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Biomedical subjects

Tim J Peters

Publications and source records attributed to Tim J Peters.

At least 37 records · Page 2Linked to original sources
PubMed2005

Nurse-led adherence support in hypertension: a randomized controlled trial.

BACKGROUND: Lack of medication adherence is a common reason for poor control of blood pressure in the community, increasing the risk of heart attacks and strokes. OBJECTIVE: To evaluate the effect of nurse-led adherence support for people with uncontrolled high blood pressure compared with usual care. METHODS: We recruited 245 women and men with uncontrolled hypertension (> or = 150/90 mmHg) from 21 general practices in Bristol, UK. Participants were randomized to receive nurse-led adherence support or usual care alone. Main outcome measures were adherence to medication ('timing compliance') and blood pressure. RESULTS: Mean baseline timing compliance (+/- SD) was high in both the intervention (90.8 +/- 15.6%) and the control group (94.5 +/- 7.6%). There was no evidence of an effect of the intervention on timing compliance at follow-up (adjusted difference in means -1.0%; 95% confidence interval (CI) -5.1 to 3.1). There was also no difference at follow-up between the groups with regard to systolic blood pressure (-2.7 mmHg; 95% CI -7.2 to 1.8) or diastolic blood pressure (0.2 mmHg; 95% CI -1.9 to 2.3). Projected costs for the primary care sector per consultation were 6.60 pound sterling for the intervention compared with 5.08 pound sterling for usual care. CONCLUSION: In this study, adherence to blood pressure medication was much higher than previously reported. There was no evidence of an effect of nurse-led adherence support on medication adherence or blood pressure compared with usual care. Nurse-led adherence support was also more expensive from a primary care perspective.

Aged↗
PubMed2005

Cluster randomized trials: another problem for cost-effectiveness ratios.

OBJECTIVES: This work has investigated under what conditions cost-effectiveness data from a cluster randomized trial (CRT) are suitable for analysis using a cluster-adjusted nonparametric bootstrap. The bootstrap's main advantages are in dealing with skewed data and its ability to take correlations between costs and effects into account. However, there are known theoretical problems with a commonly used cluster bootstrap procedure, and the practical implications of these require investigation. METHODS: Simulations were used to estimate the coverage of confidence intervals around incremental cost-effectiveness ratios from CRTs using two bootstrap methods. RESULTS: The bootstrap gave excessively narrow confidence intervals, but there was evidence to suggest that, when the number of clusters per treatment arm exceeded 24, it might give acceptable results. The method that resampled individuals as well as clusters did not perform well when cost and effectiveness data were correlated. CONCLUSIONS: If economic data from such trials are to be analyzed adequately, then there is a need for further investigations of more complex bootstrap procedures. Similarly, further research is required on methods such as the net benefit approach.

Cluster Analysis↗
PubMed2005

Social class and access to specialist palliative care services.

OBJECTIVE: To determine any social class differences in place of death of cancer patients in South Bristol; to explore the experience of carers; and to identify inequalities in access to palliative care. DESIGN: Two-part study: (1) A cross-sectional survey of all 960 cancer deaths in South Bristol between September 1999 and December 2002. (2) A qualitative in-depth interview study of 18 carers of patients who died of cancer during the same period in South Bristol. Fourteen of those who died were from social class IIIM (manual), IV and V (i.e. lower social classes). MAIN OUTCOMES: Place of death of patients according to social class and geographical distance from the hospice. Carers' accounts of the way in which illness and death were conducted, and their response to the management of death and dying. RESULTS: The cross sectional survey showed that patients from social class V were less likely to die in the hospice. This finding was independent of geographical proximity. In the qualitative study, no class specific beliefs about death and dying were identified. Attitudes to the way dying should be conducted were common across the classes. Families expected to be present and centre stage at the time of death and for it to be conducted in a dignified and personal manner. Health care staff in all settings supported them in this aim. No one in this study died without a family member present. Some elderly carers were less open than younger carers in the way they talked about death and did not wish to be present at the death. Some carers from social class IV and V were less active in seeking information or asking for hospice admission than carers from other classes. Unrealistic expectations about the availability of hospice beds were common to all carers. Anxiety was common among carers. It was reduced by the provision of reliable and consistent healthcare support, by information provided in a timely and sensitive way, and by open and shared decision making between carer and patient. Most important in reducing anxiety was the support of a second carer who lived locally and was reliable. Carers from social classes IIIM (manual), IV and V were more likely to have this kind of support than carers from social classes I, II and IIIN (non-manual). CONCLUSION: Although cancer patients from social class V were less likely than others to die in the hospice, social inequality in access to or utilisation of healthcare in terminal illness was not prominent in carers' accounts. When it did arise, it was associated with passivity in seeking information and support on the part of some carers from social classes IV and V. Carers from social classes IIIM-V received more regular and reliable support from their families than those from social classes I-IIIN.

Aged↗
PubMed2005

Birth weight and psychological distress at age 45-51 years: results from the Aberdeen Children of the 1950s cohort study.

BACKGROUND: It is unclear whether the effect of low birth weight on common affective disorders in later life is direct or mediated through childhood factors. AIMS: To determine whether birth weight has a direct effect on psychological distress in adulthood not mediated by childhood IQ or behavioural problems. METHOD: Participants (n=5572) of the Aberdeen Children of the 1950s study had data on birth weight for gestational age and adult psychological distress. Logistic regression was used to examine the association between these factors, with adjustment for confounders and potential childhood mediators. RESULTS: Children born full term but weighing less than 5.5 lb had increased odds of psychological distress in later life after adjustment for potential confounders (OR=1.49, 95% CI 1.01-2.20). Further adjustment for childhood IQ and behaviour did not attenuate the association. A 1 s.d. decrease in birth weight for gestational age was associated with a 4% increased odds of psychological distress in adulthood (OR=1.04, 95% CI 0.97-1.12). CONCLUSIONS: Low birth weight for gestational age, particularly at term, was associated with adult psychological distress. This was not mediated by childhood factors, suggesting a direct effect of early life factors on adult mental health. A neurodevelopmental pathway may therefore be implicated.

Birth Weight↗
PubMed2005

Factors associated with change in pain and disability over time: a community-based prospective observational study of hip and knee osteoarthritis.

BACKGROUND: Hip and knee osteoarthritis are frequent causes of primary care consultations. They are considered slowly progressive disorders, often resulting in severe pain or disability and the need for joint replacements. There have been few longitudinal studies of progression to inform individual prognoses in primary care. AIM: To describe the degree of progression and investigate predictors of change in hip or knee pain and disability. DESIGN OF STUDY: Prospective community-based cohort. SETTING: An age-sex stratified survey of 27 000 people registered with 40 general practices in Avon and Somerset yielded 2437 reporting hip and/or knee symptoms at baseline (1992-1994). A 25% random sample of 587 individuals was followed up between 1998 and 1999. METHOD: Pain or disability was measured at baseline and followup using the New Zealand score. For the worst joint according to the New Zealand score at baseline, hip and knee problems were analysed separately. Regression models ascertained characteristics of nonresponders and factors associated with change in scores. Seven sociodemographic, seven comorbidity, and two healthcare utilisation variables were considered. RESULTS: Generally pain and disability worsened over the 7 years, but 35% and 29% of those initially reporting hip and knee pain respectively had improved. Reporting "other health problems" was associated with greater deterioration for both hip and knee disease, as was cardiovascular morbidity for hip disease and lower social class, being retired, hypertension, and higher body mass index for knee disease. Deteriorations in scores were strongly associated with individuals consulting their GP about joint problems. CONCLUSION: Osteoarthritis does not invariably deteriorate, but when it does social as well as biological factors appear to be important. These findings may aid outcome prediction. Future research on osteoarthritis should be conducted within a biopsychosocial rather than a purely biological paradigm.

Adult↗
PubMed2005

Three-year follow-up of a factorial randomised controlled trial of two decision aids for newly diagnosed hypertensive patients.

This study is a 3-year follow-up of a factorial randomised controlled trial of two decision aids - decision analysis and information video plus leaflet - for newly diagnosed hypertensive patients. We found no evidence of differences for either of the two decision aids compared with controls for the primary outcome of blood pressure control at follow-up. There were also no differences in any of the secondary outcomes measured - the proportion taking blood pressure lowering drugs, self-reported medication adherence, or consulting behaviour. The randomised controlled trial cohort as a whole, irrespective of randomised group, demonstrated substantial reductions in blood pressure and 10-year cardiovascular risk over the follow-up period.

Antihypertensive Agents↗
PubMed2004

Partial substitution of thyroxine (T4) with tri-iodothyronine in patients on T4 replacement therapy: results of a large community-based randomized controlled trial.

Conflicting results have recently been published about the benefits of combined T(4) and T(3) in treating hypothyroid patients. However, these studies may have been underpowered to detect differences in psychological well-being specifically related to T(4) replacement. We conducted a large, double-blind, randomized controlled trial of partial substitution of 50 microg T(4) by 10 microg T(3) vs. the original dose of T(4) in 697 hypothyroid patients. Thyroid function showed a rise in TSH (132%), a fall in free T(4) (35%, P < 0.001), and unchanged basal free T(3) levels (P = 0.92). At 3 months, there was a large (39%) placebo effect improvement in psychiatric caseness defined by the General Health Questionnaire (GHQ) 12 score in the control group compared with baseline, and this was sustained at 12 months. Differences vs. the intervention (T(3)) group were more modest with improvements in GHQ caseness (odds ratio, 0.61; 95% confidence interval, 0.42, 0.90; P = 0.01) and Hospital Anxiety and Depression questionnaire-anxiety scores at 3 months (P < 0.03) but not GHQ Likert scores, Hospital Anxiety and Depression questionnaire-depression, thyroid symptoms, or visual analog scales of mood and the initial differences were lost at 12 months. These results may be consistent with a subgroup of patients showing transient improvement after partial substitution with T(3) but do not provide conclusive evidence of specific benefit from partial substitution of T(4) by T(3) in patients on T(4) replacement. They also emphasize the large and sustained placebo effect that can follow changes in thyroid hormone administration.

Adolescent↗
PubMed2004

The epidemiology and management of self-harm amongst adults in England.

BACKGROUND: Previous research into the epidemiology and management of self-harm has been largely based in centres with a special interest in this behaviour or focused on hospital admissions only. There are no national data on the characteristics and management of people presenting to hospital following self-harm. METHODS: Data were collected from 8-week service audits carried out in a stratified random sample of 31 general hospitals in England. RESULTS: 4033 episodes of self-harm resulting in presentation to Accident and Emergency Departments were identified. Overdose alone accounted for 79 per cent of episodes, 80 per cent of presentations were outside normal office hours (9 am - 5 pm, Monday to Friday) and the peak period of attendance was from 8 pm to 2 am. In only 56 per cent of episodes was a specialist psychosocial assessment conducted prior to discharge and less than half (46 per cent) led to admission to a hospital bed. Psychiatric admission occurred in 10 per cent. Episodes involving older subjects (>45 years) and those using methods other than laceration or overdose were the most likely to lead to assessment and admission. CONCLUSIONS: Non-fatal self-harm is one of the strongest predictors of suicide, yet nearly half of all hospital attendances in England following self-harm do not lead to a specialist assessment. Patterns of service provision should take account of the observation that most self-harm attendances occur outside normal working hours and those at greatest risk of repetition are the least likely to receive assessments.

Adolescent↗
PubMed2004

Use of the bootstrap in analysing cost data from cluster randomised trials: some simulation results.

BACKGROUND: This work has investigated under what conditions confidence intervals around the differences in mean costs from a cluster RCT are suitable for estimation using a commonly used cluster-adjusted bootstrap in preference to methods that utilise the Huber-White robust estimator of variance. The bootstrap's main advantage is in dealing with skewed data, which often characterise patient costs. However, it is insufficiently well recognised that one method of adjusting the bootstrap to deal with clustered data is only valid in large samples. In particular, the requirement that the number of clusters randomised should be large would not be satisfied in many cluster RCTs performed to date. METHODS: The performances of confidence intervals for simple differences in mean costs utilising a robust (cluster-adjusted) standard error and from two cluster-adjusted bootstrap procedures were compared in terms of confidence interval coverage in a large number of simulations. Parameters varied included the intracluster correlation coefficient, the sample size and the distributions used to generate the data. RESULTS: The bootstrap's advantage in dealing with skewed data was found to be outweighed by its poor confidence interval coverage when the number of clusters was at the level frequently found in cluster RCTs in practice. Simulations showed that confidence intervals based on robust methods of standard error estimation achieved coverage rates between 93.5% and 94.8% for a 95% nominal level whereas those for the bootstrap ranged between 86.4% and 93.8%. CONCLUSION: In general, 24 clusters per treatment arm is probably the minimum number for which one would even begin to consider the bootstrap in preference to traditional robust methods, for the parameter combinations investigated here. At least this number of clusters and extremely skewed data would be necessary for the bootstrap to be considered in favour of the robust method. There is a need for further investigation of more complex bootstrap procedures if economic data from cluster RCTs are to be analysed appropriately.

Analysis of Variance↗
PubMed2004

What prevents older people from seeking treatment for urinary incontinence? A qualitative exploration of barriers to the use of community continence services.

BACKGROUND: Urinary incontinence is a significant health problem for older people. Many people with incontinence do not seek services. Simple and effective treatments exist in primary care. OBJECTIVES: Our aim was to explore reasons why older people living in the community do not present for help with problems of urinary incontinence and to identify ways in which they may be assisted to access continence services. METHODS: In-depth interviews lasting an average of 1 h were conducted with 20 people aged over 65 years living in the community, purposively selected from a sample of patients who volunteered to be interviewed. RESULTS: Older people described ageing as a natural, degenerative process and had reduced health expectations. Urinary incontinence was commonly viewed as an inevitable aspect of ageing and, as such, something to be accepted and managed independently. Shame and embarrassment combined with generational differences in attitudes to disclosure about personal matters also prevented people from seeking advice. Relatively successful strategies to manage incontinence enabled people to contain their symptoms, although this was at a social, psychological and, in some cases, health cost. Older people in this sample had considerable co-morbidity, in many cases resulting in mobility problems. Despite regular contact with primary care professionals, they had seldom disclosed their urinary incontinence. CONCLUSION: A combination of personal attitudes and practical barriers prevent older people from seeking help for urinary incontinence. It is possible that older people would be more likely to seek help if asked specifically about urinary leakage by primary health care professionals.

Aged↗
PubMed2004

The inter-observer agreement of examining pre-school children with acute cough: a nested study.

BACKGROUND: The presence of clinical signs have implications for diagnosis, prognosis and treatment. Therefore, the aim of this study was to examine the inter-observer agreement of clinical signs in pre-school children presenting to primary care. METHODS: A nested study comparing two clinical assessments within a prospective cohort of 256 pre-school children with acute cough recruited from eight general practices in Leicestershire, UK. We examined agreement (using kappa statistics) between unstandardised and standardised clinical assessments of tachypnoea, chest signs and fever. RESULTS: Kappa values were poor or fair for all clinical signs (range 0.12 to 0.39) with chest signs the most reliable. CONCLUSIONS: Primary care clinicians should be aware that clinical signs may be unreliable when making diagnosis, prognosis and treatment decisions in pre-school children with cough. Future research should aim to further our understanding of how best to identify abnormal clinical signs.

Acute Disease↗
PubMed2004

Screen-detected prostate cancer and the insulin-like growth factor axis: results of a population-based case-control study.

Higher circulating levels of IGF-I have been associated with increased risk of prostate and some other cancers. Most research on prostate cancer has been based on men with symptoms or identified following treatment of benign disease. However, increasing numbers of cancer cases are now detected in asymptomatic men following prostate-specific antigen (PSA) tests. We therefore used a population-based case-finding exercise using the PSA test to examine whether associations between the IGF axis and cancer risk were apparent in this population. A matched case-control study was conducted among 7,383 men (50-70 years) receiving a PSA test as part of a case-finding exercise. Assays of IGF-I, IGF-II, IGFBP-2 and IGFBP-3 were performed on cases and 2 controls matched on age, recruitment center and calendar time. Analyses were based on 176 cases and 324 matched controls. The risk of prostate cancer increased across quartiles of IGF-I (highest vs. lowest quartile, OR = 2.34; 95% CI = 1.26-4.34; p(trend) = 0.02) and IGF-II (OR = 1.78; 95% CI = 0.94-3.15; p(trend) = 0.09). Controlling for smoking history and IGFBP-3 strengthened associations with cancer for both IGF-I (OR = 3.00; 95% CI = 1.50-6.01; p(trend) 0.005) and IGF-II (OR = 2.02; 95% CI = 1.07-3.84; p(trend) = 0.04) Associations between the IGFs and cancer risk were stronger for advanced cases. Our findings suggest that both IGF-I and IGF-II are associated with an increased risk of screen-detected prostate cancer.

Aged↗
PubMed2004

ICIQ: a brief and robust measure for evaluating the symptoms and impact of urinary incontinence.

AIMS: To develop and evaluate the International Consultation on Incontinence Questionnaire (ICIQ), a new questionnaire to assess urinary incontinence and its impact on quality of life (QoL). METHODS: A developmental version of the questionnaire was produced following systematic literature review and views of an expert committee and patients. Several studies were undertaken to evaluate the psychometric properties of the questionnaire, including content, construct and convergent validity, reliability and sensitivity to change. RESULTS: The ICIQ was easily completed, with low levels of missing data (mean 1.6%). It was able to discriminate among different groups of individuals, indicating good construct validity. Convergent validity was acceptable, with most items demonstrating 'moderate' to 'strong' agreement with other questionnaires. Reliability was good, with 'moderate' to 'very good' stability in test-retest analysis and a Cronbach's alpha of 0.95. Items identified statistically significant reductions in symptoms from baseline following surgical and conservative treatment. Item reduction techniques were used to determine the final version and scoring scheme, which also demonstrated good psychometric properties. CONCLUSIONS: The final ICIQ comprises three scored items and an unscored self-diagnostic item. It allows the assessment of the prevalence, frequency, and perceived cause of urinary incontinence, and its impact on everyday life. The ICIQ is a brief and robust questionnaire that will be of use in outcomes and epidemiological research as well as routine clinical practice.

Adult↗
PubMed2004

Subgroup analyses in randomized trials: risks of subgroup-specific analyses; power and sample size for the interaction test.

OBJECTIVE: Despite guidelines recommending the use of formal tests of interaction in subgroup analyses in clinical trials, inappropriate subgroup-specific analyses continue. Moreover, trials designed to detect overall treatment effects have limited power to detect treatment-subgroup interactions. This article quantifies the error rates associated with subgroup analyses. STUDY DESIGN AND SETTING: Simulations quantified the risks of misinterpreting subgroup analyses as evidence of differential subgroup effects and the limited power of the interaction test in trials designed to detect overall treatment effects. RESULTS: Although formal interaction tests performed as expected with respect to false positives, subgroup-specific tests were considerably less reliable: A significant effect in one subgroup only was observed in 7% to 64% of simulations depending on trial characteristics. Regarding power of the interaction test, a trial with 80% power for the overall effect had only 29% power to detect an interaction effect of the same magnitude. For interactions of this size to be detected with the same power as the overall effect, sample sizes should be inflated fourfold, increasing dramatically for interactions smaller than 20% of the overall effect. CONCLUSION: Although it is generally recognized that subgroup analyses can produce spurious results, the extent of the problem may be underestimated.

Data Interpretation, Statistical↗
PubMed2004

Measurement of insulin-like growth factor axis does not enhance specificity of PSA-based prostate cancer screening.

OBJECTIVES: To examine whether measurement of insulin-like growth factor (IGF)-I, IGF-II, IGF binding protein (IGFBP)-2 or IGFBP-3, alone or in combination, enhanced the specificity of prostate cancer detection among men with a prostate-specific antigen (PSA) level of 3 ng/mL or greater beyond that achieved by the free/total PSA index. METHODS: Cross-sectional analysis was performed on blood samples taken from 597 asymptomatic men (79% of those biopsied) participating in a community case-finding exercise. All men had a total PSA level of 3 ng/mL or greater and had undergone prostate biopsy. Assays of IGF-I, IGF-II, IGFBP-2, IGFBP-3, and free and total PSA were performed. The predictive performance of a range of measures was assessed using receiver operating characteristic analyses and compared with the free/total PSA index, for all biopsies and for men with a PSA level of 3 to 10 ng/mL. The overall test performance was summarized using the area under the receiver operating characteristic curve (AUC). RESULTS: Of the 597 men, 185 (31.0%) had prostate cancer identified at biopsy. When all biopsies were included, the performance of the free/total PSA index (AUC 0.73) was significantly greater than for IGF-I (AUC 0.59; P <0.0001), IGF-I/PSA ratio (AUC 0.65; P = 0.002), IGF-I + IGFBP-3 (AUC 0.59; P <0.0001), IGF-II (AUC 0.66; P = 0.002), and IGF-II + IGFBP-3 (AUC 0.67; P = 0.05). The combined measurement of free/total PSA, IGF-II, and IGFBP-3 resulted in a slight improvement in performance (AUC 0.76; P = 0.01). The results were similar when the analyses were restricted to men with an initial PSA level of 3 to 10 ng/mL. CONCLUSIONS: We found no evidence that measurement of the IGF axis enhances the specificity of prostate cancer detection in clinical practice beyond that achievable using the free/total PSA index.

Adenocarcinoma↗
PubMed2004

Decision analysis for newly diagnosed hypertensive patients: a qualitative investigation.

This study adopted a qualitative approach to explore patients' views on the usefulness of a decision analytic decision aid (DA). Semi-structured interviews were conducted with 15 newly diagnosed hypertensive patients who had been recruited for a factorial randomised controlled trial of two decision aids. Issues investigated included respondents' attitudes to information, their views on the nature of their relationship with their general practitioner (GP) (paternalistic, shared or consumerist), the ease of use and potential wider application of the computerised decision aid and its influence upon their decision-making about whether or not to begin anti-hypertensive treatment. Views on the decision aid were favourable. For the majority, the decision aid appeared to confirm and/or clarify their stated preferences towards medicine-taking. Occasionally it could provoke a major shift in a respondent's attitude to medicine-taking, while in a few it had no discernible effect. While views on the decision aid were favourable, it was difficult to determine whether this was due to the individualised cardiovascular risk information it provided or the decision analytic process itself.

Aged↗
PubMed2004

High incidence of mesothelioma in an English city without heavy industrial use of asbestos.

BACKGROUND: Mesothelioma rates are increasing in the industrialized world, related to occupational asbestos exposure. The highest rates have been reported from areas with specific industries such as shipbuilding or mining. Lower rates have been reported from areas without such industries. We studied an area without heavy industry to examine if such a pattern occurred in England. METHODS: We studied the population of Exeter Primary Care Trust, Devon, United Kingdom, with a population of 131,849. Exeter has no mining, shipbuilding or other heavy industry. All lung cancers and mesotheliomas were identified from the local cancer registry, supplemented by searches at all primary care practices. The cancer diagnoses were checked by inspection of histology or primary care records. Occupational data were extracted from the primary care records. RESULTS: The searches revealed 291 lung cancers, 283 of which had either histological proof or strong clinical evidence for the diagnosis. Twenty-two (8 per cent) of these were pleural mesotheliomas, 17 of these occurring in men. The incidence rate of mesothelioma in men over 40 years was 12.1 per 100,000 per year (95 per cent confidence intervals 7.0-19.3), one of the highest reported rates in the world. CONCLUSION: The mesothelioma epidemic will extend to areas without local heavy industrial exposure.

Adult↗