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Recent interest in modern regression modelling has focused on extending available (mean) regression models by describing more general properties of the response distribution. An alternative approach is quantile regression where regression effects on the conditional quantile function of the response are assumed. While quantile regression can be seen as a generalization of median regression, expectiles as alternative are a generalized form of mean regression. Generally, quantiles provide a natural interpretation even beyond the 0.5 quantile, the median. A comparable simple interpretation is not available for expectiles beyond the 0.5 expectile, the mean. Nonetheless, expectiles have some interesting properties, some of which are discussed in this article. We contrast the two approaches and show how to get quantiles from a fine grid of expectiles. We compare such quantiles from expectiles with direct quantile estimates regarding efficiency. We also look at regression problems where both quantile and expectile curves have the undesirable property that neighbouring curves may cross each other. We propose a modified method to estimate non-crossing expectile curves based on splines. In an application, we look at the expected shortfall, a risk measure used in finance, which requires both expectiles and quantiles for estimation and which can be calculated easily with the proposed methods in the article.

Transcranial alternating current stimulation (tACS) sees increased use in neurosciences as a tool for the exploration of brain oscillations. It has been shown that tACS stimulation in specific frequency bands can result in aftereffects of modulated oscillatory brain activity that persist after the stimulation has ended. The general relationship between persistency of the effect and duration of stimulation is sparsely investigated but previous research has shown that the occurrence of tACS aftereffects depends on the brain state before and during stimulation. Early alpha neurofeedback research suggests that particularly in the alpha band the responsiveness to a manipulation depends on the ambient illumination during measurement. Therefore, in the present study we assessed the brain's susceptibility to tACS at the individual alpha frequency during darkness compared to ambient illumination. We measured alpha power after 10 min of stimulation in 30 participants while they continuously performed a visual vigilance task. Our results show that immediately after stimulation, the alpha power in the illumination condition for both the stimulated and sham group has increased by only about 7%, compared to about 20% in both groups in the 'dark' condition. For the group that did not receive stimulation, the power in darkness remained stable after stimulation, whereas the power in light increased by an additional 10% during the next 30 min. For the group that did receive stimulation, alpha power during these 30 min increased by another 11% in light and 22% in darkness. Since alpha power already increased by about 10% without stimulation, the effect of illumination does not seem to have interacted with the effect of stimulation. Instead, both effects seem to have added up linearly. Although our findings do not show that illumination-induced differences in oscillatory activity influence the susceptibility toward tACS, they stress the importance of controlling for factors like ambient light that might add an independent increase or decrease to the power of brain oscillations during periods, where possible persistent effects of stimulation are explored.

The use of triage systems such as the Manchester Triage System (MTS) is a standard procedure to determine the sequence of treatment in emergency departments (EDs). When using the MTS, time targets for treatment are determined. These are commonly displayed in the ED information system (EDIS) to ED staff. Using measurements as targets has been associated with a decline in meeting those targets. This study investigated the impact of displaying time targets for treatment to physicians on processing times in the ED. We analyzed the effects of displaying time targets to ED staff on waiting times in a prospective crossover study, during the introduction of a new EDIS in a large regional hospital in Germany. The old information system version used a module that showed the time target determined by the MTS, while the new system version used a priority list instead. Evaluation was based on 35,167 routinely collected electronic health records from the preintervention period and 10,655 records from the postintervention period. Electronic health records were extracted from the EDIS, and data were analyzed using descriptive statistics and generalized additive models. We evaluated the effects of the intervention on waiting times and the odds of achieving timely treatment according to the time targets set by the MTS. The average ED length of stay and waiting times increased when the EDIS that did not display time targets was used (average time from admission to treatment: preintervention phase=median 15, IQR 6-39 min; postintervention phase=median 11, IQR 5-23 min). However, severe cases with high acuity (as indicated by the triage score) benefited from lower waiting times (0.15 times as high as in the preintervention period for MTS1, only 0.49 as high for MTS2). Furthermore, these patients were less likely to receive delayed treatment, and we observed reduced odds of late treatment when crowding occurred. Our results suggest that it is beneficial to use a priority list instead of displaying time targets to ED personnel. These time targets may lead to false incentives. Our work highlights that working better is not the same as working faster.

Methodological challenges arise with the analysis of patient satisfaction as a measure of health care quality. One of them is the necessity to adjust for differences in patient characteristics or other variables. A combination of several helpful extensions to regression analysis is shown based on patients with inflammatory bowel disease (IBD) to help identify important covariates associated with the distribution of satisfaction. Analyses were based on cross-sectional data from a postal survey on the health care of patients with IBD aged 15-25, with satisfaction assessed using a 32-item validated questionnaire weighing experience by perceived relevance. The weighted summary score was modeled using a Beta distribution in a generalized additive model for location, scale and shape. Covariates were distinguished in 3 groups and the model was entered in separate, consecutive analyses. First, demographic and disease-related variables were included. Next, information about the IBD specialist was added. The third step added care quality indicators. Results are presented as OR with 95% CI. In the survey, 619 questionnaires were returned and the data set had 453 complete cases for analysis. Satisfaction appeared increased for patients working (OR 1.59, 95% CI: 1.19-2.11) or studying (1.25, 1.00-1.56) as compared to those still at school or in non-academic job training. High anxiety scores and an older age of onset were associated with lower satisfaction. The variation of satisfaction is higher for patients with Crohn's disease or who have statutory insurance (1.19, 1.01-1.40 and 1.22, 1.06-1.40). Modeling the entire distribution of the response uncovered additional influences on the variance of patient satisfaction not previously identified by classical regression. It also resulted in a richer model for the mean. The construction of a combined model for different features of the distribution also helped to improve the control of confounding.

IntroductionPatients with neurological or neurosurgical disease can suffer from impaired cough, which may result in life-threatening retention of tracheobronchial secretions, atelectasis, pneumonia and finally death. Due to a lack of alternatives and pathophysiological plausibility, the application of mechanical insufflation-exsufflation (MI-E) has already become international standard care in neuromuscular disease and spinal cord injury although a lack of evidence for efficacy. High-quality studies to support the use of MI-E in neurological and neurosurgical patients during weaning from mechanical ventilation are missing. The goal of this exploratory study is to display the effect size of MI-E intervention on the duration of mechanical ventilation and additional outcomes.Methods and analysisOne hundred adult patients with a cough deficiency or retention of secretion admitted to a neurological intensive care unit (ICU) are planned to be recruited for this randomised controlled trial. Patients are randomised 1:1 to receive either MI-E or best standard care. Observation will take place until discharge from the hospital, death or end of the study period. The primary endpoint of this trial is the duration of mechanical ventilation from randomisation until successful weaning. The outcome will be analysed with Kaplan-Meier estimation and competing risks analyses. Secondary endpoint is the proportion of patients with successful weaning. Further outcomes will include the incidence of hospital-acquired pneumonia, mortality, decannulation rate, length of stay on the ICU and the total score of the Glasgow Coma Scale.Ethics and disseminationThe study was approved by the Medical Ethics Committee of the University of Oldenburg. The findings of this study will be submitted for publication in a peer-reviewed journal.Trial registration numberDRKS00020981.

Patient satisfaction is frequently used as a health care quality measure despite methodological challenges. By the example of pediatric inflammatory bowel disease (IBD), we assessed factors associated with low satisfaction and examined differences by type of provider. In a cross-sectional design, a 32-item questionnaire and global questioning were used to assess satisfaction in patients aged 15-25 years. Determinants of low satisfaction were identified by logistic regression (OR with 95% CI). Separate models were calculated for patient-related variables such as age, socioeconomic status (SES), health status (emotional, somatic, quality of life) or region of residence (step 1), and impact of provider (pediatric specialist, adult specialist, no specialist) (step 2). As secondary analysis, we studied the effect of additional indicators such as waiting time, consultation time, and an IBD Management Quality Index (IMQI) on effect estimates (step 3). A total of 567 cases were available for analysis (response 48.2%). The strongest predictors of low satisfaction were anxiety symptoms (OR 2.49, CI 1.14 to 5.45). In step 2, not being seen by a specialist (1.89, 1.16 to 3.10) and having been with the new provider for less than 12 months (1.71, 1.03 to 2.83) were associated with low satisfaction. Satisfaction with adult care provider was similar to pediatric care if adjusted for anxiety, health status, and time with provider (0.95, 0.59 to 1.51). Presence of other quality indicators (step 3), waiting time >30 minutes, consultation time <15 minutes, and low IMQI were all associated with low satisfaction. Age, SES, and region of residence were not found to affect satisfaction in any of the models. Anxiety symptoms were most strongly associated with low patient satisfaction. The relevance of recent provider change and not being seen by a specialist underlines the importance of well-planned transition in this age group.

The German short form of the Speech, Spatial, and Qualities of Hearing Scale (SSQ) was administered in a cross-sectional study based on stratified random samples complemented by audiometric tests and a general interview. Data from 1,711 unaided adults aged 18 to 97 years were analyzed in order to determine a distribution of hearing abilities considered as normal and the main factors that impact self-assessments. An innovative mathematical approach was used to overcome the constraints of statistics based on the mean. Quantile regression analysis yielded a benchmark distribution of SSQ scores that might support audiologists in setting realistic SSQ score targets and estimated how the effect of auditory and nonauditory factors changes across the distribution of SSQ scores. Regression models showed significant effects for nonauditory factors on SSQ ratings when controlled for pure-tone hearing and interaural asymmetry. Self-reporting of hearing difficulties, when asked in general terms, was substantially related to SSQ ratings. This effect was observed in both high and low scoring participants and led to a considerable score decrease in all SSQ subscales. Gender, educational level, and self-reporting of health issues also were significantly related to SSQ ratings, but the corresponding effects were regularly unbalanced across the score distribution and particularly large at lower quantiles. The estimated effects of age, however, were mostly small in size, inconsistent regarding the direction, and failed significance for all SSQ items. Overall, the results suggest that nonauditory factors and cumulative effects must be considered when evaluating rehabilitative interventions against an ideal outcome.

Pain remains insufficiently treated in hospitals. Increasing evidence suggests human factors contribute to this, due to nurses failing to administer opioids. This behavior might be the consequence of nurses' mental models about opioids. As personal experience and conceptions shape these models, the aim of this prospective survey was to identify model-influencing factors. A questionnaire was developed comprising of 14 statements concerning ideations about opioids and seven questions concerning demographics, indicators of adult learning, and strength of religious beliefs. Latent variables that may underlie nurses' mental models were identified using undirected graphical dependence models. Representative items of latent variables were employed for ordinal regression analysis. Questionnaires were distributed to 1,379 nurses in two London, UK, hospitals (n=580) and one German (n=799) hospital between September 2014 and February 2015. A total of 511 (37.1%) questionnaires were returned. Mean (standard deviation) age of participants were 37 (11) years; 83.5% participants were female; 45.2% worked in critical care; and 51.5% had more than 10 years experience. Of the nurses, 84% were not scared of opioids, 87% did not regard opioids as drugs to help patients die, and 72% did not view them as drugs of abuse. More English (41%) than German (28%) nurses were afraid of criminal investigations and were constantly aware of side effects (UK, 94%; Germany, 38%) when using opioids. Four latent variables were identified which likely influence nurses' mental models: \"conscious decision-making\"; \"medication-related fears\"; \"practice-based observations\"; and \"risk assessment\". They were predicted by strength of religious beliefs and indicators of informal learning such as experience but not by indicators of formal learning such as conference attendance. Nurses in both countries employ analytical and affective mental models when administering the opioids and seem to learn from experience rather than from formal teaching. Additionally, some attitudes and emotions towards opioids are likely the result of nurses' cultural background.

Abstract Background The patient perspective is essential for assessing disease severity, but it is not always adequately considered. We describe how a comprehensive clinical disease severity index (DSI) for inflammatory bowel disease (IBD) correlates with patient global self-assessment (PGSA). Methods In an individually linked parallel online survey, physicians provided the DSI, and patients provided self-assessed severity using a global question and visual analog scale (0-100) (PGSA). Mean DSI values by PGSA were calculated with 95% confidence intervals. Pearson correlation (r) and the intraclass correlation coefficient were calculated for PGSA vs DSI. Positive predictive values for identifying severe disease with PGSA categories as a reference were based on a threshold >22 points. Results The primary analysis included 89 pairs (46 Crohn’s disease [CD], 43 ulcerative colitis [UC]) with strict criteria and 147 pairs when less stringent. Common reasons for exclusion were missing values for albumin or colonoscopy. Mean DSI values showed no clear trend with increasing PGSA in CD but good discrimination between moderate, severe, and very severe PGSA in UC. For PGSA on the visual analog scale, r was 0.54 for CD and 0.59 for UC (difference in means: CD 27.7, UC 13.8; intraclass correlation coefficient: CD 0.48, UC 0.58). A high DSI predicted severe disease in 76.2% of CD and 65.2% of UC. Conclusions The DSI showed good discrimination for patient-reported disease severity in UC but performed unsatisfactorily in CD. Correlations were moderate. Further refinement of the DSI is suggested to better reflect the patient perspective. Lay Summary The performance of an inflammatory bowel disease severity score was compared with self-perceived severity based on an individually linked online survey of patients and their physicians. Agreement and prediction of severe disease were moderate and should be improved by integrating the patients’ perspective.

Periodic demographic health surveillance and surveys are the main sources of health information in developing countries. Conducting a survey requires extensive use of paper-pen and manual work and lengthy processes to generate the required information. Despite the rise of popularity in using electronic data collection systems to alleviate the problems, sufficient evidence is not available to support the use of electronic data capture (EDC) tools in interviewer-administered data collection processes. This study aimed to compare data quality parameters in the data collected using mobile electronic and standard paper-based data capture tools in one of the health and demographic surveillance sites in northwest Ethiopia. A randomized controlled crossover health care information technology evaluation was conducted from May 10, 2016, to June 3, 2016, in a demographic and surveillance site. A total of 12 interviewers, as 2 individuals (one of them with a tablet computer and the other with a paper-based questionnaire) in 6 groups were assigned in the 6 towns of the surveillance premises. Data collectors switched the data collection method based on computer-generated random order. Data were cleaned using a MySQL program and transferred to SPSS (IBM SPSS Statistics for Windows, Version 24.0) and R statistical software (R version 3.4.3, the R Foundation for Statistical Computing Platform) for analysis. Descriptive and mixed ordinal logistic analyses were employed. The qualitative interview audio record from the system users was transcribed, coded, categorized, and linked to the International Organization for Standardization 9241-part 10 dialogue principles for system usability. The usability of this open data kit-based system was assessed using quantitative System Usability Scale (SUS) and matching of qualitative data with the isometric dialogue principles. From the submitted 1246 complete records of questionnaires in each tool, 41.89% (522/1246) of the paper and pen data capture (PPDC) and 30.89% (385/1246) of the EDC tool questionnaires had one or more types of data quality errors. The overall error rates were 1.67% and 0.60% for PPDC and EDC, respectively. The chances of more errors on the PPDC tool were multiplied by 1.015 for each additional question in the interview compared with EDC. The SUS score of the data collectors was 85.6. In the qualitative data response mapping, EDC had more positive suitability of task responses with few error tolerance characteristics. EDC possessed significantly better data quality and efficiency compared with PPDC, explained with fewer errors, instant data submission, and easy handling. The EDC proved to be a usable data collection tool in the rural study setting. Implementation organization needs to consider consistent power source, decent internet connection, standby technical support, and security assurance for the mobile device users for planning full-fledged implementation and integration of the system in the surveillance site.