Table 3.

Hierarchical Regression Analysis Evaluating Predictors of Quality of Life of Adolescents With SCD^a.

Quality of Life	β	R 2	ΔR2	ΔF (df)
Step 1: Demographics		0.138***
Age	−1.66
Female sexb	−5.16
Secondary educationc	15.12***
Tertiary educationc	10.19*
Step 2: Knowledge score	−0.63	0.153***	0.015	2.488 (1, 142)
Step 3: Severity score	−4.93***	0.338***	0.186	39.540 (1, 141)***
Step 4: Illness perceptions		0.459***	0.121	4.265 (7, 134)***
Identity	−1.01
Timeline (acute/chronic)	−0.35
Personal control	0.12
Treatment control	−0.58
Illness coherence	0.61
Cyclical timeline	−1.13*
Emotional representation	−0.65*

Abbreviation: SCD, sickle cell disease; df, degrees of freedom.

^aBetas reported are those from the step at which the variable was entered into the model.

^bReference category is “Male Sex.”

^cReference category is “Primary Education.”

^***P < .001. *P < .05.