SPD (Severity–Phenotype–Dynamics) Multiaxial Staging System for Idiopathic Pulmonary Fibrosis

The SPD system (Severity–Phenotype–Dynamics) was developed within the Assiut University IPF Research Program (2022–2026) as a structured multiaxial staging framework for idiopathic pulmonary fibrosis (IPF).

SPD integrates three independently derived and prospectively locked components to construct a unified disease-state architecture: Severity (S), Phenotype (P), and Dynamics (D).

The framework enables longitudinal state-space classification across predefined coordinate combinations without recalibration, refitting, smoothing, interpolation, or structural modification.

SPD represents a probabilistic staging architecture derived from longitudinal transition behavior under fixed governance constraints. It does not constitute a deterministic prediction model and does not replace clinical judgment.

The system was prospectively locked as Version 1 in August 2024 following completion of structural validation, transition-matrix freeze, and architectural consolidation under the governance doctrine of the Assiut University IPF Research Program.

No recalibration, reclassification, threshold retuning, structural alteration, or derivative staging modification is permitted outside formally declared future versions.