[Case-control study: the importance of selecting the right controls].

Important non-experimental study designs to assess the relation between a possible determinant (e.g. a treatment, a risk factor, a diagnostic or prognostic marker) and a clinical outcome are the follow-up and the case-control study design.

A prospective validation of the HEART score for chest pain patients at the emergency department.

Background: The focus of the diagnostic process in chest pain patients at the emergency department is to identify both low and high risk patients for an acute coronary syndrome (ACS). The HEART score was designed to facilitate this process. This study is a prospective validation of the HEART score.

Time-course of depressive symptoms in patients with heart failure.

Background: It is unclear how depressive symptoms in patients with heart failure develop over time and whether this trajectory of depressive symptoms is associated with hospital admission and prognosis.

Aim: To describe the time-course of depressive symptoms and determine the relationship with hospitalisation and mortality.

Method: Data was analysed using 611 patients with completed CES-D questionnaires at baseline and at 18 months.

Electrocardiographic characteristics of patients with chronic obstructive pulmonary disease.

Patients with chronic obstructive pulmonary disease (COPD) are at increased risk of cardiovascular disease. Electrocardiography (ECG) carries information about cardiac disease and prognosis, but studies comparing ECG characteristics between patients with and without COPD are lacking. We related ECG characteristics of patients with COPD, to ECG characteristics of patients without COPD, and determined whether ECG abnormalities are related to COPD severity.

Time-dependent propensity score and collider-stratification bias: an example of beta2-agonist use and the risk of coronary heart disease.

Stratification and conditioning on time-varying cofounders which are also intermediates can induce collider-stratification bias and adjust-away the (indirect) effect of exposure. Similar bias could be expected when one conditions on time-dependent PS. We explored collider-stratification and confounding bias due to conditioning or stratifying on time-dependent PS using a clinical example on the effect of inhaled short- and long-acting beta2-agonist use (SABA and LABA, respectively) on coronary heart disease (CHD).

Diagnostic value of a heart-type fatty acid-binding protein (H-FABP) bedside test in suspected acute coronary syndrome in primary care.

Background: To determine the diagnostic accuracy of a rapid heart-type fatty acid-binding protein (H-FABP) test in patients suspected of acute coronary syndrome (ACS) in primary care.

Methods: General practitioners included 298 patients suspected of ACS. In all patients, whether referred to hospital or not, ECG and cardiac biomarker testing was performed.

Immediate adenoidectomy vs initial watchful waiting strategy in children with recurrent upper respiratory tract infections: an economic evaluation.

Objective: To compare the costs associated with 2 clinical strategies in children with recurrent upper respiratory tract infections (URTIs): immediate adenoidectomy vs an initial watchful waiting strategy.

Design: A cost-minimization analysis from a societal perspective including both direct and indirect costs, alongside an open randomized controlled trial with a 2-year follow-up.

Setting: Multicenter study, including 11 general and 2 university hospitals in the Netherlands.

Should non-inferiority drug trials be banned altogether?

Non-inferiority (NI) trials can be used in a situation when a new drug is expected to have a similar efficacy to its comparator but can offer other advantages over the existing drug, such as a more convenient method of administration or fewer side effects. Here, we discuss the advantages and disadvantages of NI trials from an ethical, methodological and regulatory perspective. We suggest that such trials should be designed to address simultaneously the objective of showing NI with regard to drug efficacy and the objective of establishing superiority of the additional advantages of a drug over its active comparator.

Reduced in-hospital survival rates of out-of-hospital cardiac arrest victims with obstructive pulmonary disease.

Aim: Out-of-hospital cardiac arrest (OHCA) due to sustained ventricular tachycardia/fibrillation (VT/VF) is common and often lethal. Patient's co-morbidities may determine survival after OHCA, and be instrumental in post-resuscitation care, but are poorly studied. We aimed to study whether patients with obstructive pulmonary disease (OPD) have a lower survival rate after OHCA than non-OPD patients.

Safe exclusion of pulmonary embolism using the Wells rule and qualitative D-dimer testing in primary care: prospective cohort study.

Objective: To validate the use of the Wells clinical decision rule combined with a point of care D-dimer test to safely exclude pulmonary embolism in primary care.

Design: Prospective cohort study.

Setting: Primary care across three different regions of the Netherlands (Amsterdam, Maastricht, and Utrecht).

Early assessment of acute coronary syndromes in the emergency department: the potential diagnostic value of circulating microRNAs.

Previous studies investigating the role of circulating microRNAs in acute coronary syndrome (ACS) were based on small patient numbers, performed no comparison with established markers of cardiac injury and did not have appropriate controls. We determined the potential diagnostic value of circulating microRNAs as novel early biomarkers in 332 suspected ACS patients on presentation to the emergency department (ED) in a prospective single-centre study including cardiac miRNAs (miR-1, -208a and -499), miR-21 and miR-146a. Levels of all miRs studied were significantly increased in 106 patients diagnosed with ACS, even in patients with initially negative high-sensitive (hs) troponin or symptom onset <3 h.

Cardiac arrhythmias in adult patients with asthma.

Objective: The pathogenesis of cardiac arrhythmias in asthma patients has not been fully elucidated. Adverse drug effects, particularly those of β2-mimetics, may play a role. The aim of this study was to determine whether asthma is associated with the risk of cardiac arrhythmias and electrocardiographic characteristics of arrhythmogenicity (ECG) and to explore the role of β2-mimetics.

Accuracy of symptoms, signs, and C-reactive protein for early chronic obstructive pulmonary disease.

Background: Guidelines recommend detection of early chronic obstructive pulmonary disease (COPD), but evidence on the diagnostic work-up for COPD only concerns advanced and established COPD.

Aim: To quantify the accuracy of symptoms and signs for early COPD, and the added value of C-reactive protein (CRP), in primary care patients presenting with cough.

Design And Setting: Cross-sectional diagnostic study of 73 primary care practices in the Netherlands.

The impact of heart failure on the classification of COPD severity.

Background: Pulmonary restriction-a reduction of lung volumes-is common in heart failure (HF), rendering severity grading of chronic obstructive pulmonary disease (COPD) potentially problematic in subjects with both diseases. We compared pulmonary function in patients with either HF or COPD, or the combination to assess whether grading of COPD using the Global Initiative of Chronic Obstructive Lung Disease classification is hampered in the presence of HF.

Methods And Results: In 2 cohorts involving 591 patients with established HF and 405 with a primary care diagnosis of COPD, the presence of HF and COPD was assessed according to guidelines.

Development and initial validation of a simple clinical decision tool to predict the presence of heart failure in primary care: the MICE (Male, Infarction, Crepitations, Edema) rule.

Aims: Diagnosis of heart failure in primary care is often inaccurate, and access to and use of echocardiography is suboptimal. This study aimed to develop and provisionally validate a clinical prediction rule to optimize referral for echocardiography of people identified in primary care with suspected heart failure.

Methods And Results: A systematic review identified studies of diagnosis of heart failure set in primary care.