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D Ashby

Publications and source records attributed to D Ashby.

At least 37 records · Page 2Linked to original sources
PubMed1996

An analysis of papers published in the British and European Journals of Orthodontics.

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 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. More papers in BJO were case reports, clinical opinions, and update articles, and reported on orthodontic materials or assessed methods of measuring the outcome of treatment. Ninety per cent of papers in EJU reported the results of research projects. More papers were related to animal studies; were laboratory based on epidemiological. CONCLUSION: Despite the RCT being regarded as the 'Gold Standard' for the evaluation of therapeutic interventions and materials only six (5.1 per cent) of such studies used this method. Significant differences in the type, setting and subject of papers published in BJO and EJO between 1989 and 1993 were found.

Animals↗
PubMed1995

Fibrosing colonopathy in cystic fibrosis: results of a case-control study.

Fibrosing colonopathy was first described in cystic fibrosis (CF) children in 1994. We have done a nested case-control study to identify possible associations with this condition. A case ascertainment within the UK CF population to identify any cases that occurred between January, 1984, and April, 1994, found 14 cases, all under 14 years and confirmed by independent histopathological review. All had presented since April, 1993; 12 were boys and six had received some or all of their care in Liverpool. Each case was matched, by date of birth, with four controls from the UK CF Registry. Information was obtained about cases and controls from their case records and by a structured interview with the families. In the 12 months before surgery, there was an association between the occurrence of fibrosing colonopathy and use of high-strength pancreatic enzyme preparations. This association was dose related. Odds ratio per extra 1000 high-strength capsules was 1.45 (95% CI 1.14-1.84). For use of protease, the odds ratio per million extra units per kg was 1.55 (1.19-2.03). For usage of individual high-strength products at any time during the 12 months before surgery some differences were observed; for Creon 25000 the odds ratio was 0.38 (0.10-1.42), for Nutrizym 22 43.4 (2.51-751), and for Pancrease HL 8.4 (1.95-36.1). These last two confidence intervals are extremely wide and compatible with these two products having the same odds ratios. Laxative use was independently predictive (odds ratio 2.42 [1.20-4.94]). We conclude that there is a dose-related association between high-strength pancreatic enzyme preparations and fibrosing colonopathy.

Adolescent↗
PubMed1995

Conversations in ethics: exploring the literature.

Because of changes in the healthcare industry, many questions have surfaced concerning ethical dilemmas. We, on the ethics committee, thought it a good idea to publish some updated and informative literature concerning these dilemmas.

Ethics, Nursing↗
PubMed1994

Simple Bayesian analysis in clinical trials: a tutorial.

In this tutorial paper we give a simple Bayesian analysis of data that arise in clinical trials. We consider the case when there are two treatment groups and the response in each group can be assumed to be binomially distributed. We also assume that prior beliefs about the rate parameter in each group can be adequately expressed by a Beta distribution. Using such a model approximate posterior inferences can then be made about the odds ratio between the two groups. We illustrate this methodology by analyzing a randomized trial to assess the benefits of treating patients with carcinoma of the pelvic region (rectum, bladder, colon, cervix) using high-energy fast neutrons as opposed to conventional megavoltage x-rays (photons). In this trial there was prior information about the relative efficacy of neutron therapy based on the beliefs of 10 clinicians. Some of the deficiencies of this simple approach are high-lighted and other approaches to analysis indicated. The paper facilitates practical consideration of a Bayesian approach without the complexities that a fuller analysis necessitates.

Bayes Theorem↗
PubMed1994

Axial length biometry in infants with retinopathy of prematurity.

Ultrasound axial length measurements were obtained on infants under a birthweight of 1500 g or 32 weeks gestation undergoing screening for retinopathy of prematurity (ROP). A total of 496 readings were obtained on 171 infants between 32 and 41 weeks post-conceptual age. Other details recorded were maximum stage of acute ROP, birthweight, gestational age, sex, and biparietal and occipitofrontal head diameters. The relationship of these variables to axial growth of the eye was examined using analysis of covariance with a repeated measures approach. Mean axial length increased from 15.27 mm to 16.65 mm in the left eye during this period. Following adjustment for repeated readings a growth rate of 0.18 mm/week was obtained for both eyes. Male infants were found to have longer axial lengths despite correction for birthweight, gestation and head size (p < 0.0001 right and left). Higher stages of acute ROP were also associated with shorter axial length (p < 0.05 for all stages of both eyes) but the rate of growth during the study period did not demonstrate significant differences between stages. Stage 3 infants reaching the threshold for cryotherapy had shorter axial length than stage 3 infants not receiving treatment. The effect of prematurity on the growth of the eye and the significance of these findings with respect to the subsequent development of refractive errors in premature infants are discussed.

Analysis of Variance↗
PubMed1994

A brief sensitive screening instrument for depression in late life.

Data collected with the depression scale (DEP) of the Brief Assessment Scale (BAS) at interviews with 811 elderly subjects were analysed to determine which of its 21 individual items could be selected to produce a short screening scale for depression which would have less than 10 items and a Cronbach's alpha above 0.8. Eight items which fulfilled these requirements were selected to form the Even Briefer Assessment Scale for Depression (EBAS DEP). The validity of the scale was assessed against psychiatric diagnoses made on a subset of 211 subjects. The EBAS DEP had a sensitivity and specificity for a diagnosis of a DSM-III-R mood disorder (depressed) of 0.91 and 0.72, respectively. The EBAS DEP could be useful as a brief screen for depression in busy hospital and primary care settings where a full assessment of mood for every patient is impractical. The EBAS DEP is presented, together with instructions for its use, to enable independent study of its reliability and validity in other populations.

Aged↗
PubMed1994

Prognostic value of ambulatory ST segment monitoring compared with exercise testing at 1-3 months after acute myocardial infarction.

The relative value of ambulatory ST segment monitoring for assessing prognosis following acute myocardial infarction is currently uncertain. Ambulatory monitoring was performed in 177 patients at a mean of 38 days (range 22-93) post-myocardial infarction and its prognostic value was compared with exercise treadmill testing (n = 170). Cardiac events (myocardial infarction, cardiac death or coronary revascularisation) were noted during at least 1 year of follow-up. The presence or absence of ST depression on ambulatory monitoring did not predict increased fatal or non-fatal cardiac events although more severe ST depression had some predictive power: after adjusting for clinical variables and coronary prognostic indices, the duration/24 h (P = 0.03) and magnitude (P = 0.007) of ST depression had independent value. ST deviation on exercise testing was associated (P < 0.05) with increased events (19/90; 21% vs 7/80; 9%) and in patients with a positive exercise test ST depression on ambulatory monitoring did not identify any additional events (8/41; 20% vs 11/49; 22%). No factor available from ambulatory monitoring was predictive of outcome once variables from exercise testing were taken into account. Ambulatory ST segment monitoring performed in the late recovery phase (1-3 months) after acute myocardial infarction is inferior to exercise testing for predicting prognosis and does not increase the predictive power of an exercise test. Ambulatory monitoring may only be indicated in patients unable to perform an exercise test.

Electrocardiography, Ambulatory↗
PubMed1993

Prognostic significance of transient myocardial ischemia on ambulatory monitoring after acute myocardial infarction.

The prognostic value of ambulatory ST-segment monitoring after myocardial infarction was prospectively assessed in 203 patients both early (mean 6 days, n = 201) and late (38 days, n = 177). During at least 1 year of follow-up there were 21 cardiac deaths and 44 cardiac events (death, reinfarction or coronary revascularization). ST depression was seen less often during early than late monitoring (29 of 201 [14%] vs 56 of 177 [32%]). Early ST depression was significantly associated with increased mortality (7 of 29 [24%] vs 14 of 172 [8%]) (< 0.05) and increased cardiac events (13 of 29 [45%] vs 30 of 172 [17%]) (p < 0.001) and had independent value after allowing for clinical factors and coronary prognostic indexes (adjusted relative risks 3.40 and 2.70, respectively). ST depression on late monitoring was only associated with increased cardiac events when it was: (1) frequent (e.g., > or = 3 episodes/day [10 of 31 patients, 32% vs 18 of 146, 12%]) (p < 0.01); (2) prolonged (e.g., > or = 20 minutes/day [8 of 25, 32% vs 20 of 152, 13%]) (p < 0.05); or (3) severe (e.g., maximum of > or = 1.5 mm [8 of 28, 29% vs 20 of 149, 13%]) (p < 0.05). Thus, ST depression occurs less frequently during ambulatory monitoring before discharge than during late monitoring, but is a more specific prognostic indicator; however, it is more benign during late monitoring. Ambulatory ST-segment monitoring can be used to predict prognosis in the first year after myocardial infarction, although its relative value as a screening test compared with exercise testing remains to be established.

Electrocardiography, Ambulatory↗
PubMed1993

Tuberculin testing in residential homes for the elderly.

BACKGROUND: Evidence from the United States has shown that tuberculin sensitivity increases with length of stay among residents in homes for the elderly, implying an increasing risk of infection. There is no evidence as to whether or not residents in homes in the United Kingdom have a similar risk. METHODS: A study was undertaken to determine whether residence in a home for the elderly increases the risk of tuberculosis infection. Over a six month period all residents in homes for the elderly in Liverpool received a tuberculin test. A health questionnaire was completed by the field team for each resident. A total of 2665 residents in homes for the elderly were surveyed. RESULTS: Heaf test grade positivity declined with age, the odds ratio being 0.71 for each 10 year period. Adjusting for age, there was no change in Heaf test grade with length of stay in the home. Heaf test positivity was stronger in smokers (odds ratio 1.59) than ex-smokers (odds ratio 1.20) and non-smokers. Heaf test grade positivity was directly related to pack years. Allowing for age and smoking, the odds ratio for men compared with women for a positive test was 1.62 (95% confidence interval 1.32 to 1.99). CONCLUSIONS: Heaf test positivity declines with age. Residence in a home for the elderly is not associated with increased rate of tuberculosis sensitivity. Smoking and male gender is associated with increased Heaf test positivity.

Adult↗
PubMed1992

Power calculation for cohort studies with improved estimation of expected numbers of deaths.

This paper focuses on improving the accuracy of sample size calculations for cohort studies by careful calculation of the expected number of deaths in the population, taking into account either prior information or realistic assumptions about variables which may affect the mortality or incidence. Sometimes small changes in the assumptions can dramatically alter the expected numbers and may necessitate modifications in the design of the study. Possible modification include extension of the follow-up time, and recognition that the real strength of the study may lie in the potential for pooling several similar studies. The problem will be discussed with reference to two examples of occupational cohort studies where differing prior information was available.

Adult↗
PubMed1992

A prospective randomised controlled trial comparing the efficacy of somatostatin with injection sclerotherapy in the control of bleeding oesophageal varices.

Since previous reports have suggested that somatostatin may be of value in the control of acute variceal haemorrhage, we compared its efficacy with that of injection sclerotherapy in a randomised controlled clinical trial. Eighty consecutive patients with endoscopically-proven severe variceal bleeding were randomised to injection sclerotherapy (n = 41) or somatostatin (n = 39) given as a continuous infusion of 250 micrograms/h for 5 days plus daily bolus administration of 250 micrograms. The efficacy of injection sclerotherapy and somatostatin infusion in controlling haemorrhage and preventing rebleeding (censored at 5 days), mortality (censored at 28 days) and complications was compared. The aetiology of the portal hypertension and transfusion requirements was similar between the two groups, but there were more patients with severe liver disease (Child's C) in the somatostatin group. There was no significant difference between the two treatments in the initial (p = 1.0) or overall control of bleeding (p = 0.58). Furthermore, somatostatin was as effective as injection sclerotherapy in controlling bleeding in patients with severe liver disease or in those actively bleeding at the time of their endoscopy. The relative risk of rebleeding whilst receiving somatostatin compared to injection sclerotherapy was 1.39 [95% Confidence Interval (CI) 3.73; 0.52], but this was reduced to 0.98 (95% CI 0.37; 2.67) when readjusted for Child's grading, the only prognostic factor shown to be of significance. Mortality was not significantly different between the two groups of patients (p = 0.31). The relative risk of dying whilst receiving somatostatin compared to injection sclerotherapy was 1.6 (95% CI 3.93; 0.66) but was reduced to 1.03 (95% CI 0.47; 2.47) when adjusted for Child's grading, the only significant prognostic factor. Complications in the somatostatin group were minor and less frequent than after injection sclerotherapy. The results of this study indicate that somatostatin is a safe treatment, which is as effective an endoscopic injection sclerotherapy for acute variceal bleeding.

Adult↗
PubMed1991

High energy neutron treatment for pelvic cancers: study stopped because of increased mortality.

OBJECTIVE: To compare high energy fast neutron treatment with conventional megavoltage x ray treatment in the management of locally advanced pelvic carcinomas (of the cervix, bladder, prostate, and rectum). DESIGN: Randomised study from February 1986; randomisation to neutron treatment or photon treatment was unstratified and in the ratio of 3 to 1 until January 1988, when randomisation was in the ratio 1 to 1 and stratified by site of tumour. SETTING: Mersey regional radiotherapy centre at Clatterbridge Hospital, Wirral. PATIENTS: 151 patients with locally advanced, non-metastatic pelvic cancer (27 cervical, 69 of the bladder, seven prostatic, and 48 of the rectum). INTERVENTION: Randomisation to neutron treatment was stopped in February 1990. MAIN OUTCOME MEASURES: Patient survival and causes of death in relation to the development of metastatic disease and treatment related morbidity. RESULTS: In the first phase of the trial 42 patients were randomised to neutron treatment and 14 to photon treatment, and in the second phase 48 to neutron treatment and 47 to photon treatment. The relative risk of mortality for photons compared with neutrons was 0.66 (95% confidence interval 0.40 to 1.10) after adjustment for site of tumour and other important prognostic factors. Short term and long term complications were similar in both groups. CONCLUSIONS: The trial was stopped because of the increased mortality in patients with cancer of the cervix, bladder, or rectum treated with neutrons.

Fast Neutrons↗
PubMed1990

Urine flow rates in male and female urodynamic patients compared with the Liverpool nomograms.

The Liverpool male and female nomograms provide normal reference ranges for the maximum and average urine flow rates over a wide range of voided volumes. A known urine flow rate, in combination with the respective voided volume (and in men the age), can be converted into an equivalent centile ranking, using the equation for the relevant nomogram. Centile rankings allow the urine flow rates of specific male and female populations to be compared. The maximum and average urine flow rates of urodynamic patients (504 consecutive male and 168 consecutive female) were converted into centile rankings. These centile rankings were then compared with the respective urodynamic diagnoses. The median centile rankings for their maximum and average urine flow rates were 21 and 11 (male) respectively and 31 and 18 (female) (vs 50 for the normal populations). The low urine flow rates applied to all diagnostic groups, including those symptomatic men and women who were found to be urodynamically normal. Low urine flow rates may be one of a number of subtle manifestations of urological disease in these patients. Men with obstruction and women with voiding difficulties had the lowest urine flow rates. The 25th centile (men) and the 10th centile (women) appeared to be most appropriate lower limits of normality for both urine flow rates to identify those men more likely to be obstructed and those women at higher risk of voiding difficulties. Men and women with detrusor instability had the highest urine flow rates. Detrusor instability was present in 71% of men with centile rankings for the maximum urine flow rate over 50; 50% of women whose maximum urine flow rate centiles were over 90 had detrusor instability.

Adolescent↗