Dendritic cell reconstitution is associated with relapse-free survival and acute GVHD severity in children after allogeneic stem cell transplantation.

DCs are potent APCs and key regulators of innate and adaptive immunity. After allo-SCT, their reconstitution in the peripheral blood (PB) to levels similar to those in healthy individuals tends to be slow. We investigate the age- and sex-dependant immune reconstitution of myeloid (mDC) and plasmacytoid DC (pDC) in the PB of 45 children with leukaemia or myelodysplastic syndrome (aged 1-17 years, median 10) after allo-SCT with regard to relapse, acute GVHD (aGVHD) and relapse-free survival. Low pDC/µL PB up to day 60 post SCT are associated with higher incidence of moderate or severe aGVHD (P=0.035), whereas high pDC/µL PB up to day 60 are associated with higher risk of relapse (P<0.001). The time-trend of DCs/µL PB for days 0-200 is a significant predictor of relapse-free survival for both mDCs (P<0.001) and pDCs (P=0.020). Jointly modelling DC reconstitution and complications improves on these simple criteria. Compared with BM, PBSC transplants tend to show slower mDC/pDC reconstitution (P=0.001, 0.031, respectively), but have no direct effect on relapse-free survival. These results suggest an important role for both mDCs and pDCs in the reconstituting immune system. The inclusion of mDCs and pDCs may improve existing models for complication prediction following allo-SCT.

Age-matched dendritic cell subpopulations reference values in childhood.

Dendritic cells (DCs) are the most potent antigen-presenting cells and are the key link between the innate and adaptive immune response. Only a few reports with study populations of up to 50 individuals have been published with age-based reference values for DC subpopulations in healthy children. Therefore, we aimed to establish reference ranges in a larger study population of 100 healthy children, which allowed age-matched subgroups. Most previous studies were performed using a dual-platform approach. In this study, a single-platform approach in a lyse no-wash procedure was used. DC subpopulations were defined as follows: CD45(+) CD85k(+) HLA-DR(+) CD14(-) CD16(-) CD33(+) cells as myeloid DCs (mDCs) and CD45(+) CD85k(+) HLA-DR(+) CD14(-) CD16(-) CD123(+) cells as plasmacytoid DCs (pDCs). Reference ranges were established using a semi-parametric regression of age-matched absolute and relative DC counts. We found a significant decline with increasing age in the medians of mDCs (P = 0.0003) and pDCs per µl peripheral blood (PB) (P = 0.004) and in the 50%, 90% and 95% reference ranges. We also identified significantly lower absolute cell counts of mDCs per µl PB in girls than in boys for all age groups (P = 0.0015). Due to the larger paediatric study population and single-platform approach, this study may give a more precise overview of the normal age-matched development of DC subpopulations and may provide a basis for analyzing abnormal DC counts in different illnesses or therapies such as post stem cell transplantation.

Fetal growth and birthweight standards as screening tools: methods for evaluating performance.

OBJECTIVE: To discuss different methods for evaluating fetal growth and population-based birthweight standards relevant to different uses: either in antenatal care or in epidemiology. DESIGN: Population-based cohort study. SETTING: Routinely collected data in Scotland. POPULATION: A total of 540,849 singletons born after 24 weeks between 1980 and 2003. METHODS: The performance of a fetal growth standard and a population-based birthweight standard are compared in two ways. First, we consider the accuracy of estimated risks of stillbirth at any point during the remaining pregnancy, a measure that is relevant in antenatal care. Second, the rates of stillbirth at each gestation, which are measures relevant in epidemiology, are compared with the actual rates. MAIN OUTCOME MEASURES: Standard measures of screening and diagnostic performance: sensitivity, specificity, and positive and negative predictive values. RESULTS: In clinical care, the evidence points towards using fetal growth standards: sensitivity at term is about 30%, increasing to 43% for preterm births (24-31 weeks of gestation), compared with about 29% across all ages under the birthweight standard. Positive predictive values are about 1% across gestations. For epidemiology, the evidence is not so clear-cut: preterm, the population birthweight standard has higher sensitivity and specificity, but this is not the case in the full-term weeks. CONCLUSIONS: The performance of fetal growth and birthweight standards should be evaluated in different ways, depending on whether they are intended for use in antenatal care or in epidemiological investigations.

Modelling bounded health scores with censored skew-normal distributions.

Health care interventions that use quality of life or health scores often provide data which are skewed and bounded. The scores are typically formed by adding up numerical responses to a number of questions. Different questions might have different weights, but the scores will be bounded, and are often scaled to the range 0-100. If improvement in health over time is measured, scores will tend to cluster near the 'healthy' or 'good' boundary as time progresses, leading to a skew distribution. Further, some patients will drop-out as time progresses, hence the scores reflect a selected population.We fit models based on the skew-normal distribution to data from a randomized controlled trial of treatments for sprained ankles, in which scores were recorded at baseline and at 1, 3 and 9 months after injury. We consider the extent to which skewness in the data can be explained by clustering at the boundary via a comparison between a censored normal and a censored skew-normal model.As this analysis is based on the complete data only, a formula for the bias of the treatment effects due to informative drop-out is given. This allows us to assess under what conditions the conclusions drawn from the complete data might be either reinforced or reversed, when the informative drop-out process is taken into account.

Meta-regression with partial information on summary trial or patient characteristics.

We present a model for meta-regression in the presence of missing information on some of the study level covariates, obtaining inferences using Bayesian methods. In practice, when confronted with missing covariate data in a meta-regression, it is common to carry out a complete case or available case analysis. We propose to use the full observed data, modelling the joint density as a factorization of a meta-regression model and a conditional factorization of the density for the covariates. With the inclusion of several covariates, inter-relations between these covariates are modelled. Under this joint likelihood-based approach, it is shown that the lesser assumption of the covariates being Missing At Random is imposed, instead of the more usual Missing Completely At Random (MCAR) assumption. The model is easily programmable in WinBUGS, and we examine, through the analysis of two real data sets, sensitivity and robustness of results to the MCAR assumption.

Mechanical supports for acute, severe ankle sprain: a pragmatic, multicentre, randomised controlled trial.

BACKGROUND: Severe ankle sprains are a common presentation in emergency departments in the UK. We aimed to assess the effectiveness of three different mechanical supports (Aircast brace, Bledsoe boot, or 10-day below-knee cast) compared with that of a double-layer tubular compression bandage in promoting recovery after severe ankle sprains. METHODS: We did a pragmatic, multicentre randomised trial with blinded assessment of outcome. 584 participants with severe ankle sprain were recruited between April, 2003, and July, 2005, from eight emergency departments across the UK. Participants were provided with a mechanical support within the first 3 days of attendance by a trained health-care professional, and given advice on reducing swelling and pain. Functional outcomes were measured over 9 months. The primary outcome was quality of ankle function at 3 months, measured using the Foot and Ankle Score; analysis was by intention to treat. This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN37807450. RESULTS: Patients who received the below-knee cast had a more rapid recovery than those given the tubular compression bandage. We noted clinically important benefits at 3 months in quality of ankle function with the cast compared with tubular compression bandage (mean difference 9%; 95% CI 2.4-15.0), as well as in pain, symptoms, and activity. The mean difference in quality of ankle function between Aircast brace and tubular compression bandage was 8%; 95% CI 1.8-14.2, but there were little differences for pain, symptoms, and activity. Bledsoe boots offered no benefit over tubular compression bandage, which was the least effective treatment throughout the recovery period. There were no significant differences between tubular compression bandage and the other treatments at 9 months. Side-effects were rare with no discernible differences between treatments. Reported events (all treatments combined) were cellulitis (two cases), pulmonary embolus (two cases), and deep-vein thrombosis (three cases). INTERPRETATION: A short period of immobilisation in a below-knee cast or Aircast results in faster recovery than if the patient is only given tubular compression bandage. We recommend below-knee casts because they show the widest range of benefit. FUNDING: National Co-ordinating Centre for Health Technology Assessment.

Treatment of severe ankle sprain: a pragmatic randomised controlled trial comparing the clinical effectiveness and cost-effectiveness of three types of mechanical ankle support with tubular bandage. The CAST trial.

OBJECTIVE: To estimate the clinical effectiveness and cost-effectiveness of three methods of ankle support compared with double layer tubular compression bandage. DESIGN: A randomised controlled trial, designed to reflect practice in UK hospital emergency departments. SETTING: Eight emergency departments in England. PARTICIPANTS: Aged 16 or over with acute severe ankle sprain, unable to weight bear, no fracture. INTERVENTIONS: 584 participants were randomised to one of four treatment arms: tubular bandage, below knee cast, Aircast ankle brace or Bledsoe boot, all applied 2-3 days after presentation to allow swelling to resolve. MAIN OUTCOME MEASURES: Response to treatment was assessed using the Foot and Ankle Outcome Score and generic measures (Functional Limitations Profile, SF-12 and EQ-5D). RESULTS: When adjusted for age, sex and baseline scores, the below knee cast offered a small but statistically significant benefit at 4 weeks in terms of pain (FAOS pain difference 5.1; 95% CI 0.4-9.8), foot- and ankle-related quality of life (QoL) (FAOS QoL difference 5.9; 95% CI 0.1-11.8) and the physical component of the SF-12 (SF-12 score difference 2.2; 95% CI 0.0-4.4). Neither the Aircast brace nor the Bledsoe boot was statistically or clinically better. At 12 weeks the below knee cast was significantly better than tubular bandage in terms of pain (FAOS pain difference 5.1; 95% CI 0.3-10.0), activities of daily living (FAOS ADL difference 3.5; 95% CI 0.4-6.6), sports (FAOS sports difference 8.7; 95% CI 1.6-15.7) and QoL (FAOS QoL difference 8.7; 95% CI 2.4-15.0), and the Aircast brace was better only in terms of ankle-related QoL and mental health. The Bledsoe boot conferred no significant advantage over tubular bandage. By 9 months there were no significant differences. Based on mean direct health-care costs per participant, the Bledsoe boot was the most expensive (215 pounds) and tubular bandage the least so (1 pound 44 pence). Inclusion of indirect costs (sick leave) raised overall costs substantially and removed any significant differences between the therapies. Cost-utility analysis demonstrated that the Aircast brace [301 pounds per quality-adjusted life-year (QALY)] and below knee cast (339 pounds per QALY) were more cost-effective than the Bledsoe boot (2116 pounds per QALY). However, inclusion of indirect costs produced different rank orders, depending on the assumptions made, and results should be treated with caution. CONCLUSIONS: The below knee cast and the Aircast brace offered cost-effective alternatives to tubular bandage for acute severe ankle sprain, the former having the advantage in terms of overall recovery at 3 months. As there were no differences in long-term outcome, practitioners should consider likely compliance and acceptability to patients when choosing a brace.

Reporting and analysis of open-label extension studies of anti-epileptic drugs.

PURPOSE: Open-label extension studies, or follow-on randomised controlled trials (FORCTs) are widely believed to be prone to patient selection biases which may inflate effect estimates. This study investigates the reporting and analysis of efficacy outcomes in FORCTs and critically evaluates the associated underlying assumptions. We propose an alternative method of analysis, in line with that recommended in the analysis of RCTs, the intention to treat (ITT) approach, in which it is assumed that all patients who discontinue treatment are non-responders. METHODS: A systematic review of FORCTs and randomised controlled trials (RCT) of topiramate, levetiracetam and gabapentin as adjuvant therapy in refractory adult epilepsy was conducted. Sample sizes and numbers of responders, along with reported outcomes were extracted. To evaluate the feasibility of the assumptions underlying the various methods of analysis, the most common causes of discontinuation were evaluated. For each FORCT, we compared the reported outcome to the proposed ITT analysis. RESULTS: The 10 FORCT reports identified all excluded from the analysis patients who dropped out of the RCT. Adverse events or inefficacy were the main reasons for treatment discontinuation. Analysis based on the ITT method, led to smaller effect estimates than those reported. For example, a FORCT of levetiracetam reported a responder rate of 43%, which reduced to 28% under an ITT analysis, comparable to an ITT analysis outcome of 26% for the parent RCT. CONCLUSIONS: FORCTs can provide important information about long-term efficacy and tolerability of newer therapies. However, current reporting methods are likely to be misleading as outcomes are reported for the subset of patients continuing with treatment at the end of the FORCT. Since the majority of patients who discontinue treatment do so for reasons associated with inefficacy, an analysis based on the ITT approach more closely reflects the outcomes of the patients.

Overwhelming heterogeneity in systematic reviews of observational anti-epileptic studies.

PURPOSE: Observational studies may provide important information on the long-term effects of treatments for epilepsy, but systematic reviews of observational studies may be more prone to heterogeneity and biases. These issues were investigated in a systematic review of non-randomised add-on anti-epileptic drug studies. METHODS: Searches of MEDLINE (1966-2006), EMBASE (1974-2006), CINAHL (1982-2006), the Cochrane database of systematic reviews, the Cochrane Controlled Trials register, the DARE database and hand-searching congress proceedings were conducted. Randomised controlled trials, follow-on randomised controlled trials and prospective and retrospective cohort studies of gabapentin, topiramate, or levetiracetam as add-on therapy in adults (>12 years old) were identified. Outcomes were 50% responders and proportion seizure free. RESULTS: Thirty-eight non-randomised gabapentin studies, 82 topiramate and 84 levetiracetam studies were identified. There was marked heterogeneity of effect estimates from observational studies which prohibited the pooling of estimates in random effects models. Median effect estimates were larger and more varied for observational studies than randomised placebo-controlled trials (RCTs). For example, the median value (10th and 90th percentile) for 50% responders for gabapentin was 36% (15 and 71%) compared to 23% (19 and 38%) for gabapentin RCTs. Patient and study covariates in meta-regression models could not explain the vast heterogeneity. Publication bias was evident and a sensitivity analysis, allowing for the effects of publication bias, showed that effect estimates could increase by up to 6% for seizure freedom rates. DISCUSSION: Reports of observational anti-epileptic studies give limited information on patient selection and characteristics. Systematic reviews of observational studies are prone to significant heterogeneity and bias which cannot adequately be explained by reported study characteristics. Reporting standards for observational studies of anti-epileptic drugs could be improved by following guidelines for reporting non-randomised studies of interventions.

Intrauterine growth and survival in cerebral palsy.

BACKGROUND AND OBJECTIVES: Deviations in birth weight from an optimum, thought to be just above average for gestational age, are known to increase both the risk of developing cerebral palsy and the risk of developing cerebral palsy of a more severe form. Influences on survival of such deviations from average birth weight for gestational age are not known. METHODS: Using a well-established, well-defined and large UK cohort of children and adults with cerebral palsy, followed from birth for nearly 25 years, we investigate the influence of deviations from average birth weight for gestational age, on survival duration, after allowing for severity of impairments. RESULTS: A total of 3946 cases, born between 1980 and 1996 were included. For those born much lighter than average for gestational age, more than 30% (n = 313) had a severe motor or cognitive impairment, rising to as much as 40% (n = 239) for extremely low weights. For female infants, the proportions severely impaired increased to as much as 35% (n = 49) among those born much heavier than average; no such increase was observed for heavier than average male infants. For those with four severe impairments and a birth weight close to average for gestational age, around 60% (n = 140) survived to age 15 years, compared with less than 40% (n = 9) of those born much heavier than average for gestational age. A 2-year-old child with four severe impairments and born heavy for gestational age has a predicted median life expectancy of 79% (95% CI 70% to 88%) of the average. CONCLUSIONS: Infants with a birth weight lighter than average for gestational age have an increased likelihood of developing a more severe form of cerebral palsy. Surprisingly, among the infants who are very severely impaired, those born much lighter than average for gestational age have the longest life expectancy, and those born much heavier than average for gestational age have the shortest life expectancy.

Differences between European birthweight standards: impact on classification of 'small for gestational age'.

We describe a quantitative and comparative review of a selection of European birthweight standards for gestational age for singletons, to enable appropriate choices to be made for clinical and research use. Differences between median values at term across standards in 10 regions and misclassification of 'small for gestational age' (SGA), were studied. Sex and parity differences, exclusion criteria, and methods of construction were considered. There was wide variation between countries in exclusion criteria, methods of calculating standards, and median birthweight at term. The lightest standards (e.g. France's medians are 255g lower than Norway's medians) were associated with fewer exclusion criteria. Up to 20% of the population used in the construction of the Scottish standard would be classified as SGA using the Norwegian standard. Substantial misclassification of SGA is possible. Assumptions about variation used in the construction of some standards were not justified. It is not possible to conclude that there are real differences in birthweight standards between European countries. Country-based standards control for some population features but add misclassification due to the differing ways in which standards are derived. Standards should be chosen to reflect clinical or research need. If standards stratified by sex or parity are not available, adjustments should be made. In multinational studies, comparisons should be made between results using both a common standard and country-based standards.

Life expectancy in severe cerebral palsy.

Cerebral palsy comprises an important component of paediatric and obstetric practice and has major medico-legal implications. The prognosis for survival in cerebral palsy determines the financial provision made in cases that come to litigation. Issues of data quality and estimation methods are critical. Estimating the probability of survival in cerebral palsy based on clinical experience is liable to serious error unless numerical data can be produced. Only an actuarial analysis based on a standard life table of cases of cerebral palsy will enable a valid estimate of survival. Construction of the table requires a total cohort of cases of cerebral palsy with their date of birth. Each case must conform to a specified definition of the syndrome. Notification of all those who die, with their date of death is mandatory. Estimating the probability of survival according to the severity of functional disability requires specific definitional criteria for each severity category and for those categories to be mutually exclusive. Survival is significantly poorer in those with severe disability. Severe cognitive, motor (manual and ambulatory), and visual disabilities have independent effects on the probability of survival. Severe hearing disability does not add additional information when the other four functional disability categories are included.

Outcome selection bias in meta-analysis.

Publication bias has been previously identified as a threat to the validity of a meta-analysis. Recently, new evidence has documented an additional threat to validity, the selective reporting of trial outcomes within published studies. Several diseases have several possible measures of outcome. Some articles might report only a selection of those outcomes, perhaps those with statistically significant results. In this article, we review this problem while addressing the questions: what is within-study selective reporting? how common is it? why is it done? how can it mislead? how can it be detected?, and finally, what is the solution? We recommend that both publication bias and selective reporting should be routinely investigated in systematic reviews.

Clinical and cost effectiveness of mechanical support for severe ankle sprains: design of a randomised controlled trial in the emergency department [ISRCTN 37807450].

BACKGROUND: The optimal management for severe sprains (Grades II and III) of the lateral ligament complex of the ankle is unclear. The aims of this randomised controlled trial are to estimate (1) the clinical effectiveness of three methods of providing mechanical support to the ankle (below knee cast, Aircast brace and Bledsoe boot) in comparison to Tubigrip, and (2) to compare the cost of each strategy, including subsequent health care costs. METHODS/DESIGN: Six hundred and fifty people with a diagnosis of severe sprain are being identified through emergency departments. The study has been designed to complement routine practice in the emergency setting. Outcomes are recovery of mobility (primary outcome) and usual activity, residual symptoms and need for further medical, rehabilitation or surgical treatment. Parallel economic and qualitative studies are being conducted to aid interpretation of the results and to evaluate the cost-effectiveness of the interventions. DISCUSSION: This paper highlights the design, methods and operational aspects of a clinical trial of acute injury management in the emergency department.

Ethical issues in research on control of the HIV/AIDS epidemic: report from a workshop of the world federation of scientists, Erice, Sicily, Italy, 22-24 August 2003.

In research on control of the HIV/AIDS epidemic there are many ethical issues to be considered. The problem of personal autonomy versus the interest of society to prevent the spread of the disease in various settings makes it difficult to follow the regulations of the Declaration of Helsinki in all respects. This is particularly clear in the evaluation of trials aimed at preventing mother-to-child transmission of HIV. The interest of the child does not always conform to the policy of avoiding stigmatization of the mother. Programmes for the implementation of antiretroviral therapy and vaccine trials may differ in countries with different mean incomes of the inhabitants, and are also influenced by local patterns. For this reason, the Declaration of Helsinki should be changed in such a way that it conforms with the ways in which it may be possible to combat such a disastrous epidemic as that caused by HIV.

Retrospective analysis of the occurrence of internal malignancy in patients treated with PUVA between 1986 and 1999 in South Warwickshire.

Concerns were raised in our department when four of our patients receiving PUVA treatment developed internal malignancy. We reviewed the medical and phototherapy case notes of patients who received either systemic or bath PUVA therapy in our department between 1986 and 1999. Among the 197 patients for whom we were able to trace the hospital records we identified five patients with internal malignancies. Over the same period (1986-1999) we calculated, using the Kaplan-Meier nonparametric estimator, that 4.6 cases of internal malignancy would have been anticipated in our study population. Therefore PUVA therapy did not appear to be a risk factor for internal malignancy.

Choice of parametric accelerated life and proportional hazards models for survival data: asymptotic results.

We discuss the impact of misspecifying fully parametric proportional hazards and accelerated life models. For the uncensored case, misspecified accelerated life models give asymptotically unbiased estimates of covariate effect, but the shape and scale parameters depend on the misspecification. The covariate, shape and scale parameters differ in the censored case. Parametric proportional hazards models do not have a sound justification for general use: estimates from misspecified models can be very biased, and misleading results for the shape of the hazard function can arise. Misspecified survival functions are more biased at the extremes than the centre. Asymptotic and first order results are compared. If a model is misspecified, the size of Wald tests will be underestimated. Use of the sandwich estimator of standard error gives tests of the correct size, but misspecification leads to a loss of power. Accelerated life models are more robust to misspecification because of their log-linear form. In preliminary data analysis, practitioners should investigate proportional hazards and accelerated life models; software is readily available for several such models.