Statistical inference for agreement between multiple raters on a binary scale

Agreement studies often involve more than two raters or repeated measurements. In the presence of two raters, the proportion of agreement and of positive agreement are simple and popular agreement measures for binary scales. These measures were generalized to agreement studies involving more than two raters with statistical inference procedures proposed on an empirical basis. We present two alternatives. The first is a Wald confidence interval using standard errors obtained by the delta method. The second involves Bayesian statistical inference not requiring any specific Bayesian software. These new procedures show better statistical behaviour than the confidence intervals initially proposed. In addition, we provide analytical formulas to determine the minimum number of persons needed for a given number of raters when planning an agreement study. All methods are implemented in the R package simpleagree and the Shiny app simpleagree.

Review of sample size determination methods for the intraclass correlation coefficient in the one-way analysis of variance model

Reliability of measurement instruments providing quantitative outcomes is usually assessed by an intraclass correlation coefficient. When participants are repeatedly measured by a single rater or device, or, are each rated by a different group of raters, the intraclass correlation coefficient is based on a one-way analysis of variance model. When planning a reliability study, it is essential to determine the number of participants and measurements per participant (i.e. number of raters or number of repeated measurements). Three different sample size determination approaches under the one-way analysis of variance model were identified in the literature, all based on a confidence interval for the intraclass correlation coefficient. Although eight different confidence interval methods can be identified, Wald confidence interval with Fisher's large sample variance approximation remains most commonly used despite its well-known poor statistical properties. Therefore, a first objective of this work is comparing the statistical properties of all identified confidence interval methods-including those overlooked in previous studies. A second objective is developing a general procedure to determine the sample size using all approaches since a closed-form formula is not always available. This procedure is implemented in an R Shiny app. Finally, we provide advice for choosing an appropriate sample size determination method when planning a reliability study.

Chasing consistency: On the measurement error in self-reported affect in experiments

How feelings change over time is a central topic in emotion research. To study these affective fluctuations, researchers often ask participants to repeatedly indicate how they feel on a self-report rating scale. Despite widespread recognition that this kind of data is subject to measurement error, the extent of this error remains an open question. Complementing many daily-life studies, this study aimed to investigate this question in an experimental setting. In such a setting, multiple trials follow each other at a fast pace, forcing experimenters to use a limited number of questions to measure affect during each trial. A total of 1398 participants completed a probabilistic reward task in which they were unknowingly presented with the same string of outcomes multiple times throughout the study. This allowed us to assess the test-retest consistency of their affective responses to the rating scales under investigation. We then compared these consistencies across different types of rating scales in hopes of finding out whether a given type of scale led to a greater consistency of affective measurements. Overall, we found moderate to good consistency of the affective measurements. Surprisingly, however, we found no differences in consistency across rating scales, which suggests that the specific rating scale that is used does not influence the measurement consistency.

Reliability and agreement in intrapartum fetal heart rate monitoring interpretation: A systematic review

INTRODUCTION

Fetal heart rate (FHR) monitoring is routine in intrapartum care worldwide and one of the most common obstetrical procedures. Intrapartum FHR monitoring helps assess fetal wellbeing and interpretation of the FHR help form decisions for clinical management and intervention. It relies on the observers' subjective assessments, with variation in interpretations leading to variations in intrapartum care. The purpose of this systematic review was to summarize and evaluate extant inter- and intrarater reliability research on the human interpretation of intrapartum FHR monitoring.

MATERIAL AND METHODS

We searched for the terms "fetal heart rate monitoring," "interpretation agreement" and related concepts on Embase, Medline, Maternity and Infant Care Database and CINAHL. The last search was made on January 31, 2022. The protocol for the study was prospectively registered in PROSPERO (CRD42021260937). Studies that assess inter- and intrarater reliability and agreement of health professionals' intrapartum FHR monitoring were included and studies including other assessment of fetal wellbeing excluded. We extracted data in reviewer pairs using quality appraisal tool for studies of diagnostic reliability (QAREL) forms. The data retrieved from the studies are presented as narrative synthesis and in additional tables.

RESULTS

Forty-nine articles concerning continuous FHR monitoring were included in the study. For interrater reliability and agreement, in total 577 raters assessed 6315 CTG tracings. There was considerable heterogeneity in quality and measures across the included articles. We found higher reliability and agreement for the basic FHR features than for overall classification and higher agreement for intrarater reliability and agreement than for their interrater counterparts.

CONCLUSIONS

There is great variation in reliability and agreement measures for continuous intrapartum FHR monitoring, implying that intrapartum CTG should be used with caution for clinical decision making given its questionable reliability. We found few high-quality studies and noted methodological concerns in the studies. We recommend a more standardized approach to future reliability studies on FHR monitoring.

Affective Symptoms and Oropharyngeal Dysphagia in Head-and-Neck Cancer Patients: A Systematic Review

Oropharyngeal dysphagia (OD) is a high impact morbidity in head-and-neck cancer (HNC) patients. A wide variety of instruments are developed to screen for affective symptoms and OD. The current paper aims to systematically review and appraise the literature to obtain insight into the prevalence, strength, and causal direction of the relationship between affective symptoms and OD in HNC patients. This review was conducted in accordance with the PRISMA statement. A systematic search of the literature was performed using PubMed, PsycINFO, Cochrane, and Embase. All available publications reporting on the relationship between affective conditions and swallowing function in HNC patients were included. Conference papers, tutorials, reviews, and studies with less than 5 patients were excluded. Fifteen studies met the inclusion criteria. The level of evidence and methodological quality were assessed using the ABC-rating scale and QualSyst critical appraisal tool. Eleven studies reported a positive relationship between affective symptoms and OD. The findings of this paper highlight the importance of affective symptom screening in dysphagic HNC patients as clinically relevant affective symptoms and OD seems to be prevalent and coincident in this population. Considering the impact of affective symptoms and OD on patients' daily life, early detection and an integrated interdisciplinary approach are recommended. However, due to the heterogeneity of study designs, outcomes, and outcome measures, the generalization of study results is limited.

Modelling agreement for binary intensive longitudinal data

Devices that measure our physical, medical and mental condition have entered our daily life recently. Such devices measure our status in a continuous manner and can be useful in predicting future medical events or can guide us towards a healthier life. It is therefore important to establish that such devices record our behaviour in a reliable manner and measure what we believe they measure. In this article, we propose to measure the reliability and validity of a newly developed measuring device in time using a longitudinal model for sequential kappa statistics. We propose a Bayesian estimation procedure. The method is illustrated by a validation study of a new accelerometer in cardiopulmonary rehabilitation patients.

Affective symptoms and swallow-specific quality of life in total laryngectomy patients

Background

The aim of this study is to determine the prevalence of clinically relevant affective symptoms and level of swallow‐specific quality of life (QoL) in dysphagic patients with total laryngectomy (TL) and to explore the relationship between affective symptoms and swallow‐specific QoL.

Methods

Thirty‐five TL patients completed the Hospital Anxiety and Depression Scale (HADS) and the MD Anderson Dysphagia Inventory (MDADI). Student's t test and linear regression were used.

Results

Eight (23%) patients showed clinically relevant symptoms of anxiety, 8 (23%) of depression, and 11 (31%) showed either one. These groups had significantly lower mean MDADI scores. One‐point increase in HADS‐anxiety or HADS‐depression subscale score corresponds with a decrease of 2.7 or 3.0 points, on average, respectively, of the MDADI total score.

Conclusions

Clinically relevant affective symptoms were present in approximately one‐third of the TL patients. These preliminary results show that increased affective symptom scores correlate with a decreased swallow‐specific QoL.

Voice and Vocal Fold Condition Following Short-Term General Anesthesia: A Prospective Study

BACKGROUND

Dysphonia, with or without laryngeal changes, has been reported as a complication following prolonged intubation. In contrast, it is unknown if laryngeal changes also occur following short-term airway instrumentation. The objectives of this study were to determine the prevalence of laryngeal changes in patients undergoing short-term routine general anesthesia using an endotracheal tube (ETT) or supraglottic airway (SGA), and to identify predictors to these changes.

METHODS

Standardized voice assessments were performed preoperatively, postoperatively, and at follow-up on adults undergoing general anesthesia for an elective procedure of less than three hours requiring an ETT or a SGA. The standardized voice assessment protocol comprised a rigid videolaryngostroboscopy, the Voice Handicap Index (VHI), and acoustic voice analysis. The effects of demographic and anesthetic characteristics and type of airway instrumentation on the videolaryngostroboscopic variables were studied using multilevel logistic regression. Multilevel linear regression was used to reveal preoperative versus postoperative changes in VHI and acoustic voice scores.

RESULTS

Overall, the prevalence of postoperative laryngeal changes was low. Significant postoperative laryngeal changes were found for the variables right-sided vocal fold redness in the ETT group (P = 0.048) and right-sided vocal fold blood vessels in both groups (ETT versus SGA). However, after adjustment for all demographic and anesthetic characteristics in the regression model, the effect of the type of airway instrumentation (ETT versus SGA) on the variable right-sided vocal fold redness was no longer significant.

CONCLUSIONS

ETT and SGA short-term airway instrumentation are vocal fold function sparing techniques with negligible laryngeal changes.

Prevalence and clinical associations of wheezes and crackles in the general population: the Tromsø study

BACKGROUND

Wheezes and crackles are well-known signs of lung diseases, but can also be heard in apparently healthy adults. However, their prevalence in a general population has been sparsely described. The objective of this study was to determine the prevalence of wheezes and crackles in a large general adult population and explore associations with self-reported disease, smoking status and lung function.

METHODS

We recorded lung sounds in 4033 individuals 40 years or older and collected information on self-reported disease. Pulse oximetry and spirometry were carried out. We estimated age-standardized prevalence of wheezes and crackles and associations between wheezes and crackles and variables of interest were analyzed with univariable and multivariable logistic regressions.

RESULTS

Twenty-eight percent of individuals had wheezes or crackles. The age-standardized prevalence of wheezes was 18.6% in women and 15.3% in men, and of crackles, 10.8 and 9.4%, respectively. Wheezes were mostly found during expiration and crackles during inspiration. Significant predictors of expiratory wheezes in multivariable analyses were age (10 years increase - OR 1.18, 95%CI 1.09-1.30), female gender (1.45, 1.2-1.8), self-reported asthma (1.36, 1.00-1.83), and current smoking (1.70, 1.28-2.23). The most important predictors of inspiratory crackles were age (1.76, 1.57-1.99), current smoking, (1.94, 1.40-2.69), mMRC ≥2 (1.79, 1.18-2.65), SpO₂ (0.88, 0.81-0.96), and FEV₁ Z-score (0.86, 0.77-0.95).

CONCLUSIONS

Nearly over a quarter of adults present adventitious lung sounds on auscultation. Age was the most important predictor of adventitious sounds, particularly crackles. The adventitious sounds were also associated with self-reported disease, current smoking and measures of lung function. The presence of findings in two or more auscultation sites was associated with a higher risk of decreased lung function than solitary findings.

Asymptotic variability of (multilevel) multirater kappa coefficients

Agreement studies are of paramount importance in various scientific domains. When several observers classify objects on categorical scales, agreement can be quantified through multirater kappa coefficients. In most statistical packages, the standard error of these coefficients is only available under the null hypothesis that the coefficient is equal to zero, preventing the construction of confidence intervals in the general case. The aim of this paper is triple. First, simple analytic formulae for the standard error of multirater kappa coefficients will be given in the general case. Second, these formulae will be extended to the case of multilevel data structures. The formulae are based on simple matrix algebra and are implemented in the R package “multiagree”. Third, guidelines on the choice between the different mulitrater kappa coefficients will be provided.

Medically Unexplained Oropharyngeal Dysphagia at the University Hospital ENT Outpatient Clinic for Dysphagia: A Cross-Sectional Cohort Study

Medically unexplained oropharyngeal dysphagia (MUNOD) is a rare condition. It presents without demonstrable abnormalities in the anatomy of the upper aero-digestive tract and/or swallowing physiology. This study investigates whether MUNOD is related to affective or other psychiatric conditions. The study included patients with dysphagic complaints who had no detectible structural or physiological abnormalities upon swallowing examination. Patients with any underlying disease or disorder that could explain the oropharyngeal dysphagia were excluded. All patients underwent a standardized examination protocol, with FEES examination, the Hospital Anxiety and Depression Scale (HADS), and the Dysphagia Severity Scale (DSS). Two blinded judges scored five different FEES variables. None of the 14 patients included in this study showed any structural or physiological abnormalities during FEES examination. However, the majority did show abnormal piecemeal deglutition, which could be a symptom of MUNOD. Six patients (42.8%) had clinically relevant symptoms of anxiety and/or depression. The DSS scores did not differ significantly between patients with and without affective symptoms. Affective symptoms are common in patients with MUNOD, and their psychiatric conditions could possibly be related to their swallowing problems.

International perception of lung sounds: a comparison of classification across some European borders

Introduction

Lung auscultation is helpful in the diagnosis of lung and heart diseases; however, the diagnostic value of lung sounds may be questioned due to interobserver variation. This situation may also impair clinical research in this area to generate evidence-based knowledge about the role that chest auscultation has in a modern clinical setting. The recording and visual display of lung sounds is a method that is both repeatable and feasible to use in large samples, and the aim of this study was to evaluate interobserver agreement using this method.

Methods

With a microphone in a stethoscope tube, we collected digital recordings of lung sounds from six sites on the chest surface in 20 subjects aged 40 years or older with and without lung and heart diseases. A total of 120 recordings and their spectrograms were independently classified by 28 observers from seven different countries. We employed absolute agreement and kappa coefficients to explore interobserver agreement in classifying crackles and wheezes within and between subgroups of four observers.

Results

When evaluating agreement on crackles (inspiratory or expiratory) in each subgroup, observers agreed on between 65% and 87% of the cases. Conger's kappa ranged from 0.20 to 0.58 and four out of seven groups reached a kappa of ≥0.49. In the classification of wheezes, we observed a probability of agreement between 69% and 99.6% and kappa values from 0.09 to 0.97. Four out of seven groups reached a kappa ≥0.62.

Conclusions

The kappa values we observed in our study ranged widely but, when addressing its limitations, we find the method of recording and presenting lung sounds with spectrograms sufficient for both clinic and research. Standardisation of terminology across countries would improve international communication on lung auscultation findings.

Observer Agreement for Measurements in Videolaryngostroboscopy

OBJECTIVE

This study evaluated the levels of intraobserver and interobserver agreement for measurements of visuoperceptual variables in videolaryngostroboscopic examinations and compared the observers' behavior during independent versus consensus panel rating.

STUDY DESIGN

This is a retrospective study.

SETTING

This study was conducted in a single-center tertiary care facility.

PARTICIPANTS

Sixty-four patients with dysphonia of heterogeneous etiology were included.

EXPOSURE

All subjects underwent a standardized videolaryngostroboscopic examination.

MAIN OUTCOME AND MEASURES

Two experienced and trained observers scored exactly the same examinations, first independently and then on a consensus panel. Specific visuoperceptual variables and the clinical diagnosis (as recommended by the Committee on Phoniatrics and the Phonosurgery Committee of the European Laryngological Society and advised by the American Speech-Language-Hearing Association) were scored. Descriptive and kappa statistics were used.

RESULTS

In general, intraobserver agreement was better than agreement between observers for measurements of several variables. The intrapanel observer agreement levels were slightly higher than the intraobserver agreement levels on the independent rating task. When rating on the consensus panel, the observers deviated considerably from the scores they had previously given on the independent rating task.

CONCLUSION AND RELEVANCE

Observer agreement in videolaryngostroboscopic assessment has important implications not only for the diagnosis and treatment of dysphonic patients but also for the interpretation of the results of scientific studies using videolaryngostroboscopic outcome parameters. The identification of factors that can influence the levels of observer agreement can provide a better understanding of the rating process and its limitations. The results of this study suggest that future research could achieve better agreement levels by rating the visuoperceptual variables in a panel setting.

Affective symptoms in patients with oropharyngeal dysphagia: A systematic review

OBJECTIVE

Affective disorders are prevalent in different somatic conditions and influence somatic symptom bother and quality of life. Mood and anxiety disorders impact patients' compliance and adherence to treatment. This systematic review summarizes published studies on affective complaints in patients with oropharyngeal dysphagia (OD) in order to determine the quality of studies concerning any association of OD with symptoms of depression and/or anxiety.

METHODS

A literature search was carried out using electronic databases Embase, Medline, Web-of-science, PsycINFO, Cochrane Library, and Google scholar. Two reviewers made the preselecting cut by screening all articles on title and abstract and independently screened the full texts of this initial set of articles. Methodological quality of the studies that met the inclusion criteria was assessed independently.

RESULTS

Twenty-six articles were included in the analysis after full-text screening and by applying the inclusion and exclusion criteria. All studies concluded that symptoms of depression were associated with impaired swallowing function, and 9 out of 12 studies concluded that symptoms of anxiety were associated with functional impairment of swallowing. The reviewers found heterogeneous outcomes and methodological limitations, which prevented data from pooling.

CONCLUSION

Although no meta-analytic conclusions can be drawn, it appears that symptoms of anxiety and depression are common in OD. Caregivers have to be aware of this in order to detect affective comorbidity. Given that affective conditions influence patients' treatment adherence and compliance, integrated care approaches should be advocated in case of comorbidity. Studies on treatment effect are lacking and well-designed prospective research is needed.

Modeling agreement on bounded scales

Agreement is an important concept in medical and behavioral sciences, in particular in clinical decision making where disagreements possibly imply a different patient management. The concordance correlation coefficient is an appropriate measure to quantify agreement between two scorers on a quantitative scale. However, this measure is based on the first two moments, which could poorly summarize the shape of the score distribution on bounded scales. Bounded outcome scores are common in medical and behavioral sciences. Typical examples are scores obtained on visual analog scales and scores derived as the number of positive items on a questionnaire. These kinds of scores often show a non-standard distribution, like a J- or U-shape, questioning the usefulness of the concordance correlation coefficient as agreement measure. The logit-normal distribution has shown to be successful in modeling bounded outcome scores of two types: (1) when the bounded score is a coarsened version of a latent score with a logit-normal distribution on the [0,1] interval and (2) when the bounded score is a proportion with the true probability having a logit-normal distribution. In the present work, a model-based approach, based on a bivariate generalization of the logit-normal distribution, is developed in a Bayesian framework to assess the agreement on bounded scales. This method permits to directly study the impact of predictors on the concordance correlation coefficient and can be simply implemented in standard Bayesian softwares, like JAGS and WinBUGS. The performances of the new method are compared to the classical approach using simulations. Finally, the methodology is used in two different medical domains: cardiology and rheumatology.

Comparing dependent kappa coefficients obtained on multilevel data

Reliability and agreement are two notions of paramount importance in medical and behavioral sciences. They provide information about the quality of the measurements. When the scale is categorical, reliability and agreement can be quantified through different kappa coefficients. The present paper provides two simple alternatives to more advanced modeling techniques, which are not always adequate in case of a very limited number of subjects, when comparing several dependent kappa coefficients obtained on multilevel data. This situation frequently arises in medical sciences, where multilevel data are common. Dependent kappa coefficients can result from the assessment of the same individuals at various occasions or when each member of a group is compared to an expert, for example. The method is based on simple matrix calculations and is available in the R package “multiagree”. Moreover, the statistical properties of the proposed method are studied using simulations. Although this paper focuses on kappa coefficients, the method easily extends to other statistical measures.

A New Interpretation of the Weighted Kappa Coefficients

Reliability and agreement studies are of paramount importance. They do contribute to the quality of studies by providing information about the amount of error inherent to any diagnosis, score or measurement. Guidelines for reporting reliability and agreement studies were recently provided. While the use of the kappa-like family is advised for categorical and ordinal scales, no further guideline in the choice of a weighting scheme is given. In the present paper, a new simple and practical interpretation of the linear- and quadratic-weighted kappa coefficients is given. This will help researchers in motivating their choice of a weighting scheme.

The relationship between fiberoptic endoscopic evaluation of swallowing outcome and symptoms of anxiety and depression in dysphagic patients

OBJECTIVES/HYPOTHESIS

Affective complaints are involved in bothersome oropharyngeal dysphagia (OD). The aim was to determine the relationship between the severity of OD and affective symptoms.

STUDY DESIGN

Prospective cohort study.

METHODS

One hundred seven patients underwent a standardized examination protocol including the Hospital Anxiety and Depression Scale and fiberoptic endoscopic evaluation of swallowing (FEES). Two observers independently assessed patient performance on four ordinal FEES-variables (for thin and thick liquid consistency, blindly assessed). The relationship between FEES outcome and the presence of clinically relevant symptoms of anxiety and depression was analyzed using binary logistic regression.

RESULTS

Significant associations were found between clinically relevant symptoms of anxiety and two variables: piecemeal deglutition (thin liquid consistency only) (P = .026) and postswallow vallecular pooling (thick liquid consistency only) (P = .015). The probability of presenting with anxiety symptoms decreased as the severity of piecemeal deglutition and postswallow vallecular pooling increased. No significant association was found between clinically relevant symptoms of depression and any specific FEES variable.

CONCLUSIONS

These data revealed few associations between anxiety symptoms and the measured FEES variables. However, the more severe the score on FEES variables, the less important the affective complaints were. Anxiety seems to play a role in OD, but no causal relationship was found, commensurate with a cross-sectional study design. The contribution of affective symptoms to the development and treatment of OD warrants longitudinal research.

LEVEL OF EVIDENCE

2b Laryngoscope, 126:E199-E207, 2016.

Modeling agreement on categorical scales in the presence of random scorers

Kappa coefficients are often used to assess agreement between two fixed scorers on categorical scales. Cohen's version is popular for nominal scales and the weighted version for ordinal scales. In the present paper, similar agreement coefficients are defined for random scorers. A partial-Bayesian methodology is then developed to directly relate these agreement coefficients to predictors through a multilevel model. Statistical properties of the proposed approach are studied using simulations. Finally, the approach is applied to gynecological and medical imaging data.

Medically unexplained otorhinolaryngological symptoms: Towards integrated psychiatric care

OBJECTIVE

To evaluate the presence of medically unexplained otorhinolaryngological symptoms in a patient cohort and propose an interdisciplinary approach for their care.

STUDY DESIGN

Prospective cohort study.

METHODS

The study describes the population of patients presenting consecutively at the Department of Otorhinolaryngology at the Maastricht University Medical Center. Patients with symptoms who did not meet clear "medical" criteria and were associated with psychological distress and high health care utilization were enrolled in the study by two experienced otorhinolaryngologists following informed consent. The aim of the study is 1) to specify the presence of medically unexplained otorhinolaryngological symptoms and 2) to evaluate the integration of otorhinolaryngological and psychiatric treatment in an interdisciplinary approach in order to help otorhinolaryngologists improve patient care.

RESULTS

Of the 102 patients included, 41% (N = 42) did not have a proven somatic otorhinolaryngological diagnosis. For only 10.8% (N = 4) of the latter, no psychiatric diagnosis had been established. Overall, 78% of the study population (N = 80) was diagnosed with psychiatric morbidity/comorbidity, as defined in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition.

CONCLUSION

The preliminary data suggest that the majority of patients with these unexplained complaints may suffer from under- or undiagnosed psychiatric morbidity. Therefore, easy access to integrated interdisciplinary care (otorhinolaryngology and psychiatry) should be offered to patients with medically unexplained otorhinolaryngological symptoms after detailed information is made available to them about the pathogenesis of the complaints and the foreseen psychosomatic approach.

Prevalence and clinical characteristics of remission during treatment in generalized anxiety

OBJECTIVE

Although the remission criteria for generalized anxiety are well defined, there is not much data available on the point prevalence of remission. The Measuring Impact of Remission in Anxiety Disorders in Belgium (MIRABEL) study is a naturalistic study designed to document the point prevalence of remission in patients treated for general anxiety and potential factors affecting this prevalence.

METHODS

The study population consisted of 618 adult outpatients being treated for generalized anxiety. The sample is defined by the key symptoms of generalized anxiety disorder rather than by fulfilling the exact DSM-IV-TR diagnostic criteria. Remission was defined as a Hamilton Anxiety Scale (HAM-A) score of less than or equal to 7. To reduce the interrater reliability, the HAM-A was assessed by the attending physicians who had no specific training. Factors investigated as possibly related to remission included sociodemographic, disease and treatment characteristics.

RESULTS

The point prevalence of remission in the study population was estimated at 13.3%. Remission prevalence varied with occupational status and severity of the current anxiety episode. Remission prevalence was lower in the presence of comorbidity and was proportional to the number of comorbid symptoms. Remitters took fewer medications but were treated longer. Remission prevalence was higher in patients who were taking antidepressants, but was lower in patients who were taking sedatives.

CONCLUSIONS

These findings underline the poor prognosis of generalized anxiety.

The effects of short-term treatment with levamisole on cytokines in volunteers and cancer-patients

In search for clues to the potential immunomodulating mechanism of action of levamisole which might be used as monitoring parameters, we have determined a variety of cytokines in the peripheral blood of volunteers and carcinoma patients before and after a single or a 3-day-treatment with 150 mg/day. In cancer patients no changes could be detected 4 days after a 3-day-treatment course in the levels of TNF-alpha, IL-1beta, IL-2 or IL-6. In a placebo-controlled volunteer study the same treatment did not affect the levels of beta2-microglobulin, IL-1beta, IL-1alpha, IL-2 or IL-6. However, 24hr after the last treatment the concentration of neopterin was slightly but significantly increased and the concentration of soluble IL-2 receptors decreased. A single treatment failed to produce such an effect. It is suggested that the measurement of neopterin and soluble IL-2 receptors may provide useful information in future trials.

Hierarchical modeling of agreement

Kappa-like agreement indexes are often used to assess the agreement among examiners on a categorical scale. They have the particularity of correcting the level of agreement for the effect of chance. In the present paper, we first define two agreement indexes belonging to this family in a hierarchical context. In particular, we consider the cases of a random and fixed set of examiners. Then, we develop a method to evaluate the influence of factors on these indexes. Agreement indexes are directly related to a set of covariates through a hierarchical model. We obtain the posterior distribution of the model parameters in a Bayesian framework. We apply the proposed approach on dental data and compare it with the generalized estimating equations approach.

Effect of an audiovisual message for tetanus booster vaccination broadcast in the waiting room

Background

General practitioners (GPs) often lack time and resources to invest in health education; audiovisual messages broadcast in the waiting room may be a useful educational tool. This work was designed to assess the effect of a message inviting patients to ask for a tetanus booster vaccination.

Methods

A quasi experimental study was conducted in a Belgian medical practice consisting of 6 GPs and 4 waiting rooms (total: 20,000 contacts/year). A tetanus booster vaccination audiovisual message was continuously broadcast for 6 months in 2 randomly selected waiting rooms (intervention group - 3 GPs) while the other 2 waiting rooms remained unequipped (control group - 3 GPs). At the end of the 6-month period, the number of vaccine adult-doses delivered by local pharmacies in response to GPs' prescriptions was recorded. As a reference, the same data were also collected retrospectively for the general practice during the same 6-month period of the previous year.

Results

During the 6-month reference period where no audiovisual message was broadcast in the 4 waiting rooms, the number of prescriptions presented for tetanus vaccines was respectively 52 (0.44%) in the intervention group and 33 (0.38%) in the control group (p = 0.50). By contrast, during the 6-month study period, the number of prescriptions differed between the two groups (p < 0.0001), rising significantly to 91 (0.79%) in the intervention group (p = 0.0005) while remaining constant in the control group (0.38% vs 0.39%; p = 0.90).

Conclusions

Broadcasting an audiovisual health education message in the GPs' waiting room was associated with a significant increase in the number of adult tetanus booster vaccination prescriptions delivered by local pharmacies.

Penetration of oxytetracycline into the nasal secretions and relationship between nasal secretions and plasma oxytetracycline concentrations after oral and intramuscular administration in healthy pigs

The penetration of oxytetracycline (OTC) in plasma and nasal secretions of healthy pigs was evaluated during the first study, in response to oral dose of 20 mg of OTC per kg of body weight (bwt) per day as a 400 mg/kg feed medication (n = 5) and to intramuscular (i.m.)-administered formulations at 10 mg/kg bwt (n = 5), 20 mg/kg bwt (n = 5), 40 mg/kg bwt (n = 5). Concentrations of OTC in plasma and nasal secretions were determined by a validated ultra-high performance liquid chromatography associated to tandem mass spectrometry method (UPLC/MS/MS). The objectives were to select the efficacy treatment and to evaluate the possibility to predict nasal secretions concentrations from those determined in plasma. The animals were housed together in each experiment. In each group, the treatment was administered once daily during 6 consecutive days, and nasal secretions and plasma were collected after 4 and 24 h at day 2 and day 6. For oral administration, only one medicated feed was prepared and distributed to all the animals together and was consumed in approximately 1 h. To meet recommendations of efficacy for OTC in nasal secretions, only the i.m. of 40 mg/kg bwt associated to an inter-dosing interval of 24 h provides and maintains concentrations in nasal secretions ≥1 μg/mL, appropriate to the MIC 50 and 90 of Pasteurella multocida and Bordetella bronchiseptica, respectively, the main pathological strains in nasal secretions. It has been demonstrated that, using a generalized linear mixed model (GLMM), OTC in the nasal secretions (μg/mL) can be predicted taking into account the OTC concentrations in plasma (μg/mL), according to the following equation: OTC(nasal secretions)  = 0.28 OTC(plasma) -1.49. In a second study, the pharmacokinetic behaviour of OTC in plasma and nasal secretions of healthy pigs was investigated, after single-dose i.m. of 40 mg/kg bwt of the drug. Blood samples and nasal secretions were collected at predetermined times after drug administration. The data collected in 10 pigs for OTC were subjected to non-compartmental analysis. In plasma, the maximum concentration of drug (C(max) ), the time at which this maximum concentration of drug (T(max) ) was reached, the elimination half-life (t½) and the area under the concentration vs. time curve (AUC) were, respectively, 19.4 μg/mL, 4.0, 5.1 h and 150 μg·h/mL. In nasal secretions, C(max) , T(max) , t½ and AUC were, respectively, 6.29 μg/mL, 4.0, 6.6 h and 51.1 μg·h/mL.

Lack of efficacy of low-dose spironolactone as adjunct treatment to conventional congestive heart failure treatment in dogs

Aldosterone plays an important role in the pathophysiology of heart failure. Aldosterone receptor blockade has been shown to reduce morbidity and mortality in human patients with advanced congestive left ventricular heart failure. This study was designed to assess the efficacy and tolerance of long-term low-dose spironolactone when added to conventional heart failure treatment in dogs with advanced heart failure. Eighteen client-owned dogs with advanced congestive heart failure due to either degenerative valve disease (n=11) or dilated cardiomyopathy (n=7) were included in this prospective, placebo-controlled, double-blinded, randomized clinical study. After initial stabilization including furosemide, angiotensin-converting enzyme inhibitors, pimobendan and digoxin, spironolactone at a median dose of 0.52 mg/kg (range 0.49-0.8 mg/kg) once daily (n=9) or placebo (n=9) was added to the treatment, and the dogs were reassessed 3 and 6 months later. Clinical scoring, echocardiography, electrocardiogram, systolic blood pressure measurement, thoracic radiography, sodium, potassium, urea, creatinine, alanine aminotransferase, aldosterone and aminoterminal atrial natriuretic propeptide were assessed at baseline, 3 and 6 months. Survival times were not significantly different between the two treatment groups. Spironolactone was well tolerated when combined with conventional heart failure treatment.

Penetration of enrofloxacin into the nasal secretions and relationship between nasal secretions and plasma enrofloxacin concentrations after intramuscular administration in healthy pigs

The pharmacokinetic behaviour of enrofloxacin (ENRO) in plasma and nasal secretions of healthy pigs was investigated, after a single-dose intramuscular administration of 2.5 mg/kg body weight of the drug. Blood samples and nasal secretions were collected at predetermined times after drug administration. Concentrations of ENRO and its active metabolite ciprofloxacin (CIPRO) were determined in plasma and nasal secretions by high-performance liquid chromatography (HPLC). CIPRO was not detected probably because we investigated young weaned pigs. The data collected in 12 pigs for ENRO were subjected to noncompartmental analysis. In plasma, the maximum concentration of drug (C(max)), the time at which this maximum concentration of drug (T(max)) was reached, the elimination half-life (t(1/2)(beta)) and the area under the concentration vs. time curve (AUC) were, respectively, 694.7 ng/mL, 1.0 h, 9.3 h and 8903.2 ngxh/mL. In nasal secretions, C(max), T(max), t(1/2)(beta) and AUC were, respectively, 871.4 ng/mL, 2.0 h, 12.5 h and 11 198.5 ngxh/mL. In a second experiment conducted in 10 piglets, the relationship between concentrations of ENRO measured in the plasma and the nasal secretions has been determined following single-dose intramuscular administration of 2.5, 10 or 20 mg/kg body weight of the drug. It has been demonstrated that, among several variables, i.e., (1) the dose administered, (2) the time between intramuscular injection and blood sampling, (3) the age, (4) the sex, (5) the animal body weight and (6) the plasma concentration of the drug, only the latter influenced significantly the ENRO concentration in nasal secretions. Practically, using a generalized linear mixed model, ENRO concentrations in the nasal secretions (microg/mL) can be predicted taking into account the ENRO concentrations in plasma (microg/mL), according to the following equation:

Early termination of ISRCTN45828668, a phase 1/2 prospective, randomized study of sulfasalazine for the treatment of progressing malignant gliomas in adults

BACKGROUND

Sulfasalazine, a NF-kappaB and x(c)-cystine/glutamate antiport inhibitor, has demonstrated a strong antitumoral potential in preclinical models of malignant gliomas. As it presents an excellent safety profile, we initiated a phase 1/2 clinical study of this anti-inflammatory drug for the treatment of recurrent WHO grade 3 and 4 astrocytic gliomas in adults.

METHODS

10 patients with advanced recurrent anaplastic astrocytoma (n = 2) or glioblastoma (n = 8) aged 32-62 years were recruited prior to the planned interim analysis of the study. Subjects were randomly assigned to daily doses of 1.5, 3, 4.5, or 6 grams of oral sulfasalazine, and treated until clinical or radiological evidence of disease progression or the development of serious or unbearable side effects. Primary endpoints were the evaluation of toxicities according to the CTCAE v.3.0, and the observation of radiological tumor responses based on MacDonald criteria.

RESULTS

No clinical response was observed. One tumor remained stable for 2 months with sulfasalazine treatment, at the lowest daily dose of the drug. The median progression-free survival was 32 days. Side effects were common, as all patients developed grade 1-3 adverse events (mean: 7.2/patient), four patients developed grade 4 toxicity. Two patients died while on treatment or shortly after its discontinuation.

CONCLUSION

Although the proper influence of sulfasalazine treatment on patient outcome was difficult to ascertain in these debilitated patients with a large tumor burden (median KPS = 50), ISRCTN45828668 was terminated after its interim analysis. This study urges to exert cautiousness in future trials of Sulfasalazine for the treatment of malignant gliomas.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN45828668.

Reasoning versus knowledge retention and ascertainment throughout a problem-based learning curriculum

CONTEXT

Since 2000, problem-based learning (PBL) seminars have been introduced into the curriculum of medical studies at the University of Liège. We aimed to carry out a cross-sectional investigation of the maturational increase in biomedical reasoning capacity in comparison with factual knowledge retention throughout the curriculum.

METHODS

We administered a factual knowledge test (i.e. a true/false test with ascertainment degree) and a biomedical reasoning test (i.e. an adapted script concordance test [SCT]) to 104 students (Years 3-6) and a reference panel. The selected topic was endocrinology.

RESULTS

On the SCT, the students obtained higher scores in Years 5 and 6 than in Years 3 and 4. In Year 3, the scores obtained on SCT questions in a new context indicated transfer of reasoning skills. On the true/false test, the scores of Year 3 students were significantly higher than those of students in the other three year groups. A positive correlation between SCT scores and true/false test scores was observed only for students in Years 3 and 4. In each group, the ascertainment degree scores were higher for correct than for incorrect responses and the difference was calculated as an index of self-estimation of core knowledge. This index was found to be positively correlated to SCT scores in the four year groups studied.

CONCLUSIONS

Biomedical reasoning skills are evidenced early in a curriculum involving PBL and further increase during training. This is accompanied by a decrease in factual knowledge retention. The self-estimation of core knowledge appears to be related to reasoning capacity, which suggests there is a link between the two processes.

Baseline inflammation is not predictive of periprocedural troponin elevation after elective percutaneous coronary intervention

High-sensitivity C-reactive protein predicts future cardiovascular events in both healthy individuals and patients with unstable and stable coronary syndromes. Few data are available about the incidence and the relation to inflammation of troponin elevation following percutaneous coronary intervention (PCI), a potential predictor of longterm outcome. We sought to confirm the impact of embolization on long-term outcome and evaluate the ability of baseline inflammation to predict troponin elevation induced by PCI. We prospectively analyzed 200 patients treated by PCI for stable or Braunwald IIA class unstable angina. The patients were recruited between January 1997 and May 1999, and the population was followed during a mean follow-up of 32 months. Major adverse cardiac events (MACEs) were defined as the occurrence of death, myocardial infarction or recurrent angina requiring repeat PCI, or coronary artery bypass grafting. During the follow-up period, 58 MACEs were observed. By multivariate analysis, independent predictors for the occurrence of MACEs were unstable angina and troponin I level after PCI (P < 0.0001 for both). No correlation was found between baseline inflammation and significant troponin I elevation post PCI and by multivariate analysis, no biological variable was a predictor of troponin I elevation post PCI. Baseline inflammation cannot predict onset of minor myonecrosis damage (expressed by troponin elevation) induced by PCI, a significant predictor of long-term outcome in this setting.

Pancreatic cellular injury after cardiac surgery with cardiopulmonary bypass: frequency, time course and risk factors

Although often clinically silent, pancreatic cellular injury (PCI) is relatively frequent after cardiac surgery with cardiopulmonary bypass; and its etiology and time course are largely unknown. We defined PCI as the simultaneous presence of abnormal values of pancreatic isoamylase and immunoreactive trypsin (IRT). The frequency and time evolution of PCI were assessed in this condition using assays for specific exocrine pancreatic enzymes. Correlations with inflammatory markers were searched for preoperative risk factors. One hundred ninety-three patients submitted to cardiac surgery were enrolled prospectively. Blood IRT, amylase, pancreatic isoamylase, lipase, and markers of inflammation (alpha1-protease inhibitor, alpha2-macroglobulin, myeloperoxidase) were measured preoperatively and postoperatively until day 8. The postoperative increase in plasma levels of pancreatic enzymes and urinary IRT was biphasic in all patients: early after surgery and later (from day 4 to 8 after surgery). One hundred thirty-three patients (69%) experienced PCI, with mean IRT, isoamylase, and alpha1-protease inhibitor values higher for each sample than that in patients without PCI. By multiple regression analysis, we found preoperative values of plasma IRT >or=40 ng/mL, amylase >or=42 IU/mL, and pancreatic isoamylase >or=20 IU/L associated with a higher incidence of postsurgery PCI (P < 0.005). In the PCI patients, a significant correlation was found between the 4 pancreatic enzymes and urinary IRT, total calcium, myeloperoxidase, alpha1-protease inhibitor, and alpha2-macroglobulin. These data support a high prevalence of postoperative PCI after cardiac surgery with cardiopulmonary bypass, typically biphasic and clinically silent, especially when pancreatic enzymes were elevated preoperatively.

Effect of different contraceptive methods on the oxidative stress status in women aged 40 48 years from the ELAN study in the province of Liege, Belgium

BACKGROUND

Oxidative stress is associated with the development of several disorders including cardiovascular disease and cancer. Among conditions known to influence oxidative stress, the use of oral contraception (OC) in women has been a matter of ongoing discussion.

METHODS

A total of 897 eligible and healthy volunteers were recruited from among the patients of 50 general practitioners participating in the ELAN study (Etude Liégeoise sur les ANtioxydants). A subsample consisting of 209 women aged 40-48 years was studied for a comprehensive oxidative stress status (OSS), including the analysis of antioxidants, trace elements and three markers of oxidative damage to lipids. Among 209 subsample, 49 (23%) were OC users (OCU), 119 (57%) non-contraception users (NCU) and 41 (20%) were intrauterine (hormonal and copper) devices users (IUD).

RESULTS

After adjustment for smoking, systolic and diastolic blood pressure and BMI (or waist circumference), a marked and significant increase in lipid peroxides was observed among OCU women when compared with NCU and IUD users. A cut-off value of 660 microM in lipid peroxides allowed the discrimination of OCU from the two other groups. In contrast, no difference was observed in the plasma concentration of both oxidized low-density lipoprotein (LDL) and their related antibodies. The increased level in lipid peroxides was strongly related to higher concentrations of copper (r < 0.84; P < 0.0001, cut-off value 1.2 mg/l). When compared with NCU and IUD users, plasma antioxidant defences were significantly altered in OCU women as shown by lower levels of beta-carotene (decrease of 39%; P < 0.01) and gamma-tocopherol (decrease by 22%; P < 0.01). In contrast, higher concentrations of selenium (increased by 11.8%; P < 0.01) were observed in OCU women. Blood concentrations of vitamin C, alpha-tocopherol and zinc were unaffected by OC use.

CONCLUSIONS

The intake of OC significantly increases the lipid peroxidation in women aged 40-48 years. This may represent a potential cardiovascular risk factor for these women.

Long-term prognostic significance of high-sensitivity C-reactive protein before and after coronary angioplasty in patients with stable angina pectoris

We examined whether an increase in high-sensitivity C-reactive protein (hs-CRP) after percutaneous coronary intervention (PCI) predicts long-term prognosis in patients with stable angina pectoris. hs-CRP is an inflammatory marker that predicts future cardiovascular events in healthy subjects and patients with unstable and stable coronary syndromes. Long-term evaluation of pre- and postprocedural inflammatory markers has not been widely reported. In particular, the effect of the magnitude of increase in hs-CRP after PCI in stable patients is unknown. We prospectively analyzed 89 stable patients treated by PCI for stable angina pectoris. Patients were recruited between August 1998 and May 1999, and the population was followed until August 2005 (mean follow-up 79.5 +/- 10.3 months). A major adverse cardiac event (MACE) was defined as the occurrence of cardiac death, myocardial infarction, or recurrent angina requiring repeat PCI or coronary artery bypass grafting. During the follow-up period, 36 patients presented with > or =1 MACE. In multivariate analysis, independent predictors of the occurrence of MACEs were previous myocardial infarction and a significant increase in hs-CRP after PCI (p = 0.004 and 0.003, respectively). A significant increase in hs-CRP after PCI was found to be more predictive of MACEs than hs-CRP before and after PCI. In conclusion, in stable coronary artery disease, inflammation is associated with long-term adverse events, but the magnitude of the inflammatory reaction after PCI appears more predictive than the baseline value.