Background
Early onset psychosis (EOP, onset before age 18 years) is considered grave and may have worse outcomes compared to adult onset psychosis [
1,
2]. In adults, antipsychotics have proven more effective than placebo in improving psychotic symptoms and preventing relapse [
3,
4] and comparisons of benefits and harms of different antipsychotic drugs have been assessed in large meta-analyses [
5,
6]. In children and adolescents with EOP, placebo-controlled trials and, especially, active-controlled trials are limited [
7‐
10].
Seven primarily industry-sponsored randomised placebo-controlled trials covering a total of 1198 children and adolescents with schizophrenia have been published: six trials investigated effects of the second-generation antipsychotics (SGAs) aripiprazole [
11], olanzapine [
12], risperidone [
13], paliperidone [
14], quetiapine [
15], and ziprasidone [
16] in adolescents with schizophrenia. One trial compared the first-generation antipsychotic (FGA) haloperidol with placebo in children with schizophrenia [
17]. Six of these seven trials showed superiority of the antipsychotic compared with placebo. The ziprasidone trial was terminated due to lack of efficacy. Only 12 randomised clinical trials (RCTs) compared different antipsychotics in the treatment of EOP. Five RCTs were open-label head-to-head studies investigating olanzapine versus (vs) risperidone (n = 44, including adolescents and young adults aged 16-28 years) [
18]; risperidone vs olanzapine vs quetiapine (n = 30) [
19]; olanzapine vs quetiapine (n = 50) [
20]; quetiapine vs risperidone (n = 22) [
21]; and olanzapine vs risperidone (n = 25) [
22]. Six RCTs were double-blind, head-to-head trials investigating clozapine vs haloperidol (n = 21) [
23]; clozapine vs olanzapine (n = 39) [
24]; clozapine vs olanzapine (n = 25) [
25]; risperidone vs olanzapine vs haloperidol (n = 50, including both non-affective and affective psychotic disorders) [
26]; olanzapine vs risperidone vs molindone (n = 119) [
27]; and a double-blind RCT (n = 126) comparing paliperidone vs aripiprazole [
28]. One older RCT assessed thiothixene vs thioridazine (n = 21) [
29]. Across these trials, only clozapine has shown superiority compared with other antipsychotics (haloperidol or olanzapine) when used for treatment-resistant early onset schizophrenia [
23‐
25]. Each of these head-to-head RCTs included small to medium size patient samples (total n = 572). In comparison, a recent meta-analysis of antipsychotic drugs in adult schizophrenia included data from 43,049 patients [
6]. It is problematic that the use of antipsychotics in EOP to a large extent is based on extrapolations from trials conducted in adults, considering that the prevalence of adverse reactions and treatment resistance may be higher in children and adolescents [
20,
30‐
32].
Outcome of antipsychotic treatment in psychosis is typically assessed with validated psychopathology scales and unsolicited adverse effect reporting, supplemented with usually few validated adverse events scales and some physical health parameters. However, other potential outcomes are also relevant for the prognosis of EOP, including cognitive deficits [
33‐
41] and health-related quality of life (HRQoL) [
42]. It has been difficult to observe consistent effects of antipsychotics on these outcomes in adults [
38,
39,
43‐
45], and in the few studies conducted in EOP [
46‐
50].
The Food and Drug Administration (FDA) has approved the use of quetiapine and aripiprazole in the treatment of schizophrenia from age 13 years, but no trials have compared the two drugs in EOP [
51]. Here, we present the trial protocol of an investigator-initiated and independently funded RCT comparing the effects of quetiapine vs aripiprazole in EOP.
Objectives
The primary objective of the TEA (Tolerability and Efficacy of Antipsychotics) trial is to compare quetiapine vs aripiprazole in the treatment of EOP with regards to efficacy (psychopathology, cognition, HRQoL) and tolerability (motor adverse events (AEs); metabolic AEs; hormonal AEs; cardiac AEs, suicidal ideation; and other AEs) in a randomised, blinded design.
Hypotheses
The TEA trial tests the null hypothesis that there are no significant differences between quetiapine vs aripiprazole in EOP after 12 weeks of treatment on the primary outcome, Positive and Negative Syndrome Scale (PANSS) positive symptoms (PANSS-P) [
52]. Due to different receptor profiles and prior data [
7,
8,
11,
15] we expect specific differences in secondary outcomes primarily reflected in adverse effect assessments with aripiprazole causing more akathisia than quetiapine; and quetiapine causing more sedation, weight gain, and metabolic adverse effects than aripiprazole.
Methods/Design
RCT design
The TEA trial is a Danish investigator-initiated, independently funded, randomised, blinded, multi-centre superiority trial. Patients (n = 112) are randomised to a 12 weeks intervention period with quetiapine vs aripiprazole.
Participants
Patients are recruited from seven child- and adolescent mental health centres covering all Danish university clinics nationwide (University Hospitals of Copenhagen (4 centres), Southern Denmark (1 centre), Aarhus (1 centre), and Aalborg (1 centre)).
Patient inclusion criteria
Inclusion criteria: 1) Children and adolescents aged 12-17 years (both inclusive), both sexes; 2) in- or outpatients; 3) meeting the criteria for ICD-10 [
53] psychosis diagnoses (non-organic, non-drug-induced): F20 (Schizophrenia), F22 (Persistent delusional disorders), F23 (Acute and transient psychotic disorders), F24 (Induced delusional disorders), F25 (Schizoaffective disorders), F28/F29 (Other/Unspecified nonorganic psychosis), F30.2 (Mania with psychotic symptoms), F31.2 (Bipolar affective disorder, current episode manic with psychotic symptoms), F31.5 (Bipolar affective disorder, current episode severe depression with psychotic symptoms), F32.3 (Severe depressive episode with psychotic symptoms), or F33.3 (Recurrent depressive episode, current episode severe with psychotic symptoms). The diagnosis is verified by Schedule for Affective Disorders and Schizophrenia for School-Age Children Present and Lifetime version (K-SADS-PL) 4 weeks after inclusion into the trial [
54]; 4) clinical indication for antipsychotic treatment; 5) presence of psychotic symptoms scoring ≥4 on at least one of the following PANSS items: P1 (delusions), P2 (conceptual disorganisation), P3 (hallucinations), P5 (grandiosity), P6 (suspiciousness/persecution), or G9 (unusual thought content); as well as a total PANSS score >60 points; 6) antipsychotic-naïve or limited exposure (i.e., no more than 12 months in the past year for psychosis, or no more than 1 week lifetime for any non-psychotic indication); and 7) written informed consent by caretakers.
Patient exclusion criteria
Exclusion criteria: 1) Compulsory treatment; 2) drug-induced or organic psychosis; 3) severe chronic somatic illness or a history of severe head trauma; 4) pregnancy or lactation; 5) substance dependence (ICD-10 F1X.2 dependence syndrome) within the last year; 6) allergy towards the investigational drugs or lactose intolerance; 7) lack of informed consent.
Randomisation and blinding
Randomisation of patients to treatment is carried out centrally by the Copenhagen Trial Unit at the Capital Region Pharmacy using a computer-generated allocation sequence with a block size unknown to the investigators. To optimise the comparability between treatment groups, randomisation is stratified by two factors: PANSS-P score (i.e., ≤20 points or >20 points), and age (i.e., 12-14 years or 15-17 years). Computer-generated and sealed allocation sequence lists are prepared according to the stratification variables and the trial medication packages are distributed accordingly. The interventions are blinded to participants, caregivers, outcome assessors, statisticians, conclusion drawers, as well as all investigators and staff involved in the trial, except for the pharmacy personnel who pack and distribute the two study drugs and the data managers at the Copenhagen Trial Unit.
Interventions and assessments
During the first 9 days, the assigned antipsychotic is uptitrated in fixed dose steps, with slower titrations and dose adjustments if clinically indicated (see below). The target doses are quetiapine 600 mg/day vs aripiprazole 20 mg/day. However, if needed, dosing is flexible (quetiapine: 50-800 mg/day; aripiprazole 2.5-30 mg/day). Beneficial and harmful effects are assessed at three time points during the intervention period, i.e., weeks 2, 4, and 12.
Post-randomisation exclusions
Patients are excluded if there is a significant worsening of their clinical state during the course of the trial (i.e., increases of 20% or more from baseline on the PANSS total score).
Outcomes
The primary outcome is positive symptoms measured on the PANSS-P scale. Secondary outcomes are 1) other psychopathology measures assessed on PANSS negative and general scales; Dimensions of Psychosis Instrument (DIPI) [
55]; Clinical Global Impressions - Severity/Improvement/Efficacy (CGI-S/I/E) [
56]; Global Assessment of Psychosocial Disability (GAPD) [
53]); 2) cognition and cognitive daily functioning measured on Brief Assessment of Cognition in Schizophrenia (BACS) Global Score [
57]; Schizophrenia Cognition Rating Scale, Danish version (SCoRS-DK) [
58]; Behavioural Rating Inventory of Executive Functions (BRIEF) [
59]); 3) HRQoL measured on KIDSCREEN-52 [
60]; 4) adverse reactions measured on ‘Udvalget for Kliniske Undersøgelser’ Side Effect Rating Scale (UKU) [
61]; Abnormal Involuntary Movement Scale (AIMS) [
62]; Simpson Angus Scale (SAS) [
63]; Barnes Akathisia Rating Scale (BARS) [
64]; cardiac adverse reactions (such as QT-interval prolongation on Electrocardiography (ECG)); somatic events (blood pressure, pulse, body weight, height, body mass index, abdominal circumference, abnormal laboratory test results (fasting blood glucose, insulin and lipid levels, prolactin, other general blood tests)); suicidal ideation measured by K-SADS-PL (specific items); adherence (daily registration by caretakers or staff and antipsychotic blood levels); substance use (interview and urine testing) (Table
1).
Table 1
TEA RCT, schedule for outcome assessments during 12 weeks of blinded intervention
Psychopathology and adverse reactions rating scales PANSS, DIPI, CGI-S, CGI-I, CGI-E, GAPD, UKU, AIMS, SAS, and BARS | X | X | X | X |
Suicidal ideation K-SADS-PL specific items | X | X | X | X |
Cognition, cognitive daily and executive function BACS, SCoRS-DK and BRIEF | X | | | X |
Somatic examination Standard clinical examination, blood pressure, pulse, weight, height, BMI, and abdominal circumference. | X | X | X | X |
Health-related quality of life Questionnaire: KIDSCREEN-52 | X | | | X |
Laboratory tests (see list below) | X | | X | X |
Antipsychotic drugs
Quetiapine and aripiprazole
Quetiapine is a low-affinity dopamine D2 receptor antagonist [
65]. Aripiprazole has a high affinity for dopamine D2 receptors but with a partial agonist mode of action at this receptor [
66]. Both compounds are approved by FDA and the European Medicines Agency (EMA) for the treatment of schizophrenia in adults. Aripiprazole is approved by the FDA for use in schizophrenia for ages 13-17 years, and in Denmark and the rest of the EU it has obtained authorisation for use in adolescent schizophrenia for ages of 15-17 years by the EMA [
67]. Quetiapine has FDA approval for the treatment of schizophrenia for ages 13-17 years, but it has not been approved by EMA for use below age 18 years. In the present trial, quetiapine and aripiprazole were selected since these compounds are frequently used in clinical child and adolescent psychiatric practice, and because it remains unclear whether their different receptor binding profiles can be related to differences in clinical outcomes in EOP. In adults, a recent Cochrane systematic review found no significant differences between quetiapine vs aripiprazole (global state (n = 991, 12 RCTs); PANSS-P (n = 583, 7 RCTs); leaving the study early for any reason (n = 168, 2 RCTs), or general extra pyramidal symptoms (n = 348, 4 RCTs); all low to very low quality evidence). Results were significantly in favor of aripiprazole regarding Quality of Life (n = 100, 1 RCT, mean difference 2.60, 95% CI 1.31 to 3.89), however, evidence was rated very low quality [
51]. Notably, all studies were conducted in China and in adult Chinese patients. Currently, no single Western RCT has compared quetiapine with aripiprazole either in adults or in children and adolescents.
Quetiapine and quetiapine extended release
Studies have shown that quetiapine 200-800 mg/day improves psychotic symptoms in patients with EOP (age 11-17 years) [
68], and 300-800 mg/day showed acceptable long-term (88 weeks) safety and tolerability (n = 10, age 12-16 years [
69]). Patients aged 10–17 years (n = 27) tolerated quetiapine doses of 400 mg twice daily, with no serious AEs and no unexpected events reported, and compared to a parallel adult population there were similar pharmacokinetic, safety, and tolerability profiles by dose escalation, suggesting that no dosage adjustment is required when treating patients of these ages [
70]. One 6-week, double-blind, placebo-controlled RCT of quetiapine 400 or 800 mg/day in 220 adolescents with schizophrenia aged 13-17 years found significant improvements in PANSS total score changes at both quetiapine doses compared with placebo, and quetiapine was generally well tolerated with a profile broadly similar to that reported in adult populations [
15]. A 12-week open label study of quetiapine in 56 adolescents with schizophrenia spectrum disorder found a significant reduction of PANSS total and particularly positive symptom scores [
71]. It is generally assumed that younger patients require lower doses of antipsychotics than adults. However, for quetiapine this may be true for younger children with lower body weight, but adolescents typically require rapid titration to the same, or even higher, dose levels than adults for optimal clinical response [
32]. Higher doses of quetiapine than those recommended by the compound producer have proven to be effective and safe in adolescents [
26]. Extended release quetiapine allows a once-daily dosing and has been proven effective and well tolerated in adults with schizophrenia in a randomised, placebo-controlled trial [
72]. This formulation will be used in the present trial in order to match the once a day dosing of aripiprazole.
We use a 9-day fixed titration phase with a final quetiapine extended release dose of 600 mg/day (Table
2). If needed for efficacy, the possible maximum dose can be titrated up to 800 mg/day, or titrated down to a lower dose level if not tolerated (minimum 50 mg/day).
Table 2
Schedule of dosing regimen
Day
|
1
|
2
|
3
|
4
|
5
|
6
|
7
|
8
|
9
|
…
|
Quetiapine ER (mg)
| 50 | 50 | 100 | 100 | 200 | 200 | 400 | 400 | 600 | 800 |
Aripiprazole (mg)
| 2.5 | 2.5 | 5 | 5 | 10 | 10 | 15 | 15 | 20 | 30 |
Number of capsules
| 1 | 1 | 2 | 2 | 1 | 1 | 2 | 2 | 3 | 4 |
Quetiapine ER:
|
●
|
●
|
●●
|
●●
|
●
|
●
|
●●
|
●●
|
●●●
|
●●●●
|
Aripiprazole:
|
●
|
●
|
●○
|
●○
|
●
|
●
|
●○
|
●○
|
●●○
|
●●○○
|
Aripiprazole
The safety of aripiprazole used in children and adolescents from the age of 7 years has mainly been documented in open-label or naturalistic studies of disorders other than psychosis, i.e., Tourette’s syndrome or developmental disorders, using doses in the mean range of 5-17 mg/day [
73‐
78]. A double-blinded multi-centre RCT compared aripiprazole 10 mg/day and 30 mg/day with placebo in 302 adolescents (aged 13-17 years) with schizophrenia [
11]. The trial authors concluded that 6 weeks treatment with aripiprazole was generally well tolerated and lead to significant improvements in psychotic symptoms compared with placebo. An open-label trial with 21 patients aged 10-17 with bipolar or schizophrenia spectrum disorders compared daily doses of 20, 25 or 30 mg aripiprazole in a 12-days titration phase, followed by a 14-days fixed dose phase. Effectiveness and criteria for tolerability were met for all doses, and no adverse reactions met the regulatory criteria for serious adverse reactions [
79].
We use a 9-day fixed titration phase with a final aripiprazole dose of 20 mg/day (Table
2). If needed for efficacy, the possible maximum dose can be titrated up to 30 mg/day. If final doses are not tolerated, patients can be titrated down to a lower dose level (minimum 2.5 mg/day).
Concomitant medications
Patients will not be allowed any concomitant antipsychotic medication before all trial assessments at week 12 have been conducted. Concomitant medication of any kind beyond trial medications will be recorded throughout the trial intervention period.
Sample size estimation
The sample size estimation is based on the primary outcome measure, the PANSS-P score. In 2009, when the TEA trial was designed, the estimated standard deviation (SD) for PANSS-P was based on the few studies that up until then had investigated efficacy of the trial drugs (quetiapine or aripiprazole) in patients below 18 years of age with psychosis [
11,
20,
71]. The three studies reported mean PANSS-P in patients treated with quetiapine or aripiprazole with SDs ranging from 4.1 to 7.4, or standard error (SE) for change of PANSS-P from entry to end of treatment of around 0.6 (corresponding to SD = 5.9). Furthermore, in our previous case-control study of patients comparable to the TEA participants, consisting of Danish minimally medicated children and adolescents with psychosis aged 12-18 years, the SD of PANSS-P at the time of first-episode psychosis was within the above range, SD = 5.1 [
80,
81]. Consequently, we used a conservative estimate of the (at that time) highest reported SD of 7.4 in the original sample size estimation. Since then, however, more studies on aripiprazole and quetiapine in early onset psychosis point toward lower SDs on the PANSS-P ranging from 4.3 to 6.3 [
15,
21,
28] (see all relevant studies in Table
3). A weighted mean SD of PANSS-P based on data from all 6 studies in Table
3 equals 5.48 for all SDs, and 5.68 for SDs of change scores. Hence, based on the entirety of the available data, we updated our sample size calculation based on a SD of 5.7 on the PANSS-P scale.
Table 3
Data from trials on quetiapine or aripiprazole in patients below 19 years with psychosis used for final power calculation
Schimmelman et al. 2007 [ 71] | Open Label | Quetiapine | N=52 | Quetiapine: | Quetiapine: | Quetiapine: |
Non-RCT |
12 weeks | 200-800 mg | | 21.4 (5.2) | 14.5 (7.4) | -6.9 (na) |
Schiz. spectrum |
Most drug-naïve |
12-17 years |
Findling et al. 2008 [ 11] | Double-blind RCT 6 weeks | Aripiprazole 10 mg/30 mg vs placebo | N=302 (100 vs 100 vs 102) | Aripiprazole 10 mg: 22.1 (SD=5.0) | Aripiprazole 10 mg: 14.5 (SE=0.6 i.e. SD=6.0*) | Aripiprazole 10 mg: -7.6 (SE=0.6 i.e. SD=6.0*) |
Schiz. 13-17 years |
Aripiprazole 20 mg: 23.5 (SD=5.0) | Aripiprazole 20 mg: 15.4 (SE=0.6 i.e. SD=5.9*) | Aripiprazole 20 mg: -8.1 (SE=0.6 i.e. SD=5.9*) |
| Open label RCT | Quetiapine vs Olanzapine | N=50 | Quetiapine: | Quetiapine: | Quetiapine: |
6 months | (24 vs 26) | 23.3 (7.3) | 15.1 (4.1) | -8.2 (na) |
Psychotic disorders |
Most drug-naïve | flexible doses |
12-18 years |
| Open label RCT | Quetiapine up to 800 mg vs risperidone up to 6 mg | N=22 | na | na | Quetiapine: |
6 weeks | (11 vs 11) | -9.6 (5.5) |
First episode |
psychosis |
Below 19 years |
Findling et al. 2012 [ 15] | Double-blind RCT | Quetiapine 400 mg/800 mg vs placebo | N=220 (73 vs 74 vs 73) | Quetiapine 400 mg: 23.3 (5.8) Quetiapine 800 mg: 23.8 (4.8) | na | Quetiapine 400 mg: |
6 weeks Schiz. | -8.6 (SE 0.7, i.e. SD=6.3*) |
13-17 years | Quetiapine 800 mg: |
-9.3 (SE 0.6, i.e. SD=5.1*) |
| Double-blind RCT | Paliperidone ER 3-9 mg vs Aripiprazole 5-15 mg | N=226 (112 vs 114) | Aripiprazole: 22.5 (4.3) | na | Aripiprazole week 8: |
8 weeks/26 weeks | -6.2 (4.9) |
Schiz. | Aripiprazole week 26: |
12-17 years | -8.3 (6.1) |
Based on results from a 24 weeks RCT comparing olanzapine with quetiapine that found a mean difference in PANNS-P scores of 4 points in favour of olanzapine (a difference that did not reach significance probably due to the small group size of 25 patients each) [
20], we decided that a minimal clinically relevant difference between outcome responses of quetiapine vs aripiprazole after (the shorter period of) 12 weeks of treatment would be 3 points on the PANSS-P. Hence, using a power of 80% and a two-sided alpha of 5%, and expecting a SD of 5.7 on the PANSS-P, the required sample size necessary to detect or reject a difference of at least 3 points on PANSS-P was estimated as follows (N = total sample size, SD of the primary outcome measure = 5.7 (we assume SD
1 = SD
2), α = type 1 error = 0.05, β = type 2 error = 0.20, MIREDIF = minimal relevant difference of outcome measure = 3, z = fractiles in normal distribution):
N = 2 * (SD
1
2
+ SD
2
2
) * (z
α/2
+ z
β
)/MIREDIF
2
= 112. Accordingly, we should strive to include a total of 112 patients, equivalent to about 56 patients in each of the intervention groups.
Data analysis
Data will be blinded during the analysis, and the blinding will not be broken before two conclusions are drawn (i.e., the first assumes treatment A to be quetiapine and treatment B to be the aripiprazole; the second is based on the reverse assumption, i.e., that treatment A is aripiprazole and B is quetiapine) [
82]. A detailed protocol for the statistical analysis plan will be presented in a separate paper. In short, the primary analysis will be according to the modified intention-to-treat principle [
83] with adjustment for the protocol specified stratification variables [
84]. Data missingness will be investigated and if deemed necessary, generally when missingness is not completely at random, a suitable multiple imputation method will be used [
85‐
92]. The data will be analysed with a two-sided statistical testing and p-values will be assessed at a significance level of 5% with correction for multiple testing according to Holm [
93]. Covariates considered relevant to adjust for in comparative analysis will be incorporated in the statistical model. We aim at analysing the data as trajectories including multiple assessments whenever possible.
Ethical considerations
As the trial is investigating medicinal products and the participants are under 18 years of age, a surrogate written informed consent is required from the holders of custody. The trial is registered at ClinicalTrials.gov: NCT01119014, EudraCT: 2009-016715-38, and approved by Danish Medicines Agency: 2612-4168, The Ethics Committee of Capital Region: H-3-2009-123 and Danish Data Protection Agency: 2009-41-3991. All procedures for registering and reporting adverse reactions and adverse events will follow the regulations and guidelines from the Danish Health and Medicines Authority and the Ethics Committee.
Competing interests
The authors Anne Katrine Pagsberg (AKP), Pia Jeppesen (PJE), Dea Gowers Klauber (DGK), Karsten Gjessing Jensen (KGJ), Ditte Rudå (DRU), Marie Stentebjerg-Olesen (MSO), Peter Jantzen (PJA), Simone Rasmussen (SRA), Eva Ann-Sofie Saldeen (EAS), Maj-Britt Glenn Lauritsen (MGL), Niels Bilenberg (NBI), Jesper Pedersen (JPE), Louise Nyvang (LNY), Sarah Madsen (SMA), Marlene B. Lauritsen (MBL), Ditte Lammers Vernal (DLV), Jacob Paludan (JPA), Thomas M. Werge (TMW), Kristian Winge (KWI), Klaus Juul (KJU), Christian Gluud (CG), Maria Skoog (MS), Jørn Wetterslev (JW), Jens Richardt M. Jepsen (JRJ), Birgitte Fagerlund (BFA) declare that they have no competing interests. Anders Fink-Jensen (AFJ) conducts an independent investigator- and university-initiated study supported by an unrestricted grant from Novo Nordisk. Christoph U. Correll (CC) has been a consultant and/or advisor to or has received honoraria from: Actelion, Alexza, Bristol-Myers Squibb, Cephalon, Eli Lilly, Genentech, Gerson Lehrman Group, IntraCellular Therapies, Janssen/J&J, Lundbeck, Medavante, Medscape, Merck, Otsuka, Pfizer, ProPhase, Roche, Sunovion, Supernus, Takeda, and Teva. He has received grant support from the American Academy of Child and Adolescent Psychiatry, BMS, Janssen/J&J, National Institute of Mental Health (NIMH), Novo Nordisk A/S, Otsuka, and the Thrasher Foundation, Anne Dorte Stenstrøm (ADS) has received honoraria from Otsuka. Per Hove Thomsen (PHT) has received speaker’s honoraria from Novartis, Shire, Medice and Janssen.
Authors’ contributions
AKP, the study sponsor, has initiated the study and made important contributions to the study conception, design and protocol, and has led the manuscript drafting. BFA initiated and created the primary study protocol, made important contributions to the study conception and design, and has been involved in drafting and critically revising the manuscript. PJA, AFJ, CC, DGK, KGJ, DRU, MSO, CG, MS, JW, and JRJ have contributed significantly to the study conception, design and protocol, and have been involved in drafting and critically revising the manuscript. EAS, TMW, KWI, KJU, PJA, SR, MGL, NBI, ADS, JPE, LNY, SMA, MBL, DLV, PHT, and JPA have contributed to the study conception and in critically revising the manuscript. All authors approved the final version of the manuscript.