Uncertainty about autism screening efficacy

A federal panel is asking for more research to support regular autism screening, stating in new draft guidance that there is not enough evidence that early, routine screenings recommended by the American Academy of Pediatrics (AAP) and many others are worthwhile.

The new draft recommendation by the US Preventive Services Task Force (USPSTF) has the autism community up in arms over what seems to be a position against routine autism spectrum disorder (ASD) screening.

Contrary to the first impression of the report, however, the draft report does not recommend against routine screening, but rather puts out a call for more studies on the benefits and disadvantages of early general screening.

The draft recommendation statement, released in early August by the USPSTF, states that current evidence is insufficient to assess the efficacy of ASD screening for children who have no symptoms or for whom no concerns have been raised by their caregivers.

The recommendation to withhold screening unless a parent expresses concerns or the child displays symptoms has been compared by some experts to avoiding car maintenance until something breaks.

Sandra G. Hassink, MD, FAAP, president of the AAP, says early identification and intervention is critical for ensuring that children with autism have access to effective treatment. The AAP recommends all children be screened for ASD at 18 and 24 months of age.

“The draft recommendation statement on autism screening released August 3 by the [USPSTF] runs counter to AAP guidelines,” Hassink says. “The AAP remains committed to its recommendation for the timely screening and identification of children who would benefit from early intervention and treatment.”

Hassink says research has indicated that early intervention in ASD results in significant improvement in long-term development and social behaviors. One in 68 children has ASD-compared with 1 in 150 in 2000, according to the most recent figures from the Centers for Disease Control and Prevention (CDC), and half of those children are diagnosed by age 4 years. The AAP’s guidelines state that many children with ASD begin to display symptoms even before 18 months of age. The National Institutes of Health indicates that a reliable and valid ASD diagnosis can be made by age 2 years.

Boys are 5 times more likely to have ASD than girls, and children who have siblings already diagnosed with ASD have a high likelihood of having their own diagnosis.

As far as cost, treating ASD can run $10,000 to $20,000 per year per child-roughly 4% to 6% more than children without an ASD diagnosis. That equates to more than $9 billion nationwide and does not include behavioral interventions that are necessary to manage ASD.

Studies have shown that early detection, diagnosis, and intervention in ASD can be extremely helpful for children with ASD, and may even result in a child losing his or her ASD diagnosis at some point.

Part of the argument against the draft recommendation is that, especially considering the benefit they could potentially yield, autism screening is a low-cost service pediatricians could offer.

A common screening tool for early autism is a parent questionnaire called the Modified Checklist for Autism in Toddlers (MCHAT) that includes questions about a child’s response to his/her name being called, smiling, and general responsiveness. Roughly half the children flagged during that screening end up with an ASD diagnosis, and many others are diagnosed with other developmental issues.

The CDC says today’s tools for screening for developmental disorders such as autism are about 70% accurate and only take about 15 minutes to administer-2 minutes of professional time.

Still, the USPSTF apparently requires more concrete facts to secure a positive recommendation.

Task force member, pediatrician, and Duke University professor of pediatrics Alex Kemper, MD, MPH, MS, says the expert panel wants all children with ASD to get the support they need, but adds more research is needed to determine whether screening all children leads to better outcomes.

Kemper stresses that the task force does not make specific recommendations about ASD diagnosis or treatment. “We respect our colleagues’ expert opinions and believe doctors should use their clinical judgment when deciding when and whom to screen for autism,” he says.

The USPSTF found adequate evidence that currently available screening tests can detect ASD in children aged 18 to 30 months, or in toddlers and preschool-aged children.

“There are no studies meeting inclusion criteria of clinical outcomes of children identified with ASD through screening,” the draft states. “The USPSTF also found inadequate evidence on the efficacy of treatment of cases of ASD detected through screening. Treatment studies were generally very small, few were randomized trials, most included children who were older than would be identified through screening, and all were in clinically referred rather than screen-detected patients.”

Although the USPSTF acknowledges that screening poses no significant harms for children who have no ASD or development disabilities, the draft recommendation stands for asymptomatic children who have no ASD diagnoses or for whom concerns have not been raised by caregivers. The task force says positive screening results that lead to more testing can cause anxiety in children and caregivers, especially if additional testing is delayed for some reason. Both screenings and treatments for ASD can place a large time, stress, and financial burden on families, notes the USPSTF.

“Good quality studies are needed to better understand the intermediate and long-term health outcomes of screening for ASD in children, and whether earlier identification through screening is associated with clinically important improvements in health outcomes,” says the USPSTF. “Studies following large samples of screen-negative children, though resource intensive, would provide valuable information regarding screening specificity. Treatment studies that enroll younger children, especially those with screen-detected ASD, are critical to understanding the potential benefits of screening.”

The USPSTF acknowledges the AAP’s guidelines to screen for ASD at 18- and 24-month visits, and the American Academy of Neurology and the Child Neurology Society’s recommendation to screen for ASD at all well-child visits from infancy through school age and beyond as concerns are raised.

However, even CDC notes that the majority of cases of ASD-70% to 80%-are spurred by parent concerns.

The USPSTF’s draft recommendation raises the question of whether parental concern is the more effective screening tool, rather than a formal test. “In general, children identified through screening rather than through case finding are likely to be younger and possibly less severely affected than those in study populations,” the USPSTF states. “It is therefore unclear whether young children with ASD detected by screening and not because of parental or teacher concern will experience similar, or any, benefit.”

However, children who display any sort of developmental abnormality during routine visits also should be screened.

“Children failing routine developmental surveillance procedures should be screened for autism using one of the validated instruments,” the USPSTF notes.

Symptoms of ASD include impairment in reciprocal social interaction and communication, restrictive or repetitive patterns of behavior and activity, impairment of nonverbal behaviors, failure to develop age-appropriate peer relationships, lack of social-emotional reciprocity, land of spontaneous seeking to share interests or enjoyment, absent or delayed language, impaired ability to sustain conversation, lack of make-believe or social imitative play, abnormal focus, restricted interests, and nonfunctional or inflexible routines.

The draft stresses that the recommendation is geared toward children for whom ASD is not suspected. The full draft recommendation can be viewed here, and is open for comment until August 31.