Loes C. M. Bertens and colleagues survey the published diagnostic research literature for use of expert panels to define the reference standard, characterize components and missing information, and recommend elements that should be reported in diagnostic studies. Please see later in the article for the Editors' Summary

PurposePrediction models for exacerbations in patients with chronic obstructive pulmonary disease (COPD) are scarce. Our aim was to develop and validate a new model to predict exacerbations in patients with COPD.Patients and methodsThe derivation cohort consisted of patients aged 65 years or over, with a COPD diagnosis, who were followed up over 24 months. The external validation cohort consisted of another cohort of COPD patients, aged 50 years or over. Exacerbations of COPD were defined as symptomatic deterioration requiring pulsed oral steroid use or hospitalization. Logistic regression analysis including backward selection and shrinkage were used to develop the final model and to adjust for overfitting. The adjusted regression coefficients were applied in the validation cohort to assess calibration of the predictions and calculate changes in discrimination applying C-statistics.ResultsThe derivation and validation cohort consisted of 240 and 793 patients with COPD, of whom 29% and 28%, respectively, experienced an exacerbation during follow-up. The final model included four easily assessable variables: exacerbations in the previous year, pack years of smoking, level of obstruction, and history of vascular disease, with a C-statistic of 0.75 (95% confidence interval [CI]: 0.69–0.82). Predictions were well calibrated in the validation cohort, with a small loss in discrimination potential (C-statistic 0.66 [95% CI 0.61–0.71]).ConclusionOur newly developed prediction model can help clinicians to predict the risk of future exacerbations in individual patients with COPD, including those with mild disease.

dyspnoea is very common in older people, but estimates vary considerably between studies. Only one study describes the underlying causes.

Background: Reduced exercise tolerance and dyspnea are common in older people, and heart failure (HF) and chronic obstructive pulmonary disease (COPD) are the main causes. We want to determine the prevalence of previously unrecognized HF, COPD, and other chronic diseases in frail older people using a nearhome targeted screening strategy.Methods: Community-dwelling frail persons aged >65 years underwent a 2-step screening strategy. First, they received a questionnaire inquiring about dyspnea and exercise tolerance. Those with exercise intolerance and/or dyspnea were invited to visit their primary care physician's office for a screening program, including medical history taking, physical examination, blood tests, electrocardiography, spirometry, and echocardiography. The final diagnosis of every patient was determined by a panel consisting of 3 physicians.

BackgroundPrevalence of undetected heart failure in older individuals is high in the community, with patients being at increased risk of morbidity and mortality due to the chronic and progressive nature of this complex syndrome. An essential, yet currently unavailable, strategy to pre-select candidates eligible for echocardiography to confirm or exclude heart failure would identify patients earlier, enable targeted interventions and prevent disease progression. The aim of this study was therefore to develop and validate such a model that can be implemented clinically.Methods and resultsIndividual patient data from four primary care screening studies were analysed. From 1941 participants >60 years old, 462 were diagnosed with heart failure, according to criteria of the European Society of Cardiology heart failure guidelines. Prediction models were developed in each cohort followed by cross-validation, omitting each of the four cohorts in turn. The model consisted of five independent predictors; age, history of ischaemic heart disease, exercise-related shortness of breath, body mass index and a laterally displaced/broadened apex beat, with no significant interaction with sex. The c-statistic ranged from 0.70 (95% confidence interval (CI) 0.64–0.76) to 0.82 (95% CI 0.78–0.87) at cross-validation and the calibration was reasonable with Observed/Expected ratios ranging from 0.86 to 1.15. The clinical model improved with the addition of N-terminal pro B-type natriuretic peptide with the c-statistic increasing from 0.76 (95% CI 0.70–0.81) to 0.89 (95% CI 0.86–0.92) at cross-validation.ConclusionEasily obtainable patient characteristics can select older men and women from the community who are candidates for echocardiography to confirm or refute heart failure.