Risk of mis-diagnosis, Health related Quality of Life and Body Mass Index in Overweight Patients with doctor diagnosed asthma.
Chest. 2011 Aug 25 Scott S, Currie J, Albert P, Calverley P, Wilding JP. Clinical Science Centre, University Hospital Aintree, Liverpool University, Liverpool, UK.
BACKGROUND: Obesity and asthma both cause breathlessness and there is a risk of mis-diagnosis of asthma in obese patients. Impaired Health related quality of life (HRQoL) and increased body mass index (BMI) increase physician attendance rates increasing this risk. We explored the possibility of mis-diagnosis and the relationship between BMI, HRQoL and other traditional measures of asthma severity in obese subjects with a doctor diagnosis of asthma.
METHODS: Data was obtained from overweight subjects with physician diagnosed asthma screened as part of another study including bronchial responsiveness to methacholine (PC20) or reversibility to bronchodilators, HRQoL measured using generic (Short Form-36 (SF-36)) and disease specific (St George Respiratory Questionnaire (SGRQ), Impact of Weight on Quality of Life-Lite (IWQOL-Lite)) questionnaires. Exhaled nitric oxide (FeNO), height, weight and atopic status were also recorded.
RESULTS: Of 91 subjects, (mean BMI 38Kg/m(2), mean FEV1% 85.8%, mean FEV1/FVC ratio 70.0%, mean FeNO 25.1 ppb taking a mean CFC-beclomethasone-equivalent dose of 1273.5 μg/d) 36.3% had no bronchial hyper-responsiveness (possible mis-classification of asthma diagnosis.) BMI and HRQoL were significantly related: SGRQ total (r=0.33, p<0.001), SF36 Physical Health subtotal (r=-0.42, p<0.001), SF36 Mental Health subtotal (r=-0.39, p<0.001) and IWQOL-Lite total (r=0.51, p<0.001) with no relationship to airway inflammation and bronchial reactivity. There was no significant difference in quality of life scores in subjects with or without bronchial hyper-reactivity.
CONCLUSIONS: We found evidence of mis-diagnosis of asthma in obese people. BMI in obese asthmatics negatively correlates with HRQoL which may relate to the diagnostic uncertainty and requires further exploration