Friday, 29 January 2016

Mortality and autism: comorbidity counts

I don't enjoy talking about mortality and autism on this blog but once again I'm drawn to discuss this important topic based on some recent findings published by Diana Schendel and colleagues [1]. I say these are important findings on the basis of how researchers took into account the possible role played by psychiatric and neurological comorbidity occurring alongside autism when it comes to the quite alarming mortality statistics.

Drawing on the findings reported in their paper and an interview discussing the study (see here), the Schendel results are again based on the examination of one of those very useful Scandinavian registries (several in fact) based in Denmark. Following the "unique 10-digit identifier assigned to all live births and new residents in Denmark" researchers were able to track down the records of over 20,000 children and young adults diagnosed with an autism spectrum disorder (ASD) from a total population of some 1.9 million people "born in Denmark during the period from 1980 to 2010 who were alive at 1.5 years of age and followed up through 2013." The presence of "comorbid mental, behavioral, and neurologic disorders" was also deciphered from records and the rather grim process of determining death and causes of death among any cohort members was carried out.

Results: perhaps unsurprisingly there was a difference in mortality risk between those with ASD compared with those without. Those with autism had a 2-fold higher mortality risk, bearing in mind that older children and young adults were the focus of this study - "Of the 20 492 persons with ASD, 68 died (0.3%)." Most of those who had passed away also had additional comorbidity (83%). Worryingly, in about a quarter of deaths, suicide was listed as the cause; a further quarter died in accidents. Also: "The co-occurrence of ASD added no additional mortality risk for persons with neurologic... or mental/behavioral disorders...  compared with persons with these disorders and no ASD."

There is quite a bit to take from these results. First and foremost is that they provide further evidence that the risk of [early] mortality is seemingly heightened when a diagnosis of autism is received. Sixty-eight deaths out of over 20,000 might not sound a lot in cold statistical terms, but those were 68 people with 68 families and loved ones.

Next is the idea that comorbidity often plays a big role in relation to autism. I've lost count of the number of times that both medical and psychiatric comorbidity attached to autism have been discussed on this blog. Suffice to say that the label of autism is seemingly protective of nothing when it comes to other diagnoses/labels appearing (see here for example) and certain types of comorbidity carry their own early mortality risks (see here). I might also add that, on occasion, the diagnosis of autism may also represent an obstacle to receiving another appropriate medical diagnosis and where possible, intervention (see here).

The suggestion that suicide was represented in the mortality figures detailed by Schendel et al is a real worry although not entirely a new finding. Previous research has talked about levels of suicide ideation when it comes to the autism spectrum (see here) and even some extreme examples of euthanasia requests from individuals on the autism spectrum (see here). A lot more needs to be done to find out why suicide is over-represented and what we can do about it. I might suggest that preferential screening and monitoring for potential correlates of suicide (ideation or attempted) might be a good starting point (see here).

Finally, the idea that accidental death featured in the statistics is also concerning. I can't comment on the specific types of accident that may more readily feature when it comes to early mortality and autism but one only needs to look at the literature and very sad reports on the issue of wandering and autism to see what might potentially figure (see here). With this issue in mind, I'll draw your attention to some positive activities designed to counteract or mitigate such risk (see here).

And just before I leave you, I might also draw your attention to some other research from some of the authors on the Schendel paper talking about an increased mortality risk in cases of obsessive-compulsive disorder (OCD) [2] potentially also relevant in light of the topic of comorbidity and autism (see here)...

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[1] Schendel DE. et al. Association of Psychiatric and Neurologic Comorbidity With Mortality Among Persons With Autism Spectrum Disorder in a Danish Population. JAMA Pediatr. 2016 Jan 11:1-8.

[2] Meier SM. et al. Mortality Among Persons With Obsessive-Compulsive Disorder in Denmark. JAMA Psychiatry. 2016. 27 Jan.

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ResearchBlogging.org Schendel, D., Overgaard, M., Christensen, J., Hjort, L., Jørgensen, M., Vestergaard, M., & Parner, E. (2016). Association of Psychiatric and Neurologic Comorbidity With Mortality Among Persons With Autism Spectrum Disorder in a Danish Population JAMA Pediatrics DOI: 10.1001/jamapediatrics.2015.3935