COMMENTARY

Is There a Role for Weight Loss in Obese Patients With Asthma?

Nicholas Gross, MD, PhD

Disclosures

May 19, 2017

Obese asthmatic patients present a problem and an opportunity. Their asthma control is typically difficult, as is their obesity.[1] A small number of approaches to weight loss in obese asthmatics have been attempted, including some surgical procedures. However, the studies have been few and relatively small, and controlled nonsurgical studies have been lacking.

A recent prospective, randomized, controlled trial looked at the potential of using exercise as a weight loss modality to improve asthma.[2] The study enrolled 51 adult patients with obesity (mean body mass index of 38 kg/m2) and severe asthma, FEV1/FVC ratio of 70% or less, and abnormal asthma-specific questionnaire scores. Of these, 26 patients were randomly assigned to an exercise program consisting of twice-weekly sessions of aerobic programs based on 50%-75% of peak VO2 and resistance training. The 25 control group patients received a weight-loss program plus sham exercises consisting of stretching and breathing routines. The primary outcome was clinical improvement of asthma at the end of 3 months, as assessed by the Asthma Quality of Life Questionnaire (AQLQ).

The AQLQ was significantly improved only in the group that received the weight loss plus aerobic exercise program. Tests of aerobic capacity and work-rate were improved only in the weight loss plus aerobic exercise group; however, lung function (eg, FEV1) was unchanged in both groups. Both groups experienced statistically significant weight loss compared with their initial weights, but the weight loss was significantly greater in the group assigned to weight loss plus aerobic exercise (6.1 kg vs 2.9 kg in the weight loss plus sham exercise group).

The investigators took advantage of the study to measure a range of systemic inflammatory markers, such as interleukin-4, interleukin-6, leptin, tumor necrosis factor alpha, and C-reactive protein. Although the numbers of inflammatory markers are relatively few, many decreased only in the weight-loss plus aerobic exercise group—but of interest, the anti-inflammatory agent interleukin-10 was increased in this group. These changes have been reported in some other studies.[3,4]

Viewpoint

This is the first controlled, nonsurgical study to show that weight loss associated with exercise training can improve the asthma quality of life as measured by the AQLQ, the primary outcome, as well as body mass index and some features of aerobic capacity. These results suggest that weight loss achieved by exercise can improve asthma in obese asthmatics. Incidentally, some inflammatory markers were also improved, suggesting that exercise may improve the inflammatory burden of asthma.

Although similar findings have been reported in a few other studies,[3,4,5] the improvements in asthma were seen after only 3 months of initiation of the weight-loss program. This relatively short period of exercise may stimulate patients to maintain weight loss in the future.

One limitation of the study is the high loss of potential participants. The program started with 645 patients and eliminated 594 (92%). The majority of these persons were excluded because they failed to meet inclusion criteria. Perhaps the rigors of weight loss by exercise and diet account for much of the loss of potential participants. One wonders whether these difficulties will also make it difficult for patients to maintain the weight-loss program indefinitely.

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