Poor sleep quality is associated with exercise limitation in precapillary pulmonary hypertension

BACKGROUND Patients with precapillary pulmonary hypertension (PH) have been reported to suffer from poor sleep quality, however, if this is related to physical exercise performance has not yet been thoroughly investigated. METHODS Clinically stable out-patients with idiopathic pulmonary arterial hypertension (IPAH, n = 52) and chronic thromboembolic PH (CTEPH, n = 64) in NYHA classes II and III were prospectively enrolled. 54 healthy volunteers matched for anthropometric variables served as a control group. The Pittsburgh Sleep Quality Index (PSQI) was used to rate subjective sleep quality. In the PH patients, six-minute walk tests (6MWT) were performed to assess exercise capacity. RESULTS Poor sleep quality (i.e. a PSQI score > 5) occurred more frequently in PH (IPAH: n = 25 [48.1%], CTEPH: n = 39 [60.9%], controls: n = 10 [18.5%]; p < 0.01 when compared to controls). In addition, poor vs. good sleepers had significantly higher average NYHA class (IPAH: 2.6 ± 0.1 vs. 2.3 ± 0.1, CTEPH: 2.8 ± 0.1 vs. 2.3 ± 0.2; p < 0.01) and shorter 6MWT distances (IPAH: 338 ± 23 vs. 441 ± 29 m, CTEPH: 355 ± 15 vs. 413 ± 26 m; p < 0.05). CONCLUSIONS Self-reported poor sleep quality is more common in PH than in healthy controls. Furthermore, it is related to reduced physical exercise capacity.