Chronic back pain (CBP) is defined as back pain that persists for more than 3 months and is associated with substantial socioeconomic burden and reduced quality of life. A key cognitive-affective factor implicated in the maintenance and exacerbation of CBP is pain catastrophising, which can vary within and across days.
Conventional treatments for CBP often do not capture or address these momentary fluctuations in psychological and pain-related states. Just-in-time adaptive interventions (JITAIs) aim to deliver tailored, brief support at moments of increased need by using time-varying information. In this protocol, the investigators propose using ecological momentary assessment (EMA) to measure momentary pain-related states and to guide delivery of adaptive microinterventions targeting pain catastrophising.
To date, the authors report that no randomised controlled trial has specifically evaluated a JITAI that targets pain catastrophising in people with CBP. This trial is designed to address that gap by testing whether an EMA-guided JITAI can reduce catastrophising compared with a control condition that receives EMA without adaptive interventions.
This study is a pragmatic, two-arm randomised controlled trial. The planned recruitment target is 100 participants to obtain an evaluable sample of 86.
Eligible participants are adults with chronic back pain persisting for more than 3 months and reporting an average pain intensity over the previous week of at least 3 on a 0–10 Numerical Rating Scale. Participants will be randomised to either the JITAI intervention or to enhanced treatment as usual (TAU+).
Participants randomised to the intervention group will receive an app-based JITAI. The app uses repeated ecological momentary assessment (EMA) responses on variables such as momentary pain catastrophising and pain intensity to trigger brief, adaptive microinterventions. Examples of microinterventions described in the protocol include relaxation exercises and recommended physical activities tailored to the participant’s current state as captured by EMA.
The JITAI is intended to provide timely, context-sensitive support that complements standard care by intervening at moments when catastrophising or pain intensity are elevated.
Participants randomised to the TAU+ arm will complete the same EMA assessments as the intervention arm but will not receive adaptive microinterventions. This design isolates the effect of the microinterventions triggered by EMA from the potential effects of self-monitoring via EMA.
The primary outcome is reduction in pain catastrophising, assessed with the Pain Catastrophizing Scale. A range of secondary outcomes will also be measured, including:
Assessments are scheduled at baseline before randomisation (T0), at mid-treatment 2 weeks after intervention start (T1), at end of treatment 4 weeks after intervention start (T2), and at follow-ups 3 months (T3) and 6 months (T4) after end of treatment.
The trial aims to recruit 100 participants to achieve an evaluable sample of 86. Primary and secondary outcomes will be analysed using between-group comparisons under the intention-to-treat principle. The protocol specifies that analyses will compare outcome trajectories between the JITAI and TAU+ arms, preserving randomised group allocation for inference.
In addition to the main between-group analyses, the study will perform exploratory analyses to examine proximal, short-term effects of individual microinterventions. These proximal effects will be modelled using dynamic structural equation modelling to evaluate within-person, time-varying relations between EMA-reported states, microintervention delivery, and subsequent outcomes.
Ethics approval for the study was granted by the Ethics Committee of the Charité Universitätsmedizin Berlin (approval number: EA4/207/21, 18 October 2021). The trial is registered under DRKS00028494. The investigators plan to submit results for publication in peer-reviewed journals and to present findings at scientific conferences.
Note: All details in this summary are drawn directly from the source protocol. The source provided no additional information on specific microintervention content beyond examples, detailed randomisation procedures, or power calculations beyond the recruitment target and planned evaluable sample size.