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Background: Poor adherence to inhaled medications in COPD patients seems to be associated with an increased risk of death and hospitalization. Knowing the determinants of nonadherence to inhaled medications is important for creating interventions to improve adherence., Objectives: To identify disease-specific and health-related quality of life (HRQoL) factors, associated with adherence to inhaled corticosteroids (ICS) and tiotropium in COPD patients., Methods: Adherence of 795 patients was recorded over 3 years and was deemed optimal at >75%-≤125%, suboptimal at ≥50%-<75%, and poor at <50% (underuse) or >125% (overuse). Health-related quality of life was measured with the Clinical COPD Questionnaire and the EuroQol-5D questionnaire., Results: Patients with a higher forced expiratory volume in 1 second (FEV1)/vital capacity (VC) (odds ratio [OR] =1.03) and ≥1 hospitalizations in the year prior to inclusion in this study (OR =2.67) had an increased risk of suboptimal adherence to ICS instead of optimal adherence. An increased risk of underuse was predicted by a higher FEV1/VC (OR =1.05). Predictors for the risk of overuse were a lower FEV1 (OR =0.49), higher scores on Clinical COPD Questionnaire-question 3 (anxiety for dyspnea) (OR =1.26), and current smoking (OR =1.73). Regarding tiotropium, predictors for suboptimal use were a higher FEV1/VC (OR =1.03) and the inability to perform usual activities as asked by the EuroQol-5D questionnaire (OR =3.09). A higher FEV1/VC also was a predictor for the risk of underuse compared to optimal adherence (OR =1.03). The risk of overuse increased again with higher scores on Clinical COPD Questionnaire-question 3 (OR =1.46)., Conclusion: Several disease-specific and quality of life factors are related to ICS and tiotropium adherence, but a clear profile of a nonadherent patient cannot yet be outlined. Overusers of ICS and tiotropium experience more anxiety.

Unlabelled: In the pathophysiology of chronic obstructive pulmonary disease (COPD) oxidative stress plays an important role, which can be determined by measuring hydrogen peroxide. Hydrogen peroxide can be measured fluorimetrically in exhaled breath condensate (EBC), however, not standardized. The objective of this study was to investigate the sensitivity and reproducibility of measuring the hydrogen peroxide concentration in EBC of COPD patients using an automated flow injection device with varying flow rates and measurements., Methods: 10 microl p-hydroxyphenylacetic acid (1.0 mmol/l) and 10 microl horseradish peroxidase (15 mU/l) were manually added to several hydrogen peroxide containing solutions and EBC of patients suffering from COPD. The fluorescence of the reaction product was measured with an automated sampler, flow injection and scanning fluorescence detector, excitation wave 295 nm, emission wave 405 nm, at different flow rates. The degree of fluorescence was expressed as either the area under the curve or the peak value., Results: A flow rate of 1 ml/min gave the best results. There were no significant differences in calibration curves or detection limits using area under the curve or peak value (respectively 0.007 and 0.005 micromol/l) (flow rate 1.0 ml/min). The mean volume of EBC was 2.8 ml, the mean hydrogen peroxide concentration in the patient group was 0.2 micromol/l and the standard deviation of duplication 0.009 micromol/., Conclusions: The low detection limit may be explained by using flow injection, because it measures the fluorescence over a period of time. It is important to choose an appropriate flow rate. There is no difference in the detection limit between measuring the fluorescence as area under the curve or as peak value.