Development of PozQoL
The PozQoL scale was developed in four stages: a review of the existing literature, conceptualization, item development, and validation. As with many countries, the Australian response to HIV is characterised by an active partnership between PLHIV, the community sector, researchers, clinicians and government [9]. To maintain this commitment and to deepen the understanding of QoL of PLHIV, the PozQoL study was conducted using an approach embedded in the Greater Involvement of People with HIV/AIDS (GIPA) principles [23] of a direct partnership with peer-led organisations representing PLHIV. The term Poz is a colloquial term used in a number of western countries to refer to HIV Positive people in the context of empowerment and self-determination. The term is used primarily by peer based PLHIV organisations, including those involved in this study. It was incorporated into PozQoL to reflect the strong PLHIV leadership within the study. Peer-led organisations were involved in all aspects of the study, including the conceptualisation and prioritisation of the domains, development of items, and decisions concerning the refinement of the final scale. The aim was to construct a scale that would be easy to administer and comprehensive, but also limited to no more than 15 items.
Conceptualisation of QoL and assessment of domains
A structured literature search was conducted on relevant databases (Google Scholar, PubMed, Web of Science) to identify key definitions and domains of HRQoL of PLHIV. Keywords included “quality of life” in combination with “HIV” or “AIDS”. Preference was given to more recent studies (published in 2000 or after), and studies conducted in Australia and other English-speaking countries.
We found that most definitions agree that QoL refers to subjective evaluations of one’s life across different domains. However, there was no consensus as to which domains constitute QoL. Based on the definitions we found, the World Health Organization’s (WHO) definition of QoL was identified as the most comprehensive and relevant for the purposes of this study:
“[An] individual’s perception of their position in life in the context of the culture and value systems in which they live and in relation to their goals, expectations, standards, and concerns. It is a broad-ranging concept affected in a complex way by the persons’ physical health, psychological state, level of independence, social relationships and their relationship to salient features of their environment.” [24]
The literature review formed the basis of consultation with study partners including PLHIV peer organisations, allowing for articulation of the four key domains. These conceptual domains were then ranked by a panel of experts from PLHIV peer organisations according to their conceptual accuracy, as well as relevance and usefulness to health and community programs. The four identified domains were ranked in the following order: 1) psychological domain (including mood, coping, hope and fear of the future, and self-worth); 2) social domain (including personal and social life, belonging, support, and social stigma); 3) health domain (including perception of one’s health, health-related concerns, energy, and HIV management); and 4) functional domain (including ability to live a “normal” life, independence, meaningful occupation, and satisfactory standard of living). These domains closely resemble the WHO conceptualisation of QoL with the functional domain effectively incorporating a level of independence and relationship to the environment.
Development of items
The initial pool of items was developed by the first four authors of this article. A large number of candidate items were developed (over 100 items across the four domains). The items were pre-tested for face and content validity through an online survey with a panel of experts from PLHIV peer organisations (n = 13), and other HIV experts and stakeholders (n = 5). The panel members were asked to assess the relevance of the proposed items and whether they thought items should be retained for the next stage of the study. Based on the input from the panel the pool of items was reduced to 64.
Validation study
Study design
To develop and test PozQoL psychometrically, we conducted an online survey of adult Australians living with HIV, including a one-month follow-up survey to examine test-retest reliability. The study had the following aims: 1) to identify scale items for inclusion in PozQoL and test construct validity; 2) to assess the internal and test-retest reliability of PozQoL; 3) to examine the concurrent and convergent validity of PozQoL against other established QoL measures, and measures of health, psychological and social wellbeing.
Data collection
The baseline survey was hosted online between 22 March and 31 May 2017. Participants were invited to complete a follow-up survey 1 month after they completed the initial survey. This included a subset of questions from the baseline survey that enabled assessment of the test-retest reliability of PozQoL. The baseline survey was advertised through PLHIV community organisations and online platforms including Facebook, the Facebook page of the Institute of Many (an online community of over 1000 Australian PLHIV), and Grindr (dating app for gay and bisexual men). Additionally, hard copies of the survey were distributed through PLHIV community organisations in Victoria. As an incentive, participants had the option to enter into a prize draw to win a tablet computer. Participants were asked to confirm that they consent to use their partial data at two points in the survey. In addition, by the end of the survey participants were given the option of withdrawing all their data by ticking an appropriate box.
Those who completed the baseline survey were asked to provide their email address if they wished to complete the follow-up survey. These participants were contacted approximately 1 month after they completed the baseline. The follow-up survey included the pilot PozQoL scale and basic demographic information from the baseline survey. In addition, to control for potential changes in QoL unrelated to HIV, participants were asked to list any major changes or events that occurred in the month leading to the follow-up survey. In both the baseline and follow-up surveys, participants were asked to provide their month of birth and the initials of their name, which enabled us to generate a unique participant code for matching baseline and follow-up responses while protecting anonymity. It took participants 33 min on average to complete the baseline survey and 15 min to complete the follow-up survey.
Survey measures
PozQoL
The pilot version of PozQoL including 64 items was used (see Table 2 for examples of item wording). Participants scored their response to each item on a 5-point scale (1 - not at all, 2 - slightly, 3 - moderately, 4 - very, 5 - extremely). A 5-point scale was chosen to balance sufficient gradation in responses with psychometric quality.
Other QoL measures
For the assessment of concurrent validity, we selected two established QoL measures which were previously validated on PLHIV samples and were freely available (thus could potentially be used by the community organisations). We chose one generic and one HIV-specific QoL measure to verify how well PozQoL corresponds both with broader and more specific conceptualizations of QoL.
Generic QoL
Medical Outcomes Study Short Form-36 (SF-36) [25] is a widely used generic measure of HRQoL, validated for use with PLHIV [26]. The scale incorporates 36 items grouped into eight domains, including physical and mental health (e.g., How much of the time during the past 4 weeks have you been a very nervous person?, I am as healthy as anybody I know), as well as functional wellbeing and role impairment (e.g., During the past 4 weeks, how much did pain interfere with your normal work?). Response format and recall period vary between the items (for most items participants are asked to report on their QoL in 4 weeks prior to the survey). Responses were recoded in line with the RAND 36-Item Health Survey scoring algorithm [27] so that higher scores indicated a more favourable health state. Subsequently, summary scores for the physical (PCS) and mental component (MCS) were computed and normalized in line with Australian population scoring coefficients [28]. Correlation between the two composite scores was r (378) = .88, p < .001.
HIV-specific QoL
Functional Assessment of Human Immunodeficiency Virus Infection (FAHI; [18] Version 4) is an HIV-specific validated measure of HRQoL. The scale includes 47 items grouped into five domains: physical wellbeing, functional and global wellbeing, emotional wellbeing/living with HIV, social wellbeing, and cognitive functioning. Participants rated to what extent each statement (e.g., I feel fatigued) described their experiences in the 7 days prior to the survey on a 1 (not at all) to 5 (very much) scale. Responses were recoded so that higher scores indicated better QoL (α = .97).
Mental health and wellbeing measures
To determine convergent validity, we selected a number of measures assessing mental health and wellbeing:
Psychological distress
Kessler Psychological Distress Scale (K6) ([29] is used widely in Australia as a screening measure for depression and anxiety. Participants reported how often they felt in a particular way (e.g., ‘restless or fidgety’) in the 30 days prior to the survey on a 1 (all the time) to 5 (none of the time) scale (α = .93).
Wellbeing
The Short Warwick-Edinburgh Mental Wellbeing Scale (S-WEMWBS) [30] was used to assess positive mental health. Participants indicated how much each of the seven items included in the scale (e.g., I’ve been feeling useful) described their experiences during 2 weeks prior to the survey, on a 1 (none of the time) to 5 (all of the time) scale (α = .93).
Satisfaction with life
Satisfaction with Life Scale (SWLS) [31] was used. Participants indicated their agreement with five items, (e.g., In most ways my life is close to my ideal), on a 1 (strongly disagree) to 7 (strongly agree) scale (α = .92).
Resilience
The Brief Resilience Scale (BRS) [32] was used. Participants indicated their agreement with six items (e.g., I tend to bounce back quickly after hard times), on a 1 (strongly disagree) to 5 (strongly agree) scale (α = .91).
AIDS-related stigma
Internalized AIDS-Related Stigma Scale (IA-RSS) [33] was used. Participants indicated their agreement with six items (e.g., Being HIV positive makes me feel dirty) by choosing 1 (agree) or 2 (disagree); (α = .87).
Social support
Interpersonal Support Evaluation List [34]; ISEL-12 version [35] was used. Participants indicated to what extent each of the 12 statements (e.g., I feel that there is no one I can share my most private worries and fears with) was true of them, on a 1 (definitely true) to 4 (definitely false) scale. Responses were recoded so that higher scores indicated stronger social support (α = .93).
Statistical analysis
Exploratory Factor Analysis (EFA) was used to explore the underlying factor structure and reduce the number of items. The final model comprising selected items was tested in a Confirmatory Factor Analysis (CFA) using a range of goodness-of-fit measures. Prior to analyses, the sample was randomly divided into two subsamples for conducting the EFA and CFA, respectively. Due to the iterative nature of the steps in these analyses, the detailed methods are described in the results section. Inter-item reliability for the final scale and subscales was assessed with Cronbach’s alpha. Temporal stability (test-retest reliability) of the scale was assessed among the participants who completed the follow-up sample, with intraclass correlation coefficients (ICCs). Descriptive statistics including means, standard deviations, and skewness coefficients of the scale were also assessed. Concurrent and convergent validity was assessed by analysing Pearson bi-variate correlation coefficients between the scale and other QoL, mental health, and wellbeing measures.