Weighing up the evidence -- a systematic review of measures used for the sensation of breathlessness in obesity.

Breathlessness on exertion is common in people with obesity. Assessments of breathlessness may include sensation (intensity, sensory quality or unpleasantness) and/ or the behavioral/emotional consequences of the sensation (respiratory-related functional impairment, disability or quality of life). This systematic review of primary studies published since 2005 evaluated how has the sensation of breathlessness been assessed in adults with increased adiposity. A total of 41 articles were retained from the systematic search strategy resulting in 20 instruments. The Modified Borg Scale (perceived exertion-intensity), the Medical Research Council (MRC) Scale and Baseline Dyspnea Index (BDI; both assess respiratory-related functional impairment) were, respectively, the most frequently reported instruments. Few instruments had been tested for reliability and validity in people with increased adiposity. Visual Analog Scale, Modified Borg Scale, descriptors of sensory quality, MRC and BDI can be recommended as instruments based on their psychometric properties (reliability (correlations >0.8) and concurrent validity (correlation with severity of airways obstruction and walking distance)). A greater number of instruments were identified that assessed the consequences of the breathlessness rather than breathlessness as a sensation. If sensation drives behavior, comprehensive data on the sensation of breathlessness might assist in understanding the behavioral consequences of interventions.