Scatterplot showing linear relationship between POHR and CI. In the subgroup of patients with steady-state SCD studied at BL ( BL, n = 11) and 28 days PT ( PT, n = 11), POHR demonstrated a good negative correlation with the blood CI (BL, Spearman ρ = −0.82; P = .0025; PT, Spearman ρ = −0.85; P = .0014).