Assessing workload in general practice in England before and after the introduction of the pay-for-performance contract.

AIM: This paper is a report of a study conducted to describe changes in practice team size and composition, and the workload of doctors and nursing staff, before (2003) and after (2005) the introduction of the pay-for-performance contract for general practice. BACKGROUND: In 2004, a new pay-for-performance contract for general practice was introduced in England. This improved the quality but may also have altered practice workload, including the workload of nursing staff. METHOD: Practice profile questionnaires and staff workload diaries were completed in 42 practices in England in 2003 and 2005. Managers provided information on team size and composition in 2003 and 2005. One week workload diaries were completed by doctors and nursing staff in both years. Diaries recorded: hours of work, number and complexity of patient visits, and types of problems (acute, chronic, preventative). FINDINGS: The number of practice staff increased with greater increases observed for nursing staff than doctors. There was no change in the average number of hours worked per week by nursing staff or doctors but nurse visit rates increased while doctors' rates decreased. The proportion of presenting problems described as chronic or preventative increased for doctors (chi(2)= 8.54, d.f. = 1, P < 0.004) but was unchanged for nursing staff. Nursing staff dealt with more complex visits in 2005 compared to 2003 (chi(2) = 30.70, d.f. = 3, P < 0.001) but there was no change for doctors. CONCLUSION: General practices may have responded to the 2004 contract by increasing staffing levels, with nursing staff absorbing a higher proportion of the clinical workload and doctors focusing more attention on chronic and preventive care. Expanding nursing staff roles may increase the quality of primary care but may lead also to intensification of nurses' work.

Small vessel remodeling and impaired endothelial-dependent dilatation in subcutaneous resistance arteries from patients with acromegaly.

CONTEXT: Patients with acromegaly have increased morbidity and mortality, predominantly from cardiovascular disease. Hypertension and diabetes are more prevalent, and both cause small vessel remodeling and endothelial dysfunction. OBJECTIVE: To understand the structure and function of small arteries in acromegaly, sc blood vessels from gluteal fat biopsies were harvested from 18 patients with active disease (AD; age, 56 +/- 15 yr; 14 males), 23 patients in remission (CD; age, 55 +/- 12 yr; 15 males), and 20 healthy controls (age, 55 +/- 11 yr; 10 males) and examined in vitro using pressure myography. DESIGN: Contractile responses to cumulative noradrenaline concentrations were recorded and followed by dose-dependent dilator responses to acetylcholine. The acetylcholine protocol was repeated after incubation with a nitric oxide synthase inhibitor (N-nitro-L-arginine methyl ester) and cyclooxygenase inhibitor (indomethacin). After perfusion with Ca(2+)-free physiological saline solution, structural measurements were recorded at varying intraluminal pressures (3-180 mm Hg). RESULTS: Wall thickness and wall:lumen ratio were increased in AD, reduced with treatment but remained greater in CD than controls. Wall cross-sectional area was increased in AD vs. controls (P < 0.001), decreased with treatment (AD vs. CD, P < 0.001), but remained higher than controls (CD vs. controls, P = 0.015). Growth index was increased in AD (20%) compared to controls (CD, 9%). Contractility was similar in all groups. Endothelial-dependent dysfunction was evident in AD compared with CD (P < 0.001) and controls (P < 0.01). Dilation did not change after N-nitro-L-arginine methyl ester but was impaired after indomethacin incubation. CONCLUSION: Active acromegaly is associated with hypertrophic remodeling of the vascular wall and embarrassed endothelial function due to reduced nitric oxide and endothelium-derived hyperpolarizing factor bioavailability, both of which may contribute to the early mortality from cardiovascular disease.

Moving specialist care into the community: an initial evaluation.

OBJECTIVES: To assess the likely impact on patients and local health economies of shifting specialist care from hospitals to the community in 30 demonstration sites in England. METHODS: The evaluation comprised: interviews with service providers at 30 sites, supplemented by interviews with commissioners, GPs and hospital doctors at 12 sites; economic case studies in six sites; and patient surveys at 30 sites plus at nine conventional outpatient services. Outcomes comprised: staff views of service organization and development, impact on primary and secondary care, and benefits for patients; cost per consultation and cost per patient in new services compared to estimates of the price of services if undertaken by hospitals; patients' views of waiting time, access, quality (technical and interpersonal), coordination and satisfaction. RESULTS: New services required high initial investment in staff, premises and equipment, and the support of hospital consultants. Most new services were added to existing hospital services so expanded capacity. Patient reported waiting times (6.7 versus 10.1 weeks; p = 0.001); technical quality of care (96.2 versus 94.5; p < 0.001), overall satisfaction (88.2 versus 85.4; p = 0.04); and access (72.2 versus 65.8; p = 0.001) were significantly better for new compared to conventional services but there was no significant difference in coordination or interpersonal quality of care. Some service providers expressed concerns about service quality. New services dealt with less complex conditions and undercut the price tariff applied to hospitals thus providing a cost saving to commissioners. There was some concern that expansion of new services might destabilize hospitals. CONCLUSIONS: Moving specialist care into the community can improve patient access, particularly when new services are added to existing hospital services. Wider impacts on health care quality, capacity and cost merit closer scrutiny before rollout.

General practice factors and MMR vaccine uptake: structure, process and demography.

BACKGROUND: Despite the fall in MMR uptake between 1998 and 2004, some general practices managed to sustain remarkably high MMR coverage. METHODS: The aim of the study was to identify general practice factors associated with high MMR vaccine coverage. The study population included 257 general practices in Cumbria and Lancashire in 2005. Practice level MMR coverage data for 2002-04 were obtained from the child health information systems of eight Primary Care Trusts (PCTs) and linked to information on practice structure, census indicators for deprivation and ethnicity data at lower level super output area and information from a questionnaire survey of practice nurses. RESULTS: Mean MMR uptake was 86.4% with a range from 59 to 98%. Twenty-eight per cent (74/257) practices achieved the Department of Health higher target payment level of 90%. The uptake was not associated with practice size, the number of general practitioners (GPs) or practice nurses. There was no correlation between uptake and deprivation or the percentage of non-white population. There was a strong negative association between MMR uptake and barriers to housing and services (r = -0.230, P < 0.001). On the basis of a questionnaire response rate of 75.9%, having a strategic approach to MMR with clear objectives was associated with MMR uptake of 90% or above (odds ratio, 3.76, 1.26-12.04). There was no association between immunization by GP, practice nurse or health visitor. CONCLUSIONS: There are no easily identifiable characteristics of high-uptake MMR practices although having a strategic approach to MMR is important. Practices in rural areas should endeavour to ensure easy access to child vaccination. High uptake can be achieved by practices in deprived areas. Further research is needed to identify practice system factors associated with high MMR uptake.

Effects of early growth on blood pressure of infants of British European and South Asian origin at one year of age: the Manchester children's growth and vascular health study.

OBJECTIVE: The objective of this study was to investigate early influences of postnatal growth on blood pressure (BP) in healthy, British-born South Asian and European origin infants. We tested the hypotheses that South Asian infants would be smaller in all body dimensions (length and weight) with higher relative truncal skinfold thickness at birth, and that increased (central) adiposity and accelerated growth up to 1 year would be associated with higher BP in both ethnic groups. PATIENTS AND METHODS: Five hundred and sixty infants were followed prospectively from birth to 3 and/or 12 months with measures of anthropometry and resting BP, compared against a UK 1990 growth reference, and analysed using regression methods. RESULTS: Marked differences in birth size persisted, as expected, between European and South Asian babies, but with a sexual dichotomy: South Asian boys were smaller in all anthropometric parameters (P < 0.001), including skinfolds (P < 0.05), than European boys, but South Asian girls, although smaller in length and weight, had similar skinfolds to European girls and thus a slightly larger subscapular skinfold thickness relative to birth weight [1.3 versus 1.2, mean difference 0.07, 95% confidence interval (CI) 0.0009-0.14, P = 0.047]. The dichotomy persisted postnatally; South Asian boys showed a striking early increase in weight and length compared with European boys, associated with significant accrual of subscapular fat (6.1 versus 5.3 mm, mean difference 0.8, 95% CI 0.3-1.3, P = 0.003). In gender and ethnicity adjusted regression models, infants with the largest weight standard deviation score (SDS) increases in the first 3 months had the highest 12-month systolic BP (beta = 2.4, 95% CI 0.5-4.2, P = 0.01), while those with the greatest birth length (beta = 0.7, 95% CI 0.05-1.4, P = 0.04) but the smallest changes in length over 3-12 months (beta = -0.57, 95% CI -0.95 to -0.19, P = 0.004) had the highest diastolic BP. CONCLUSIONS: Ethnic and gender differences in growth and adiposity present in early infancy include truncal fat preservation in South Asian girls from birth, which in boys is related to rapid early weight gain. Weight gain during the first 3 months appears to drive the rise in systolic BP to 1 year, itself a likely driver of later BP.

Critical appraisal for public health: a new checklist.

OBJECTIVES: There have been a number of attempts to develop critical appraisal tools, but few have had a public health focus. This paper describes a new checklist with public health aspects. STUDY DESIGN: Review of previous appraisal instruments and pilot test of new checklist. METHODS: Criteria of particular reference to public health practice were added to well-established appraisal criteria. The checklist was piloted with 21 public health professionals, research staff or postgraduate students. RESULTS: The checklist is organized using the 'ask', 'collect', 'understand' and 'use' categories of the Population Health Evidence Cycle. Readers are asked to assess validity, completeness and transferability of the data as they relate to: the study question; key aspects of the methodology; possible public health implications of the key results; and the implications for implementation in their own public health practice. Of the 21 public health professionals that piloted the checklist, 20 said that they found the checklist useful and 18 would use it or recommend it in the future. Participants were prepared to commit to the majority of the questions, and there was good agreement with a consensus of 'correct' answers. CONCLUSIONS: The public health critical appraisal checklist adds public health aspects that were missing from previous critical appraisal tools.

Should we encourage over-the-counter statins? A population perspective for coronary heart disease prevention.

BACKGROUND: Prescribed statin therapy has contributed to a dramatic reduction in primary and secondary coronary heart disease (CHD). In the UK, simvastatin is currently available without prescription; however, the US FDA rejected an application for nonprescription lovastatin in 2005. OBJECTIVE AND METHODS: We used population impact measures for three hypothetical levels of CHD risk to estimate the number of CHD events that would be prevented in the US over 5 years under three scenarios: (i) prescription-only regulations; (ii) approval of over-the-counter (OTC) statins; and (iii) implementation of lifestyle interventions. RESULTS: For people at very low risk of CHD, 429,299 CHD events could be prevented by the availability of OTC statins and 560,243 CHD events could be prevented among this group by implementing lifestyle interventions. For those at moderate risk of CHD, 244,388 CHD events could be prevented by OTC statins compared with 318 866 by lifestyle interventions. For people at high risk of CHD, prescription statins could prevent 374,897 CHD events over the next 5 years. CONCLUSIONS: Provision of OTC statins to US adults at low or moderate risk of CHD would have a greater impact on CHD prevention than providing prescription statins for those at high risk of CHD. Provision of OTC statins alongside lifestyle interventions among those at low or moderate risk of CHD could substantially reduce the number of CHD events in the population.

The population effect of crime and neighbourhood on physical activity: an analysis of 15,461 adults.

Area-based interventions offer the potential to increase physical activity for many sedentary people in countries such as the UK. Evidence on the effect of individual and area/neighbourhood influences on physical activity is in its infancy, and despite its value to policy makers a population focus is rarely used. Data from a population-based health and lifestyle survey of adults in northwest England were used to analyse associations between individual and neighbourhood perceptions and physical activity. The population effect of eliminating a risk factor was expressed as a likely effect on population levels of physical activity. Of the 15,461 responders, 21,923 (27.1%) were physically active. Neighbourhood perceptions of leisure facilities were associated with physical activity, but no association was found for sense of belonging, public transport or shopping facilities. People who felt safe in their neighbourhood were more likely to be physically active, but no associations were found for vandalism, assaults, muggings or experience of crime. The number of physically active people would increase by 3290 if feelings of "unsafe" during the day were removed, and by 11,237 if feelings of "unsafe" during the night were removed. An additional 8342 people would be physically active if everyone believed that they were "very well placed for leisure facilities". Feeling safe had the potential largest effect on population levels of physical activity. Strategies to increase physical activity in the population need to consider the wider determinants of health-related behaviour, including fear of crime and safety.

Prioritising between direct observation of therapy and case-finding interventions for tuberculosis: use of population impact measures.

BACKGROUND: Population impact measures (PIMs) have been developed as tools to help policy-makers with locally relevant decisions over health risks and benefits. This involves estimating and prioritizing potential benefits of interventions in specific populations. Using tuberculosis (TB) in India as an example, we examined the population impact of two interventions: direct observation of therapy and increasing case-finding. METHODS: PIMs were calculated using published literature and national data for India, and applied to a notional population of 100,000 people. Data included the incidence or prevalence of smear-positive TB and the relative risk reduction from increasing case finding and the use of direct observation of therapy (applied to the baseline risks over the next year), and the incremental proportion of the population eligible for the proposed interventions. RESULTS: In a population of 100,000 people in India, the directly observed component of the Directly Observed Treatment, Short-course (DOTS) programme may prevent 0.188 deaths from TB in the next year compared with 1.79 deaths by increasing TB case finding. The costs of direct observation are (in international dollars) 5960 I dollars and of case finding are 4839 I dollars or 31702 I dollars and 2703 I dollars per life saved respectively. CONCLUSION: Increasing case-finding for TB will save nearly 10 times more lives than will the use of the directly observed component of DOTS in India, at a smaller cost per life saved. The demonstration of the population impact, using simple and explicit numbers, may be of value to policy-makers as they prioritize interventions for their populations.

The assessment of autonomic function in chronic atrial fibrillation: description of a non-invasive technique based on circadian rhythm of atrioventricular nodal functional refractory periods.

AIMS: Heart rate variability (HRV) parameters can be used to assess autonomic function and to predict outcome, but this has been done exclusively in patients with sinus rhythm. Atrial fibrillation (AF) is the commonest sustained arrhythmia and is particularly prevalent in heart failure. We have developed a simple index to assess autonomic function in patients with chronic AF. METHODS AND RESULTS: Forty patients with chronic AF (>1 month) and symptoms of heart failure underwent ambulatory 24 h electrocardiography recording as well as evaluation of symptoms, exercise capacity (6 min walk distance), ventricular function (echocardiography and radionuclide ventriculography), and neuroendocrine activation. A number of standard HRV parameters shown to have prognostic significance in sinus rhythm were also determined. A modified in-house HRV statistical programme was used to filter labelled QRS intervals and to compute the 5th percentile RR interval in each hour. This parameter has been shown to approximate the functional refractory period (FRP) of the atrioventricular node (AVN). A cosine curve was fitted to hourly 5th percentile RR intervals for each patient and from this was estimated the diurnal change in hourly 5th percentile RR interval (approximating DeltaFRP of the AVN) and, by inference, diurnal variation in sympathovagal input to the AVN. Digoxin was the sole agent permitted for control of ventricular rate. DeltaFRP of the AVN varied and revealed a significant correlation, on multivariate analysis, with mean RR interval (P<0.001), SDARR (SD of 5-min average RR intervals during 24 h, P<0.001), and NYHA class of heart failure (classes III and IV heart failure vs. classes I and II, P=0.02). SDARR has previously been shown independently to predict mortality in patients with chronic AF and heart failure. CONCLUSION: This analysis describes a novel non-invasive method for assessing autonomic function in chronic AF. Whether DeltaFRP in chronic AF patients can independently predict adverse prognosis or sudden death requires further study.

Impact of specialist care on clinical outcomes for medical emergencies.

General hospitals have commonly involved a wide range of medical specialists in the care of unselected medical emergency admissions. In 1999, the Royal Liverpool University Hospital, a 915-bed hospital with a busy emergency service, changed its system of care for medical emergencies to allow early placement of admitted patients under the care of the most appropriate specialist team, with interim care provided by specialist acute physicians on an acute medicine unit - a system we have termed 'specialty triage'. Here we describe a retrospective study in which all 133,509 emergency medical admissions from February 1995 to January 2003 were analysed by time-series analysis with correction for the underlying downward trend from 1995 to 2003. This showed that the implementation of specialty triage in May 1999 was associated with a subsequent additional reduction in the mortality of the under-65 age group by 0.64% (95% CI 0.11 to 1.17%; P=0.021) from the 2.4% mortality rate prior to specialty triage, equivalent to approximately 51 fewer deaths per year. No significant effect was seen for those over 65 or all age groups together when corrected for the underlying trend. Length of stay and readmission rates showed a consistent downward trend that was not significantly affected by specialty triage. The data suggest that appropriate specialist management improves outcomes for medical emergencies, particularly amongst younger patients.

Using economic analyses for local priority setting : the population cost-impact approach.

INTRODUCTION: Standard methods of economic analysis may not be suitable for local decision making that is specific to a particular population. BACKGROUND: We describe a new three-step methodology, termed 'population cost-impact analysis', which provides a population perspective to the costs and benefits of alternative interventions. The first two steps involve calculating the population impact and the costs of the proposed interventions relevant to local conditions. This involves the calculation of population impact measures (which have been previously described but are not currently used extensively) - measures of absolute risk and risk reduction, applied to a population denominator. In step three, preferences of policy-makers are obtained. This is in contrast to the QALY approach in which quality weights are obtained as a part of the measurement of benefit. METHODS: We applied the population cost-impact analysis method to a comparison of two interventions - increasing the use of beta-adrenoceptor antagonists (beta-blockers) and smoking cessation - after myocardial infarction in a scaled-back notional local population of 100,000 people in England. Twenty-two public health professionals were asked via a questionnaire to rank the order in which they would implement four interventions. They were given information on both population cost impact and QALYs for each intervention. RESULTS: In a population of 100,000 people, moving from current to best practice for beta-adrenoceptor antagonists and smoking cessation will prevent 11 and 4 deaths (or gain of 127 or 42 life-years), respectively. The cost per event prevented in the next year, or life-year gained, is less for beta-adrenoceptor antagonists than for smoking cessation. Public health professionals were found to be more inclined to rank alternative interventions according to the population cost impact than the QALY approach. DISCUSSION: The use of the population cost-impact approach allows information on the benefits of moving from current to best practice to be presented in terms of the benefits and costs to a particular population. The process for deciding between alternative interventions in a prioritisation exercise may differ according to the local context. We suggest that the valuation of the benefit is performed after the benefits have been quantified and that it takes into account local issues relevant to prioritisation. It would be an appropriate next step to experiment with, and formalise, this part of the population cost-impact analysis to provide a standardised approach for determining willingness to pay and provide a ranking of priorities. CONCLUSION: Our method adds a new dimension to economic analysis, the ability to identify costs and benefits of potential interventions to a defined population, which may be of considerable use for policy makers working at the local level.

Helping to prioritise interventions for depression and schizophrenia: use of Population Impact Measures.

BACKGROUND: To demonstrate the potential of Population Impact Measures in helping to prioritise alternative interventions for psychiatry, this paper estimates the number of relapses and hospital readmissions prevented for depression and schizophrenia by adopting best practice recommendations. The results are designed to relate to particular local populations. METHODS: Literature-based estimates of disease prevalence, relapse and re-admission rates, current and best practice treatment rates, levels of adherence with interventions and relative risk reduction associated with different interventions were obtained and calculations made of the Number of Events Prevented in your Population (NEPP). RESULTS: In a notional population of 100,000 adults, going from current to 'best' practice for different interventions, the number of relapses prevented in the next year for schizophrenia were 6 (increasing adherence to medication), 23 (family intervention), 43 (relapse prevention), and 44 (early intervention); and for depression the number of relapses prevented in the next year were 100 (increasing care management), 227 (continuing treatment with antidepressants), 279 (increasing rate of diagnosis), and 325 (Cognitive Behaviour Therapy). Hospital re-admissions prevented in the next year for schizophrenia were 6 (increasing adherence to medication), 36 (relapse prevention) and 40 (early intervention). CONCLUSION: Population Impact measures provide the possibility for a policy-maker to see the impact of a new intervention on the population as a whole, and to compare alternative interventions to best improve psychiatric disease outcomes. The methods are much simpler than others, and have the advantage of being transparent.

Factors influencing emergency medical readmission risk in a UK district general hospital: A prospective study.

BACKGROUND: Over recent years increased emphasis has been given to performance monitoring of NHS hospitals, including overall number of hospital readmissions, which however are often sub-optimally adjusted for case-mix. We therefore conducted a study to examine the effect of various patient and disease factors on the risk of emergency medical readmission. METHODS: The study setting was a District General Hospital in Greater Manchester and the study period was 4.5-years. All index emergency medical admission during the study period leading to a live discharge were included in the study (n = 20,209). A multivariable proportional hazards modelling was used, based on Hospital Episodes Statistics data, to examine the influence of various baseline factors on readmission risk. Deprivation status was measured with the Townsend deprivation index score. Hazard ratios (HR) and associated 95% confidence intervals (CI) of unplanned emergency medical admission by sex, age group, admission method, diagnostic group, number of coded co-morbidities, length of stay and patient's deprivation status quartile, were calculated. RESULTS: Significant independent predictors of readmission risk at 12 months were male sex (HR 1.13, CI: 1.07-1.2), age (age >75 (HR 1.57, CI 1.45-1.7), number of coded co-morbidities (HR for >4 coded co-morbidities: 1.49 CI: 1.26-1.76), admission via GP referral (HR 0.93, CI 0.88-0.99) and primary diagnosis of heart failure (HR 1.33, CI: 1.16-1.53) and chronic obstructive pulmonary disease/asthma (HR 1.34, CI: 1.21-1.48). Higher level of deprivation was also significantly and independently associated and with increased emergency medical readmission risk at three (HR for the most deprived quartile 1.21, CI: 1.08-1.35), six (HR 1.21, CI: 1.1-1.33) and twelve months (HR 1.25, CI: 1.16-1.36). CONCLUSIONS: There is a potential for improving health and reducing demand for emergency medical admissions with more effective management of patients with heart failure and chronic obstructive airways disease/asthma. There is also a potential for improving health and reducing demand if reasons for increased readmission risk in more deprived patients are understood. The potential influence of deprivation status on readmission risk should be acknowledged, and NHS performance indicators adjustment for deprivation case-mix would be prudent.

Capture-recapture estimates of problem drug use and the use of simulation based confidence intervals in a stratified analysis.

STUDY OBJECTIVE: To establish the prevalence of problem drug use in the 10 local authorities within the Metropolitan County of Greater Manchester between April 2000 and March 2001. SETTING AND PARTICIPANTS: Problem drug users aged 16-54 resident within Greater Manchester who attended community based statutory drug treatment agencies, were in contact with general practitioners, were assessed by arrest referral workers, were in contact with the probation service, or arrested under the Misuse of Drugs Act for offences involving possession of opioids, cocaine, or benzodiazepines. DESIGN: Multi-sample stratified capture-recapture analysis. Patterns of overlaps between data sources were modelled in a log-linear regression to estimate the hidden number of drug users within each of 60 area, age group, and gender strata. Simulation methods were used to generate 95% confidence intervals for the sums of the stratified estimates. MAIN RESULTS: The total number of problem drug users in Greater Manchester was estimated to be 19 255 giving a prevalence of problem drug use of 13.7 (95% CI 13.4 to 15.7) per 1000 population aged 16-54. The ratio of men to women was 3.5:1. The distribution of problem drug users varied across three age groups (16-24, 25-34, and 35-54) and varied between the 10 areas. CONCLUSIONS: Areas in close geographical proximity display different patterns of drug use in terms of prevalence rates and age and gender patterns. This has important implications, both for future planning of service provision and for the way in which the impact of drug misuse interventions are evaluated.

Carvedilol alone or in combination with digoxin for the management of atrial fibrillation in patients with heart failure?

OBJECTIVES: This study examined the relative merits of digoxin, carvedilol, and their combination for the management of patients with atrial fibrillation (AF) and heart failure (HF). BACKGROUND: In patients with AF and HF, both digoxin and beta-blockers reduce the ventricular rate, and both may improve symptoms, but only beta-blockers have been shown to improve prognosis. If combined therapy is not superior to beta-blockers alone, treatment of patients with HF and AF could be simplified by stopping digoxin. METHODS: We enrolled 47 patients (29 males; mean age 68 years) with persistent AF and HF (mean left ventricular ejection fraction [LVEF] 24%) in a randomized, double-blinded, placebo-controlled study. In the first phase of the study, digoxin was compared with the combination of digoxin and carvedilol (four months). In the second phase, digoxin was withdrawn in a double-blinded manner in the carvedilol-treated arm, thus allowing a comparison between digoxin and carvedilol (six months). Investigations were undertaken at baseline and at the end of each phase. RESULTS: Compared with digoxin alone, combination therapy lowered the ventricular rate on 24-h ambulatory electrocardiographic monitoring (p < 0.0001) and during submaximal exercise (p < 0.05), whereas LVEF (p < 0.05) and symptom score (p < 0.05) improved. In phase 2, there was no significant difference between digoxin alone and carvedilol alone in any variable. The mean ventricular rate rose and LVEF fell when patients switched from combination therapy to carvedilol alone. Six-minute walk distance was not significantly influenced by any therapy. CONCLUSIONS: The combination of carvedilol and digoxin appears generally superior to either carvedilol or digoxin alone in the management of AF in patients with HF.

Hierarchical statistical modelling of influenza epidemic dynamics in space and time.

An infectious disease typically spreads via contact between infected and susceptible individuals. Since the small-scale movements and contacts between people are generally not recorded, available data regarding infectious disease are often aggregations in space and time, yielding small-area counts of the number infected during successive, regular time intervals. In this paper, we develop a spatially descriptive, temporally dynamic hierarchical model to be fitted to such data. Disease counts are viewed as a realization from an underlying multivariate autoregressive process, where the relative risk of infection incorporates the space-time dynamic. We take a Bayesian approach, using Markov chain Monte Carlo to compute posterior estimates of all parameters of interest. We apply the methodology to an influenza epidemic in Scotland during the years 1989-1990.