Immediate and long term effects of weight reduction in obese people with asthma: randomised controlled study

Objective To investigate the influence of weight reduction on obese patient s with asthma. Design Open study two randomised parallel groups. Setting Private outpatients centre, Helsinki, Finland. Participants Two groups of 19 obese patients with asthma (body mass index ( kg/m(2)) 30 to 42) recruited through newspaper advertisements. Intervention Supervised weight reduction programme including 8 week very lo w energy diet. Main outcome measures Body weight morning peak expiratory flow (PEF), force d vital capacity (FVC), forced expiratory volume in one second (FEV1); and also asthma symptoms, number of acute episodes, courses of oral steroids, h ealth status (quality of life). Results At the end of the weight reducing programme, the participants in th e treatment group had lost a mean of 14.5% of their pretreatment weight, th e controls 0.3%. The corresponding figures after one) ear were 11.3% and a weight gain of 2.2%. After the 8 week dieting period the difference in chan ges in percentage of predicted FEV1 from baseline in the treatment and cont rol groups was 7.2% (95% confidence interval 1.9% to 12.5%, P = 0.009). The corresponding difference in the changes in FVC was 8.6% (4.8% to 12.5%, P < 0.0001). After one lear the differences in the changes in the two groups were still significant: 7.6% for FEV1 (1.5% to 13.8%, P = 0.02) and 7.6% fo r FVC (3.5% to 11.8%, P = 0.001). By the end of the weight reduction progra mme, reduction in dyspnoea was 13 mm (on a visual analogue scale 0 mm to 10 0 mm) in the treatment group and 1 mm in the control group (P = 0.02). The reduction of rescue medication was 1.2 and 0.1 doses respectively (P = 0.03 ). After one year the differences in the changes between the two groups wer e - 12 for symptom scores (range - 1 to - 22, P = 0.04) and - 10 for total scores (- 18 to - 1, P = 0.02). The median number of exacerbations in the t reatment group was 1 (0-4) and in the controls 4 (0-7), P = 0.001. Conclusion Weight reduction in obese patients with asthma improves lung fun ction, symptoms, morbidity and health status.