Based on the values of the primary outcome variable (24-h ambulatory SBP) obtained in previous studies, at least 36 patients (18 per group) were required to identify a difference of 6 mmHg in the primary efficacy variable between altitude exposure conditions.
Descriptive statistics are presented as means and standard deviations and absolute and relative frequencies overall and separately for non-HT and HT subjects. Shapiro–Wilk test was used for assessing normality in group data. Log transformation was applied to data without normal distribution. Levene's test was used for assessing variance homogeneity. To determine the effects of altitude (3: sea level, SL; high altitude day 1, HA-D1; and high-altitude day 7, HA-D7) and group (2: NT and HT) effects on the primary outcome (24-h ambulatory SBP) and on other variables of interest (other ambulatory BP variables, clinic HR, SBP, DBP, and SpO2), a mixed model multivariate analysis of variance (MANOVA) was applied. The follow-up was carried out by means of univariate analyses contrasts. Finally, in the case of significant effects, pairwise comparisons with Tukey correction were performed. The data were analyzed using the
SPSS 25.0 statistical package (SPSS Inc, Chicago, IL, USA). For all statistical tests, an alpha level of 0.05 was used.
Lang M., Paéz V., Maj G., Silva-Urra J., Labarca-Valenzuela C., Caravita S., Faini A., Cantuarias J., Perez O., Bilo G, & Parati G. (2021). Blood Pressure Response in Miners Exposed to Chronic Intermittent Hypoxia in Chile. Frontiers in Cardiovascular Medicine, 8, 701961.