Urinary Sodium Excretion, Blood Pressure, and Risk of Future Cardiovascular Disease and Mortality in Subjects Without Prior Cardiovascular Disease.

Hypertension is a risk factor for cardiovascular disease. Increased urinary sodium excretion, representing dietary sodium intake, is associated with hypertension. Low sodium intake has been associated with increased mortality in observational studies. Further studies should assess whether confounding relationships explain associations between sodium intake and outcomes. We studied UK Biobank participants (n=457 484; mean age, 56.3 years; 44.7% men) with urinary electrolytes and blood pressure data. Estimated daily urinary sodium excretion was calculated using Kawasaki formulae. We analyzed associations between sodium excretion and blood pressure in subjects without cardiovascular disease, treated hypertension, or diabetes mellitus at baseline (n=322 624). We tested relationships between sodium excretion, incidence of fatal and nonfatal cardiovascular disease, heart failure, and mortality. Subjects in higher quintiles of sodium excretion were younger, with more men and higher body mass index. There was a linear relationship between increasing urinary sodium excretion and blood pressure. During median follow-up of 6.99 years, there were 11 932 deaths (1125 cardiovascular deaths) with 10 717 nonfatal cardiovascular events. There was no relationship between quintile of sodium excretion and outcomes. These relationships were unchanged after adjustment for comorbidity or excluding subjects with events during the first 2 years follow-up. No differing risk of incident heart failure (1174 events) existed across sodium excretion quintiles. Urinary sodium excretion correlates with elevated blood pressure in subjects at low cardiovascular risk. No pattern of increased cardiovascular disease, heart failure, or mortality risk was demonstrated with either high or low sodium intake.

A cardiovascular disease policy model: part 2-preparing for economic evaluation and to assess health inequalities.

OBJECTIVES: This is the second of the two papers introducing a cardiovascular disease (CVD) policy model. The first paper described the structure and statistical underpinning of the state-transition model, demonstrating how life expectancy estimates are generated for individuals defined by ASSIGN risk factors. This second paper describes how the model is prepared to undertake economic evaluation. DESIGN: To generate quality-adjusted life expectancy (QALE), the Scottish Health Survey was used to estimate background morbidity (health utilities) and the impact of CVD events (utility decrements). The SF-6D algorithm generated utilities and decrements were modelled using ordinary least squares (OLS). To generate lifetime hospital costs, the Scottish Heart Health Extended Cohort (SHHEC) was linked to the Scottish morbidity and death records (SMR) to cost each continuous inpatient stay (CIS). OLS and restricted cubic splines estimated annual costs before and after each of the first four events. A Kaplan-Meier sample average (KMSA) estimator was then used to weight expected health-related quality of life and costs by the probability of survival. RESULTS: The policy model predicts the change in QALE and lifetime hospital costs as a result of an intervention(s) modifying risk factors. Cost-effectiveness analysis and a full uncertainty analysis can be undertaken, including probabilistic sensitivity analysis. Notably, the impacts according to socioeconomic deprivation status can be made. CONCLUSIONS: The policy model can conduct cost-effectiveness analysis and decision analysis to inform approaches to primary prevention, including individually targeted and population interventions, and to assess impacts on health inequalities.

A cardiovascular disease policy model that predicts life expectancy taking into account socioeconomic deprivation.

OBJECTIVES: A policy model is a model that can evaluate the effectiveness and cost-effectiveness of interventions and inform policy decisions. In this study, we introduce a cardiovascular disease (CVD) policy model which can be used to model remaining life expectancy including a measure of socioeconomic deprivation as an independent risk factor for CVD. DESIGN: A state transition model was developed using the Scottish Heart Health Extended Cohort (SHHEC) linked to Scottish morbidity and death records. Individuals start in a CVD-free state and can transit to three CVD event states plus a non-CVD death state. Individuals who have a non-fatal first event are then followed up until death. Taking a competing risk approach, the cause-specific hazards of a first event are modelled using parametric survival analysis. Survival following a first non-fatal event is also modelled parametrically. We assessed discrimination, validation and calibration of our model. RESULTS: Our model achieved a good level of discrimination in each component (c-statistics for men (women)-non-fatal coronary heart disease (CHD): 0.70 (0.74), non-fatal cerebrovascular disease (CBVD): 0.73 (0.76), fatal CVD: 0.77 (0.80), fatal non-CVD: 0.74 (0.72), survival after non-fatal CHD: 0.68 (0.67) and survival after non-fatal CBVD: 0.65 (0.66)). In general, our model predictions were comparable with observed event rates for a Scottish randomised statin trial population which has an overlapping follow-up period with SHHEC. After applying a calibration factor, our predictions of life expectancy closely match those published in recent national life tables. CONCLUSIONS: Our model can be used to estimate the impact of primary prevention interventions on life expectancy and can assess the impact of interventions on inequalities.

Sex-specific time trends in first admission to hospital for peripheral artery disease in Scotland 1991-2007.

BACKGROUND: This study examined trends for all first hospital admissions for peripheral artery disease (PAD) in Scotland from 1991 to 2007 using the Scottish Morbidity Record. METHODS: First admissions to hospital for PAD were defined as an admission to hospital (inpatient and day-case) with a principal diagnosis of PAD, with no previous admission to hospital (principal or secondary diagnosis) for PAD in the previous 10 years. RESULTS: From 1991 to 2007, 41,593 individuals were admitted to hospital in Scotland for the first time for PAD. Some 23,016 (55.3 per cent) were men (mean(s.d.) age 65.7(11.7) years) and 18,577 were women (aged 70.4(12.8) years). For both sexes the population rate of first admissions to hospital for PAD declined over the study interval: from 66.7 per 100,000 in 1991-1993 to 39.7 per 100,000 in 2006-2007 among men, and from 43.5 to 29.1 per 100,000 respectively among women. After adjustment, the decline was estimated to be 42 per cent in men and 27 per cent in women (rate ratio for 2007 versus 1991: 0.58 (95 per cent confidence interval 0.55 to 0.62) in men and 0.73 (0.68 to 0.78) in women). The intervention rate fell from 80.8 to 74.4 per cent in men and from 77.9 to 64.9 per cent in women. The proportion of hospital admissions as an emergency or transfer increased, from 23.9 to 40.7 per cent among men and from 30.0 to 49.5 per cent among women. CONCLUSION: First hospital admission for PAD in Scotland declined steadily and substantially between 1991 and 2007, with an increase in the proportion that was unplanned.

Aldosterone status associated with insulin resistance in patients with heart failure--data from the ALOFT study.

BACKGROUND: Aldosterone has a key role in the pathophysiology of heart failure. In around 50% of such patients, aldosterone "escapes" from inhibition by drugs that interrupt the renin-angiotensin axis; such patients have a worse clinical outcome. Insulin resistance is a risk factor in heart failure and cardiovascular disease. The relation between aldosterone status and insulin sensitivity was investigated in a cohort of heart failure patients. METHODS: 302 patients with New York Heart Association (NYHA) class II-IV heart failure on conventional therapy were randomised in the ALiskiren Observation of heart Failure Treatment study (ALOFT), designed to test the safety of a directly acting renin inhibitor. Plasma aldosterone and 24-hour urinary aldosterone excretion, as well as fasting insulin and homeostasis model assessment of insulin resistance (HOMA-IR) were measured. Subjects with aldosterone escape and high urinary aldosterone were identified according to previously accepted definitions. RESULTS: 20% of subjects demonstrated aldosterone escape and 34% had high urinary aldosterone levels. At baseline, there was a positive correlation between fasting insulin and plasma (r = 0.22 p<0.01) and urinary aldosterone(r = 0.19 p<0.03). Aldosterone escape and high urinary aldosterone subjects both demonstrated higher levels of fasting insulin (p<0.008, p<0.03), HOMA-IR (p<0.06, p<0.03) and insulin-glucose ratios (p<0.006, p<0.06) when compared to low aldosterone counterparts. All associations remained significant when adjusted for potential confounders. CONCLUSIONS: This study demonstrates a novel direct relation between aldosterone status and insulin resistance in heart failure. This observation merits further study and may identify an additional mechanism that contributes to the adverse clinical outcome associated with aldosterone escape.

Survival after liver transplantation in the United Kingdom and Ireland compared with the United States.

BACKGROUND AND OBJECTIVE: Surgical mortality in the US is widely perceived to be superior to that in the UK. However, previous comparisons of surgical outcome in the two countries have often failed to take sufficient account of case-mix or examine long-term outcome. The standardised nature of liver transplantation practice makes it uniquely placed for undertaking reliable international comparisons of surgical outcome. The objective of this study is to undertake a risk-adjusted disease-specific comparison of both short- and long-term survival of liver transplant recipients in the UK and Ireland with that in the US. METHODS: A multicentre cohort study using two high quality national databases including all adults who underwent a first single organ liver transplant in the UK and Ireland (n = 5925) and the US (n = 41,866) between March 1994 and March 2005. The main outcome measures were post-transplant mortality during the first 90 days, 90 days to 1 year and beyond the first year, adjusted for recipient and donor characteristics. RESULTS: Risk-adjusted mortality in the UK and Ireland was generally higher than in the US during the first 90 days (HR 1.17; 95% CI 1.07 to 1.29), both for patients transplanted for acute liver failure (HR 1.27; 95% CI 1.01 to 1.60) and those transplanted for chronic liver disease (HR 1.18; 95% CI 1.07 to 1.31). Between 90 days and 1 year post-transplantation, no statistically significant differences in overall risk-adjusted mortality were noted between the two cohorts. Survivors of the first post-transplant year in the UK and Ireland had lower overall risk-adjusted mortality than those transplanted in the US (HR 0.88; 95% CI 0.81 to 0.96). This difference was observed among patients transplanted for chronic liver disease (HR 0.88; 95% CI 0.81 to 0.96), but not those transplanted for acute liver failure (HR 1.02; 95% CI 0.70 to 1.50). CONCLUSIONS: Whilst risk-adjusted mortality is higher in the UK and Ireland during the first 90 days following liver transplantation, it is higher in the US among those liver transplant recipients who survived the first post-transplant year. Our results are consistent with the notion that the US has superior acute perioperative care whereas the UK appears to provide better quality chronic care following liver transplantation surgery.

Dental caries experience and use of dental services among preschool children in Ajman, UAE.

OBJECTIVE: The aim of this study was to estimate the prevalence and severity of dental caries in the primary dentition of young children in Ajman, UAE, and investigate its association with sociodemographic characteristics and use of dental services. METHODS: A cluster-sampling approach was used to randomly select children aged 5 or 6 years who were enrolled in public or private schools. Clinical examinations for caries were conducted by a single examiner using World Health Organization criteria. Parents completed questionnaires seeking information on socioeconomic background and dental service utilization. Zero-inflated negative binomial (ZINB) regression modelling was used to identify risk markers and risk indicators for caries experience. RESULTS: The prevalence of dental caries in the sample was high 76.1%. The average dmfs score 10.2. Caries severity was greater among older children and among male children of less educated mothers. Emirati (local) children had higher caries severity than others. Children who had higher level of caries visited the dentist more frequently than other children whose visits were for check-up only. CONCLUSIONS: Dental caries prevalence and severity in young children in Ajman are high, and socioeconomic characteristics and dental utilization are important determinants of their dental caries experience. There is an urgent need for oral health programmes targeted at the treatment and underlying causes of dental caries in these children.

Continuous monitoring of the performance of hip prostheses.

New brands of joint prosthesis are released for general implantation with limited evidence of their long-term performance in patients. The CUSUM continuous monitoring method is a statistical testing procedure which could be used to provide prospective evaluation of brands as soon as implantation in patients begins and give early warning of poor performance. We describe the CUSUM and illustrate the potential value of this monitoring tool by applying it retrospectively to the 3M Capital Hip experience. The results show that if the clinical data and methodology had been available, the CUSUM would have given an alert to the underperformance of this prosthesis almost four years before the issue of a Hazard Notice by the Medical Devices Agency. This indicates that the CUSUM can be a valuable tool in monitoring joint prostheses, subject to timely and complete collection of data. Regional or national joint registries provide an opportunity for future centralised, continuous monitoring of all hip and knee prostheses using these techniques.

Effectiveness of electrochemically activated water as an irrigant in an infected tooth model.

AIM: To test the effectiveness of electrochemically activated aqueous solutions in the debridement of Enterococcus faecalis biofilms in root canals of extracted teeth. METHODOLOGY: Extracted, human, single-rooted teeth (198) assembled into 11 sets (n = 18) with matching anatomical characteristics were randomly assigned to eight experimental groups. After decoronation, the root canals were prepared to a standard size. Enterococcus faecalis biofilms were grown in the root canals of autoclaved, individually mounted teeth over 48 h. Electrolysed saline collected as anolyte at the anode and catholyte at the cathode were the test agents. The four ultrasonication and four without ultrasonication irrigant groups included: neutral anolyte (NA) (pH 6.5), acidic anolyte (AA) (pH 3.0), catholyte (C) (pH 11.5) and C alternated with neutral anolyte (C/NA). Phosphate-buffered saline (PBS) with and without ultrasonication formed negative and NaOCl (3%) positive control groups. After irrigation, root canal samples were serially diluted, cultured and enumerated. The data were analysed as ratios of residual colony-forming units (CFUs) in PBS versus the test irrigants and using multivariate regression. RESULTS: The NA and NA (ultrasonicated, U), C/NA and AA (U) groups had significantly (alpha = 0.05) less and C (U) and C/NA (U) significantly (alpha = 0.05) more bacteria (CFUs mL(-1)) compared with their respective PBS controls. Ultrasonicated C/NA had significantly (alpha = 0.05) higher CFU counts than the nonultrasonicated solution. Other comparisons between ultrasonic and nonultrasonic groups were not significant. Of the nonultrasonicated groups, C/NA and NA were most effective, whilst of the ultrasonicated groups, AA and NA were most effective. None of these was as effective as 3% NaOCl. CONCLUSIONS: All but two groups (AA and C) were significantly different from their PBS controls. There was a significant difference between the C/NA groups with and without ultrasonication but not between other combinations. NA (U) and AA (U) were the most effective test solutions but NaOCl (3%) gave by far the highest bacterial kills.

The utility of the zero-inflated Poisson and zero-inflated negative binomial models: a case study of cross-sectional and longitudinal DMF data examining the effect of socio-economic status.

OBJECTIVES: To examine the utility of the zero-inflated Poisson (ZIP) and zero-inflated negative binomial (ZINB) modelling approaches for modelling four sets of dental caries data from the same cohort study [with particular attention to the influence of childhood socioeconomic status (SES)]: cross-sectional data on the deciduous dentition at age 5 years; cross-sectional data on the permanent dentition at age 18 and 26 years; and longitudinal data on caries increment between ages 18 and 26 years. METHODS: Data on dental caries occurrence at ages 5, 18 and 26 years were obtained from the Dunedin Multidisciplinary Health and Development Study (DMHDS). ZIP and ZINB models were fitted to the cross-sectional (n = 745) and longitudinal (n = 809) data sets using Stata (Intercooled Stata 7.0). The dependent variables for the three cross-sectional analyses were the DMFS indices at age 5, 18, and 26 years, and net DFS increment (NETDFS) was the dependent variable for the longitudinal analysis. RESULTS: The empty ZIP model was a poor fit for all four data sets, whereas the empty ZINB model showed good fit; consequently both the cross-sectional and longitudinal analyses were conducted using ZINB modelling. Being in the high-SES group during childhood was associated with a greater probability of being caries-free by age 18 years, over and above that which would be expected from the negative binomial process. Low childhood SES also had the largest coefficient in the modelling of the negative binomial process, but at age 5 years, where the adjusted mean dmfs score in the low-SES group was 6.8 (compared with 4.7 and 2.9 in the medium- and high-SES groups, respectively). The substantial SES differences which existed at age 5 years (in the deciduous dentition) had reduced somewhat by age 18 years, and had widened again by age 26 years. In the longitudinal analysis, "baseline" caries experience (age 18-year DMFS) was a predictor both of being an extra zero and of caries severity. CONCLUSION: This investigation of the utility of the zero-inflated approach for modelling both cross-sectional and longitudinal caries data has shown that ZIP/ZINB models can provide new insight into disease patterns. It is anticipated that they will become increasingly useful in epidemiological studies that use the DMF index as the outcome measure.

Comparing completely and stratified randomized designs in cluster randomized trials when the stratifying factor is cluster size: a simulation study.

Stratified randomized designs are popular in cluster randomized trials (CRTs) because they increase the chance of the intervention groups being well balanced in terms of identified prognostic factors at baseline and may increase statistical power. The objective of this paper is to assess the gains in power obtained by stratifying randomization by cluster size, when cluster size is associated with an important cluster level factor which is otherwise unaccounted for in data analysis. A simulation study was carried out using a CRT where UK general practices were the randomized units as a template. The results show that when cluster size is strongly associated with a cluster level factor which is predictive of outcome, the stratified randomized design has superior power results to the completely randomized design and that the superiority is related to the number of clusters.

Fluticasone propionate spray and betamethasone sodium phosphate mouthrinse: a randomized crossover study for the treatment of symptomatic oral lichen planus.

BACKGROUND: Symptomatic oral lichen planus (OLP) has been palliated with a wide spectrum of topical and systemic therapies. Although the majority of management strategies include corticosteroids, few have been evaluated in randomized controlled trials. OBJECTIVE: We investigated the acceptability and efficacy of topical fluticasone propionate spray (FP) and betamethasone sodium phosphate mouthrinse (BSP) upon the signs and symptoms of OLP, assessing patient quality of life changes as a consequence of these therapies. METHODS: We implemented a randomized, crossover study in which each drug was administered for a period of 6 weeks with an intervening washout period of 2 weeks at an outpatient oral medicine unit in London, United Kingdom. We treated 48 patients with biopsy-proven symptomatic OLP, and 44 patients (92%) completed the study. The dosage was 50 microg two dose unit sprays and BSP 500 microg, each 4 times daily. Symptomatic improvement was evaluated by means of a visual analogue scale (VAS), the McGill pain score, the Oral Health Impact Profile (OHIP), and Oral Health Quality of Life (OHQoL) questionnaires. The total surface area of the lesions, including all white, erythematous, and ulcerative lesions was measured at each visit. The efficacy, ease of application, and adverse effects associated with each medication were recorded. RESULTS: Both FP and BSP mouthwash caused both a statistically significant reduction in painful symptoms as measured by the VAS and improvement in quality of life as measured by the OHIP and OHoQL indices. There was no significant difference between the two corticosteroids in their efficacy in reducing painful symptoms (measured by the VAS) or in their effect on patient quality of life. Both FP and BSP significantly reduced the surface area of oral lesions. However, FP was statistically significantly better than BSP in reducing lesion surface area. There was no statistically significant difference between the patient-assessed effects of the 2 therapies. CONCLUSIONS: FP and BSP are both effective in the short-term clinical management of symptomatic OLP. FP is more acceptable to patients than BSP because of the convenience of the spray form.

Management of recalcitrant ulcerative oral lichen planus with topical tacrolimus.

OBJECTIVE: Our purpose was to investigate the efficacy and safety of 0.1% topical tacrolimus in erosive or ulcerative oral lichen planus. METHODS: This was an open-label, noncomparative study conducted in an outpatient oral medicine unit in London, United Kingdom. The study covered an 8-week period with a 22-week follow-up after cessation of therapy. Nineteen patients, aged 28 to 87 years with biopsy-proven oral lichen planus refractory to, or dependent on, systemic immunosuppressive agents, were enrolled. Seventeen patients (89%) completed the study. Application of 0.1% tacrolimus was administered to all symptomatic oral mucosal lesions. Clinical review took place 1, 3, 5, 7, and 8 weeks after commencing therapy. Alleviation of symptoms was evaluated by using a visual analogue scale as well as the McGill Pain and Oral Health Impact profile questionnaires. The extent of the oral mucosal erosion or ulceration was directly measured by the same clinician at all visits. Safety assessments included monitoring of adverse events, complete blood cell count, renal and hepatic clinical chemistry, and tacrolimus blood concentrations. RESULTS: Tacrolimus caused a statistically significant improvement in symptoms within 1 week of commencement of therapy. A mean decrease of 73.3% occurred in the area of ulceration over the 8-week study period. Local irritation (in 6 subjects, 35%) was the most commonly reported adverse effect. Laboratory values showed no significant changes with time. Therapeutic levels of tacrolimus were demonstrated in 8 subjects but were unrelated to the extent of oral mucosal involvement. Thirteen of 17 patients suffered a relapse of oral lichen planus within 2 to 15 weeks of cessation of tacrolimus therapy. CONCLUSION: Topical tacrolimus is effective therapy for erosive or ulcerative oral lichen planus.

An introduction to meta-analysis within the framework of multilevel modelling using the probability of success of root canal treatment as an illustration.

OBJECTIVE: To introduce the statistical methodology of meta-analysis within the framework of multilevel modelling (MLM) using an illustrative example. BASIC RESEARCH DESIGN: In meta-analysis it is important that the quantitative pooling of study results should be carried out in conjunction with careful consideration of the variation apparent between studies. If statistical heterogeneity is found to be significant, it is due, at least in part, to clinical heterogeneity. It is possible to account for clinical heterogeneity by including covariates that are thought to be responsible, using meta-regression. CLINICAL SETTING: A total of 38 studies of root canal treatment outcome were identified as being suitable for introducing the meta-analysis methodology. Two covariates were considered for modelling: a 'loose' or 'strict' (loose--incomplete radiographic healing; strict--complete radiographic healing) criterion for judging outcome of treatment and the year in which the study was performed. RESULTS: There was considerable statistical heterogeneity between the study results. The effect of employing loose criteria for judging success significantly increased the probability of success when compared to employing strict criteria. Furthermore, the variance between studies was significantly reduced when this covariate was included in the modelling process when compared to the variation estimated in the model which did not consider covariates. CONCLUSION: MLM is a good facilitator for meta-analysis and meta-regression.

Perceptions of vocational trainees on gender and racial disadvantage within the Thames vocational training programme.

BACKGROUND: A recent report has suggested that vocational trainees within London experienced racial or gender disadvantage during their selection. This exploratory study did not investigate the extent or the nature of this disadvantage. AIM: To undertake a survey using a pre-tested questionnaire with dental vocational trainees on the Thames Scheme. The questionnaire explored perceived and experienced aspects of gender and racial disadvantage during their vocational training programme. RESULTS: 127 trainees completed the questionnaire (response rate 92%). Minority ethnic respondents were more than twice as likely to feel their selection was influenced by gender (odds ratio [OR] 2.25, 95% Confidence Interval [CI] 1.02, 5.10) and more than three times likely to feel selection was influenced by their race when compared with their white colleagues (OR 3.05, 95%; CI 1.01,11.45). The majority of trainees did not perceive any disadvantage whilst on the vocational training course. For example, only five respondents (4%) felt that minority ethnic individuals were treated less favourably during the vocational training course. CONCLUSION: In conclusion, this preliminary study has attempted to explore inter-ethnic differences within the profession on perceived racial disadvantage and possible strategies for change. It is clear that the perception of disadvantage is greater than the reality within the experience of most trainees.

Using routine data to complement and enhance the results of randomised controlled trials.

BACKGROUND: Randomised controlled trials (RCTs) are widely accepted as the best way to assess the outcomes and safety of medical interventions, but are sometimes not ethical, not feasible, or limited in the generalisability of their results. In such circumstances, routinely available data could help in several ways. Routine data could be used, for example, to conduct 'pseudo-trials', to estimate likely outcomes and required sample size to help design and conduct trials, or to examine whether the expected outcomes observed in an RCT will be realised in the general population. OBJECTIVES: The project was undertaken to explore how routinely assembled hospital data might complement or supplement RCTs to evaluate medical interventions: in contexts where RCTs are not feasible for defining the context and design of an RCT for assessing whether the benefits indicated by RCTs are achieved in wider clinical practice. METHODS: The project was based on the system of linked Scottish morbidity records, which cover 100% of acute hospital care episodes and statutory death records from 1981 to 1995. Three case studies were undertaken as a way of investigating the utility of these records in different applications. First, an attempt was made to analyse the link between the timing of surgery for subarachnoid haemorrhage (SAH) and subsequent outcomes (a question not easily susceptible to RCT design). A subsample was derived by excluding patients for which a diagnosis of SAH may not have been established or that may not have been admitted to a neurosurgical unit, and the data were assessed to attempt to inform the design of a trial of early versus late surgery. Transurethral prostatectomy (TURP), the second case study, has become the surgery of choice for benign prostatic hyperplasia without systematic assessment of its effectiveness and safety, and an RCT would now be considered unethical. However, there is a need to investigate long-term effects and the influence of co-morbidities on outcomes. A retrospective comparison of mortality and re-operation following either open prostatectomy (OPEN) or TURP was, therefore, undertaken. Patients for whom it was not possible to establish the initial procedure were excluded. The third case study compared coronary artery bypass grafting (CABG) with percutaneous transluminal angioplasty (PTCA) for coronary revascularisation. RCTs have been conducted in limited patient subgroups with short follow-up periods. A meta-analysis of RCTs could be augmented by routine data, which are available for large populations. This would allow assessment of subgroup effects, and outcomes over a long period. A subgroup of patients was therefore constructed for whom relevant routine data were available and who reflected the entry criteria for major RCTs, thus enabling a comparison between the results expected from this subgroup and those of the general population. RESULTS AND CONCLUSIONS: The uses of routine data in these contexts had strengths and weaknesses. The SAH study suggested a means of assessing outcomes and survival rates following haemorrhage, which could have value in informing the design of more precise trials and in evaluating changes in outcome following the introduction of new treatments such as embolisation. However, the potential of the data was not realised because their scope and content were insufficient. For example, lack of data on the time of onset of symptoms and patients' conditions at hospital admission made it difficult to establish the link between timing of surgery and the outcome, and there was insufficient information on patients' conditions at discharge to enable a comparison of outcomes. The prostatectomy study was able to address questions not answered by RCT literature because the large number of cases it included allowed exploration of subgroup effects. (ABSTRACT TRUNCATED)

Changes in oral health over ten years amongst UK children aged 4-5 years living in a deprived multiethnic area.

OBJECTIVE: To examine the changes over a decade in caries experience amongst children aged 4-5 years living in a deprived multiethnic community in the United Kingdom. DESIGN: Cross-sectional surveys. SETTING: Schools and nurseries in the Old Trafford area, Manchester, England, 1989, 1990, 1991 and 1998. MAIN OUTCOME MEASURES: Mean dmft, oral cleanliness and proportion of children with rampant caries. RESULTS: The unadjusted Odds Ratio for caries free children examined in 1998 compared with children examined prior to 1998, was only significant amongst the white group. White children examined in 1998 were over three times more likely to be caries free than white children examined previously. South Asian children whose mothers were non English speaking examined in 1998 were almost twice as likely to have good/fair oral cleanliness than those examined prior to 1998. Moreover, South Asian children whose mothers were non-English speaking in 1998 were over three times more likely not to have rampant caries than their counterparts in the earlier years. CONCLUSION: There were significant improvements in caries and oral health amongst white children over the decade, and although less marked these were mirrored amongst South Asian children.

Is modelling dental caries a 'normal' thing to do?

OBJECTIVE: To introduce and encourage the use of generalised linear models (GLMs) in analysing caries data that do not require the response to be treated necessarily as a sample from a normal distribution. BASIC RESEARCH DESIGN: At the present time, it is most likely that the sampling distribution of dmf/DMF in industrialised countries will not approximate normality. Generalised linear modelling can be conducted assuming many underlying distributions which, in fact, includes the normal distribution. In this paper three GLMs are employed (normal, Poisson, negative binomial) for modelling an example caries data set. In addition, a binomial model is used to model the dichotomous outcome of caries-free/caries-present. CLINICAL SETTING: The data comprised 871 Old Trafford, Manchester primary school children aged between 4 years 0 months and 5 years 11 months. RESULTS: The effect of one study covariate was prominent in a normal model applied to all available dmf data but not in two non-normal models which used dmf > 0 data only. Furthermore, the same covariate was significant at the 5% level in a binomial model indicating that it influenced whether or not caries was present and not the level of dmf. CONCLUSION: A suitable modelling approach for caries data is to employ a Poisson or a negative binomial model for the dmf/DMF response and a binomial model for the caries-free/caries-present outcome. This allows separate estimation of those factors which influence the magnitude of caries and those factors which influence whether caries is actually present or not.

The initial dental health status of British Army Gurkha recruits.

AIM: To describe the initial dental health status of British Army Gurkhas who were recruited in 1999 and to compare the present caries data with previous unpublished data from before 1970 and 1983. DESIGN AND SETTING: A clinical examination was conducted on the 228 Gurkhas, the entire UK intake for 1999, during their second week of military training. The focus of the examinations was on caries experience. A questionnaire was employed to collect demographic data as well as information on the recruits' reported dental behaviour and beliefs. RESULTS: 1999 recruits who reported a dental problem within the past year were significantly more likely to have visited a dentist before compared to those recruits who reported no dental problems. The frequency distributions of D3MFT for the 1983 and 1999 recruits were very similar. CONCLUSIONS: Gurkha men are at relatively low risk of dental caries and predicted treatment time suggests a relatively small use of resources would be needed to make this group dentally fit. These recruits are an extremely homogeneous group who remain discernible from the general Nepalese population.

Comparing outcomes of percutaneous transluminal coronary angioplasty with coronary artery bypass grafting; can routine health service data complement and enhance randomized controlled trials?

AIM: To compare outcomes of percutaneous transluminal coronary angioplasty (PTCA) with coronary artery bypass graft surgery (CABG) for a population stemming from routinely collected data, in order to assess the merits of such data sources as a complement, and possible enhancement, to randomized controlled trial results. METHODS AND RESULTS: A population of Scottish patients were taken from a routine discharge summary and from this data source patients comparable to those from randomized controlled trial settings were identified. Between 1989 and 1995, 12 238 pseudo randomized controlled trial patients were identified from the routine data set, of which 3714 (30.3%) received PTCA and 8524 (69.7%) received CABG. The baseline characteristics of the pseudo randomized controlled trial and randomized controlled trial patients were similar. The evidence from both the randomized controlled trials and routine data indicate that for 1 year follow-up the risk of cardiac death and/or non-fatal myocardial infarction is not significantly different between the two treatment groups. CONCLUSION: The outcomes expected of PTCA and CABG following trial evidence have been realized in the routine data which are representative of a complete, non-selective population. Due to the size of the routine data set it would be possible to set up hypotheses for potential subgroup effects at the outset.