A randomised controlled trial of clinical and cost-effectiveness of the PASS Plus intervention for young children with autism spectrum disorder in New Delhi, India: study protocol for the COMPASS trial

Background Autism Spectrum Disorder (ASD) is a neurodevelopmental disability affecting at least 5 million children in South Asia. Majority of these children are without access to evidence-based care. The UK Pre-school Autism Communication Therapy (PACT) is the only intervention to have shown sustained impact on autism symptoms. It was systematically adapted for non-specialist community delivery in South Asia, as the 'Parent-mediated Autism Social Communication Intervention for non-Specialists (PASS)' and extended 'PASS Plus' interventions. RCTs of both showed feasibility, acceptability and positive effect on parent and child dyadic outcomes. Methods The Communication-centred Parent-mediated treatment for Autism Spectrum Disorder in South Asia (COMPASS) trial is now a scale-up two- centre, two-arm single (rater) blinded random allocation parallel group study of the PASS Plus intervention in addition to treatment as usual (TAU) compared to TAU alone, plus health economic evaluation embedded in the India health system. Two hundred forty children (approximately 120 intervention/120 TAU) with ASD aged 2-9 years will be recruited from two tertiary care government hospitals in New Delhi, India. Accredited Social Health Activists will be one of the intervention delivery agents. Families will undertake up to 12 communication sessions over 8 months and will be offered the Plus modules which address coexisting problems. The trial's primary endpoint is at 9 months from randomisation, with follow-up at 15 months. The primary outcome is autism symptom severity; secondary outcomes include parent-child communication, child adaptation, quality of life and parental wellbeing. Primary analysis will follow intention-to-treat principles using linear mixed model regressions with group allocation and repeated measures as random effects. The cost-effectiveness analysis will use a societal perspective over the 15-month period of intervention and follow-up. Discussion If clinically and cost-effective, this programme will fill an important gap of scalable interventions delivered by non-specialist health workers within the current care pathways for autistic children and their families in low-resource contexts. The programme has been implemented through the COVID-19 pandemic when restrictions were in place; intervention delivery and evaluation processes have been adapted to address these conditions.