Supplementary data: A US national update of health conditionprevalence among privately-insuredautistic adults

This is a peer-reviewed supplementary table for the article 'A US national update of health condition prevalence among privately-insured autistic adults' published in the Journal of Comparative Effectiveness Research.

• Supplementary Table 1: Study definitions of mental and physical health conditions using Healthcare Cost and Utilization Project (HCUP) Beta Multilevel Clinical Classification Software (CCS) or specific International Classification of Diseases, 10^th edition (ICD-10) diagnosis codes.

Aim: Previous research using state or regional samples has shown that autistic adults have a higher

prevalence of health conditions in comparison to the general population. Methods: To build upon this

important previous research, we conducted a cross-sectional retrospective study of 2019–2020 healthcare

claims to determine the prevalence of conditions in a US national sample of privately insured autistic adults

(n = 30,258) and an age- and sex-matched population comparison (n = 60,516) group of adults without

autism diagnoses. Results: Like previous studies, we found that autistic adults had significantly greater

odds of most mental and physical health conditions. However, our prevalence estimates differed from

previous studies for several mental and physical health conditions. For example, our sample of autistic

adults had higher prevalence of anxiety disorders (55%) and attention deficit hyperactivity disorders

(34%), but lower prevalence of asthma (9%) and sleep disorders (3%) than previous studies. Discussion

& conclusion: Our use of a large US national sample, more recent healthcare claims data, and different

methods for identifying health conditions may have contributed to these differences. Our findings alert

healthcare providers and policymakers to the health conditions most common among the growing

population of autistic adults. We hope these findings lead to improved screening and management of

these conditions, inform initiatives to improve access to healthcare, and guide future funding.