Stuart Neilson, June 2013
Summary
An autism spectrum disorder was recorded in 711 acute hospital inpatient episodes per year over the 5-year period 2007-2011, with a gender ratio of 3:1 male:female. The trend was from 429 episodes in 2007 to 1,087 in 2011, a growth rate of 26% per year.
Childhood autism (72.3%) and Asperger syndrome (17.2%) were the most frequent autism spectrum disorders recorded. Autism spectrum disorder was the primary diagnosis in only 3.6% of episodes. The average length of stay was 23.5 days for people with Asperger syndrome and 8.9 days overall – it is probable that the longer stays for people with Asperger syndrome are associated with psychiatric in-patient care.
The direct cost of admissions due to autism as a primary diagnosis was €205,000 per year, with an indirect cost (including secondary diagnoses) of €5.6 million per year. These cost estimates are also rising at 26% per annum with increasing recognition of autism as a diagnosis. Economic cost estimates can not be causatively linked with autism, but may form a context in which to evaluate interventions that reduce hospital admission rates or increase quality of life for people with autism.
Data
Data were obtained from the Hospital In-Patient Enquiry System (https://www.esri.ie/health_information/hipe/) for all episodes of hospital inpatient admission in which a diagnosis of autism was recorded. HIPES records 1.3 million hospital discharges per year from all acute hospitals in Ireland.
Diagnostic codes in the ICD-10 category F84 “Pervasive developmental disorder” were requested. This category includes the codes F84.0 “Childhood autism”, F84.1 “Atypical autism”, F84.2 “Rett syndrome”, F84.3 “Other Childhood Disintegrative Disorder”, F84.4 “Overactive disorder associated with mental retardation and stereotyped movements”, F84.5 “Asperger syndrome”, F84.8 “Other pervasive developmental disorders” and F84.9 “Pervasive developmental disorder, unspecified”. There were no cases recorded as F84.3 “Other Childhood Disintegrative Disorder”, F84.4 “Overactive disorder associated with mental retardation and stereotyped movements” or F84.9 “Pervasive developmental disorder, unspecified”. There was a total of 8 episodes recorded as F84.8 “Other pervasive developmental disorders”, which is too small for any further analysis.
The data reported here therefore represent episodes of autism spectrum disorder, including childhood autism, atypical autism, Rett syndrome and Asperger syndrome.
Results
For the 5-year period 2007-2011 (the most recent years available), there were 3,555 hospital inpatient episodes in which a autism spectrum disorder was recorded as the primary or a secondary diagnostic category. This is an evarge of 711 episodes per year. There were 2,669 male and 886 (25%) female episodes, a gender ratio of 3:1 (Figure 1).
The specific diagnostic codes were recorded as 2,572 (72.3%) episodes of childhood autism, 186 (5.2%) episodes of atypical autism, 176 (5.0%) episodes of Rett syndrome and 613 (17.2%) episodes of Asperger syndrome. These are displayed graphically in Figure 2.
Autism spectrum disorder was recorded as the primary diagnosis in 130 (3.6%) of these 3,555 episodes, and these 130 episodes utilised a total of 1,154 inpatient bed days. The number of hospital bed days was not available for episodes in which autism was a secondary diagnosis. The majority of episodes were associated with children aged under 15 (84.3%) and a minority with people aged 15 years and older (15.7%), as shown in Figure 3.
Growth rate
Episodes in which autism spectrum disorder was a diagnosis grew from 429 in 2007 to 1,087 in 2011, as displayed in Table 1. This is a growth of 153% over a four-year interval, equating to a compound growth rate of 26% per annum. The number of episodes per year is shown in Table 1 and Figure 4.
Table 1 - Number of episodes of autism spectrum disorder, 2007-2011
2007 2008 2009 2010 2011
Male 320 444 437 668 800
Female 109 134 181 175 287
TOTAL 429 578 618 843 1087
The same pattern was observed for male (150%) and for female (163%) inpatients, as well as for each diagnostic code of childhood autism (152%), Rett syndrome (122%) and Asperger syndrome (98%), as displayed in Table 2 and in Figure 5.
Table 2 - Diagnoses of autism spectrum disorder, 2007-2011
2007 2008 2009 2010 2011
F84.0 Childhood autism 318 364 450 640 800
F84.1 Atypical autism 0 68 0 65 53
F84.2 Rett's syndrome 27 36 53 0 60
F84.5 Asperger's syndrome 84 110 115 138 166
Length of Stay
The mean average length of stay was 8.9 days overall, but this was lower for childhood autism (5.7 days) and Rett syndrome (2.4 days) than the average length of stay for inpatients recorded as Asperger syndrome (23.5 days). Only 15.7% of episodes were of people aged 15 years or older, but this older age group accounted for 90% of total bed days in which an autism spectrum disorder was recorded as the primary diagnosis.
Discussion
Autism spectrum disorder was recorded as a primary diagnosis in 26 inpatient episodes per year over 2007-2011 in Ireland, within a population of 4.6 million, a rate of 5.6 episodes per million people per year. This is considerably lower than comparable data for England (http://hscic.gov.uk/) which record autism spectrum disorder as a primary diagnosis in 1,251 episodes of inpatient activity in a population of 53 million, a rate of 23.6 per million people per year. However, autism spectrum disorder is only recorded as a primary diagnosis in 3.6% of Irish episodes.
The mean length of stay was 8.9 days in Ireland, as compared with 84 days (12 weeks) in England. The mean length of stay was 23.5 days (3.4 weeks) for people with Asperger syndrome in Ireland. There are considerable organisational differences between the UK National Health Service and the wider availability of residential care and the public-private health system in Ireland. It is therefore probable that much care of people with autism in Ireland takes place in settings other than acute hospitals, except in the case of adults with autism or with Asperger syndrome who live in the community. Almost all (97%) of adults in English consultant episodes were admitted to hospital, and 19% were admitted as an emergency. Admission to psychiatric inpatient care is a probable explanation for the longer stays associated with older people and with Asperger syndrome in both countries.
The number of episodes recorded as autism spectrum disorder has risen continuously by 26% per annum. The recognition of autism as the underlying cause for admission may be increasing the frequency of autism as a recorded primary diagnosis, rather than any real increase in the rate of autism or of hospitalization. Autism is currently recorded as the primary diagnosis in only 3.6% of inpatient episodes.
The directly-measurable cost of acute hospital inpatient episodes where autism spectrum disorder was the primary diagnosis was €205,000 per year, based on 230.8 bed days per year at an average HSE cost of €890 per bed day (PA Consulting Group 2007 p155, O’Regan 2010, Dillon 2011). The indirect costs of all hospital inpatient episodes associated with autism spectrum disorder (secondary as well as primary diagnoses) would be approximately €5.6 million euro per year, based on 711 episodes per year totalling 6,300 bed days at a mean length of stay of 8.9 days. Both of these estimated costs are rising at 26% per year as the recording of autism as a diagnosis increases. These costs can not be interpreted as a cost “of autism” because the treatment courses and reasons for hospital admission are not known. They do provide a context in which the costs of services for people with autism can be evaluated, particularly any that might improve quality of life or reduce the rate of hospitalization.
References
ESRI. Hospital In-Patient Enquiry Scheme (HIPE). https://www.esri.ie/health_information/hipe/
Health and Social Care Information Centre. http://hscic.gov.uk/
O’Regan, E (2010) It’s dearer than the Ritz, your €889-a-day public hospital bed. Independent 16 March 2010. http://www.independent.ie/irish-news/its-dearer-than-the-ritz-your-889aday-public-hospital-bed-26641374.html
Dillon, Fiona (2011) Cost of just one hospital bed rises to €331k a year. Herald 14 February 2011. http://www.herald.ie/news/cost-of-just-one-hospital-bed-rises-to-f331k-a-year-27973268.html
PA Consulting Group (2007) Acute Hospital Bed Capacity Review: A Preferred Health System in Ireland to 2020, Detailed Report, 7 September 2007.