Correlates of Quality of Life in Adults with ASD: A Systematic Review and Meta-Regression Analysis

Background: Quality of life (QoL) is a multi-dimensional construct that includes subjective well-being, personal characteristics, and environmental variables (Schalock, 2004). When applied to individuals with ASD, QoL provides a criterion by which to assess satisfaction with various domains of their life as an outcome measure. Previous studies on the relationship between personal and contextual factors and QoL of individuals with ASD have provided inconclusive results (Chiang & Wineman, 2014). As improvement of QoL is one of the main objectives in interventions and social services of adults with ASD (Hong et al., 2016), it is important to identify factors associated with a favorable QoL to develop services that effectively support this goal.

Objectives: This study is a structured literature search and meta-analysis. The goal of this exploratory meta-analysis study was to synthesize the extant research to investigate the following hypotheses:

1. Are IQ, social functioning, and autism severity positively associated with QoL?
2. Is the correlation between QoL and social functioning higher than those between QoL and IQ or autism severity?
3. Is there a relationship between age and QoL?

Methods: This study used a structured search in ERIC, ERC, Medline, PsychINFO, and ProQuest Dissertations and Theses databases to locate studies that included correlations between QoL and (a) age, (b) IQ, (c) autism severity or (d) social functioning of adults with ASD (over 18 years). The first and third author independently reviewed the 117 articles in full, and two studies were included (Figure 1). Reliability of decisions on inclusion/exclusion was 100%. The authors of 22 studies that included measures of interest but did not report Pearson’s r or partial r were contacted, and 14 provided the requested information. The first and third authors independently coded the email correspondences. For continuous variables, the average ICC was .855 (range 0.74–0.95). For categorical variables, the average agreement was 85.48%. This analysis utilized a robust variance estimation approach to meta-analysis and meta-regression using the ROBUMETA macro in Stata (StataCorp, 2013).

Results: The meta-analysis was conducted on a total of 80 effect sizes (16 studies), which represented 1000 participants with ASD (mean age= 29.6; male= 83.55%). A total of 14 reports and 75 effect sizes were gathered from unpublished sources. The coefficients in the simple meta-regression for age, IQ and autism severity were close to zero and statistically insignificant while the coefficient for social functioning was statistically significant (p=0.0476), and with coefficient 0.259. See table 1 for coefficients and p-values.

Conclusions: The meta-analysis shows that social functioning is more highly correlated with QoL than age, IQ and autism severity. The strong relationship between social functioning and QoL suggested by this study has implications for future studies to target social functioning to effectively support better QoL of adults with ASD. Increasing awareness and acceptance on the part of neurotypical individuals and improving social support are discussed as methods to improve social functioning.

Table 1. Summary effect sizes in unconditional models

Correlate constructs	Coefficient	P-value
Age	-0.0337	0.5934
IQ	-0.008	0.9602
Autism severity	-0.003	0.9639
Social functioning	0.259	0.0476