P255 The relationship between body mass index and COPD exacerbations

IntroductionIt is unclear if adipose tissue has a detrimental or protective effect in COPD. Whilst in various chronic diseases a protective effect of adipose tissue against mortality has been observed, adipose tissue promotes a low-grade chronic pro-inflammatory state that may be deleterious in COPD patients.MethodsData were analysed from a well-established prospective cohort of 475 COPD patients. Exacerbations were defined by symptomatic criteria (Seemungal, Donaldson et al. 1998). BMI (Kg/m2) was the average value over follow-up. Random effect models were used to analyse the interaction between BMI over time and frequent (≥2/year) and infrequent exacerbators.ResultsPatients had a mean (SD) age of 68.8 (8) years and 64.6% were males. Mean (SD) FEV1% and FEV1/FVC was 47.6 (16.6) and 0.47 (0.12), respectively. 160 (34.0%) were smokers at recruitment and the mean smoking pack years was 52.3 (37.4). BMI was 25 in 10%, 36% and 54% of patients. Median number of observation days was 1172 (IQR 682–2024) and the median number of exacerbations per year was 2.28 (IQR 1.11 – 3.62).Compared to BMI 20–25, FEV1 decline over time was slower in those with BMI>25 (+8.02 (95% CI 3.2 – 12.8) vs -39.9 (95% CI -48.0 - -31.7) ml/year, and faster in those with BMI