"Are you available for the next 18 months?" - methods and aims of a longitudinal birth cohort study investigating a universal developmental surveillance program: the ‘Watch Me Grow’ study

Importance of Universal Surveillance

There is increasing evidence that early detection and intervention for developmental disorders has the potential to alter adverse development and provide significant short- and long-term benefits to human capacity. These benefits include increased school retention and reduced unemployment [1–3]. Unfortunately, the majority of developmental difficulties are not detected until children start school [3]. The Australian National Health and Medical Research Council [4] and the American Academy of Paediatrics (AAP) [5] recommend a system of universal developmental surveillance where the risk of significant developmental problems, and the need for further assessment and early intervention, can be identified early. Developmental surveillance is a continuous and cumulative process whereby knowledgeable healthcare professionals identify children who may have developmental problems [5]. The key components of developmental surveillance include eliciting and attending to parents’ concerns about their child’s development; documenting and maintaining a developmental history; making accurate observations of the child; identifying risk and protective factors; and maintaining an accurate record of findings. It is critical that there is ongoing contact with families and children coupled with anticipatory guidance and promotion of child development within families as well as responding to developmental concerns reported by parents, followed by clinical observation and the use of a validated surveillance tool over multiple time periods [4, 5].

What is currently known about Universal Surveillance methods?

Reviews of current practice in primary healthcare and anecdotal Australian evidence suggest that there is inconsistency in how developmental surveillance is undertaken in primary healthcare [6, 7]. Studies have documented the difficulties with approaches to monitoring developmental progress in child health settings [8], which typically involve parents/carers raising concerns during a consultation, and/or the administration of screening tools. While there are benefits of surveillance, there are also barriers to developmental surveillance achieving its potential positive impact. These include time constraints and difficulties in accessing high quality and affordable primary healthcare for children according to need [9], and obstacles for children receiving appropriate interventions even when they are recognised as being at risk of developmental delay [10–13]. For example, in Australia there are long waiting periods for both private and public assessment and intervention services for identified developmental problems such as speech and language disorders or global developmental delay [14]. Moreover, the lack of data regarding the uptake of the developmental surveillance program and service utilisation creates challenges for policy makers, service providers, and clinicians in developing appropriate care pathways; a key issue that the 'Watch Me Grow' (WMG) study seeks to address [15].

We are not aware of any robust, longitudinal evidence on the uptake of universal developmental surveillance in communities, particularly those with high levels of socioeconomic disadvantage. Additional gaps in existing evidence include the nature of the barriers and enablers to the uptake of developmental surveillance by families and the accuracy of developmental surveillance in identifying children at risk of developmental disorders such as autism spectrum disorder (ASD) [16, 17] and intellectual disability. Finally, there is scant data regarding models of partnership between policy makers and service providers to meet the challenges in delivering universal or targeted interventions for those at risk.

Developmental Surveillance in New South Wales

In 2007, the New South Wales (NSW) Ministry of Health introduced the Parents’ Evaluation of Developmental Status (PEDS) [18] for routine administration as a surveillance tool to be completed by child health professionals such as a Child and Family Health Nurse (what we will refer to as a community nurse in this paper) or by general practitioners (GPs). The PEDS is a 10-item standardised parent-report questionnaire that systematically elicits parental concerns regarding their child’s health, development, and behaviour to estimate that child’s developmental risk [5, 19]. The PEDS has moderate reported sensitivity of 74–80%, and specificity of 70–80% in validation studies from the USA [20], however to our knowledge no diagnostic test accuracy study has yet been conducted within Australia, notwithstanding a small study examining the PEDS’ capacity to detect symptoms of ASD [21]. The PEDS is designed for completion by parents/carers of children from birth to 7 years and 11 months of age. It takes about two minutes to administer. Of the ten questions, eight cover expressive and receptive language, fine motor, gross motor, behaviour, socialisation, self-care, and learning while the other two are about more general learning, development, and behaviour. Parents can respond ‘yes’, ‘a little’, or ‘no’. Two or more predictive concerns places a child at high developmental risk; one predictive concern places a child at moderate developmental risk, and one or more non-predictive concerns or no concerns places a child at low or no risk [22]. In NSW, the Department of Health recommends that children at high and moderate developmental risk are further assessed by a child health professional using a secondary developmental screening tool, the Ages and Stages Questionnaire (ASQ) [23] and Ages and Stages Questionnaire: Social-Emotional (ASQ:SE) [24].

In NSW, the PEDS is included in the child’s Personal Health Record (PHR; commonly known as the ‘Blue Book’), which is given to all parents at their child’s birth, and is to be completed at regular check-ups (at 6 months, 12 months, 18 months, 2 years, 3 years and 4 years). In Australia, developmental surveillance varies among states and territories. The PEDS is now the first line developmental surveillance tool used in many states and territories of Australia, including NSW, Victoria, Tasmania, the Australian Capital Territory, Western Australia and urban areas of the Northern Territory. In South Australia, the ASQ is used for developmental surveillance. The ASQ is also used in NSW and Western Australia as the second tier developmental surveillance tool as described above, while in Victoria and the Northern Territory the Brigance Screens [25] are used to follow-up developmental risk detected by the PEDS. In Queensland, community nurses conduct developmental reviews, but standardised tools are not used. In addition, the Queensland primary care program, which is run by nurses, targets families who are identified as high risk, mainly through the child’s first two years of life.

There are also significant between- and within-state differences with regard to pathways to diagnostic assessment following identification of children at developmental risk. For example, in NSW, the subsequent assessment depends on the pathway developed by areas within local health districts, and can include referral to a paediatrician, GP or a local child development clinic.

In addition to the issues inherent in the choice of tools, procedures and follow-up pathways, there are also significant barriers and enablers relating to health systems and policies as well as in parental behaviours that influence the uptake and participation in surveillance programs. Based on a national survey in the USA, the AAP reported that while most paediatricians agreed that developmental issues should be addressed, they were less confident about their ability to undertake this activity [26]. This survey identified a number of barriers for health professionals in completing developmental monitoring, including time constraints, inadequate reimbursement, lack of non-physician support staff, lack of further diagnostic and treatment services, insufficient training, and lack of familiarity with assessment tools. In Australia a survey of GPs in central and south western Sydney identified that less than half (44%) use the NSW Blue Book which includes the PEDS to discuss developmental concerns with parents [27]. At the same time, 60% of GPs who were surveyed reported that there were barriers to families seeking help for their children at risk of developmental disorders. These barriers included waiting times, cost, availability and access to services, and being from a non-English speaking background [27]. Using a case scenario method in which a developmental paediatrician considered a 2.5-year-old child as needing further follow-up, a study observed that one fifth of GPs responded that they would not initiate further assessment [27]. In this regard, the uptake of current developmental surveillance methods appears to be poor.

Unfortunately, families with the greatest needs for basic services such as food, housing and healthcare are often the least likely to receive support because of difficulties encountered in accessing these basic services [28]. These families are also likely to have children with a higher than average risk of having a developmental or behavioural difficulty. Furthermore, the predominant needs of children with developmental or behavioural problems including developmental assessment, speech and language therapy, and support for parents in managing challenging behaviours, are often limited in disadvantaged areas, making it difficult for families to access these services [29].

Methodological considerations for the Watch Me Grow study

To date, studies providing evidence about surveillance programs have provided key pieces of information, but in a way that has been disconnected from other information that is required. This has been because study design was cross-sectional rather than longitudinal, only quantitative or qualitative rather than both, and often not embedded within a service system. These are key methodological limitations in the existing literature that form part of the rationale for the WMG study.

Aims

The WMG study is a mixed methods study that includes both quantitative and qualitative components. The qualitative component is designed to evaluate the feasibility, and barriers and enablers of the current universal surveillance program in NSW (objective 1), whereas the quantitative component seeks to provide data addressing objectives 2, 3 and 4.

Setting

This study is being conducted in south western Sydney, an area of significant social disadvantage about 40 km from the Sydney central business district. The South Western Sydney Local Health District (SWSLHD) provides tertiary (including neonatal intensive care, inpatient and outpatient paediatric care) and community health services to the residents of this region. Children are referred to the Sydney Children’s Hospital Network for subspecialist paediatric services. SWSLHD is the largest health service in NSW and comprises seven local government areas. In 2011, the population of SWSLHD was estimated at 875,384 persons (11.7% of the NSW population), and is projected to increase by 18,000 people per annum over the next decade. By 2016, the population is expected to reach 958,397 people and 1.06 million by 2021. There were 12,997 births in south western Sydney in 2012, representing about 13 per cent of all births in NSW [30]. The total fertility rate ranges from 1.90 to 2.34 infants per woman compared to the NSW rate of 1.97 infants per woman [31]. This is a fast growing population including a large indigenous and culturally and linguistically diverse (CALD) community, characterised as having high unemployment, and the accompanying health and psychosocial concerns of disadvantaged populations [31].

Study design

Objectives 2 and 3: longitudinal study

A cohort of children will be recruited in three main study arms (see Figure 1). A birth cohort from two teaching hospitals in SWSLHD will form the primary target sample (birth arm). An additional prospective cohort will be recruited through community nurses in the community as this is the pathway being used currently in NSW for developmental surveillance (community nurse arm). These two study arms will be combined into the main prospective cohort of the study (prospective cohort). In addition, a retrospective arm of the study will recruit infants born in the two teaching hospitals that are currently in the age range of 18 to 21 months (retrospective cohort) and will serve as a comparison group.

For the birth arm, the WMG research team will attend the postnatal wards on a daily basis to recruit mothers who have given birth in the previous 24 hours at the two teaching hospitals in SWSLHD. The nursing staff on the postnatal wards will be consulted and their support sought for recruitment into the study. Recruitment information will be made available in English, Arabic, Vietnamese, Khmer, and Chinese - the predominant community languages used in south western Sydney. Families who agree to participate in the study will be asked to complete a Newborn Baseline Questionnaire (NBQ) which includes baseline sociodemographic and health service-use information, and will be informed about the subsequent follow-up telephone interviews when their infant is 6, 12, and 18 months of age.

For recruitment to the community nurse arm, parents will be informed about the study by community nurses during the Universal Health Home Visit that occurs by four weeks post-birth. If the family shows interest in learning more about the study, the contact information of parents who express interest will be provided to the WMG study research team. Researchers will then contact these parents and mail study information and consent forms with reply-paid envelopes to be returned.

The retrospective arm of the study will comprise infants born in the two teaching hospitals who are in the age range of 18 to 21 months at the time of recruitment. This sample of children will serve as a ‘surveillance as usual in the community’ comparison group (i.e., a control group). This will help to determine any participation bias by ensuring that the WMG study is not influencing the help seeking and health related behaviours of study participants via a Hawthorne effect. For example, it is possible that the awareness gained through participation in the study might make the families more compliant with the developmental surveillance programs being assessed.

The total target sample for the study from all three arms is expected to be 2000 children.

Follow-up of prospective cohort

Telephone follow-up interviews for the prospective cohort (i.e. those recruited through the birth and community nurse arms of the study) will consist of a 10-minute interview that will ask about their use of universal developmental screening services using a purposively developed Prospective Developmental Surveillance Questionnaire (PDSQ). These telephone interviews will occur after the infants reach 6, 12, and 18 months of age. The key questions will include whether the child has been taken for the recommended scheduled checks, which health service(s) has been used, satisfaction level with the service, whether a PEDS had been completed, and by whom. The researcher contacting the family for the follow-up calls will complete the PEDS with any parent who has not completed a PEDS as part their child’s personal health record developmental surveillance schedule. At the 18-month telephone call, components of the NBQ will be re-administered so that it is possible to compare the sociodemographic characteristics at the child’s birth and 18 months later, as well as further questions on social capital, access to early childhood education services, and parenting. The same procedures will be followed for the retrospective cohort, but all the data will be collected in one telephone call.

Underlying theoretical model and data analysis for longitudinal study

In order to plan comprehensive service models from the findings of the longitudinal study, we need to examine the complex transactional relationship between the child’s environment and biology over time [33]. We have developed a composite of a bio-ecological and life course model to serve as a framework within which to do this [34–37]. These theoretical models will be linked to appropriate analytical models and in this regard multilevel modelling will be employed to examine the independent impacts of community variables (e.g., socio-economic status), parental/family variables (e.g., family health, substance use, mental health history, country of birth, language spoken at home, parental perceptions about preventive healthcare and access to childcare and preschools), and child variables (e.g., temperament, preterm/low birth weight, intrauterine exposure to drugs, medicines, infections, low Apgar scores, perinatal complications, presence of developmental and behavioural concerns) on developmental risk and access to services. A combined risk index will be created that includes measures of biological, psychosocial, developmental and socioeconomic risk used in the previous multivariate analyses. Cumulative risk analysis will be undertaken to determine the relationship between burden of risk and uptake of referral recommendations and utilisation of services. In addition, we will examine the transactional impacts of these variables on the uptake of referral recommendations provided by the research team following the reference standard assessment and utilisation of health services.