Six-Month Change and Follow-up Patterns in AbilityScore During Routine Paediatric Developmental Care in India: Protocol for the PINNACLE-TRAJ Retrospective Multicentre Cohort Study

Study protocol with statistical analysis plan. Version 1.1. Preprint; not peer reviewed. BHCL-RET-2026-001. Background: Repeated developmental assessments collected during routine care can describe change and gaps in reassessment across a service network. Their interpretation depends on comparable measurement over time and inclusion of children who do not return. A clearly defined cohort and transparent analysis of missing follow-up are needed to characterize changes in AbilityScore, a developmental index recorded in paediatric services. Objective: To estimate mean change in AbilityScore between baseline and a prespecified six-month assessment window in a baseline-defined cohort, and to describe the availability and characteristics of follow-up. Secondary objectives concern longer-term scores, recorded developmental domains and associations with baseline characteristics. Methods: PINNACLE-TRAJ is a planned retrospective observational study of routine records from eligible Pinnacle Blooms Network centres in India. The proposed database close is 30 June 2026. A documented comparable scoring era and eligible centres will be fixed from deployment and measurement records before outcome inspection. Children aged under 13 years at their first eligible baseline will enter the cohort without any requirement for a subsequent visit. Baselines must permit the full 150–210-day primary window; with the proposed close, the latest permissible baseline is 2 December 2025. The primary endpoint is the comparable score nearest day 180 within that window. Mean within-child change will be estimated with multilevel multiple imputation under a stated missing-at-random assumption and centre-aware uncertainty. Observed-case, weighting and missing-not-at-random analyses will assess sensitivity. Postbaseline care exposure will not define cohort membership or the primary contrast. Results: Ethics review, study registration and selection of the final scoring era are pending. The eligible cohort size will be established after the required approvals and deployment review. This protocol reports the planned study; results are not yet available for publication. Conclusions: The study is intended to describe score change and reassessment patterns within an eligible service population. Its uncontrolled design cannot estimate treatment effectiveness, isolate an AI contribution, establish an important clinical difference or provide population developmental norms. Files include the full protocol and statistical analysis plan in PDF and editable Word, blank reporting templates, and supplementary study-design figures. This repository publication is not an ethics approval or a clinical-trial registry entry.