Reliability, Validity and Measurement Invariance of the WHO’s Quality of Life Scale among Women of Reproductive Age Living with HIV in Ethiopia - a Quasi-Experimental Study

Abstract

Despite its widespread global adoption and use, studies have not examined measurement invariance of the 31-question World Health Organization Quality of Life–HIV BREF scale among HIV/AIDS patients. The current study seeks to (a) evaluate the scale’s internal consistency reliability, and concurrent validity, and (b) test if the same latent construct of quality of life was consistently measured at two time-points, for a sample of HIV-positive women from two sites in Addis Ababa, Ethiopia. The study used data from two cross-sectional interviews with 926 HIV-positive women of reproductive age who participated in a quasi-experimental study. All participants were receiving antiretroviral therapy and related treatment support services from 51 service providers in two non-contiguous sub-cities. We used One-Way ANOVA, chi square test and Kruskal Wallis test to compare demographic characteristics and quality of life scores of study participants. Further, we used Cronbach’s coefficient alpha (α) to assess internal consistency reliability and Pearson product-moment correlation (r) to assess concurrent validity. Finally, multiple-group confirmatory factor analysis with maximum likelihood estimation was used to assess measurement invariance of the quality of life scale. Findings suggest that the WHOQOL-HIV BREF exhibited acceptable psychometric properties. There was evidence for strong internal consistency reliability demonstrated by Cronbach’s α >0.80 and coefficient ω >0.80. The scale’s six domains also exhibited good concurrent validity, with coefficient r = 0.63–0.82. In measurement invariance analysis, configural invariance was found for the scale’s six domains, suggesting measurement noninvariance for factor loadings, item intercepts and factor variances when comparing QOL among participants in the two sites at baseline and follow-up. Our findings suggest that the WHOQOL-HIV BREF has internal consistency reliability and concurrent validity in this study sample. The differences in the levels of observed responses for QOL across intervention and non-intervention groups at baseline and follow-up suggest participants had dissimilar understanding, interpretation, and responses to the scale’s items, which may have resulted from significant measurement, cultural, and developmental differences between study groups. The WHOQOL-HIV BREF exhibited internal consistency reliability, concurrent validity and configural invariance. However, strong invariance was not achieved, making it difficult to compare levels of QOL between groups in this study sample.

Appendices

Appendix 1: Details of the methodology of parent study by measure evaluation researchers

Data are from a quasi-experimental referral network study conducted by MEASURE Evaluation. Kirkos was the site of an intervention aimed at improving ties among providers. Providers were identified using snowball sampling, beginning with well-known service providers as the seeds. All service providers that offered, and could refer clients to one another for, HIV care and treatment sup - port and family planning services to HIV-positive women of ages 18–49 were included. Saturation was reached when nominated organizational representatives, who were also the interviewees for the study, named service providers that had already been named by others. Ultimately, 25 providers in Kirkos and 26 in Kolfe-Keranyo were included in the study. The data included provider characteristics and linkages among providers. To obtain referral network data, T1 (baseline) and T2 (follow-up) interviews were conducted with nominated key informants in each provider organization about HIV services and the nature and types of referrals offered, provider characteristics, collaborations, joint programs, and linkages with other providers. Intervention A referral network strengthening intervention was implemented in Kirkos where 21 of the 25 providers were represented in at least one of the meetings. Kirkos was selected for the intervention after T1 results showed lower network density there compared with Kolfe-Keranyo. The intervention consisted of a series of three 2-day educational meetings held 2 months apart at different times after T1 data collection. During the meetings, participants learned about strategies for client referral, collaboration, joint programming, and partner - ships. They also learned about services offered by other facilities in the network. Service directories, listing contact information and services offered, were developed and shared, with each participating provider receiving at least one directory. No intervention was implemented in Kolfe-Keranyo, the control network. Characteristics of service providers Service providers in the two networks were owned and operated by the Ethiopian government or various types of non-governmental bodies. The government owned and operated 10 out of the 51 service providers, whereas non-governmental organizations (NGOs), faith-based providers (FBOs) or private individuals owned and operated the remainder. Kirkos had significantly fewer (three) government owned and operated providers compared with Kolfe-Keranyo, which had seven. There was a significant increase in the number of providers self-identifying as NGOs in Kirkos from five at T1 to 14 at T2. Conversely, Kolfe-Keranyo experienced a reduction in the number of NGOs from eight at T1 to five at T2. Providers in both networks reported significant increases in their budgets at T2 compared with T1, Kirkos had a total budget of US$685,535 and US$ 1,910,340, whereas Kolfe-Keranyo had US$583,171 and US$ 5,510,505 at T1 and T2, respectively. Kolfe-Keranyo had more staff at both time-points compared with Kirkos

Appendix 2: WHOQOL-HIV bref questionnaire

Mental health: evidence and research department of mental health and substance dependence world health organization geneva

Instructions

This assessment asks how you feel about your quality of life, health, or other areas of your life. Please answer all the questions. If you are unsure about which response to give to a question, please choose the one that appears most appropriate. This can often be your first response. Please keep in mind your standards, hopes, pleasures and concerns. We ask that you think about your life in the last two weeks. For example, thinking about the last two weeks, a question might ask:

		Not at all	A little	A moderate amount	Very much	Extremely
11 (F5.3)	How well are you able to concentrate?	1	2	3	4	5

You should circle the number that best fits how well are you able to concentrate over the last two weeks. So you would circle the number 4 if you were able to concentrate very much. You would circle number 1 if you were not able to concentrate at all in the last two weeks

Please read each question, assess your feelings, and circle the number on the scale for each question that gives the best answer for you

		Very poor	Poor	Neither poor nor good	Good	Very good
1 (G1)	How would you rate your quality of life?	1	2	3	4	5
		Very dissatisfied	Dissatisfied	Neither satisfied nor dissatisfied	Satisfied	Very satisfied
2 (G4)	How satisfied are you with your health?	1	2	3	4	5

The following questions ask about how much you have experienced certain things in the last two weeks

		Not at all	A little	A moderate amount	Very much	An extreme amount
3 (F1.4)	To what extent do you feel that physical pain prevents you from doing what you need to do?	1	2	3	4	5
4 (F50.1)	How much are you bothered by any physical problems related to your HIV infection?	1	2	3	4	5
5 (F11.3)	How much do you need any medical treatment to function in your daily life?	1	2	3	4	5
6 (F4.1)	How much do you enjoy life?	1	2	3	4	5
7 (F24.2)	To what extent do you feel your life to be meaningful?	1	2	3	4	5
8 (F52.2)	To what extent are you bothered by people blaming you for your HIV status	1	2	3	4	5
9 (F53.4)	How much do you fear the future?	1	2	3	4	5
10 (F54.1)	How much do you worry about death?	1	2	3	4	5
		Not at all	A little	A moderate amount	Very much	Extremely
11 (F5.3)	How well are you able to concentrate?	1	2	3	4	5
12 (F16.1)	How safe do you feel in your daily life?	1	2	3	4	5
13 (F22.1)	How healthy is your physical environment?	1	2	3	4	5

The following questions ask about how completely you experience or were able to do certain things in the last two weeks

		Not at all	A little	Moderately	Mostly	Completely
14 (F2.1)	Do you have enough energy for everyday life?	1	2	3	4	5
15 (F7.1)	Are you able to accept your bodily appearance?	1	2	3	4	5
16 (F18.1)	Have you enough money to meet your needs?	1	2	3	4	5
17 (F51.1)	To what extent do you feel accepted by the people you know?	1	2	3	4	5
18 (F20.1)	How available to you is the information that you need in your day-to-day life?	1	2	3	4	5
19 (F21.1)	To what extent do you have the opportunity for leisure activities?	1	2	3	4	5
		Very poor	Poor	Neither poor nor good	Good	Very good
20 (F9.1)	How well are you able to get around?	1	2	3	4	5

The following questions ask you how good or satisfied you have felt about various aspects of your life over the last two weeks

		Very dissatisfied	Dissatisfied	Neither satisfied nor dissatisfied	Satisfied	Very satisfied
21 (F3.3)	How satisfied are you with your sleep?	1	2	3	4	5
22 (F10.3)	How satisfied are you with your ability to perform your daily living activities?	1	2	3	4	5
23 (F12.4)	How satisfied are you with your capacity for work?	1	2	3	4	5
24 (F6.3)	How satisfied are you with yourself?	1	2	3	4	5
25 (F13.3)	How satisfied are you with your personal relationships?	1	2	3	4	5
26 (F15.3)	How satisfied are you with your sex life?	1	2	3	4	5
27 (F14.4)	How satisfied are you with the support you get from your friends?	1	2	3	4	5
28 (F17.3)	How satisfied are you with the conditions of your living place?	1	2	3	4	5
29 (F19.3)	How satisfied are you with your access to health services?	1	2	3	4	5
30 (F23.3)	How satisfied are you with your transport?	1	2	3	4	5

The following question refers to how often you have felt or experienced certain things in the last two weeks

		Never	Seldom	Quite often	Very often	Always
31 (F8.1)	How often do you have negative feelings such as blue mood, despair, anxiety, depression?	1	2	3	4	5

SCORING OF THE WHOQOL 31-BREF

The WHOQOL-HIV BREF produces six domain scores. Whereas the WHOQOL-100 has four items to present each facet, the WHOQOL-HIV BREF has only one item. Included in these, there are two items that examine General quality of life: question 1 asks about an individual’s overall perception of quality of life and question 2 asks about an individual’s overall perception of his or her health. Hence there are 31 items, representing the 30 facets. Five of these facets are specific to HIV/AIDS

Like the WHOQOL-100, individual items are rated on a 5 point Likert scale where 1 indicates low, negative perceptions and 5 indicates high, positive perceptions. F or example, an item in the positive feeling facet asks “How much do you enjoy life?” and the available responses are 1 (not at all), 2 (a little) 3 (a moderate amount), 4 (very much) and 5 (an extreme amount). As such, domain and facet scores are scaled in a positive direction w here higher scores denote higher quality of life. Some facets (Pain and Discomfort, Negative Feelings, Dependence on Medication, Death and Dying) are not scaled in a positive direction, meaning that for these facets higher scores do not denote higher quality of life. These need to be recoded so that high scores reflect better QOL. Items are organized by response scale (capacity, frequency, intensity or satisfaction). Instructions for calculation of scores are given below. These follow the syntax file, which can be obtained from the WHOQOL HIV Coordinator, Mental Health: Evidence and Research, Department of Mental Health and Substance Dependence, CH-1211 Geneva 27, Switzerland

SCORING PROCEDURE

First, all scores need to be checked that they are in the appropriate range (between 1 and 5)

Compute domain scores

Domain 1 (physical) = (Q3 + Q4 + Q14 + Q21)/4 * 4 Domain 2 (psychological) = (Q6 + Q11 + Q15 + Q24 + Q31)/5 *4 Domain 3 (level of independence) = (Q5 + Q22 + Q23 + Q20)/4 * 4 Domain 4 (social relationships) = (Q27 + Q26 + Q25 + Q17)/4*4 Domain 5 (environment) = (Q12+ Q13+ Q16+ Q18+ Q19 + Q28 + Q29 + Q30)/8*4 Domain 6 (spirituality/religion/personal beliefs) = (Q7 + Q8 + Q9+ Q10)/4 *4 (These equations calculate the domain scores. All scores are multiplied by 4 so as to be directly comparable with scores derived from the WHOQOL-100)

Check all items from assessment have a range of 1–5

Steps	SPSS syntax for carrying out data checking, cleaning and computing total scores
Check all 26 items from assessment have a range of 1–5	RECODE Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q8 Q9 Q10 Q11 Q12 Q13 Q14 Q15 Q16 Q17 Q18 Q19 Q20 Q21 Q22 Q23 Q24 Q25 Q26 Q27 Q28 Q29 Q30 Q31 (1 = 1) (2 = 2) (3 = 3) (4 = 4) (5 = 5) (ELSE = SYSMIS). (This recodes all data outside the range 1–5 to system missing.)

Domain scores are scaled in a positive direction w here higher scores denote higher quality of life. Some items are not scaled in a positive direction (e.g. Pain and Discomfort, Negative Feelings, Dependence on Medication, Death and Dying), meaning that for these facets higher scores do not denote higher quality of life. These need to be recoded so that high scores reflect better QOL. Domain scores are scaled in a positive direction (i.e. higher scores denote higher quality of life). Instructions for calculation of scores are given below

Reverse negatively phrased items

Reverse 6 negatively phrased items

RECODE Q3 Q4 Q5 Q8 Q9 Q10 Q31 (1 = 5) (2 = 4) (3 = 3) (4 = 2) (5 = 1).(This transforms negatively framed questions to positively framed questions.)

The mean score of items within each domain is used to calculate the domain score. Mean scores are then multiplied by 4 in order to make domain scores comparable with the scores used in the WHOQOL, so that scores range between 4 and 20

Calculate Domain Scores

The WHOQOL-BREF can also be scored by hand. To do this, negative scores must be reversed. Hence the formula 6 - x is used. This will ensure, for example, that if someone reports fearing the future a great deal (5), subtracting the score by six, will automatically recode the item to 1. Instructions for this are provided on the first page of the instrument

Appendix 3. Correlation and covariance matrices for scores of six quality of life domains by study group

Appendix 3a. Correlation matrix for T1 control group

Domain	Physical	Independence	Psychological	Spirituality	Social	Environmental
Physical	1.00
Independence	0.52	1.00
Psychological	0.49	0.36	1.00
Spirituality	0.30	0.43	0.25	1.00
Social	0.47	0.47	0.43	0.49	1.00
Environmental	0.43	0.37	0.28	0.41	0.48	1.00

Appendix 3b. Covariance matrix for T1 control group

QOL Domain	Physical	Independence	Psychological	Spirituality	Social	Environmental
Physical	13.40
Independence	3.94	4.26
Psychological	4.41	1.83	6.05
Spirituality	2.92	2.39	1.67	7.13
Social	2.98	1.70	1.82	2.29	3.02
Environmental	5.22	2.56	2.29	3.64	2.78	11.21

Appendix 3c. Correlation matrix for T1 intervention group

QOL Domain	Physical	Independence	Psychological	Spirituality	Social	Environmental
Physical	1.00
Independence	0.62	1.00
Psychological	0.50	0.52	1.00
Spirituality	0.36	0.52	0.49	1.00
Social	0.48	0.57	0.54	0.58	1.00
Environmental	0.54	0.48	0.43	0.34	0.41	1.00

Appendix 3d. Covariance matrix for T1 intervention group

QOL Domain	Physical	Independence	Psychological	Spirituality	Social	Environmental
Physical	12.95
Independence	6.06	7.30
Psychological	4.55	3.56	6.41
Spirituality	4.05	4.37	3.84	9.55
Social	4.20	3.76	3.31	4.39	5.96
Environmental	6.38	4.26	3.64	3.47	3.35	11.01

Appendix 3e. Correlation matrix for T2 control group

QOL Domain	Physical	Independence	Psychological	Spirituality	Social	Environmental
Physical	1.00
Independence	0.67	1.00
Psychological	0.62	0.63	1.00
Spirituality	0.45	0.51	0.39	1.00
Social	0.38	0.39	0.39	0.48	1.00
Environmental	0.44	0.58	0.37	0.48	0.26	1.00

Appendix 3f. Covariance matrix for T2 control group

QOL Domain	Physical	Independence	Psychological	Spirituality	Social	Environmental
Physical	7.31
Independence	5.20	8.27
Psychological	4.63	5.00	7.56
Spirituality	4.20	4.99	3.64	11.73
Social	2.04	2.27	2.16	3.27	4.03
Environmental	2.40	3.34	2.01	3.29	1.04	4.00

Appendix 3g. Correlation matrix for T2 intervention group

QOL Domain	Physical	Independence	Psychological	Spirituality	Social	Environmental
Physical	1.00
Independence	0.67	1.00
Psychological	0.70	0.76	1.00
Spirituality	0.40	0.53	0.49	1.00
Social	0.44	0.52	0.44	0.43	1.00
Environmental	0.51	0.54	0.49	0.40	0.26	1.00

Appendix 3h. Covariance matrix for T2 intervention group

QOL Domain	Physical	Independence	Psychological	Spirituality	Social	Environmental
Physical	7.07
Independence	5.03	7.88
Psychological	5.55	6.37	8.93
Spirituality	3.46	4.79	4.78	10.56
Social	2.34	2.92	2.61	2.79	4.02
Environmental	2.95	3.30	3.19	2.82	1.13	4.80