Background
Several studies, government documents and policy guidelines highlight the difficulty that young people face who require a transition from child to adult services [
1]. Transition between services is particularly difficult for young people with Attention Deficit Hyperactivity Disorder (ADHD) [
1]. Two types of transition can be conceptualised;
developmental when a child moves from adolescence to adulthood, and
situational, moving from one service to another [
1]. In the current paper, the term transition refers to a situational transition between child and adult mental health services, however this is driven by young people reaching a developmental transition. There is currently limited evidence available on the need for transition between services for young people with long term health conditions who require ongoing care. A case note review study would most commonly be used to capture the transition process; however it suffers from limitations such as requiring intensive researcher or clinician time, being very localised in focus, and the availability and quality of data are dependent on the clinician who records it [
2‐
4]. This paper reports on two existing methods that have been adjusted to estimate the national need for young people with ADHD to transition to adult services; they were a surveillance system and an electronic case note review method. Paediatric surveillance studies have traditionally focussed on the incidence of rare conditions [
5], however the current study focussed on the incidence of transition between child and adult services for young people with ADHD as an
event or process as opposed to the incidence of ADHD as a
condition. ADHD itself is not rare; it is one of the most common long term conditions managed by child and adolescent mental health service (CAMHS) and community paediatric services [
6].
The prevalence of ADHD is estimated at approximately 5% [
7], and population based studies suggest that 15% of those with childhood ADHD still meet the full diagnostic criteria for the disorder at age 25 [
8]. However, existing research suggests a seamless transition process between child and adult services happens much less often than can be expected based on adult prevalence rates [
9]. Two previous studies [
1,
10] have reviewed case notes narratively to identify transition cases between CAMHS and adult mental health services (AMHS) over a twelve month period. The first study identified an average of 12 cases of neurodevelopmental disorder per CAMHS team that were eligible for transition in one year, but 40% were not referred to any adult service, and only 67% of those referred actually made the transition [
1,
11]. The study was based on a limited number of health trusts in England and identified neurodevelopmental cases in general, not ADHD specifically. The second study focussed on ADHD cases in Ireland, and identified 20 patients from four CAMHS teams that required a transition. No cases were directly transitioned to AMHS; they were either retained by CAMHS, referred to a private service, or discharged to their General Practitioners (GP) [
10]. Extrapolating from epidemiological studies can be helpful in the estimation of population level need, but does not necessarily provide information about service access and service-level need, and may not be relevant to populations other than those studied. An existing prospective North American longitudinal study used assessment at three time points from age 9 to 30 years, as a method to quantify patterns of transitions, and it was found that ADHD in particular showed a strong continuity across the transition from adolescence to adulthood [
12]. Studies of long term conditions such as ADHD rarely follow participants across developmental transitions [
13] and national empirical data on the number of young people that wish to access ongoing care for ADHD in adulthood, or the number that successfully and seamlessly access follow up care in early adulthood, is sparse. This hampers commissioning and provision of services for this group.
The current paper describes how two existing methods were adjusted to assess the need for transition between child and adult services for those with ADHD at a national level; it evaluates how feasible and transferable these methods were to quantify and capture the need for transition or other rare events or processes in health services. To estimate incident service need for young people with ADHD to transition to an adult service we used a paediatric surveillance methodology, in particular the Child and Adolescent Psychiatry Surveillance System (CAPSS), and an electronic clinical case note search using the Maudsley Biomedical Research Centre (BRC) Clinical Records Interactive Search (CRIS) [
14].
Discussion
A well-established surveillance method, and a case note review method have been used to assess the need for, and process of, transition between child and adult services for young people with ADHD. Utilised together, both methods have provided an insight into the need for transition of patients with ADHD in CAMHS settings in the UK.
CAPSS was chosen in order to most closely reflect the common health setting that patients with ADHD are reviewed in within the UK, and the monthly notification card completion rate throughout the study, which was similar to the average CAPSS rates, shows that this method of surveillance is successful. It also has the potential to be used to monitor a health service event seen by psychiatrists, in addition to incidence of rare conditions which it is traditionally used for. CAPSS had the potential to provide a national picture, in contrast to the case note review that is localised. When compared to the clinical case note review via CRIS, there was a significant difference in the number of cases identified using CAPSS. However, the case note review method allowed all cases to be captured within a NHS trust that required transition due to ongoing medication needs, regardless of the treating or supervising clinician, whereas surveillance relies on the clinician to accurately report each case.
Using CAPSS, only consultant level psychiatry clinicians are sent reporting cards each month. The case note review with CRIS demonstrated clearly that ADHD patients in this mental health trust are frequently reviewed by other health professionals, such as junior doctors and specialist nurses. These clinicians would not be able to report to CAPSS. Similarly locum clinicians also may not be registered with, or reporting via CAPSS due to frequent employment moves. Even if locums are registered and do notify cases, they may have moved posts between notification and baseline questionnaire, or between baseline and follow up, and therefore not be able to provide data. Patients may also be reviewed in settings other than CAMHS, such as primary care or forensic services [
28], while a study of surveillance approaches has highlighted the absence of surveillance in the private sector despite it playing an important role in health care provision [
29]. This is perhaps particularly relevant for young people with ADHD for whom there can be long waits for treatment in the public sector and gaps in the provision of adult services [
15,
30].
Enrolment with CAPSS is voluntary, and therefore not all consultants may be registered to receive the reporting cards. A census in 2017 reported there to be 5395 registered consultant psychiatrists (approximately a quarter of which are child and adolescent psychiatrists), whilst CAPSS have approximately 1000 on their database [
31‐
33]. It is possible that although clinicians are registered with CAPSS, they may be academics and not hold relevant clinical caseloads, and would therefore not be reviewing patients with ADHD. Some contact details provided by the surveillance organisation were out of date, inevitably due to clinicians frequently changing NHS Trusts, location, role, retiring, or working as locum. Incomplete records present a factor in non-return despite efforts to update records and the use of alternative methods to contact clinicians.
The surveillance system relies wholly on accurate reporting from the clinician, and the average return rate of the reporting cards was low in CAPSS when compared to previous BPSU studies [
17]. The BPSU system was adopted and replicated by CAPSS in 2009, and perhaps it is yet to become routine practice for child and adolescent psychiatrists. The lower return rate of notification cards may indeed indicate a lack of awareness of the system and not necessarily a reflection of clinicians actively being non-compliant. It is possible that the difficulties with the case definition could also have led to a lack of reported cases. Previous surveillance studies have also cited difficulties with reporting, case definitions and lower return rates [
26,
34‐
36]. Clinicians were offered certificates to demonstrate time committed to research to be used for appraisal, as an incentive to return questionnaires to the study. There is no evidence to suggest that this had an impact on return of questionnaires, however certificates were generally received with thanks.
It is important to estimate the accuracy of case ascertainment in surveillance [
37] and verify findings [
38]. It is recommended that researchers conducting surveillance studies reconcile their data with other sources to help improve completeness and accuracy [
16]. Previous surveillance studies [
20,
39,
40] have used ‘capture recapture’ analysis to maximise case ascertainment, but for this matched cases must be identifiable and the population under study must be closed [
20]. This was not possible in the current study of transition in ADHD. The CRIS database was used as an alternative data source to estimate the incidence of transition among young people with ADHD and to compare against the data collected using surveillance.
There were limitations to this comparison. While clinicians completing the surveillance questionnaires had direct knowledge of the young people as well as the case notes that they themselves may have written, the data collected using CRIS relied on information recorded by other people in the clinical notes [
38]. Inevitably, this involved some subjective judgements on behalf of the researchers as the clinical notes may not necessarily include readily available concrete information such as prescribed medication, comorbidities or details of diagnosis. Similarly, the information gathered by the surveillance questionnaires was specified by the study researchers, and required short, succinct responses. It was not always possible to identify the same succinct information from the clinical case notes.
While the surveillance system has the advantage of its national cover, the case note review was limited to a single NHS trust covering one part of a metropolitan city. How representative these services and the young people attending them are of all young adults with ADHD is difficult to judge. Existing research has alluded that patients identified in case registers are not always representative of all cases with that disorder [
3]. Importantly, and a key limitation of this study is that the geographic location of SLaM clinics and hospitals could not be directly replicated in the surveillance data, as the address provided from the surveillance notifications was that of the clinician, and not of the clinic or hospital in which the patient was seen. The broader term of ‘London’ was used in the CAPSS data which almost certainly gathered cases from a wider boundary than is included in SLaM. There are nine mental health trusts in London, of which eight have CAMHS services [
41] (SLaM is one of them), suggesting that the data collected in CRIS only represents a fraction of the ADHD transition cases in London.
Data protection and information governance meant that data could not be directly linked which would have allowed more direct inference of the completeness of case ascertainment from CAPSS to be drawn. Interestingly, data protection rules may be more stringent than the attitudes of many patients and public. A previous study has highlighted the benefits of linking data to provide information that is missing and reduce bias [
42] and a study of attitudes towards linking data concluded that it was perceived acceptable to share health data in a medical context [
43]. A study using medication registers has previously been used to examine trends over transition [
44], but not all trusts have such registers, and prescribing for ADHD is often led by primary rather than secondary health care.
While the case note review clearly provides the most efficient local data, both methods offer strengths and weaknesses in terms of our attempt to provide robust national estimates. While imperfect, these results, particularly when combined, provide an insight in to the issue of transition for young people with ADHD nationally that has not been achieved by studies previously. Ideally, routine data linkage could inform service planning and provision at national and local levels in real time, but whilst systems like CRIS are located within a limited number of trusts, additional methods will be required. Many data protection and information governance issues currently mean that access to such data is difficult to obtain when it exists.
Previous research has suggested that traditional public health approaches for monitoring incidence of conditions is too late, too costly and often inaccurate [
45]. Managing and running a surveillance study is labour intensive, both from the perspective of the surveillance organisation and from the individual study team, but it provides value for money as research studies can be conducted simultaneously [
5] and data can be gathered on a national level. It is worth noting that case note review, even using an isolated system such as CRIS, is also labour intensive if the questions asked requires active data extraction. For most conditions, surveillance studies are still the only source of national data [
46]. The existing surveillance organisations stress that studies should not generate more than 360 cases per year [
22]; for valuable national surveillance to be effective for more than just incidence of rare conditions, and to continue to inform public health policy [
46], these systems need to be properly funded and supported to enable large scale national studies to be carried out. Previous research has highlighted that national data are not necessarily sufficient to address gaps and advance knowledge; the establishment of the international network of paediatric surveillance units (INOPSU) and the replication of the methodology in certain specialities, potentially provides methodological opportunities for researchers to gather invaluable data on uncommon conditions or health service events internationally [
47] that should be further explored.
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