B.P.A. Thoonen

Self-management of asthma in general practice, asthma control and quality of life: a randomised controlled trial

Background: A study was undertaken to determine the effectiveness of asthma self-management in general practice. Methods: Nineteen general practices were randomly allocated to usual care (UC) or self-management (SM). Asthma patients were included after confirmation of the GP diagnosis. Follow up was 2 years. Patients kept diary cards and visited the lung function laboratory every 6 months. Outcomes were number of successfully treated weeks, limited activity days, asthma specific quality of life, forced expiratory volume in 1 second (FEV1), FEV1 reversibility, concentration of histamine provoking a fall in FEV1 of 20% or more (PC20 histamine), and amount of inhaled steroids. Results: A total of 214 patients were included in the study (104 UC/110 SM; one third of the total asthma population in general practice); 62% were female. The mean percentage of successfully treated weeks per patient in the UC group was 72% (74/103 weeks) compared with 78% (81/105 weeks) in the SM group (p=0.003). The mean number of limited activity days was 1.2 (95% CI 0.5 to 1.9) in the SM group and 3.9 (95% CI 2.5 to 5.4) in the UC group. The estimated increase in asthma quality of life score was 0.10 points per visit in the UC group and 0.21 points per visit in the SM group (p=0.055). FEV1, FEV1 reversibility, and PC20 histamine did not change. There was a saving of 217 puffs of inhaled steroid per patient in favour of the SM group (p<0.05). Conclusion: Self-management lowers the burden of illness as perceived by patients with asthma and is at least as effective as the treatment usually provided in Dutch primary care. Self-management is a safe basis for intermittent treatment with inhaled corticosteroids.

Current clinical guideline definitions of airflow obstruction and COPD overdiagnosis in primary care

The aim of the present study was to establish the agreement between two recommended definitions of airflow obstruction in symptomatic adults referred for spirometry by their general practitioner, and investigate how rates of airflow obstruction change when pre-bronchodilator instead of post-bronchodilator spirometry is performed. The diagnostic spirometric results of 14,056 adults with respiratory obstruction were analysed. Differences in interpretation between a fixed 0.70 forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) cut-off point and a sex- and age-specific lower limit of normal cut-off point for this ratio were investigated. Of the subjects, 53% were female and 69% were current or ex-smokers. The mean post-bronchodilator FEV1/FVC was 0.73 in males and 0.78 in females. The sensitivity of the fixed relative to the lower limit of normal cut-off point definition was 97.9%, with a specificity of 91.2%, positive predictive value of 72.0% and negative predictive value of 99.5%. For the subgroup of current or ex-smokers aged ≥50 yrs, these values were 100, 82.0, 69.2 and 100%, respectively. The proportion of false positive diagnoses using the fixed cut-off point increased with age. The positive predictive value of pre-bronchodilator airflow obstruction was 74.7% among current or ex-smokers aged ≥50 yrs. The current clinical guideline-recommended fixed 0.70 forced expiratory volume in one second/forced vital capacity cut-off point leads to substantial overdiagnosis of obstruction in middle-aged and elderly patients in primary care. Using pre-bronchodilator spirometry leads to a high rate of false positive interpretations of obstruction in primary care.

Helpen huisstofmijtwerende hoezen

SamenvattingDe Vries MP, Van den Bemt L, Aretz K, Thoonen BPA, Muris JWM, Kester A, Cloosterman S, Van Schayck CP. Helpen huisstofmijtwerende hoezen? Huisarts Wet 2008;51(1):12-7.Achtergrond De effectiviteit van huisstofmijt (HSM) werende hoezen is nog steeds onderwerp van discussie.Doel Onderzoeken of de combinatie van HSM-werende hoezen en zelfbehandeling, gebaseerd op piekstroomwaarden en symptomen, leidt tot gebruik van minder inhalatiecorticosteroïden (ICS) in vergelijking met zelfbehandeling alleen.Opzet Prospectief, gerandomiseerd, dubbelblind, placebogecontroleerd onderzoek.Methoden We includeerden astmapatiënten van zestien tot zestig jaar, die een een allergie hadden voor HSM, en ICS gebruikten. We legden ze uit hoe ze het zelfbehandelplan moesten gebruiken op basis van piekstroomwaarden en symptomen. Na een oefenperiode van drie maanden startte de interventieperiode van twee jaar met HSM-ondoorlaatbare of placebo hoezen. De primaire uitkomstmaat was gebruik van ICS, daarnaast keken we ook naar piekstroomparameters, astmacontrole en symptomen.Resultaten Er begonnen 126 patiënten aan de interventieperiode met de hoezen. Na een en twee jaar was er een significant verschil in blootstelling aan allergenen tussen de groep met HSM-werende hoezen en de placebogroep (p < 0,001). We vonden geen significant verschil tussen de groepen in gebruik van ICS (p = 0,08), ochtend piekstroomwaarde (p = 0,52), piekstroomvariabiliteit (p = 0,36), dyspnoe (p = 0,46), piepen (p = 0,77) en hoesten (p = 0,41). Er was ook geen verschil in astmacontrole tussen de interventie- en controlegroep.Conclusie HSM-werende hoezen in combinatie met zelfbehandeling leiden niet tot minder gebruik van ICS dan zelfbehandeling alleen.