Multicenter Mixed-Methods Pilot Study Evaluating a Personalized Care Management Model (GAP-421) for Chronic Pain in Primary Care Physiotherapy: Feasibility, Care Coordination, and Patient-Reported Outcomes

BACKGROUND:

Primary care faces a structural mismatch between the growing complexity of patients with chronic pain and an organizational architecture designed for acute episodes and independent schedules. International guidelines (NICE NG193, WHO 2023) recommend multimodal approaches with a function-centered focus consistent with physiotherapy competencies, yet interprofessional coordination relies on unrecognized informal work, generating hidden workload, care fragmentation, and inappropriate transfer of organizational responsibilities to patients.

The Burden of Treatment Theory and Cumulative Complexity Model explain that when organizational burden exceeds patient capacity, the result is organizational design failure rather than patient non-adherence. Recent evidence from the Community of Madrid (Izquierdo Enriquez et al., 2026) revealed a striking paradox: 72.8% of primary care physicians consider education and exercise superior to pharmacological treatment, yet 62.8% still consider opioids effective for chronic non-cancer pain, illustrating the gap between declarative adherence to biopsychosocial approaches and pharmacologically-dominated practice.

THE GAP MODEL:

The GAP (Personalized Care Management) model proposes a time-limited functional modality that reconfigures the interaction between schedules, resources, and professionals so that care is organized around a specific person and their trajectory. It operates through four features: temporality (activates and deactivates), reconfiguration (reorganizes existing resources without creating parallel structures), person-centeredness (designed from the patient trajectory), and organizational legitimacy (converts invisible coordination into explicit, recorded, and evaluable work).

INTERVENTION:

The GAP-421 model operates on Service 421 (chronic pain) of the Primary Care Service Portfolio of the Community of Madrid through a 6-week window structured in four phases:

• Day 0 (Activation): Lead physiotherapist identifies 2 or more organizational mismatch signals. Documented in standardized GAP Activation Form.
• Week 1 (Characterization): Concentrated comprehensive assessment. Protected non-face-to-face coordination time. Classification of functional status, burden-capacity profile, shared clinical message.
• Weeks 2-4 (Intervention): Therapeutic education, graded exercise, pharmacological adjustment if indicated. Aligned messages across professionals. Exercise plan with adherence monitoring.
• Weeks 4-6 (Closure): Semi-annual plan with milestones, de-escalation criteria, return to standard circuit. Follow-up plan, reactivation signals, patient feedback.

Key organizational changes include: physiotherapist schedule incorporating comprehensive GAP assessment slot (45-60 min), weekly protected interprofessional coordination time (15-20 min), and closure session (30-40 min); family physician allocating 5-15 min/week for coordination and message alignment; nursing conducting socio-familial assessment when indicated.

THEORETICAL FRAMEWORK:

The study is grounded in Normalization Process Theory (NPT), Burden of Treatment Theory, and the GAP conceptual model.

SAMPLE SIZE:

n=66 patients (22 per center) calculated with design effect correction (DEFF=2.05, ICC=0.05, effect size d=0.60, 20% attrition).

ANALYSIS:

Quantitative: Wilcoxon/paired t-tests, exploratory multilevel mixed models (patients nested within centers), Cohen's d with 95% CI. R v4.3.

Qualitative: Reflexive thematic analysis with inductive-deductive coding using NPT constructs. Atlas.ti v24.

Integration: Joint Display convergence matrix, Pillar Integration Process, Onwuegbuzie and Johnson 9-type legitimation framework. Quality: MMAT 2018, GRAMMS checklist.