The Modified Borg Dyspnea Scale does not predict hospitalization in pulmonary arterial hypertension

Background Breathlessness is the most common symptom reported by patients with pulmonary arterial hypertension (PAH). The Modified Borg Dyspnea Scale (MBS) is routinely obtained during the six-minute walk test in the assessment of PAH patients, but it is not known whether the MBS predicts clinical outcomes such as hospitalizations in PAH. Methods We performed a retrospective study of World Health Organization (WHO) Group 1 PAH patients followed at our center. The dates of the first three MBS and hospitalizations that occurred within three months of a documented MBS were collected. Marginal Cox hazard regression modeling was used to assess for a relationship between MBS and all-cause as well as PAH-related hospitalization. Results A total of 50 patients were included; most (92%) were functional class III/IV, 44% and 65% were treatment-naïve prior to their first MBS and hospitalization, respectively. The first recorded MBS was inversely correlated with the first recorded six-minute walk distance (6MWD) (r = -0.41, P < 0.01) but did not track with WHO functional class (r = 0.07, P = 0.63). MBS did not predict all-cause (hazard ratio [HR], 0.91; 95% confidence interval [CI], 0.76-1.08; P = 0.28) or PAH-related hospitalization (HR, 1.04; 95% CI, 0.89-1.23; P = 0.61), though there was a strong relationship between 6MWD and PAH-related hospitalization ( P = 0.01). These findings persisted after multivariable adjustment. Conclusions Breathlessness as assessed by MBS does not predict all-cause or PAH-related hospitalization. Robust and validated patient-reported outcomes are needed in pulmonary vascular disease.