mortality. This monitoring has frequently taken the form of limiting interim analyses to be few in number, and specifying an extreme p-value of, for example, p < 0.001 or p < 0.01 as grounds for early termination of the trial. Group-sequential methods are also used. However, none of these approaches formally assesses the impact that the results of a clinical trial may have upon clinical practice. Thus a trial might be terminated early because of apparent treatment benefits, but might fail to influence sceptical clinicians to modify their future treatment policy. We discuss the application of Bayesian methods, including the use of uninformative, sceptical and enthusiastic priors, and demonstrate that the necessary calculations are both straightforward to perform and easy to interpret statistically and clinically. Methods are illustrated with interim analyses of a clinical trial in oesophageal cancer.
Cheng K, Ashby D, Smyth R, 1997, Ursodeoxycholic acid in cystic fibrosis-related liver disease: A systematic review, JOURNAL OF THE ROYAL SOCIETY OF MEDICINE, Vol: 90, Pages: 6-12, ISSN: 0141-0768
- Author Web Link
- Cite
- Citations: 10
Harrison JE, Ashby D, Lennon MA, 1996, An analysis of papers published in the British and European Journals of Orthodontics., Br J Orthod, Vol: 23, Pages: 203-209, ISSN: 0301-228X
UNLABELLED: The aims of this study were to assess the type, subject, setting and methods of papers published in British Journal of Orthodontics (BJO) and European Journal of Orthodontics (EJO) between 1989 and 1993 to allow all published randomized controlled trials (RCTs) to be identified and a comparison of the papers published in the journals to be made. A hand search of all papers published in BJO and EJO between 1989 and 1993 was performed, and the type, subject, setting, and methods of each paper were classified and recorded. Of the studies, 59.3 per cent related to clinical orthodontics, but only three RCTs were identified in each journal. This comprised 2.8 per cent of the clinical research papers which were analysed. The remaining studies used non-randomized controls or were uncontrolled. Significant differences were found between the type (P < 0.001), subject (P < 0.001), setting (P < 0.01) and methods (P < 0.05) of papers published in the two journals. Relatively more papers in BJO were case reports, clinical opinions and update articles, reported on orthodontic materials or assessed methods of measuring the outcome of treatment. Ninety per cent of papers in EJO reported the results of research projects and relatively more papers, than in BJO, were related to animal studies, and were laboratory based or epidemiological. OBJECTIVES: To identify all randomized controlled trials (RCTs) and compare papers published in two orthodontic journals. DESIGN: A retrospective, observational study. SETTING: The British Journal of Orthodontics (BJO) and European Journals of Orthodontics) (EJO). DATA SOURCE: Papers published between 1989 and 1993. METHOD: A hand search of all papers was performed. The type, subject, setting and methods of each paper were classified and recorded. RESULTS: 200 papers were identified in BJO and 275 in EJO. Six RCTs were identified which represents 2.8 per cent of clinical research papers. Significant differences were found betwe
Abrams K, Ashby D, Errington D, 1996, A Bayesian approach to Weibull survival models--application to a cancer clinical trial., Lifetime Data Anal, Vol: 2, Pages: 159-174, ISSN: 1380-7870
In this paper we outline a class of fully parametric proportional hazards models, in which the baseline hazard is assumed to be a power transform of the time scale, corresponding to assuming that survival times follow a Weibull distribution. Such a class of models allows for the possibility of time varying hazard rates, but assumes a constant hazard ratio. We outline how Bayesian inference proceeds for such a class of models using asymptotic approximations which require only the ability to maximize the joint log posterior density. We apply these models to a clinical trial to assess the efficacy of neutron therapy compared to conventional treatment for patients with tumours of the pelvic region. In this trial there was prior information about the log hazard ratio both in terms of elicited clinical beliefs and the results of previous studies. Finally, we consider a number of extensions to this class of models, in particular the use of alternative baseline functions, and the extension to multi-state data.
SMYTH RL, ASHBY D, OHEA U, et al., 1995, FIBROSING COLONOPATHY IN CYSTIC-FIBROSIS - RESULTS OF A CASE-CONTROL STUDY, LANCET, Vol: 346, Pages: 1247-1251, ISSN: 0099-5355
- Author Web Link
- Cite
- Citations: 110
ABRAMS K, ASHBY D, ERRINGTON D, 1994, SIMPLE BAYESIAN-ANALYSIS IN CLINICAL-TRIALS - A TUTORIAL, CONTROLLED CLINICAL TRIALS, Vol: 15, Pages: 349-359, ISSN: 0197-2456
- Author Web Link
- Cite
- Citations: 16
ALLEN N, AMES D, ASHBY D, et al., 1994, A BRIEF SENSITIVE SCREENING INSTRUMENT FOR DEPRESSION IN LATE-LIFE, AGE AND AGEING, Vol: 23, Pages: 213-218, ISSN: 0002-0729
- Author Web Link
- Cite
- Citations: 35
CURRIE P, ASHBY D, SALTISSI S, 1994, PROGNOSTIC VALUE OF AMBULATORY ST SEGMENT MONITORING COMPARED WITH EXERCISE TESTING AT 1-3 MONTHS AFTER ACUTE MYOCARDIAL-INFARCTION, EUROPEAN HEART JOURNAL, Vol: 15, Pages: 54-60, ISSN: 0195-668X
- Author Web Link
- Cite
- Citations: 4
LAWS DE, HASLETT R, ASHBY D, et al., 1994, AXIAL LENGTH BIOMETRY IN INFANTS WITH RETINOPATHY OF PREMATURITY, EYE, Vol: 8, Pages: 427-430, ISSN: 0950-222X
- Author Web Link
- Cite
- Citations: 52
ASHBY D, MACHIN D, 1993, STOPPING RULES, INTERIM ANALYSES AND DATA MONITORING COMMITTEES, BRITISH JOURNAL OF CANCER, Vol: 68, Pages: 1047-1050, ISSN: 0007-0920
- Author Web Link
- Cite
- Citations: 7
NISAR M, WILLIAMS CSD, ASHBY D, et al., 1993, TUBERCULIN TESTING IN RESIDENTIAL HOMES FOR THE ELDERLY, THORAX, Vol: 48, Pages: 1257-1260, ISSN: 0040-6376
- Author Web Link
- Cite
- Citations: 71
CURRIE P, ASHBY D, SALTISSI S, 1993, PROGNOSTIC-SIGNIFICANCE OF TRANSIENT MYOCARDIAL-ISCHEMIA ON AMBULATORY MONITORING AFTER ACUTE MYOCARDIAL-INFARCTION, AMERICAN JOURNAL OF CARDIOLOGY, Vol: 71, Pages: 773-777, ISSN: 0002-9149
- Author Web Link
- Cite
- Citations: 32
SHIELDS R, JENKINS SA, BAXTER JN, et al., 1992, A PROSPECTIVE RANDOMIZED CONTROLLED TRIAL COMPARING THE EFFICACY OF SOMATOSTATIN WITH INJECTION SCLEROTHERAPY IN THE CONTROL OF BLEEDING ESOPHAGEAL-VARICES, JOURNAL OF HEPATOLOGY, Vol: 16, Pages: 128-137, ISSN: 0168-8278
- Author Web Link
- Cite
- Citations: 105
AMES D, ASHBY D, FLICKER L, et al., 1992, JIM WHO - RECALL OF NATIONAL LEADERS BY ELDERLY PEOPLE IN 3 COUNTRIES, INTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Vol: 7, Pages: 437-442, ISSN: 0885-6230
- Author Web Link
- Cite
- Citations: 3
DAVIES PDO, NISAR M, WILLIAMS CSD, et al., 1992, RISK OF TUBERCULOSIS INFECTION IN RESIDENTIAL HOMES FOR THE ELDERLY, THORAX, Vol: 47, Pages: P228-P228, ISSN: 0040-6376
Shaw NJ, Pilling DW, Cooke RWI, et al., 1992, The chest radiograph and outcome in chronic lung disease of prematurity, Pediatric Reviews and Communications, Vol: 6, Pages: 257-261, ISSN: 0882-9225
- Cite
- Citations: 1
BLETTNER M, ASHBY D, 1992, POWER CALCULATION FOR COHORT STUDIES WITH IMPROVED ESTIMATION OF EXPECTED NUMBERS OF DEATHS, SOZIAL-UND PRAVENTIVMEDIZIN, Vol: 37, Pages: 13-21, ISSN: 0303-8408
- Author Web Link
- Cite
- Citations: 1
ASHBY D, AMES D, WEST CR, et al., 1991, PSYCHIATRIC MORBIDITY AS PREDICTOR OF MORTALITY FOR RESIDENTS OF LOCAL-AUTHORITY HOMES FOR THE ELDERLY, INTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Vol: 6, Pages: 567-575, ISSN: 0885-6230
- Author Web Link
- Cite
- Citations: 35
Bates T, 1991, The cyclotron saga continues., BMJ, Vol: 302, Pages: 1539-1540, ISSN: 0959-8138
ERRINGTON RD, ASHBY D, GORE SM, et al., 1991, HIGH-ENERGY NEUTRON TREATMENT FOR PELVIC CANCERS - STUDY STOPPED BECAUSE OF INCREASED MORTALITY, BRITISH MEDICAL JOURNAL, Vol: 302, Pages: 1045-1051, ISSN: 0959-8138
- Author Web Link
- Cite
- Citations: 48
POCOCK S, ALTMAN D, ARMITAGE P, et al., 1991, STATISTICS AND STATISTICIANS IN DRUG REGULATION IN THE UNITED-KINGDOM, JOURNAL OF THE ROYAL STATISTICAL SOCIETY SERIES A-STATISTICS IN SOCIETY, Vol: 154, Pages: 413-419, ISSN: 0035-9238
- Author Web Link
- Cite
- Citations: 3
HAYLEN BT, PARYS BT, ANYAEGBUNAM WI, et al., 1990, URINE FLOW-RATES IN MALE AND FEMALE URODYNAMIC PATIENTS COMPARED WITH THE LIVERPOOL NOMOGRAMS, BRITISH JOURNAL OF UROLOGY, Vol: 65, Pages: 483-487, ISSN: 0007-1331
- Author Web Link
- Cite
- Citations: 55
RUGMAN FP, ASHBY D, DAVIES JM, 1990, DOES HLA-DR PREDICT RESPONSE TO SPECIFIC IMMUNOSUPPRESSIVE THERAPY IN APLASTIC-ANEMIA, BRITISH JOURNAL OF HAEMATOLOGY, Vol: 74, Pages: 545-546, ISSN: 0007-1048
- Author Web Link
- Cite
- Citations: 9
ASHBY D, WEST CR, AMES D, 1989, THE ORDERED LOGISTIC-REGRESSION MODEL IN PSYCHIATRY - RISING PREVALENCE OF DEMENTIA IN OLD PEOPLES HOMES, STATISTICS IN MEDICINE, Vol: 8, Pages: 1317-1326, ISSN: 0277-6715
- Author Web Link
- Cite
- Citations: 28
HAYLEN BT, ASHBY D, SUTHERST JR, et al., 1989, MAXIMUM AND AVERAGE URINE FLOW-RATES IN NORMAL-MALE AND FEMALE POPULATIONS - THE LIVERPOOL NOMOGRAMS, BRITISH JOURNAL OF UROLOGY, Vol: 64, Pages: 30-38, ISSN: 0007-1331
- Author Web Link
- Cite
- Citations: 232
HAYLEN BT, FRAZER MI, SUTHERST JR, et al., 1989, THE ACCURACY OF MEASUREMENT OF RESIDUAL URINE IN WOMEN BY URETHRAL CATHETERIZATION, BRITISH JOURNAL OF UROLOGY, Vol: 63, Pages: 152-154, ISSN: 0007-1331
- Author Web Link
- Cite
- Citations: 20
POCOCK SJ, ASHBY D, SHAPER AG, et al., 1989, DIURNAL-VARIATIONS IN SERUM BIOCHEMICAL AND HEMATOLOGICAL MEASUREMENTS, JOURNAL OF CLINICAL PATHOLOGY, Vol: 42, Pages: 172-179, ISSN: 0021-9746
- Author Web Link
- Cite
- Citations: 104
WILLIAMS PS, DAVENPORT A, MCDICKEN I, et al., 1988, INCREASED INCIDENCE OF ANTI-GLOMERULAR BASEMENT-MEMBRANE ANTIBODY (ANTI-GBM) NEPHRITIS IN THE MERSEY-REGION, SEPTEMBER 1984-OCTOBER 1985, QUARTERLY JOURNAL OF MEDICINE, Vol: 68, Pages: 727-733, ISSN: 0033-5622
- Author Web Link
- Cite
- Citations: 10
This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.