TABLE 5.
Associations between mean white matter CVR metrics and clinical and biological variables. Only results of variables that had at least one p ≤ 0.2 on univariate analysis in at least one outcome (white matter CVR or tau) were presented.
| CVR Z-score | Tau Z-score | |||||
|---|---|---|---|---|---|---|
| Statistical test = statistic a | p-value | Effect size b | Statistical test = statistic a | p-value | Effect size b | |
| Age (years) | r(15) = −0.03 | 0.18 | −0.03 per additional year | r(15) = +0.03 | 0.37 | +0.03 per additional year |
| SCD genotype (SS/Sβ0 vs SC/Sβ+) | t(13) = −0.60 | 0.56 | +0.34 for SC/Sβ+genotype | t(13) = +0.32 | 0.75 | −0.16 for SC/Sβ+ genotype |
| Systolic blood pressure (mmHg) | r(15) = −0.002 | 0.95 | −0.02 per 10 mmHg increase in SBP | r(15) = −0.06 | 0.11 | −0.43 per 10 mmHg increase in SBP |
| Hematocrit (L/L) | r(14) = 4.23 | 0.30 | +0.42 per 0.1 L/L increase in hematocrit | r(14) = −3.85 | 0.47 | −0.38 per 0.1 L/L increase in hematocrit |
| Hemoglobin (g/L) | r(14) = 0.01 | 0.40 | +0.11 per 10 g/L increase in hemoglobin | r(14) = −0.01 | 0.44 | −0.13 per 10 g/L increase in hemoglobin |
| White blood cells (109/L) | r(14) = 0.11 | 0.15 | +0.11 per 1 x 109/L increase in WBC | r(14) = −0.21 | 0.02 c | −0.21 per 1 x 109/L increase in WBC |
| Hydroxyurea | t(13) = 1.43 | 0.18 | +0.72 for patients on HU | t(13) = +0.52 | 0.61 | −0.29 for patients on HU |
For binary and categorical variables, results of t- and F-statistic are shown, respectively. For continuous variables, unstandardized coefficients are shown.
For binary and categorical variables, effect sizes are reported with the Cohen d and η2 statistics, respectively.
Linear correlation for Tau Z-score and neutrophils: r(13) = 0.58, p = 0.03; monocytes: r(13) = 0.30, p = 0.30; lymphocytes r(13) = 0.50, p = 0.07.
Abbreviations: CVR, cerebrovascular reactivity; HU, hydroxyurea; SBP, systolic blood pressure; SCD, sickle cell disease; WBC, white blood cells.