Postural control in COPD patients travelling from 760 m to 3200 m; randomized trial evaluating effects of dexamethasone

Abstract

Objective: To evaluate effects of acute altitude exposure and of dexamethasone treatment on postural control in patients with COPD. Methods: 104 lowlanders with COPD, GOLD 1-2, age 20-75 y, living near Bishkek (760 m), were randomized to receive either dexamethasone (2x4 mg/d p.o.) or placebo on the day before ascent and during a 3-day sojourn at Tuja-Ashu (3200 m), Kyrgyz Republic. Postural control was assessed at 760 m and one day after arrival at 3200 m by letting patients stand on a Wii Balance BoardTM recording the center of pressure path length (PL) during 5 trials of 30 s. Results: Ascending from 760 to 3200 m increased the PL in the placebo group from median (quartiles) 29.2 (25.8;38.2) to 31.5 (27.3;39.3) cm (P<0.04); in the dexamethasone group the change from 28.8 (22.8;34.5) to 29.9 (25.2;37.0) cm was nonsignificant (P=0.10). The mean difference between groups in altitude-induced PL change (treatment effect) was -0.3 cm (95% CI -3.2 to 2.5 cm, P=0.41). Regression analysis controlling for potential confounders confirmed an increase in PL at altitude (coefficient 1.6, 95% CI 0.16 to 30.8, P=0.03) but no effect of dexamethasone (coefficient 0.01, 95% CI -3.8 to 3.8, P=1.00). PL changes were related mostly to antero-posterior sway. 22 of 104 patients had an increase in antero-posterior sway velocity of >25%, what is associated with a two-fold risk of falls in previous studies (Kwok et al. Clin Biomech 2015). Conclusions: In lowlanders with COPD traveling to altitude (3200 m) postural control was impaired 24h after arriving and this was not prevented by dexamethasone. Grant: Swiss National Science Foundation, Lung League Zurich.