How much might cardiovascular disease risk be reduced by intensive therapy in people with screen-detected diabetes?

AIMS

To assess the cardiovascular disease (CVD) risk of people with screen-detected Type 2 diabetes and to estimate the risk reduction achievable through early intensive pharmacological intervention.

METHODS

In ADDITION-Cambridge, diabetic patients were identified among people aged 40-69 years through a stepwise screening procedure including a risk score, random and fasting capillary blood glucose, HbA(1c) and oral glucose tolerance test. In those without prior macrovascular disease, 10-year CVD risk was computed using UK Prospective Diabetes Study (UKPDS) and Framingham engines. The absolute risk reduction achievable and its plausible range were predicted using relative risk reductions for individual therapies from published trials and sensitivity analysis.

RESULTS

Of the 867 individuals with undiagnosed diabetes, 19% had pre-existing CVD, 97% were overweight or obese, 86% had hypertension, 75% had dyslipidaemia, 20% had microalbuminuria and 18% were smokers. Of those with hypertension, 35% were not prescribed drugs and 42% were suboptimally treated. Of participants with dyslipidaemia, 68% were not prescribed medications and 22% were poorly controlled. Median 10-year CVD risk was 34.0%[interquartile range (IQR) 26.2-44.6] in men and 21.5% (IQR 15.7-28.7) in women using the UKPDS engine; 38.6% (IQR 27.8-53.0) in men and 24.6% (IQR 17.2-32.9) in women using Framingham equations. In the most conservative scenario (no additive effect of therapies), the absolute risk reduction achievable through multifactorial therapy ranged from 4.9 to 9.5% (UKPDS) and from 5.4 to 10.5% (Framingham). The corresponding ranges of numbers needed to treat were 11-20 and 10-19.

CONCLUSIONS

People with screen-detected diabetes have an adverse cardiovascular risk profile, which is potentially modifiable through application of existing treatment recommendations.

Self-monitoring of blood glucose changed non-insulin-treated Type 2 diabetes patients' beliefs about diabetes and self-monitoring in a randomized trial

AIMS

To determine whether differences in beliefs about diabetes and its treatment resulted from different intensities of self-monitoring of blood glucose (SMBG) in non-insulin treated patients with Type 2 diabetes in the Diabetes Glycaemic Education and Monitoring (DiGEM) trial.

METHODS

Patients (n = 453) were randomized to usual care, less-intensive SMBG and more intensive SMBG. Beliefs about diabetes were measured with a standard questionnaire (the revised Illness Perceptions Questionnaire; IPQ-R). Changes in beliefs were analysed using analysis of covariance (ancova) with adjustment for baseline values. Mediation analyses assessed whether differences in behavioural outcomes between groups could be attributed to differences in beliefs.

RESULTS

Completed questionnaires were returned by 339 patients (74.8%). Respondents were mean (+/- sd) age 65.9 +/- 10 years and with diabetes duration of 4.8 +/- 4.7 years (median 36, range 1-384 months). Concerns about the consequences of diabetes increased in both self-monitoring groups, relative to control subjects [P = 0.004; Cohen's d standardized effect size = 0.19 less intensive and d = 0.36 more intensive monitoring]. No other beliefs about diabetes differed between groups. Beliefs about the importance of self-testing increased in both self-monitoring groups relative to the usual-care group (P < 0.001; d = 0.57 less intensive and d = 0.63 more intensive monitoring). Changes in psychological well-being did not differ between groups, but control patients reported greater increases in general (P = 0.014) and specific (P < 0.001) dietary adherence than did patients in the self-monitoring groups. These outcomes were not mediated by intervention-related changes in beliefs.

CONCLUSIONS

Despite changes in some beliefs about diabetes differing between groups there were no corresponding changes in self-reported health behaviours. This suggests that changes in illness beliefs resulting from SMBG do not cause changes in diabetes-related health behaviours.

Evaluation of an informed choice invitation for type 2 diabetes screening

OBJECTIVE

To evaluate an innovative invitation designed to facilitate informed choices for undergoing screening for type 2 diabetes.

METHODS

Four hundred and seventeen people aged 40-69 years (sex: F 53%/M 47%), without known diabetes, recruited from street locations. Participants were randomised to receive one of two hypothetical invitations for screening for type 2 diabetes; one based on General Medical Council guidelines and combined with a decisional balance sheet, the other a brief traditional invitation. Informed choice was assessed immediately after the invitation and 3 weeks later using measures of knowledge, attitudes and intentions.

RESULTS

Two weeks after receipt of the invitation, the proportion of informed choices was significantly higher among participants who received the informed choice invitation compared with those who received the traditional invitation (42.9% versus 11.2%; difference=31.7%, 95% CI: 22.5-40.5%; p<0.001). Mean knowledge scores were significantly higher after the receipt of the invitation designed to facilitate informed choices than after the traditional invitation (5.49 versus 3.90; t(405)=10.106, p<0.001). Intentions to participate in screening were unaffected by receipt of the informed choice invitation.

CONCLUSION

Compared with a traditional invitation, receipt of the invitation designed to facilitate informed choices increased the proportion of informed choices about type 2 diabetes screening attendance.

PRACTICE IMPLICATIONS

: Although the new invitation was associated with better knowledge of screening it had no differential effect on intention and its effect on attendance still requires evaluation.

The GRAIDS Trial: a cluster randomised controlled trial of computer decision support for the management of familial cancer risk in primary care

The objective was to evaluate the effect of an assessment strategy using the computer decision support system (the GRAIDS software), on the management of familial cancer risk in British general practice in comparison with best current practice. The design included cluster randomised controlled trial, and involved forty-five general practice teams in East Anglia, UK. Randomised to GRAIDS (Genetic Risk Assessment on the Internet with Decision Support) support (intervention n=23) or comparison (n=22). Training in the new assessment strategy and access to the GRAIDS software (GRAIDS arm) was conducted, compared with an educational session and guidelines about managing familial breast and colorectal cancer risk (comparison) were mailed. Outcomes were measured at practice, practitioner and patient levels. The primary outcome measure, at practice level, was the proportion of referrals made to the Regional Genetics Clinic for familial breast or colorectal cancer that were consistent with referral guidelines. Other measures included practitioner confidence in managing familial cancer (GRAIDS arm only) and, in patients: cancer worry, risk perception and knowledge about familial cancer. There were more referrals to the Regional Genetics Clinic from GRAIDS than comparison practices (mean 6.2 and 3.2 referrals per 10 000 registered patients per year; mean difference 3.0 referrals; 95% confidence interval (CI) 1.2–4.8; P=0.001); referrals from GRAIDS practices were more likely to be consistent with referral guidelines (odds ratio (OR)=5.2; 95% CI 1.7–15.8, P=0.006). Patients referred from GRAIDS practices had lower cancer worry scores at the point of referral (mean difference −1.44 95% CI −2.64 to −0.23, P=0.02). There were no differences in patient knowledge about familial cancer. The intervention increased GPs' confidence in managing familial cancer. Compared with education and mailed guidelines, assessment including computer decision support increased the number and quality of referrals to the Regional Genetics Clinic for familial cancer risk, improved practitioner confidence and had no adverse psychological effects in patients. Trials are registered under N0181144343 in the UK National Research Register.

Designing and evaluating complex interventions to improve health care

Determining the effectiveness of complex interventions can be difficult and time consuming. Neil C Campbell and colleagues explain the importance of ground work in getting usable results

Designing and evaluating complex interventions to improve health care

Determining the effectiveness of complex interventions can be difficult and time consuming. Neil C Campbell and colleagues explain the importance of ground work in getting usable results

What determines the cost-effectiveness of diabetes screening?

AIMS/HYPOTHESIS

The cost-effectiveness of screening for diabetes is unknown but has been modelled previously. None of these models has taken account of uncertainty. We aimed to describe these uncertainties in a model where the outcome was CHD risk.

SUBJECTS AND METHODS

Our model used population data from the Danish Inter99 study, and simulations were run in a theoretical population of 1,000,000 individuals. CHD risk was estimated using the UK Prospective Diabetes Study (UKPDS) risk engine, and risk reduction from published randomised clinical trials. Probabilistic sensitivity analysis was used to provide confidence intervals for modelled outputs. Uncertain parameter values were independently simulated from distributions derived from existing literature and deterministic sensitivity analysis performed using multiple model runs under different strategy choices and using extreme parameter estimates.

RESULTS

In the least conservative model (low costs and multiplicative risk reduction for combined treatments), the 95% confidence interval of the incremental cost-effectiveness ratio varied from pound23,300-82,000. The major contributors to this uncertainty were treatment risk reduction model parameters: the risk reduction for hypertension treatment and UKPDS risk model intercept. Overall cost-effectiveness ratio was not sensitive to decisions about which groups to screen, nor the costs of screening or treatment. It was strongly affected by assumptions about how treatments combine to reduce risk.

CONCLUSIONS/INTERPRETATION

Our model suggests that there is considerable uncertainty about whether or not screening for diabetes would be cost-effective. The most important but uncertain parameter is the effect of treatment. In addition to directly influencing current policy decisions, health care modelling can identify important unknown or uncertain parameters that may be the target of future research.

A causal modelling approach to the development of theory-based behaviour change programmes for trial evaluation

Theory-based intervention programmes to support health-related behaviour change aim to increase health impact and improve understanding of mechanisms of behaviour change. However, the science of intervention development remains at an early stage. We present a causal modelling approach to developing complex interventions for evaluation in randomized trials. In this approach a generic model links behavioural determinants, causally through behaviour, to physiological and biochemical variables, and health outcomes. It is tailored to context, target population, behaviours and health outcomes. The development of a specific causal model based on theory and evidence is illustrated by the ProActive programme, supporting increased physical activity among individuals at risk of Type 2 diabetes. The model provides a rational guide to appropriate measures, intervention points and intervention techniques, and can be tested quantitatively. Causal modelling is critically compared to other approaches to intervention development and evaluation, and research directions are indicated.

The DiGEM trial protocol--a randomised controlled trial to determine the effect on glycaemic control of different strategies of blood glucose self-monitoring in people with type 2 diabetes [ISRCTN47464659]

BACKGROUND

We do not yet know how to use blood glucose self-monitoring (BGSM) most effectively in the self-management of type 2 diabetes treated with oral medication. Training in monitoring may be most effective in improving glycaemic control and well being when results are linked to behavioural change.

METHODS/DESIGN

DiGEM is a three arm randomised parallel group trial set in UK general practices. A total of 450 patients with type 2 diabetes managed with lifestyle or oral glucose lowering medication are included. The trial compares effectiveness of three strategies for monitoring glycaemic control over 12 months (1) a control group with three monthly HbA1c measurements; interpreted with nurse-practitioner; (2) A self-testing of blood glucose group; interpreted with nurse- practitioner to inform adjustment of medication in addition to 1; (3) A self-monitoring of blood glucose group with personal use of results to interpret results in relation to lifestyle changes in addition to 1 and 2. The trial has an 80% power at a 5% level of significance to detect a difference in change in the primary outcome, HbA1c of 0.5% between groups, allowing for an attrition rate of 10%. Secondary outcome measures include health service costs, well-being, and the intervention effect in sub-groups defined by duration of diabetes, current management, health status at baseline and co-morbidity. A mediation analysis will explore the extent to which changes in beliefs about self-management of diabetes between experimental groups leads to changes in outcomes in accordance with the Common Sense Model of illness. The study is open and has recruited more than half the target sample. The trial is expected to report in 2007.

DISCUSSION

The DiGEM intervention and trial design address weaknesses of previous research by use of a sample size with power to detect a clinically significant change in HbA1c, recruitment from a well-characterised primary care population, definition of feasible monitoring and behaviour change strategies based on psychological theory and evidence, and measures along the hypothesised causal path from cognitions to behaviours and disease and well being related outcomes. The trial will provide evidence to support, focus or discourage use of specific BGSM strategies.

The impact of personal and social comparison information about health risk

OBJECTIVES

To examine the emotional and cognitive impact of personal and social comparison information about health risk.

METHODS

A total of 970 adults responded to vignettes describing risk presentation scenarios that varied in terms of having (a) a 'real world' analogue (cardiac event) versus no such analogue (a fictitious pancreatic disease) condition, (b) high versus low levels of personal risk, and (c) no comparison group information given, comparison group risk higher or lower than own risk.

RESULTS

For both the cardiac and pancreatic disease vignettes, respondents' emotional responses and estimates of their own risk were influenced by both personal and social comparison risk information. The cardiac event vignettes produced larger effects than the pancreatic disease vignettes. Unfavourable social comparison information had no discernible impact, relative to not providing any social comparison information. Favourable social comparison information resulted in greater reassurance, less worry, and perceptions of lower susceptibility. Lower personal risk generally produced similar effects, relative to higher personal risk.

CONCLUSIONS

In contrast to previous theory and research in this area, we found that both personal and (favourable) social comparison risk information have emotional and cognitive consequences. We hypothesize that the perceived clarity of the information may account for the different patterns of findings in the literature.

Evidence against the use of lumbar spine radiography for low back pain

AIM

To review abnormalities reported on plain radiographic examination of the lumbar spine in patients referred with low back pain by general practitioners. Additionally, we evaluated and stratified the prevalence of these abnormalities by age. Finally, the diagnostic impact of lumbar spine radiography for the diagnosis of degenerative change, fracture, infection and possible tumour, was modelled.

MATERIALS AND METHODS

A retrospective review of 2007 radiographic reports of patients referred with low back pain for lumbar spine radiography to a large radiology department was performed. The reports were classified into different diagnostic groups and subsequently stratified according to age. The potential diagnostic impact of lumbar spine radiography was modelled by using the prevalence of conditions studied as pre-test probabilities of disease.

RESULTS

The prevalence of reported lumbar spine degeneration increased with age to 71% in patients aged 65-74 years. The overall prevalence of fracture, possible infection, possible tumour was low in our study population: 4, 0.8 and 0.7%, respectively. Fracture and possible infection showed no association with age. Possible tumour was only reported in patients older than 55 years of age.

CONCLUSION

Although the prevalence of degenerative changes was high in older patients, the therapeutic consequences of diagnosing this abnormality are minor. The prevalence of possible serious conditions was very low in all age categories, which implies radiation exposure in many patients with no significant lesions.

A service-academic partnership in primary care research: one practice's experience

Further development of a strong research base for general practice is important if the profession is to respond appropriately to its central role in service provision. It can be difficult for general practitioners (GPs) who have not pursued an academic career path to make a significant contribution to research. The development of a service-academic partnership is described, together with an honest account of the difficulties encountered.

Participating in the United Kingdom Prospective Diabetes Study (UKPDS): a qualitative study of patients' experiences

The United Kingdom Prospective Diabetes Study (UKPDS) is one of the longest and largest clinical trials ever conducted. It explored the effects of intensive blood glucose and blood pressure control on the development of complications in patients with type 2 diabetes. Patients took part in this trial for up to 20 years and the drop-out rate was extremely low. The aim of this discussion paper is to explore patients' motivations for joining the UKPDS and for remaining in the trial, and to examine the implications of findings for good practice before, during, and after clinical trials. A qualitative, exploratory study was undertaken, involving former UKPDS patients (n = 10) at Northampton General Hospital, England. In-depth, semi-structured interviews were undertaken and the data analysed using grounded theory approaches. The results showed that patients were motivated to join the UKPDS because they believed this would give them the best clinical care and reduce the threat of the disease. However, all of the patients identified unanticipated benefits of trial participation, to which they attributed their strong commitment to the UKPDS. These included the reassurance provided by regular clinical examinations, the personal nature of clinical care, and the welcome discipline imposed by UKPDS professionals. Transition back to primary care at trial closure could be a lonely experience, despite follow-up being seen as competent. Practitioners involved in recruiting patients for clinical trials should be aware that participants may be motivated by the desire for better clinical care, irrespective of randomisation consequences. Those taking back the clinical care of trial participants with chronic disease may wish to consider a 're-entry' interview, to minimise trial bereavement.

Women's views of consultations about familial risk of breast cancer in primary care

Developments within genetic testing may increase demands on general practitioners to advise about family history of breast cancer (FHBC). This descriptive, qualitative study, investigated women's views of GP consultations about FHBC and their context. Participants were women from the general population who had experienced a primary care consultation in which FHBC was mentioned, as reported by the practitioner. Information about women's views of consultation context was obtained from 72 telephone interviews. More in-depth information about context and women's evaluations of FHBC consultations were obtained from a sub-sample of 20 face to face interviews. FHBC was rarely the main focus of consultations. It featured as a part of an overall discussion of breast symptoms, treatment and cancer risk. Women's understanding of heredity and disease was often idiosyncratic and might differ from biomedical models. A main task for clinicians appeared to be appropriate reassurance. Failure to reassure was linked to a failure to provide explanations at the woman's level of understanding. Clinicians cannot assume that patients share their perceptions of the mechanisms of disease and heredity. Instead they need to ascertain the patient's understanding and provide explanations accordingly. GPs need to have, or access, enough knowledge to inform and reassure.

Primary care referrals for lumbar spine radiography: diagnostic yield and clinical guidelines

BACKGROUND

Primary care requests for radiographs of the lumbar spine have come under increasing scrutiny. Guidelines aiming to reduce unnecessary radiographs by limiting referrals to patients at high risk of serious disease have been widely distributed. Trial evidence suggests that guidelines can reduce radiography referrals. It is not clear whether this reduction has been achieved in routine practice.

AIM

This study, using routine data, was conducted to measure trends in pnmary care referrals for lumbar spine radiography at two hospitals between 1994 and 1999.

DESIGN OF STUDY

Analysis of primary care requests for lumbar spine radiography from computerised records.

SETTING

Addenbrooke's Hospital, Cambridge (1 July 1994 to 30 June 1999), and Ipswich General Hospital (1 July 1995 to 30 June 1999), United Kingdom.

METHOD

All primary care requests for lumbar radiography were identified electronically from computerised information systems. A random sample of 2100 radiography reports were classified according to clinical importance. These classifications were used to examine whether the proportion of radiographs demonstrating potentially more serious findings had increased between 1994 and 1999.

RESULTS

There was no evidence that primary care referrals for radiography of the lumbar spine had decreased between 1994 and 1999 at either hospital. General practitioners did not progressively refer more high-risk patients for lumbar radiography. Only a small proportion of patients had important radiographic findings that might warrant specialist referral or specific therapy.

CONCLUSION

The implementation of diagnostic guidelines offers much to the NHS. However in these two hospitals, the reduction in radiograph utilisation evident in trials was not achieved. Guideline development is a resource intensive process; distribution must be supported by more effective implementation strategies.

Problems with the performance of the SF-36 among people with type 2 diabetes in general practice

OBJECTIVE

To validate the short form-36 (SF-36) among people with type 2 diabetes in general practice, and to make comparisons with the Audit of Diabetes Dependent Quality of Life (ADDQoL).

DESIGN

Postal survey with one reminder.

SETTING

Four general practices.

PATIENTS

One hundred and eighty-four eligible patients (30-70 years) with type 2 diabetes on 14 general practitioner lists.

MEASURES

SF-36 response rates, distribution of dimension scores and internal consistency. Median scores in relation to sociodemography and self-reported health. Comparisons with ADDQoL scores.

RESULTS

One hundred and thirty-one patients responded (71%). Distributions of SF-36 dimension scores were mostly skewed. Internal consistency and construct validity were acceptable, with predictable sociodemographic trends. People with illness related to or unrelated to diabetes scored significantly lower on most dimensions. SF-36 dimension scores correlated best with relevant diabetes-specific ADDQoL scores amongst respondents reporting no comorbidity.

CONCLUSIONS

Although valid and reliable, SF-36 scores are strongly affected by non-diabetic comorbidity in type 2 diabetes, supporting the complementary use of a diabetes-specific measure, providing information about the impact of diabetes specifically.

Dimensional perspective on the recognition of depressive symptoms in primary care: The Hampshire Depression Project 3

BACKGROUND

Most studies of the recognition of depression in primary care have used a categorical definition of depression. This may overstate the extent of the problem.

AIMS

Our objective was to investigate the relationship between severity and recognition of depression, and its modification by patient and practitioner characteristics.

METHOD

An association study in multiple consecutive adult cohorts of 18 414 primary care consultations drawn from a representative sample of 156 general practitioners in Hampshire, UK.

RESULTS

There was a curvilinear relationship between the severity of depression and practitioners' ratings of depression. One case of probable depression was missed in every 28.6 consultations. Anxiety and unemployment altered the chances of recognition, but age, gender and deprivation scores did not.

CONCLUSIONS

A dimensional approach to severity of depression shows that general practitioners may be better able to recognise depression than previous categorical studies have suggested. Efforts to improve the care of depression should therefore focus on doctors who have been shown to have difficulty making the diagnosis and on improving the treatment of identified patients.

Experiences and expectations of the new genetics in relation to familial risk of breast cancer: a comparison of the views of GPs and practice nurses

BACKGROUND

Advances in genetics may change the practice of medicine in many ways. Ascertaining practitioners' perceptions about managing the risk of familial breast cancer can give an insight into the current and expected impact on general practice to inform relevant education. Little is known about the practice nurses' (PNs) views of the new genetics in comparison with those of the GP.

OBJECTIVES

Our aim was to describe and compare the views of GPs and PNs on their experiences and expectations of the new genetics in relation to managing familial risk of breast cancer.

METHOD

A questionnaire, assessing views on the current and future impact of genetic advances in general and on the management of women with a familial risk of breast cancer, was sent to all GPs and PNs in the 66 practices of the Cambridge and Huntingdon Health Authority.

RESULTS

There was a 69% response rate. The words 'cautious', 'mixed feelings', 'hopeful' and 'optimistic' were used most frequently in response to views on genetic advances, but PNs chose more positive words than GPs (P < 0.001). PNs were also more optimistic than GPs in relation to the future positive impact of genetics on practice (P < 0.0001). Sixty-one per cent of GPs and 45% of PNs agreed that genetic advances in relation to breast cancer were already affecting their work. A minority of practitioners had attended recent educational events in risk assessment for breast cancer, and only 8% of GPs reported a practice policy on familial breast cancer risk management.

CONCLUSIONS

GPs and PNs show a cautious optimism in relation to advances in genetics, with PNs most optimistic. Many perceive that genetic advances in relation to breast cancer are already affecting their workloads, yet educational attendance and practice policies are lacking. Given PN involvement, multi-professional education may be appropriate. Education about risk management, including family history and genetics, might be better integrated into more general teaching on the prevention and management of breast cancer, than taught alone.

Prevalence of untreated asthma in a population sample of 6000 older adults in Bristol, UK

BACKGROUND

A study was undertaken to estimate the prevalence of untreated asthma in older adults.

METHODS

A cross sectional population based survey of 6000 men and women aged 65 years and over was performed in 21 general practices in north Bristol, south west England. The main outcome measure was untreated asthma as defined by a two stage process comprising a respiratory questionnaire (symptoms suggestive of asthma or doctor diagnosed asthma not receiving respiratory treatment) followed by lung function tests (significant reversibility following bronchodilators or corticosteroids and/or significant within day variability in peak expiratory flow).

RESULTS

4792 of the 6000 participants (80%) completed the respiratory questionnaire and, of those not receiving respiratory treatment, 55 reported a previous doctor diagnosis of asthma and a further 696 had symptoms suggestive of asthma. Lung function testing in 280 of 501 randomly selected individuals from these groups resulted in 38 being defined as having asthma and an estimated population prevalence for untreated asthma of 2.4% (95% CI 1.6% to 3.6%) in men and 1.2% (95% CI 0.7% to 2.1%) in women. Most subjects (84%) with untreated asthma had moderate or severe disease. Untreated asthma was most common in individuals with doctor diagnosed asthma (21%) and those with breathlessness or wheeze (13-20%).

CONCLUSION

Untreated asthma in the elderly is a common and important problem. Opportunistic use of appropriate lung function tests in older people with a history of doctor diagnosed asthma or wheeze or breathlessness at rest could identify untreated asthmatics who might benefit from treatment.