INR control calculation: comparison of Dutch and international methods.

Results of trials with new oral anticoagulant drugs and vitamin K antagonists (VKA) might not be directly applicable to Dutch clinical practice due to the high level of control of anticoagulation in the Netherlands. In addition, the Dutch method for assessing anticoagulation control uses cross-sectional international normalised ratio (INR) test results while the method used in the trials is based on person-time. To enable comparisons, the two calculation methods were applied to INR data of a cohort of 5422 atrial fibrillation patients treated with VKA.

Bronchodilation improves endurance but not muscular efficiency in chronic obstructive pulmonary disease.

We hypothesized that bronchodilator treatment not only improves hyperinflation and endurance capacity but also muscular efficiency in stable chronic obstructive pulmonary disease (COPD). We aimed to demonstrate that tiotropium and salmeterol improve muscular efficiency compared with placebo. Twenty-five COPD patients were studied, including 20 males of mean (standard deviation) age 62 years (7 years) with baseline forced expiratory volume in 1 second of 41% (10%) predicted, and maximal workload of 101 Watt (36 Watt).

Daily mortality and air pollution along busy streets in Amsterdam, 1987-1998.

Time-series studies on the association between daily mortality and air pollution levels have been criticized because they use background air pollution measurement sites to estimate exposure of the whole population, including those living along busy roads. To evaluate whether the exposure of people living along busy roads is estimated with error, we calculated separate effect estimates with separate exposure estimates using background and traffic-influenced measurement stations. We used Poisson regression analysis with generalized additive models to correct for long-term trends, influenza, ambient temperature and relative humidity, and day of the week.