Mis-Diagnosis, Overdiagnosis, and the Unintended Consequences of Prevention: Interpreting the Uspstf Autism Screening Report

Background: In 2016, The U.S. Preventive Services Task Force (USPSTF) concluded “insufficient” evidence to support universal primary care screening for autism spectrum disorder (ASD). The statement led to controversy among research and clinical communities. Although a number of papers have since been published arguing for the potential benefit of ASD screening, none specifically address potential harms of ASD screening. This evidence gap may relate to confusion regarding how the USPSTF measures and evaluates potential harm.

Objectives: In the current study, we reviewed how the USPSTF operationalizes “harm,” and explored how that definition impacts ASD screening

Methods: We reviewed the 18 reports released by the USPSTF between 2016 and 2018 that were issued an “I” (insufficient evidence) statement to explore: 1) how harms were operationalized, and 2) how often harms were concretely measured in the literature. We then applied this framework to the example of ASD screening

Results: We identified two categories of harm that relate to ASD screening: (1) classification error and (2) overdiagnosis. Screening classification error, defined by the National Academy of Medicine as the failure to establish an explanation of a patient’s health problems in a timely and accurate manner, or the failure to communicate such an explanation, is commonly assessed by testing sensitivity and specificity of screening tools. Because an ASD diagnosis is based on screening for a range of developmental difficulties, screening can lead to false positive and false negative errors. These errors can lead to harm in a number of ways, for example by exposing families to stigma and unnecessary services, or by delaying other needed services through inappropriate reassurance.

Distinctly, overdiagnosis refers to diagnoses that are technically correct but that will not provide benefit to the patients who receive them. The USPSTF explicitly expressed concern about overdiagnosis related to screening for skin cancer in asymptomatic adults and breast cancer in women over 75 based on evidence that screening might detect patients who met diagnostic criteria but were unlikely to benefit from treatment. Factors hypothesized to contribute to overdiagnosis in ASD include dissemination of screening to asymptomatic populations, growing awareness and an accompanying reduction in stigmatization, improvement of diagnostic procedures and changes in the diagnostic criteria, and the potential for biased clinical judgment (Merten et al., 2017). Some children who correctly meet diagnostic criteria for ASD diagnosis could have a phenotype that is less responsive to autism supports and services, thereby exposing them to the harms associated with these treatments (e.g., being pulled from class) without the benefits.

Conclusions: USPSTF screening conclusions can be better understood by clearly delineating possible causes of harm. While screening is likely to help children who are subsequently diagnosed with ASD and benefit from treatment, data on patients who receive no benefit from an accurate ASD diagnosis are severely lacking. More research on the potential harms of ASD screening is needed at the individual- and population-level. Clarity on these subjects can help inform interpretation of and response to future USPSTF reports.