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Biomedical subjects

Tim Peters

Publications and source records attributed to Tim Peters.

10 recordsLinked to original sources
PubMed2005

Evaluation of a general practitioner with special interest service for dermatology: randomised controlled trial.

OBJECTIVE: To assess the effectiveness, accessibility, and acceptability of a general practitioner with special interest service for skin problems compared with a hospital dermatology clinic. DESIGN: Randomised controlled trial. SETTING: General practitioner with special interest dermatology service and hospital dermatology clinic. PARTICIPANTS: Adults referred to a hospital dermatology clinic and assessed by a consultant or the general practitioner with special interest service,. Suitable patients had non-urgent skin problems and had been identified from the referral letter as suitable for management by a general practitioner with special interest. INTERVENTIONS: Participants were randomised in 2:1 ratio to receive management by a general practitioner with special interest or usual hospital outpatient care. MAIN OUTCOME MEASURES: Primary outcomes were disease related quality of life (dermatology life quality index) and improvement in patients' perception of access to services, assessed nine months after randomisation. Secondary outcomes were patient satisfaction, preference for site of care, proportion of failed appointments, and waiting times to first appointment. RESULTS: 49% of the participants were judged suitable for care by the general practitioner with special interest service. Of 768 patients eligible, 556 (72.4%) were randomised (354 to general practitioner with special interest, 202 to hospital outpatient care). After nine months, 422 (76%) were followed up. No noticeable differences were found between the groups in clinical outcome (median dermatology life quality index score = 1 both arms, ratio of geometric means 0.99, 95% confidence interval 0.85 to 1.15). The general practitioner with special interest service was more accessible (difference between means on access scale 14, 11 to 19) and waited a mean of 40 (35 to 46) days less. Patients expressed slightly greater satisfaction with consultations with a general practitioner with special interest (difference in mean satisfaction score 4, 1 to 7), and at baseline and after nine months 61% said they preferred care at the service. CONCLUSIONS: The general practitioner with special interest service for dermatology was more accessible and preferred by patients than hospital outpatient care, achieving similar clinical outcomes. Trial registration ISRCTN31962758.

Adolescent↗
PubMed2005

Conceptual issues in the analysis of cost data within cluster randomized trials.

Cluster randomized controlled trials (RCTs) are increasingly used in economic evaluations of social, educational and health care interventions. Methodological research has, therefore, been spread across several disciplines, with the result that it has taken many years for guidelines on good statistical practice in the design and analysis of such trials to become easily accessible to health service researchers. These guidelines remain incomplete, however, because they do not take account of issues specific to the analysis of cost data. In particular, they fail to recognize that the calculation of confidence intervals around costs needed to inform health care priority setting raises unique methodological issues. If poorly designed trials are to be avoided in future (including those by the authors), then collaboration between triallists and health economists is required. This paper sets out a framework that should facilitate such collaboration and draws attention to problems that must be addressed quickly in the design of cluster-based economic evaluations.

Cluster Analysis↗
PubMed2005

Adapting the randomized consent (Zelen) design for trials of behavioural interventions for chronic disease: feasibility study.

OBJECTIVES: Standard randomized controlled trials of interventions for chronic conditions that involve behavioural change, or that are highly desired by participants, are difficult to undertake because of problems with recruitment and contamination. Alternatives include cluster-randomized trials or pre-randomization designs such as the Zelen design. The aim here was to develop a pre-randomization design that would overcome ethical and methodological problems associated with the conventional Zelen design, and permit the rigorous evaluation of a complex package of care, involving physical therapy and behavioural changes, for patients with painful patello-femoral osteoarthritis of the knee joint. METHODS: Eligible patients were first consented to a one-year observational study of their arthritis. They were subsequently randomized into intervention and control arms. Those in the intervention arm were then asked if they were willing to participate in a further study involving regular sessions with a physiotherapist. Those in the control arm were not told about this, but were followed up as agreed. RESULTS: Eighty-seven patients consented to the observational study, 43 of whom were subsequently randomized to the intervention arm. All 43 consented to the intervention, although five of these did not receive the full package of care. Assessments were carried out at five months and one year on 82 patients, and concealment was satisfactorily maintained in the majority. CONCLUSIONS: We conclude that this study design could potentially offer an acceptable compromise between the need for scientific rigour and the ethical imperative of fully informed consent in trials that involve behavioural change or interventions that patients might want to obtain.

Chronic Disease↗
PubMed2003

Costs and concentration of cancer care: evidence for pancreatic, oesophageal and gastric cancers in National Health Service hospitals.

OBJECTIVES: To examine relationships between the cost of hospital cancer care and the degree of specialisation of patients' doctors and hospitals as indicated by their annual case-loads. METHODS: Three cohorts comprising 2294 patients with cancers of the pancreas, oesophagus and stomach in 29 acute National Health Service (NHS) hospitals in south-west England and South Wales were followed prospectively for a year. For each patient, prognostic variables, service activity and survival data were recorded, and the hospital cost of cancer care and cost per year survived were estimated. Costs were estimated from quantities of resource units provided and a single set of unit costs. Costs per day survived after presentation to hospital were calculated as estimates of cost-effectiveness. Linear regression analyses examined the effects on total costs, and on costs per day survived of doctors' and hospitals' annual patient volumes, adjusting for prognostic variables and treatments. RESULTS: General ward care rather than specific treatments and investigations accounted for most of total costs. Costs per patient increased significantly with increasing doctor volumes. After adjustment for prognosis and treatments, however, cost-volume relationships were U-shaped, reflecting more active intervention by higher volume doctors, along with little activity and long stays among patients of lower volume doctors. Cost per day survived also had U-shaped relationships with doctor volumes. Regression models using continuous rather than categorical volume terms fitted the data best. CONCLUSIONS: Doctors' specialisation is at least as important for efficiency and effectiveness as hospitals' specialisation. Cost and cost per day survived increased and then decreased with increasing doctor volumes, highlighting the need for critical attention to costs as services become highly specialised. Specialisation occurs along a continuum, with no clear volume threshold effects on survival or costs.

England↗
PubMed2003

Including a 'no active intervention' arm in surgical trials is possible: evidence from the CLasP randomised trial.

OBJECTIVES: To examine the impact of including a 'no active intervention' arm (called 'conservative management') in a randomised controlled trial comparing treatments (including surgery) for men with lower urinary tract symptoms related to benign prostatic enlargement. METHODS: Outcomes 7.5 months after randomisation were acceptability of randomisation, overall acceptability of and satisfaction with conservative management, impact on quality of life, perceived need for further treatment and treatment failure (defined a priori). RESULTS: In total, 177 (out of 755) patients refused randomisation, including 31% who did not want surgery and 22% who wanted surgery. Most men randomised to conservative management were willing to undertake it as part of a trial but at the end of the trial they were divided between those who wanted to continue with it and those who expected surgery. At follow-up, 39% of conservative management patients requested surgery, and interference of symptoms with life and an unsuccessful outcome were more commonly reported in this arm. There were no appreciable differences between treatment groups in terms of treatment failures. CONCLUSIONS: Including a 'no active intervention' arm did not appear to have a detrimental effect on patient recruitment or the completion of this trial in the short-term; overall, conservative management was successfully completed by the majority of patients during the trial period, suggesting that researchers need not avoid including a no-intervention arm in surgical trials as long as they take care with its presentation.

Aged↗
PubMed2002

Quality improvement report: Improving design and conduct of randomised trials by embedding them in qualitative research: ProtecT (prostate testing for cancer and treatment) study. Commentary: presenting unbiased information to patients can be difficult.

PROBLEM: Recruitment to randomised trials is often difficult, and many important trials are not mounted because recruitment is thought to be "impossible." DESIGN: Controversial ProtecT (prostate testing for cancer and treatment) trial embedded within qualitative research. BACKGROUND AND SETTING: Screening for prostate cancer is hotly debated, and evidence from trials about the effectiveness of treatments (surgery, radiotherapy, and monitoring) is lacking. Mounting a treatment trial is controversial because of past failures and concerns that differences in complications of treatment but not survival make randomisation unacceptable to patients and clinicians, particularly for a trial including monitoring. STRATEGY FOR CHANGE: In-depth interviews explored interpretation of study information. Audiotape recordings of recruitment appointments enabled scrutiny of content and presentation of study information by recruiters. Initial qualitative findings showed that recruiters had difficulty discussing equipoise and presenting treatments equally; they unknowingly used terminology that was misinterpreted by participants. Findings were used to determine changes to content and presentation of information. EFFECTS OF CHANGE: Changes to the order of presenting treatments encouraged emphasis on equivalence, misinterpreted terms were avoided, the non-radical arm was redefined, and randomisation and clinical equipoise were presented more convincingly. The randomisation rate increased from 40% to 70%, all treatments became acceptable, and the three arm trial became the preferred design. LESSONS LEARNT: Changes to information and presentation resulted in efficient recruitment acceptable to patients and clinicians. Embedding this controversial trial within qualitative research improved recruitment. Such methods probably have wider applicability and may enable even the most difficult evaluative questions to be tackled.

Humans↗
PubMedDate not supplied

Angiotensin II receptor binding in the locus ceruleus of spontaneously hypertensive rats and Wistar-Kyoto rats: a quantitative autoradiographic study with references to hypertension and cardiac/testicular hypertrophy.

The locus ceruleus (LC) contains a high density of angiotensin II (AII) receptors. The role of AII receptors at the LC in genetic hypertension and organ function is unclear. Spontaneously hypertensive (SHR) rats and Wistar-Kyoto (WKY) rats were studied, and blood pressure of animals was measured using the tail-cuff method. Animals were decapitated and the heart weight (HW) and testicular weight (TW) of animals measured. AII receptor binding was carried out by incubating the LC tissue sections with 200 pM [(125)I]-AII receptor ligand, and measured using quantitative autoradiography. Results showed that the HW/BW ratio was significantly higher in SHR rats than WKY rats. However, the TW/BW ratio was higher in SHR rats than WKY rats only at two hypertensive stages, whereas AII receptor binding capacity in the LC was also statistically higher in SHR rats than WKY rats. Results indicated that cardiac and testicular hypertrophies were related to higher AII receptor binding in the LC of SHR rats, when compared with WKY rats. Interestingly, the literature shows that there is an LC-testes axis. In conclusion, this study indicated that AII receptors in the LC are associated with genetic hypertension, and testicular weight could be a reasonable index for essential hypertension.

Animals↗