Assessing general and autism‐relevant quality of life in autistic adults: A psychometric investigation using item response theory

Abstract

Although many interventions and services for autistic people have the ultimate goal of improving quality of life (QoL), there is relatively little research on how best to assess this construct in the autistic population, and existing scales designed for non‐autistic individuals may not assess all meaningful facets of QoL in the autistic population. To address this need, the autism spectrum QoL form (ASQoL) was recently developed as a measure of the autism‐relevant quality of life. However, the psychometrics of the ASQoL have not been examined beyond the authors' initial validation study, and important properties such as measurement invariance/differential item functioning (DIF) have not yet been tested. Using data from 700 autistic adults recruited from the Simons Foundation's SPARK cohort, the current study sought to perform a comprehensive independent psychometric evaluation of the ASQoL using item response theory, comparing its performance to a newly‐proposed brief measure of general QoL (the WHOQOL‐4). Our models revealed substantial DIF by sex and gender in the ASQoL, which caused ASQoL scores to grossly underestimate the self‐reported QoL of autistic women. Based on a comparison of latent variable means, we demonstrated that observed sex/gender differences in manifest ASQoL scores were the result of statistical artifacts, a claim that was further supported by the lack of significant group differences on the sex/gender‐invariant WHOQOL‐4. Our findings indicate that the ASQoL composite score is psychometrically problematic in its current form, and substantial revisions may be necessary before valid and meaningful inferences can be made regarding autism‐relevant aspects of QoL. Lay summary Quality of life (QoL) is an extremely important outcome for autistic people, but many of the tools that are used to measure it does not take into account how QoL may be different for autistic people. Using data from 700 autistic adults, we examined the measurement properties of the autism spectrum quality of life form (ASQoL), a new measure of QoL designed specifically for autistic people. Our results indicate that the ASQoL shows a pronounced sex/gender bias, which causes it to underestimate QoL in autistic women. This bias needs to be eliminated before the ASQoL can be successfully used to measure QoL in the autistic population.

Current and lifetime somatic symptom burden among transition‐aged autistic young adults

“…Young adults from the United States with self‐reported professional diagnoses of autism were recruited from the Simons Foundation‐sponsored SPARK participant pool (Feliciano et al, 2018) as part of a larger study on repetitive thinking and its clinical correlates in autistic adults (project number RM0030Gotham; see Williams, Everaert, et al, 2021; Williams, McKenney, et al, 2021; Williams & Gotham, 2021a, 2021b for additional details). This larger study was advertised to all independent autistic adults between the ages of 18 and 45 in the SPARK participant pool ( n = 2887), 1014 of whom consented to complete the larger survey (35.1% response rate).…”

“…Current symptoms of depression and generalized anxiety were measured using the Beck Depression Inventory–II (BDI‐II) autism‐specific latent trait score (Williams, Everaert, et al, 2021) and the Generalized Anxiety Disorder–7 (GAD‐7; Kroenke et al, 2010) total score, respectively. Quality of life (QoL) was measured using the four‐item World Health Organization Quality of Life scale previously validated in this cohort of autistic adults (WHOQOL‐4; Williams & Gotham, 2021a). For all scales except the BDI‐II (which used a full‐information score estimator based on complete data), composite scores were calculated as the mean of all nonmissing items on each form, multiplied by the number of items on the form and rounded to the nearest integer value.…”

Current and Lifetime Somatic Symptom Burden Among Transition-aged Autistic Young Adults

“…Current symptoms of depression and generalized anxiety were measured using the Beck Depression Inventory–II (BDI-II) autism-specific latent trait score 14 and the Generalized Anxiety Disorder–7 (GAD-7 15 ) total score, respectively. Quality of life (QoL) was measured using the four-item World Health Organization Quality of Life scale previously validated in autistic adults (WHOQOL-4 17 ). Item-level missing data were imputed using the mean of remaining items on each form.…”

Neuroticism Drives Associations Between Repetitive Behaviors and Depression in Autistic Adults

“…In this first investigation of IS and RSM behaviors in the pathway to depression in autistic adults with consideration of trait neuroticism, there are several limitations to consider. First, this sample of autistic adults is comprised of disproportionately more females, adults with higher education levels, and adults with later initial diagnoses of autism as compared to typical clinical convenience samples, as noted in our previous studies ( 42 , 73 ). Second, given the nature of the SPARK dataset, autism diagnoses were not independently validated and IQ scores were not available to include as a covariate in analyses.…”