OBJECTIVE To improve chronically ill adolescents' transition to adult care by preparing and supporting the parents. The study aim is to improve parents' (of chronically ill adolescents, 16-18 years) transition readiness by offering them a brief transition program.

HYPOTHESIS Young peoples´ self-management skills are mainly developed at home, guided by their parents, rather than in consultations with health professionals.

The investigators hypothesize that a nurse-led transfer intervention focusing on parents' knowledge, skills and attitudes will:

1. improve the parents´ readiness for their child's transition to adult health care
2. support the parents' gradual handing over of treatment responsibility to the adolescent and, that an improvement in parental transition readiness will
3. strengthen the adolescent's self-management skills and increase his/her readiness for transition.

BACKGROUND Transfer from paediatric to adult care for chronically ill adolescents is associated with no-shows and low treatment adherence, as well as anxiety and concerns among parents. Studies show that support for parents results in better transition for both parties.

INTERVENTION

ParTNer-STEPs is a transfer program consisting of three initiatives:

1. a website with information about the adult department and legal changes as well as advice from other parents and young people
2. online teaching events (web based seminars) for parents
3. transfer consultations across the paediatric and adult department

METHOD The intervention will be evaluated in a randomized controlled trial (RCT) study over two years. The project will be carried out in four paediatric outpatient clinics at Rigshospitalet, Copenhagen University Hospital, Denmark: nephrology, hepatology, neurology and rheumatology. Based on a power calculation, the investigators aim to include parents of minimum 62 adolescents. Primary outcome: Parents' transition readiness (TR). Secondary outcomes: Adolescents' TR, self-management skills, and quality of life.

STUDY DESIGN The study design is a randomized controlled trail (RCT) study in a period of 6 to 18 months before the adolescent is transferred to adult care (depends on when the participant is recruited before transfer) and three months after transfer.

RECRUTMENT Potential participants will be contacted by the paediatric nurses at the four outpatient clinics and briefly informed of the study. If the parents are interested in the project, the project coordinator will provide the parents with oral and written information of the study, including the fact that they can withdraw from the study at any time without consequences for their child's treatment. There will also be provided written information to their adolescent child and the adolescent will also get the opportunity to speak directly to the project coordinator, if they have any questions. Finally, after time to consider their participation in the project, a written consent will be obtained. Under the recruitment process the investigators will carefully consider the risk of coercion, autonomy, and confidentiality.

RANDOMIZATION Randomisation will be conducted after screening and written consent of parents. Randomisation will by conducted by computer-generated (REDCap) random numbers as a dyad (adolescent and parents) with a ratio of 1:1 (using algorithm to stratify by the four outpatient's clinic). The dyads will be randomised into two groups 1) receive the intervention (standard care plus ParTNer-STEPs until their child´s transfer to adult care) or 2) standard care (control group). Once the database has defined a dyad's allocation, no changes can be made. Those randomised to the intervention arm will then receive access to the intervention materials.

SAMPLE-SIZE No previous studies have focused on whether it´s possible to increase parents´ transition readiness score (TR) by offering them a transfer program. A previous cross-sectional study found that parents of chronically ill adolescents have an average TR score of 3.12 (SD 0.68). Based on our clinical experience, advice from the author of the primary outcome questionnaire, and a review of each item in the questionnaire (Medical self-management and transition readiness), the investigators assume that it will be possible to increase the parents' TR score in the intervention group with 0,5 points.

The investigators are planning an RCT study with a continuous response variable from an independent control- and intervention group with 1 control(s) per intervention subject. Based on a previous study the investigators assume the response within each group will be normally distributed with standard deviation 0.68. If the true difference in the intervention and control means is 0.50, the investigators will need to include parents of 31 individual adolescents in each group to be able to reject the null hypothesis that the population means of the intervention and control groups are equal with probability (power) 0.80. The Type I error probability associated with this test of this null hypothesis is 0.05. Thus, the investigators need to recruit a total of parents of at least 62 individual adolescents.

SETTING The intervention will be carried out at the nephrology, hepatology, neurology and rheumatology paediatric and adult outpatient clinics at Copenhagen University Hospital, Rigshospitalet, Denmark. The investigators have chosen these four specialties, because low treatment adherence and non-attendance in the patient group could result in permanent disabilities or critical consequences. In Denmark adolescents transfer to adult care when turning 18 years old regardless of the adolescent's maturity or transitional readiness. Each paediatric clinic has at least one youth ambassador (a nurse with special interest and training in adolescent medicine). The existing transitional care includes youth consultations using the split-visit model and assessment of adolescent transition readiness. The clinics currently have no programmes targeting parents.

ETHICS The project will adhere to the regulations established by the Ethical Guidelines for Nursing Research in the Nordic Countries, all relevant laws and regulations in Denmark, and to the Declaration of Helsinki II and is approved by the Danish Data Protection Agency, reference no. VD-2018-396.

The investigators have formally enquired the regional research ethics committee with a full clinical description of the project. They have reviewed the project and given us permission to perform the study (reference no. FSP 20031083).

According to Danish legislation studies such as register research projects, interview surveys and questionnaire surveys can be performed without formal ethical approval cf. section 1 and 2 in the committee law as no human biological material is included.

Before obtaining consent from the parents, the investigator will provide all participants with oral and written information of the study, including the fact that they can withdraw from the study at any time without consequences for their child's treatment. The investigators will carefully consider the risk of coercion, autonomy, and confidentiality.

DATACOLLECTION Data will be collected though questionnaires at baseline and every six months up to three months after the adolescent's transfer to adult care. Questionnaires will be sent out via email or by post based on participants´ wishes.

DATA MANGEMENT All data will be handled confidential and stored in the password protected software REDCap.

DATA ANALYSIS A detailed statistical analysis plan (SOP) will be developed when all participants have completed the final measurement (six months after the completed intervention) in collaboration with statisticians. The investigators plan to include t tests, Pearson's Chi-square test, regression analysis, intention to treat and linear models. Logistic regression analyses will be carried out to describe transition readiness and allocation of responsibility within the intervention group and compare it to the control group's score. Socio-demographic data and the parents' uncertainty-score will be considered as variables. The SOP will be confirmed among all project group members before the investigators will be looking into data.

MISSING DATA, DROP OUT AND LOST TO FOLLOW UP Loss to follow-up and missing data for various reasons is impossible to avoid in randomized trials. The investigators will apply the analysis framework in which missing data related to the intention-to-treat approach depend on making plausible assumptions about the missingness of the data and including all participants in subsequent sensitivity analyses.

1. Attempt to follow up all randomized parents, even if they withdraw from allocated treatment.
2. Perform a main analysis of all observed data that are valid under a plausible assumption about the missingness of the data (i.e., Model-based: data as observed; using linear mixed effects models, assuming that data are 'Missing at Random' [MAR]).
3. Perform sensitivity analyses to explore the effect of departures from the assumption made in the main (#2) analysis (i.e., a non-responder-imputation: using the value at baseline to replace missing data will correspond to a non-responder imputation; these models will potentially be informative even if data are 'Missing Not At Random' [MNAR]).
4. Account for all randomized parents, at least in the sensitivity analyses (covered by #2 and #3 above, plus the corresponding analyses based on the per protocol population).

The interpretation of the corresponding statistical measures of uncertainty of the treatment effect and treatment comparisons will involve consideration of the potential contribution of bias to the P-value, 95% confidence interval, and of the inference in general.

Our primary analysis population will be all parents with available data at baseline, statistically modelled using repeated-measures linear mixed effects models (see above). These models will be valid if data are 'MAR'.

Sensitivity: The investigators will analyze all variables, with missing data being handled by multiple imputation techniques. When the different sensitivity analyses agree, and the analyses on the sensitivity analyses and the main analysis lead to essentially the same conclusions, confidence in the trial results is increased.

Inclusion Criteria:

Parents, stepparents or guardians of chronically ill adolescents, who

• are aged 16.5-17.5 years (can be recruited up to six months before transfer)
• have been diagnosed for minimum six months
• have regular check-ups at the Department of Paediatrics and Adolescent Medicine's nephrology, hepatological, neurological and rheumatological outpatient clinics at Rigshospitalet, Denmark.
• are transferred to an adult hospital department
• are mentally and cognitively able to take responsibility for their own treatment

Exclusion Criteria:

• Parents who do not read and speak Danish
• Parents of adolescents who will be transferred to their family doctor at the age of 18 year.

Full dataset to replicate the analysis will be available from the corresponding author on reasonable request until five years after completion of the study, according to Danish law.