Risk of complications due to anticoagulation during dermatosurgical procedures: a systematic review and meta-analysis

Background Management of anticoagulation and anti-platelet drugs during cutaneous surgery is still a challenge for many dermatologists and standards of care with respect to stopping, continuing or bridging vary widely. Methods We performed a systematic review (Medline, Cochrane Library, until August 27th, 2013) of studies assessing the risk of complications due to anticoagulation during cutaneous surgery. Primary outcomes were mild-moderate and severe postsurgical bleeding. The secondary outcomes were excessive and uncontrollable intraoperative bleeding and other postsurgical complications as wound dehiscence, erythema, wound infection. Results 1.287 publications were identified and 10 studies were included into the review. The frequencies of bleeding in the control groups in general were low (about 1%). In patients on aspirin, increased risks were seen neither with respect to mild-moderate postoperative bleeding (RR 1.1, CI 0.5-2.3), nor with respect to severe bleeding (RR 0.9, CI 0.2-4.6). The studies with patients on warfarin showed a risk for mild-moderate bleeding that was three times as high as in controls (RR 3.2, CI 1.4-7.1) and for severe bleeding that was 15 times higher (RR 14.8, CI 2.7-80.4). In general the study sizes were small and the methodological quality low. Conclusion The risk of bleeding due to a medication with aspirin seems to be negligible. With warfarin, the risk is increased; an exact estimate of the risk increase is difficult to give, because of the lack of sufficient high quality studies. A two-fold increase appears likely, the 15-fold increase is most likely due to statistical reasons arising from the rareness of the event in the small number of included patients. Stopping, bridging or continuing a medication should always be an individual decision. In accordance with guidelines from internal medicine for most patients it will be recommendable to continue with the medication.

A randomised, controlled, crossover study to investigate the pharmacodynamics, pharmacokinetics and safety of 1R,2S-methoxamine hydrochloride (NRL001) in healthy elderly subjects

AIMS

This study aimed to assess the effects of a single dose of 10 mg NRL001 (the 1R,2S stereoisomer of methoxamine hydrochloride) in a 2 g suppository on pharmacodynamic and pharmacokinetic (PK) variables, and safety, in a healthy elderly population.

METHODS

This was a Phase I, single-centre, randomised, double-blind, placebo-controlled crossover study during which subjects received a single 2 g suppository of 10 mg NRL001 and a matching placebo in two separate treatment periods. The main outcome measures were Holter-, vital signs- and electrocardiogram-derived cardiovascular variables; plasma PK analysis; and safety assessments.

RESULTS

Twenty-six subjects were dosed with study medication. Statistically significant reductions in Holter-derived heart rate (HR), vital signs-derived HR and diastolic blood pressure (BP) were observed comparing NRL001 with placebo treatment, and also with increasing NRL001 plasma concentration. No statistically significant relationships were observed between NRL001 concentration and systolic BP, mean arterial pressure or QTC interval (both Bazett's and Fridericia's correction). Thirty-nine adverse events were reported in 20 (76.9%) subjects, mostly after dosing with NRL001.

CONCLUSION

Administration of NRL001 suppositories led to decreases in HR when compared with placebo data. NRL001 was well tolerated with a good safety profile during the study. Healthy elderly subjects did not show significantly different biological responses to NRL001 suppositories compared with younger healthy volunteers in previous studies.

Meta-analysis for cardiovascular effects of NRL001 after rectal application in healthy volunteers

AIMS

NRL001 is a highly specific α1 -adrenoceptor agonist currently under evaluation for the treatment of faecal incontinence caused by a weak internal anal sphincter. The aim of this meta-analysis was to quantify the effect of NRL001 on cardiovascular parameters including heart rate, blood pressure and QT interval.

METHODS

Data from the four Phase I healthy volunteer studies SUM (NCT00857467), SURD (NCT01099670), SUSD (NCT00850590) and SAGE (NCT01099683) were pooled and analyses were performed on individual subject data. Mixed effects regression analysis was used to determine the effect of NRL001 on heart rate, blood pressure and QT intervals. A multivariate statistical model was used to determine the effect of covariates on heart rate.

RESULTS

Subjects given NRL001 experienced a dose related decrease in heart rate of up to 9.48 bpm compared with subjects in the placebo arms. No statistically significant evidence for a threshold effect was found. There was no clear evidence of dose effect of NRL001 on blood pressure. QT interval increased in all NRL001 subject as expected; QTC F also showed a statistically significant increase. However, QTC B was shortened with no significant treatment effect.

CONCLUSIONS

NRL001 was found to have a dose-dependent effect on heart rate; however clinically-relevant bradycardia was not reported, indicating the decrease in heart rate was not of clinical significance. Furthermore, no clinically-significant drug effect on blood pressure or mean arterial pressure was observed. QT intervals were affected by changes in heart rate. However, trends were dependant on the correction factor used. No consistent QT effect was observed, but a thorough QTC study will be required to confirm the effects of rectally applied NRL001.

A double-blind, placebo-controlled, randomised, parallel-group, dose-escalating, repeat dose study in healthy volunteers to evaluate the safety, tolerability, pharmacodynamic effects and pharmacokinetics of the once daily rectal application of NRL001 suppositories for 14 days

AIMS

The 1R,2S stereoisomer of methoxamine hydrochloride, NRL001, is a highly selective α1-adrenoceptor agonist being developed for the local treatment of non-structural faecal incontinence caused by weak internal anal sphincter tone. This study investigated the steady state pharmacokinetics (PK) and safety of 2 g rectal suppositories containing NRL001 in different strengths (7.5, 10, 12.5 or 15 mg).

METHODS

Healthy volunteers aged 18-45 years received 14 daily doses of NRL001 2 g suppositories or matching placebo. In each dose group nine participants received NRL001 and three received placebo. Blood samples to determine NRL001 concentrations were taken on Days 1, 7 and 14. Cardiovascular parameters were collected via electrocardiograms, Holter monitoring (three lead Holter monitor) and vital signs.

RESULTS

Forty-eight volunteers were enrolled; 43 completed the study and were included in the PK analysis population. AUC and Cmax broadly increased with increasing dose, Tmax generally occurred between 4.0 and 5.0 h. Although the data did not appear strongly dose proportional, dose proportionality analysis did not provide evidence against dose proportionality as the log(dose) coefficients were not significantly < 1. NRL001 did not accumulate over time for any dose. Increasing NRL001 concentrations were related to changes in vital sign variables, most notably decreased heart rate. The most commonly reported adverse events (AEs) in the active treatment groups were paraesthesia and piloerection.

CONCLUSIONS

Treatment with NRL001 was generally well tolerated over 14 days once daily dosing and plasma NRL001 did not accumulate over time. Treatment was associated with changes in vital sign variables, most notably decreased heart rate. AEs commonly reported with NRL001 treatment were events indicative of a systemic α-adrenergic effect.

A randomised, controlled, crossover study to investigate the safety and response of 1R,2S-methoxamine hydrochloride (NRL001) on anal function in healthy volunteers

AIMS

This study aimed to assess the dose and volume effects of suppository preparations and safety of NRL001 (one of four possible stereoisomers of methoxamine hydrochloride) on anal sphincter tone using rectal suppositories in healthy adult volunteers.

METHODS

This was a Phase I, single-centre, randomised, double-blind, three-way crossover study during which subjects received three single doses of 1 g rectal suppositories (containing 5 or 10 mg NRL001 or matching placebo) or 2 g rectal suppositories (containing 10 or 15 mg NRL001 or matching placebo) on three separate dosing days. The outcome measures were mean anal resting pressure (MARP) variables (monitored continuously for 20-30 min before and up to 6 h after dosing), pharmacokinetics (PK) and safety assessments.

RESULTS

Twenty-six subjects were dosed with study medication. Two subjects were withdrawn prematurely and were not included in the main analysis. There was a dose-dependent increase in anal sphincter tone (MARP) when comparing the 5 and 10 mg doses of NRL001; however, the 15 mg dose did not have a significantly greater effect than the 10 mg dose. Suppository size (1 or 2 g) did not appear to have an effect on sphincter tone. There was no evidence against dose proportionality for the PK variables, but the mean maximum plasma concentration (Cmax ) for the 1 g suppository group was higher than for the 2 g group. Twenty-one adverse events were reported in 8 (30.8%) subjects. A dose dependent decrease in heart rate was noted; however, there were no adverse events reported that were related to this reduction in heart rate.

CONCLUSIONS

The increase in anal sphincter tone supports the potential therapeutic use of NRL001 in treating faecal incontinence, with further studies in patients required. NRL001 was well tolerated in single doses of up to 15 mg.

Randomised clinical trial: study of escalating doses of NRL001 given in rectal suppositories of different weights

AIMS

The application of α-adrenoceptor agonists can improve faecal incontinence symptoms. The aim of this study was to investigate the pharmacokinetic and systemic effects of NRL001 administered as different strengths in 1 or 2 g suppositories.

METHODS

This randomised, double-blind, placebo controlled study included 48 healthy subjects. Group 1 consisted of two cohorts of 12 subjects administered either four single doses of 1 or 2 g rectal suppository with either 5, 7.5 or 10 mg NRL001, or matching placebo. Group 2 consisted of two cohorts of 12 subjects administered either four single doses of 1 or 2 g rectal suppository with either 10, 12.5 or 15 mg NRL001, or matching placebo. Doses were given in an escalating manner with placebo at a random position within the sequence.

RESULTS

Tmax was at ~4.5 h post-dose for all NRL001 doses. Median AUC0-tz , AUC0-∞ and Cmax increased with increasing dose for both suppository sizes. The estimate of ratios of geometric means comparing 2 g with 1 g suppository, and regression analysis for dose proportionality, was close to 1 for the variables AUC0-tz , AUC0-∞ and Cmax (P > 0.05). For both suppository sizes, 20-min mean pulse rate was significantly decreased compared with placebo with all doses (P < 0.05). Blood pressure decreased overall. There were 144 adverse events (AEs) and no serious AEs reported during the study. All AEs were mild in severity.

CONCLUSIONS

The regression analysis concluded that the doses were dose proportional.

S3-Guidelines for the Treatment of Inflammatory Breast Disease during the Lactation Period: AWMF Guidelines, Registry No. 015/071 (short version) AWMF Leitlinien-Register Nr. 015/071 (Kurzfassung)

Breastfeeding is widely acknowledged to be the best and most complete form of nutrition for healthy infants born at term and is associated with numerous benefits in terms of infants' health, growth, immunity and development. However, breastfeeding problems often result in early weaning. Standardized treatment recommendations for breastfeeding-related diseases are necessary to optimize the care offered to breastfeeding women. Evidence and consensus based guidelines for the treatment of puerperal mastitis, sore nipples, engorgement and blocked ducts were developed on the initiative of the National Breastfeeding Committee. These guidelines were developed in accordance with the criteria set up by the Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften (AWMF), the Association of Scientific Medical Societies in Germany. The recommendations were drawn up by an interdisciplinary group of experts and were based on a systematic search and evaluation of the literature but also took clinical experience into account. Additionally good clinical practice (GCP) in terms of expert opinion was formulated in cases where scientific investigations could not be performed or were not aimed for. This article presents a summary of the recommendations of the S3-guidelines.

A randomised, double-blind, placebo-controlled, crossover study to assess the efficacy and safety of three dosing schedules of agalsidase alfa enzyme replacement therapy for Fabry disease

Anecdotal reports suggest that the currently approved dosing interval of agalsidase alfa (0.2 mg/kg/2 weeks) for Fabry disease treatment is too long. This randomised, double-blind, placebo-controlled, crossover study investigated three altered dosing intervals. 18 Fabry patients received three agalsidase alfa dosing schedules, each for four weeks (A: 0.2 mg/kg∗2 weeks, B: 0.1 mg/kg/week, C: 0.2 mg/kg/week). Health state, pain levels, sweat volume and latency and plasma and urinary globotriaosylceramide levels were recorded throughout the study. No significant differences were found among the schedules for the primary efficacy outcome of self-assessed health state, or for pain scores. A trend toward increased sweat volume on QSART testing, and reduced urine globotriaosylceramide concentration were seen with treatment schedule C. Agalsidase alfa was safe and well tolerated with all schedules. In conclusion, the primary analyses did not find weekly infusions of agalsidase alfa to be statistically better than the approved dosing schedule however the data indicates that further studies with more patients over a longer period are required to more accurately determine the optimum dose and schedule.

Specific biomarkers of receptors, pathways of inhibition and targeted therapies: pre-clinical developments

A deeper understanding of the role of specific genes, proteins, pathways and networks in health and disease, coupled with the development of technologies to assay these molecules and pathways in patients, promises to revolutionise the practice of clinical medicine. Especially the discovery and development of novel drugs targeted to disease-specific alterations could benefit significantly from non-invasive imaging techniques assessing the dynamics of specific disease-related parameters. Here we review the application of imaging biomarkers in the management of patients with brain tumours, especially malignant glioma. In our other review we focused on imaging biomarkers of general biochemical and physiological processes related with tumour growth such as energy, protein, DNA and membrane metabolism, vascular function, hypoxia and cell death. In this part of the review, we will discuss the use of imaging biomarkers of specific disease-related molecular genetic alterations such as apoptosis, angiogenesis, cell membrane receptors and signalling pathways and their application in targeted therapies.

A filter based encoding model for mouse retinal ganglion cells

We adopt a system theoretic approach and explore the model of retinal ganglion cells as linear filters followed by a maximum-likelihood Bayesian predictor. We evaluate the model by using cross-validation, i.e., first the model parameters are estimated using a training set, and then the prediction error is computed (by comparing the stochastic rate predicted by the model with the rate code of the response) for a test set. As in system identification theory, we present spatially uniform stimuli to the retina, whose temporal intensity is drawn independently from a Gaussian distribution, and we simultaneously record the spike trains from multiple neurons. The optimal linear filter for each cell is obtained by maximizing the mutual information between the filtered stimulus values and the output of the cell (as measured in terms of a stochastic rate code). Our results show that the model presented in this paper performs well on the test set, and it outperforms the identity Bayesian model and the traditional linear model. Moreover, in order to reduce the number of optimal filters needed for prediction, we cluster the cells based on the filters' shapes, and use the cluster consensus filters to predict the firing rates of all neurons in the same class. We obtain almost the same performance with these cluster filters. These results provide hope that filter-based retinal prosthetics might be an effective and feasible idea.

Programmable large area digital microfluidic array with integrated droplet sensing for bioassays

We describe a new device concept for digital microfluidics, based on an active matrix electrowetting on dielectric (AM-EWOD) device. A conventional EWOD device is limited by the number of electrical connections that can be made practically, which restricts the number and type of droplet operations. In an AM-EWOD, the patterned electrodes of a conventional EWOD device are replaced by a thin film transistor (TFT) array, as found in a liquid crystal display (LCD), facilitating independent control of each electrode. The arrays can have many thousand individually addressable electrodes, are fully reconfigurable and can be programmed to support multiple simultaneous operations. Each element is 210 μm × 210 μm in size and contains a circuit that measures the electrical impedance of the liquid above it. This is used to determine the presence and size of a droplet, a method that can improve assay reliability and accuracy. This sensor provides feedback, error detection and closed loop control of an assay sequence. We describe the design, fabrication and testing of a 64 × 64 format AM-EWOD device with impedance sensor functionality. A colorimetric assay is implemented on the device and used to measure glucose in human blood serum. Results are compared with the same assay performed on a microtitre plate.

The impact of treatment with risperidone long-acting injection on the Belgian healthcare system: results from a budget impact model

Substantial evidence from randomised clinical trials has demonstrated that long-acting risperidone (RLAI) is efficacious and well tolerated in patients with schizophrenia. Recently, a long-term naturalistic study of treatment practices in Belgium, the electronic Schizophrenia Treatment Adherence Registry (e-STAR), reported that treatment with RLAI is associated with improvements in adherence and long-term outcomes. The present report describes the results of a budget impact model that analysed the Belgian e-STAR data, together with other available data, over a 3-year time horizon, in order to establish the potential impact of treatment with RLAI on total healthcare costs in Belgium.The model framework combined medical resource utilisation with costs of the population of interest in order to quantify the costs, and cost offsets, of RLAI treatment. For the purpose of this budget impact model, it was assumed that among patients who would discontinue their previous antipsychotic medication, 6.7% of patients would be switched to RLAI. The overall cost savings to the Belgian healthcare system were calculated to be 2.3 million Euros in Year 1, 3.7 million Euros in Year 2 and 4.4 million Euros in Year 3. The majority of these cost-savings resulted from the substantial reduction in hospitalisation costs associated with RLAI treatment. This report indicates that improvements in adherence and long-term outcomes previously demonstrated for RLAI treatment in Belgium may result in substantial cost benefits to the country's healthcare system.

CD25 signaling via STAT5 is necessary for development of cytolytic CD4 T cells (163.13)

Cytolytic CD4 cells have been identified in vivo during viral infections; however, the factors necessary for driving the cytolytic phenotype have not been characterized. Previously, we found that IL-2 is necessary and sufficient to drive the in vitro differentiation of naïve CD4 cells into cytolytic effectors. To further dissect the role of IL-2 in CD4 CTL generation, TCR transgenic mice deficient in IL-2 production or IL-2Rα (CD25) were used. In vitro, CD25 deficient cells do not express granzyme B (GrB) or acquire cytolytic activity when cultured in the presence of IL-2. In contrast, CD25+/- cells exhibit half maximal expression of GrB and reduced cytotoxicity when compared to WT cells. In vitro, IL-2 activates STAT5 phosphorylation, peaking at 18-24 h, correlating with GrB expression and cytotoxicity by 72-96 h. Inhibition of the JAK3/STAT5 pathway resulted in a dose dependent reduction of GrB expression. Surprisingly, other common γc cytokines such as IL-7 and IL-15 induce STAT5 phosphorylation but do not induce cytotoxicity, most likely due to the timing of STAT5 activation. Studies determining whether STAT5 activation synergizes with other signaling pathways to induce optimal CTL activity are underway. Further, the role of CD25 signaling in the induction of cytolytic activity in vivo during influenza infection will be discussed. These data have implications in the design of vaccines and in adoptive immunotherapy against certain tumors.

Treatment retention with risperidone long-acting injection: 24-month results from the Electronic Schizophrenia Treatment Adherence Registry (e-STAR) in six countries

OBJECTIVE

To assess treatment retention on risperidone long-acting injection (RLAI) and outcomes in schizophrenia patients for whom 24 months of follow-up data in the electronic Schizophrenia Treatment Adherence Registry (e-STAR) were available.

RESEARCH DESIGN AND METHODS

e-STAR is an ongoing, international, multicenter, prospective, observational registry assessing use of antipsychotics in patients with schizophrenia or schizoaffective disorder in a normal clinical practice setting. Parameters were assessed prior to and post-initiation of RLAI. Data presented are from six European countries that enrolled patients in e-STAR after they initiated treatment with RLAI.

MAIN OUTCOME MEASURES

Clinical and demographic information were collected at baseline and treatment-related data, including RLAI discontinuation, psychiatric hospitalization and medication utilization, were collected prospectively every 3 months. Data collection continued for 24 months, even for patients who discontinued RLAI therapy. Hospitalization and medication utilization were also collected retrospectively by chart review for the 12-month period prior to RLAI initiation.

RESULTS

A total of 1659 patients (mean age, 39.2; 18.3% inpatients) completed the study. Twenty-four months after initiating therapy (initial RLAI dose = 33.6 mg) 85% of patients (n = 1410) remained on RLAI (completers) while 15% discontinued therapy. The main reasons for discontinuation were insufficient response (28.5%), patient/family choice (26.1%), adverse events (9.6%) and unacceptable tolerability (6.0%). At baseline, compared to completers, discontinuers were younger (37.4 vs. 39.6 years, p = 0.01), had schizophrenia for a shorter time (10.2 vs. 11.9 years, p = 0.02), had lower Global Assessment of Functioning (GAF) scores (43.5 vs. 48.0, p = 0.0001), higher utilization of benzodiazepines (56.5 vs. 43.3%) and more initiated therapy as inpatients (30 vs. 16%). With RLAI therapy GAF scores improved significantly (p < 0.001) for both groups but the 24-month value for discontinuers was lower than that of completers (55.4 vs. 67.2). Compared to the pre-RLAI initiation period, at 12 months post-initiation completers had greater reductions than discontinuers in the percent of patients hospitalized (66.2% reduction vs. 29.2%) and in the length (68% reduction vs. 0%) and number (80.0 vs. 14.3%) of hospital stays, differences that remained at 24 months. The most common adverse events while patients were taking RLAI were nervous system disorders (6.8%), psychiatric disorders (5.6%), weight increase (3.2%), reproductive system and breast disorders (2.5%) and gastrointestinal disorders (2.1%).

CONCLUSIONS

These observational data confirm that RLAI is an effective treatment in schizophrenia and high levels of adherence to therapy offers an opportunity for effective long-term disease management and significant sustained decreases in hospitalization.

Impact of opioid rescue medication for breakthrough pain on the efficacy and tolerability of long-acting opioids in patients with chronic non-malignant pain

Background

There is little evidence that short-acting opioids as rescue medication for breakthrough pain is an optimal long-term treatment strategy in chronic non-malignant pain. We compared clinical studies of long-acting opioids that allowed short-acting opioid rescue medication with those that did not, to determine the impact of opioid rescue medication use on the analgesic efficacy and tolerability of chronic opioid therapy in patients with chronic non-malignant pain.

Methods

We searched MEDLINE (1950 to July 2006) and EMBASE (1974 to July 2006) using terms for chronic non-malignant pain and long-acting opioids. Independent review of the search results identified 48 studies that met the study selection criteria. The effect of opioid rescue medication on analgesic efficacy and the incidence of common opioid-related side-effects were analysed using meta-regression.

Results

After adjusting for potentially confounding variables (study design and type of opioid), the difference in analgesic efficacy between the ‘rescue’ and the ‘no rescue’ studies was not significant, with regression coefficients close to 0 and 95% confidence intervals that excluded an effect of more than 18 points on a 0–100 scale in each case. There was also no significant difference between the ‘rescue’ and the ‘no rescue’ studies for the incidence of nausea, constipation, or somnolence in both the unadjusted and the adjusted analyses.

Conclusions

We found no evidence that rescue medication with short-acting opioids for breakthrough pain affects analgesic efficacy of long-acting opioids or the incidence of common opioid-related side-effects among chronic non-malignant pain patients.

Clinical and resource-use outcomes of risperidone long-acting injection in recent and long-term diagnosed schizophrenia patients: results from a multinational electronic registry

BACKGROUND

Non-adherence to pharmacological treatment leading to frequent relapses and rehospitalizations is a major issue of concern among schizophrenia patients, especially those who are recently diagnosed. Risperidone long-acting injection (RLAI) has been shown to be efficacious, improve compliance, and increase long-term retention rate on therapy.

OBJECTIVE

To determine clinical outcomes and hospitalizations before and after the initiation of RLAI among schizophrenia patients with recent (< or =2 years) diagnosis relative to those who had long-term (> 2 years) diagnosis.

RESEARCH DESIGN AND METHODS

The electronic Schizophrenia Treatment Adherence Registry (e-STAR) is an observational study of patients with schizophrenia who start treatment with RLAI. Data were recorded at baseline, retrospectively for the 12 months prior to baseline, and prospectively every 3 months for 24 months. Data on patients with a defined length of diagnosis were pooled from eight countries.

MAIN OUTCOME MEASURES

Clinical Global Impression of Illness Severity (CGI-S), Global Assessment of Functioning (GAF) scores, and hospitalization data were key outcomes.

RESULTS

The magnitude of improvement in CGI-S scores was greater in the recent versus long-term diagnosis group [Delta -1.48 vs. Delta -0.95 (12 months); Delta -1.6 vs. Delta -1.09 (24 months)]. There were parallel improvements in GAF scores [Delta 19.4 vs. Delta 13.7 (12 months); Delta 22.3 vs. Delta 16.8 (24 months)]. The decline in the proportion of patients hospitalized from the retrospective to the prospective period was greater in the recent versus long-term diagnosis group (Delta -36.0 vs. Delta -19%, respectively) at 12 months. This was also true for the number of hospital stays (Delta -0.6 vs. Delta -0.3, respectively) and length of stay (days) (Delta -20.9 vs. Delta -6.9, respectively) at 12 months. Common adverse events in both groups included psychiatric, gastrointestinal, musculoskeletal and reproductive system and breast disorders.

CONCLUSIONS

Treatment with RLAI is associated with improved outcomes in recently diagnosed and chronic patients. However, the magnitude of improvement was higher in recently diagnosed patients.

Experimental observation of the improvement in MTF from backthinning a CMOS direct electron detector

The advantages of backthinning monolithic active pixel sensors (MAPS) based on complementary metal oxide semiconductor (CMOS) direct electron detectors for electron microscopy have been discussed previously; they include better spatial resolution (modulation transfer function or MTF) and efficiency at all spatial frequencies (detective quantum efficiency or DQE). It was suggested that a 'thin' CMOS detector would have the most outstanding properties [1-3] because of a reduction in the proportion of backscattered electrons. In this paper we show, theoretically (using Monte Carlo simulations of electron trajectories) and experimentally that this is indeed the case. The modulation transfer functions of prototype backthinned CMOS direct electron detectors have been measured at 300keV. At zero spatial frequency, in non-backthinned 700-mum-thick detectors, the backscattered component makes up over 40% of the total signal but, by backthinning to 100, 50 or 35mum, this can be reduced to 25%, 15% and 10%, respectively. For the 35mum backthinned detector, this reduction in backscatter increases the MTF by 40% for spatial frequencies between 0.1 and 1.0 Nyquist. As discussed in the main text, reducing backscattering in backthinned detectors should also improve DQE.