Niels Peek

Body mass index is associated with hospital mortality in critically ill patients: an observational cohort study.

Objective:Obesity is associated with a variety of diseases, which results in a decreased overall life expectancy. Nevertheless, some studies suggest that being overweight may reduce hospital mortality of certain patient groups, referred to as obesity paradox. Conflicting results for critically ill patients are reported. Therefore, we wished to investigate the association of body mass index and hospital mortality in critically ill patients. Design:Observational cohort study in Dutch critically ill patients. Setting:A dataset from the Dutch National Intensive Care Evaluation registry that includes patients admitted to Dutch ICUs was used. Patients:One hundred fifty-four thousand three hundred and eight ICU patients of teaching and nonteaching units in urban and nonurban hospitals. Interventions:None. Measurements and Main Results:We used logistic regression analysis, correcting for case mix (Simplified Acute Physiology Score II, age, gender, admission type, neoplasm, AIDS, hematologic malignancy, immunologic insufficiency, mechanical ventilation, and calendar year), to determine the relationship between body mass index and hospital mortality. Body mass index was included in the model as a continuous nonlinear covariate in a restricted regression spline transformation. To facilitate interpretation, adjusted odds ratios were calculated for the World Health Organization-based body mass index classes. Body mass index was found to be significantly associated with hospital mortality, with risks quickly increasing for underweight patients (body mass index < 18.5 kg/m2). Obese and seriously obese patients, with a body mass index of 30–39.9 kg/m2, had the lowest risk of death with an adjusted odds ratio of 0.86 (0.83–0.90). Conclusions:This large observational database shows an inverse association between obesity and hospital mortality in critically ill patients that could not be explained by a variety of known confounders.

Teledermatologic consultation and reduction in referrals to dermatologists: a cluster randomized controlled trial.

OBJECTIVE To determine whether teledermatologic consultations can reduce referrals to a dermatologist by general practitioners (GPs). DESIGN Multicenter cluster randomized controlled trial. SETTING AND PARTICIPANTS We recruited 85 GPs from 35 general practices in 2 regions in the Netherlands (Almere and Zeist); 5 dermatologists from 2 nonacademic hospitals were also included in the study. Interventions The GPs randomized to the intervention used a teledermatologic consultation system to confer with a dermatologist, whereas those in the control group referred their patients according to usual practice. All patients, regardless of their condition, were seen in the office by a dermatologist after approximately 1 month. OUTCOME MEASURES The main outcome measure was the proportion of office visits prevented by teledermatologic consultation, as determined by dermatologists at approximately the 1-month office visit. The secondary outcome measure was patient satisfaction, measured using the Patient Satisfaction Questionnaire III developed by Ware et al. RESULTS The 85 study GPs enrolled 631 patients (46 intervention GPs, 327 patients; 39 control GPs, 304 patients). The 5 dermatologists considered a consultation preventable for 39.0% of patients who received teledermatologic consultation and 18.3% of 169 control patients, a difference of 20.7% (95% confidence interval, 8.5%-32.9%). At the 1-month dermatologist visit, 20.0% of patients who received teledermatologic consultation had recovered compared with 4.1% of control patients. No significant differences in patient satisfaction were found between groups. CONCLUSIONS Teledermatologic consultation offers the promise of reducing referrals to a dermatologist by 20.7%. Providing teledermatologic consultation by GPs with more extended knowledge of dermatology may further reduce the need for dermatologist referrals. Trial Registration Current Controlled Trials No. ISRCTN57478950.

Effect of guideline based computerised decision support on decision making of multidisciplinary teams: cluster randomised trial in cardiac rehabilitation

Objective To determine the extent to which computerised decision support can improve concordance of multidisciplinary teams with therapeutic decisions recommended by guidelines. Design Multicentre cluster randomised trial. Participants Multidisciplinary cardiac rehabilitation teams in Dutch centres and their cardiac rehabilitation patients. Interventions Teams received an electronic patient record system with or without additional guideline based decision support. Main outcome measures Concordance with guideline recommendations assessed for two standard rehabilitation treatments—exercise and education therapy—and for two new but evidence based rehabilitation treatments—relaxation and lifestyle change therapy; generalised estimating equations were used to account for intra-cluster correlation and were adjusted for patient’s age, sex, and indication for cardiac rehabilitation and for type and volume of centre. Results Data from 21 centres, including 2787 patients, were analysed. Computerised decision support increased concordance with guideline recommended therapeutic decisions for exercise therapy by 7.9% (control 84.7%; adjusted difference 3.5%, 95% confidence 0.1% to 5.2%), for education therapy by 25.7% (control 63.9%; adjusted difference 23.7%, 15.5% to 29.4%), and for relaxation therapy by 25.5% (control 34.1%; adjusted difference 41.6%, 25.2% to 51.3%). The concordance for lifestyle change therapy increased by 3.2% (control 54.1%; adjusted difference 7.1%, −2.9% to 18.3%). Computerised decision support reduced cases of both overtreatment and undertreatment. Conclusions In a multidisciplinary team motivated to adopt a computerised decision support aid that assists in formulating guideline based care plans, computerised decision support can be effective in improving the team’s concordance with guidelines. Therefore, computerised decision support may also be considered to improve implementation of guidelines in such settings. Trial registration Current Controlled Trials ISRCTN36656997.

The impact of different prognostic models and their customization on institutional comparison of intensive care units.

Objectives:To evaluate the influence of choice of a prognostic model and the effect of customization of these models on league tables (i.e., rank-order listing) in which intensive care units (ICUs) are ranked by standardized mortality ratios using Acute Physiology and Chronic Health Evaluation (APACHE) II, Simplified Acute Physiology Score (SAPS) II, and Mortality Probability Model II (MPM24II). Design:Retrospective analysis of prospectively collected data on ICU admissions. Setting:Forty Dutch ICUs. Patients:A data set from a national registry of 86,427 patients from January 2002 to October 2006. Interventions:The league tables associated with the different models were compared to evaluate their agreement. Bootstrapping was used to quantify the uncertainty in the ranks for ICUs. First, for each ICU the median rank and its 95% confidence interval were identified for each model. Then, for a given pair of models, for each ICU the median difference in rank and its associated 95% confidence interval were computed. A difference in rank for an ICU for a given pair of models was considered relevant if it was statistically significant and if one of the models would categorize this ICU as a performance outlier (excellent performer or very poor performer) while the other did not. Measurements and Main Results:For 20 ICUs, there was a significant difference in rank (2–19 positions) between one or more pairs of models. Three ICUs were rated as performance outliers by one of the models, while the other excluded this possibility with 95% certainty. Furthermore, for ten ICUs, one or more pairs of models classified these ICUs as performance outliers while the other model did not do so with certainty. Regarding the agreement between the original models and their customized versions, in all cases the median change in rank was three positions or less and the models fully agreed with respect to which ICUs should be classified as performance outliers. Conclusions:Institutional comparison based on case-mix adjusted league tables is sensitive to the choice of prognostic model but not to customization of these models. League tables should always display the uncertainty associated with institutional ranks.

Prognostic Bayesian networks

Prognostic models are tools to predict the future outcome of disease and disease treatment, one of the fundamental tasks in clinical medicine. This article presents the prognostic Bayesian network (PBN) as a new type of prognostic model that builds on the Bayesian network methodology, and implements a dynamic, process-oriented view on prognosis. A PBN describes the mutual relationships between variables that come into play during subsequent stages of a care process and a clinical outcome. A dedicated procedure for inducing these networks from clinical data is presented. In this procedure, the network is composed of a collection of local supervised learning models that are recursively learned from the data. The procedure optimizes performance of the networks primary task, outcome prediction, and handles the fact that patients may drop out of the process in earlier stages. Furthermore, the article describes how PBNs can be applied to solve a number of information problems that are related to medical prognosis.

Effect of predefined order sets and usability problems on efficiency of computerized medication ordering

OBJECTIVES To study the effect of predefined order sets on the efficiency of computerized medication ordering, and to analyze the effect of different types of usability problems on ordering efficiency. METHODS Crossover study to comparing the efficiency of two methods of ordering (with and without use of predefined order sets) in a laboratory setting using a computerized physician order entry system (CPOE). The excess number of mouse clicks and keystrokes (the difference in number of mouse clicks and keystrokes needed by each physician and the minimally required numbers to accomplish the ordering tasks) for each method was measured and per physician, occurrences of usability problems during the task sessions were recorded. Observed usability problems were categorized using Zhang et al.s heuristic principles of good user interface design. The effect of different types of usability problems on the excess number of mouse clicks and keystrokes was statistically analyzed. RESULTS The median excess number of mouse clicks and keystrokes needed by physicians was 6.2 times lower in the method with predefined order sets (p<0.01). The excess number of mouse clicks and keystrokes was significantly increased by vague and erroneous system messages with a factor of 2.62 (95% CI 2.24-3.07), the use of unfamiliar language and terminology by a factor of 1.28 (95% CI 1.14-1.43), and non-informative system feedback by a factor of 1.15 (95% CI 1.03-1.28), respectively. Other categories of usability problems had little influence on ordering efficiency. CONCLUSIONS Predefined order sets can improve the efficiency of computerized ordering by reducing the excess number of mouse clicks and keystrokes. However, the efficiency of computerized ordering can be significantly impaired by usability problems due to vague and incorrect system messages, unfamiliar language, and non-informative system feedback.

Temporal abstraction for feature extraction: A comparative case study in prediction from intensive care monitoring data

OBJECTIVES To compare two temporal abstraction procedures for the extraction of meta features from monitoring data. Feature extraction prior to predictive modeling is a common strategy in prediction from temporal data. A fundamental dilemma in this strategy, however, is the extent to which the extraction should be guided by domain knowledge, and to which extent it should be guided by the available data. The two temporal abstraction procedures compared in this case study differ in this respect. METHODS AND MATERIAL The first temporal abstraction procedure derives symbolic descriptions from the data that are predefined using existing concepts from the medical language. In the second procedure, a large space of numerical meta features is searched through to discover relevant features from the data. These procedures were applied to a prediction problem from intensive care monitoring data. The predictive value of the resulting meta features were compared, and based on each type of features, a class probability tree model was developed. RESULTS The numerical meta features extracted by the second procedure were found to be more informative than the symbolic meta features of the first procedure in the case study, and a superior predictive performance was observed for the associated tree model. CONCLUSION The findings indicate that for prediction from monitoring data, induction of numerical meta features from data is preferable to extraction of symbolic meta features using existing clinical concepts.

Cardiac rehabilitation and survival in a large representative community cohort of Dutch patients.

AIMS To assess the effects of multi-disciplinary cardiac rehabilitation (CR) on survival in the full population of patients with an acute coronary syndrome (ACS) and patients that underwent coronary revascularization and/or heart valve surgery. METHODS AND RESULTS Population-based cohort study in the Netherlands using insurance claims database covering ∼22% of the Dutch population (3.3 million persons). All patients with an ACS with or without ST elevation, and patients who underwent coronary revascularization and/or valve surgery in the period 2007-10 were included. Patients were categorized as having received CR when an insurance claim for CR was made within the first 180 days after the cardiac event or revascularization. The primary outcome was survival time from the inclusion date, limited to a total follow-up period of 4 years, with a minimum of 180 days. Propensity score weighting was used to control for confounding by indication. Among 35 919 patients with an ACS and/or coronary revascularization or valve surgery, 11 014 (30.7%) received CR. After propensity score weighting, the adjusted hazard ratio (HR) associated with receiving CR was 0.65 (95% CI 0.56-0.77). The largest benefit was observed for patients who underwent coronary artery bypass grafting (CABG) and/or valve surgery (HR = 0.55, 95% CI 0.42-0.74). CONCLUSION In a large and representative community cohort of Dutch patients with an ACS and/or intervention, CR was associated with a substantial survival benefit up to 4 years. This survival benefit was present regardless of age, type of diagnosis, and type of intervention.

Cardiac rehabilitation uptake and its determinants in the Netherlands.

Aims: Despite its documented efficacy, cardiac rehabilitation (CR) is still not well implemented in current clinical practice. The aims of the present study were to assess CR uptake rates in the Netherlands, and to identify factors that determine uptake. Methods: The cohort consisted of persons insured with Achmea Zorg en Gezondheid. Based on insurance claims, we assessed CR uptake rates in 2007 among patients with an acute coronary syndrome (ACS), patients who underwent coronary artery bypass graft surgery, percutaneous coronary intervention (PCI), or valvular surgery, and patients with stable angina pectoris (AP) or chronic heart failure (CHF). In addition, we evaluated the relation between CR uptake and demographic, disease-related, and geographic factors for patients with an ACS and/or intervention. Results: The CR uptake rate in the entire cohort (n = 35,752) was 11.7%. The uptake rate among patients with an ACS and/or intervention (n = 12,201) was 28.5%, as opposed to 3.0% among patients with CHF or stable AP (n = 23,551). The highest CR uptake rate was observed in patients who underwent cardiac surgery (58.7%). Factors associated with lower CR uptake were female gender, older age, elective PCI (as compared to acute PCI), unstable AP (as compared to myocardial infarction), larger distance to the nearest provider of CR, and comorbidity. Conclusion: A minority of Dutch patients eligible for CR received CR. Future implementation strategies should focus on females, elderly patients, patients with unstable AP and/or after elective PCI, patients with long travelling distances to the nearest CR provider, and patients with comorbidities.

A parallel guideline development and formalization strategy to improve the quality of clinical practice guidelines

PURPOSE Clinical practice guidelines often contain ambiguities, inconsistencies, and logical errors that hamper implementation of these guidelines in practice. As guideline formalization is useful to verify the logical structure, consistency, and completeness of guidelines, several authors have argued that the formalization of guidelines concurrent with their development may improve their quality. However, experiences with such a parallel guideline development and formalization approach have not yet been reported. The goal of this study was to develop such a strategy and evaluate its application in practice. METHODS Existing methodologies for guideline development and guideline formalization were analyzed and used as a basis to develop a strategy in which guideline formalization is performed concurrently with guideline development. The developed strategy was applied in the development of a clinical practice guideline for cardiac rehabilitation. RESULTS A parallel guideline development and formalization strategy was developed that intertwines the processes of guideline development and guideline formalization. Central assets are early involvement of guideline formalization specialists and formalization tools, cooperation between guideline authors and guideline formalization specialists in the development of clinical algorithms, access to domain knowledge when formalization identifies inconsistencies or omissions, and formal verification of the guideline model prior to guideline dissemination. This strategy was applied in the development of a guideline for cardiac rehabilitation and helped to identify several vague and inconsistent recommendations and impracticabilities in the narrative guidelines that could be resolved before publication. In addition, the strategy ensured consistency between the narrative and formalized guideline. CONCLUSIONS Based on our experience, formalizing a guideline concurrent with its development is feasible in practice and we recommend applying such a strategy as it can be beneficial to the quality of and consistency between the guidelines narrative and formalized version.