Development and Validation of the Patient/Caregiver Reported Hydroxyurea Evaluation of Adherence for Life (HEAL) Scale

Figures & data

Table 1 Sample Demographic and Clinical Data

	Total Sample (N=40)			Self-Report (N=24)			Care-Giver-Report (N=16)
	Mean	SD	Range	Mean	SD	Range	Mean	SD	Range
Participant Age (Years)	25.6	18	1.8–65.0	38.7	9.6	22.6–65.0	5.9	3.5	1.8–15.2
Participant Gender
Male		16	40.0%		10			6
Female		24	60.0%		14			10
Participant Race
Black/African-American		38	95.0%		23			15
Multiracial		2	5.0%		1			1
Participant Diagnosis
HbSS		31	77.5%		16			15
HbSC		4	10.0%		3			1
HbSβ^+ thalassemia		3	7.5%		3			0
HbSβ^0 thalassemia		2	5.0%		2			0

Table 2 HEAL Item and Subscale Descriptive Statistics

	Mean (SD)	Min/Max Scores	Percentile			Self-Report Mean (SD)	Care-Giver Mean (SD)	Self vs Care-Giver t-test
			25	50	75
Dose	6.0 (1.2)	1.0/7.0	5.4	6.3	7.0	6.1 (0.9)	5.9 (1.6)	0.61
1. Give recommended amount	6.1 (1.4)	1.0/7.0	5.3	7.0	7.0	5.9 (1.3)	6.4 (1.6)	1.09
2. Know exact amount	6.6 (1.1)	1.0/7.0	7.0	7.0	7.0	6.8 (0.6)	6.4 (1.6)	1.05
3. Give incorrect amount^a	5.4 (1.9)	1.0/7.0	5.0	6.0	7.0	5.7 (1.8)	4.9 (2.0)	1.38
Remember	5.1 (1.8)	2.0/7.0	3.7	5.7	6.9	4.7 (1.8)	5.7 (1.7)	1.77
4. Forget to give^a	4.9 (2.1)	1.0/7.0	3.0	5.0	7.0	4.4 (2.0)	5.7 (2.1)	1.84
5. Skip doses^a	5.3 (1.8)	1.0/7.0	4.3	6.5	7.0	5.1 (1.8)	6.1 (1.8)	1.73
6. Miss doses^a	4.9 (1.9)	1.0/7.0	3.0	5.0	7.0	4.6 (1.9)	5.4 (1.8)	1.25
Plan	5.3 (1.5)	2.3/7.0	4.1	5.7	6.9	5.8 (1.4)	5.1 (1.6)	0.69
7. Run out of HU^a	5.5 (1.8)	1.0/7.0	4.0	6.0	7.0	5.5 (1.8)	5.5 (1.8)	0.01
8. Irregular dose because run out^a	5.5 (1.6)	1.0/7.0	5.0	5.5	7.0	5.6 (1.4)	5.4 (2.0)	0.35
9. Miss dose because run out^a	4.9 (1.9)	1.0/7.0	3.0	5.0	7.0	5.3 (1.7)	4.4 (2.2)	1.32
Cost	6.3 (1.1)	2.3/7.0	5.1	7.0	7.0	6.3 (0.9)	6.3 (1.4)	0.10
10. Too expensive to take regularly^a	6.3 (1.3)	1.0/7.0	5.1	7.0	7.0	6.3 (1.0)	6.3 (1.7)	0.15
11. Hard to afford^a	6.4 (1.0)	3.0/7.0	5.3	7.0	7.0	6.3 (0.9)	6.5 (1.2)	0.64
12. Cost is stressful^a	6.2 (1.3)	1.0/7.0	5.3	7.0	7.0	6.3 (1.0)	6.1 (1.8)	0.38
Effectiveness	6.2 (1.0)	3.7/7.0	5.3	7.0	7.0	6.1 (0.9)	6.4 (1.1)	1.02
13. HU helps	6.4 (1.0)	4.0/7.0	5.3	7.0	7.0	6.2 (1.0)	6.6 (1.0)	1.13
14. HU is effective	6.2 (1.1)	3.0/7.0	5.0	7.0	7.0	6.1 (1.1)	6.4 (1.2)	0.69
15. HU is safe	6.2 (1.1)	3.0/7.0	5.0	7.0	7.0	6.0 (1.1)	6.4 (1.2)	1.02
Understand	5.8 (1.3)	2.3/7.0	5.0	6.0	7.0	5.7 (1.2)	6.0 (1.4)	0.90
16. Understand how HU works	6.0 (1.2)	3.0/7.0	5.0	7.0	7.0	5.8 (1.2)	6.3 (1.2)	1.04
17. Could explain how HU works	5.7 (1.4)	1.0/7.0	5.0	6.0	7.0	5.7 (1.3)	5.8 (1.7)	0.31
18. Know how HU works	5.7 (1.4)	3.0/7.0	5.0	6.0	7.0	5.5 (1.3)	6.1 (1.4)	1.29
Lab	5.7 (1.2)	3.3/7.0	5.0	5.7	7.0	5.5 (1.2)	6.0 (1.1)	1.37
19. Lab work is difficult^a	5.7 (1.5)	2.0/7.0	5.0	6.0	7.0	5.4 (1.7)	6.2 (1.0)	1.69
20. Lab work is stressful^a	5.8 (1.1)	3.0/7.0	5.0	6.0	7.0	5.8 (1.0)	5.8 (1.2)	0.06
21. Getting labs done is hard^a	5.5 (1.6)	1.0/7.0	5.0	5.5	7.0	5.2 (1.8)	6.1 (1.2)	1.43
Pharmacy	5.7 (1.6)	1.0/7.0	5.0	6.0	7.0	6.4 (0.8)	4.6 (2.0)	0.39***
22. Difficulty getting HU from pharmacy^a	5.7 (1.7)	1.0/7.0	5.0	6.0	7.0	6.3 (0.9)	4.8 (2.1)	3.18**
23. Hard to find nearby pharmacy with HU^a	5.5 (1.9)	1.0/7.0	5.0	6.0	7.0	6.4 (0.8)	4.2 (2.3)	4.30***
24. Working with pharmacy is stressful^a	5.8 (1.6)	1.0/7.0	5.0	5.5	7.0	6.4 (0.8)	4.9 (2.1)	3.26**
Total	5.8 (0.8)	3.8/7.0	5.4	5.9	6.3	5.8 (0.6)	5.8 (1.0)	0.06

Notes: Subscale and total scores are in bold, italicized font (subscale and total scores are average item scores for constituent items [eg, total of all items divided by number of items]). Items are indicated by number under subscales. Item descriptions are summaries of item content; for exact item wordings, please contact the authors. ^aReverse scored item. **p < 0.01; ***p < 0.001; df for t-tests=38.

Abbreviation: HU, hydroxyurea.

Table 3 HEAL Subscale and Total Score Reliability

Subscale	Internal Consistency (Alpha)	Test-Retest Reliability		Validity Correlations
		r	t (df=15)	GAR			MEMS	Lab Values
				Participant	Provider	Composite		HbF	ANC
Dose	0.70	0.94***	1.78	0.34*	0.05	0.17	0.18	0.22	−0.14
Remember	0.90	0.75***	1.13	0.47***	0.18	0.31*	0.33	0.53**	−0.24
Plan	0.78	0.60*	0.93	0.07	0.18	0.16	−0.04	0.11	0.26
Cost	0.88	0.06	0.05	0.14	0.42**	0.39*	−0.22	0.23	−0.06
Effectiveness	0.91	0.65**	0.40	0.30*	0.48**	0.49**	0.01	0.13	−0.15
Understand	0.95	0.80***	0.86	0.23	0.28*	0.31*	−0.23	0.15	−0.34*
Lab	0.77	0.62**	0.99	0.25	0.24	0.30*	−0.34	0.19	0.04
Pharmacy	0.93	0.83***	0.22	0.00	0.01	0.01	−0.15	0.03	−0.04
Total	0.88	0.82***	0.20	0.38*	0.35*	0.42*	−0.06	0.37*	−0.14

Note: *p < 0.05; **p < 0.01; ***p < 0.001.

Abbreviations: GAR, global adherence rating; MEMS, medication event monitoring systems; HbF, fetal hemoglobin; ANC, absolute neutrophil count.