Table 1.

Planned outcome domains, outcome measures, and statistical methods.

Outcome		Hypothesis/research question	Outcome measure	Method of analysis
Primary
	Self-perceived pain disability	The development of pain disability over time after IMPTa will be more favorable for the enhanced treatment condition compared to usual care.	PDIb,c	Multilevel analysis
	Planned subgroup analysis on patients that scored 1 (“very much better”) or 2 (“much better”) on the GPEd scale at t1e.	For patients that experienced meaningful treatment success, the development of pain disability over time after IMPT will be more favorable for the enhanced treatment condition compared to usual care.	1. PDIc 2. GPEf	Multilevel analysis
Secondary (quality of life)
	Health care costs	The enhanced treatment condition will be cost-effective compared with usual care at 3 and 6 months posttreatment.	1. SF-12f,g 2. iPCQf,h	Cost-effectiveness analysis
	Illness perception	The development of illness perceptions over time after IMPT will be more favorable for the enhanced treatment condition compared to usual care.	IPQ-K DLVc,i	Multilevel analysis
	Pain self-efficacy	The development of pain self-efficacy over time after IMPT will be more favorable for the enhanced treatment condition compared to usual care.	PSEQc,j	Multilevel analysis
	Pain intensity	The development of outcome measures over time may be affected by the level of pain intensity	NRSc,k	Multilevel analysis
Engagement and usability
	Overall engagement	The level of engagement and usability will be positively associated with a change in pain disability during follow up (t4l – t1).	1. System usability scalef 2. System usage data of AGRIPPA app (see below)	Multiple linear regression
	Frequency of engagement	How does the frequency of engagement vary over time after treatment?	Average number of logins per week	Descriptive statistics
	Depth of engagement	How does the average number of features accessed per login vary after treatment?	Average number of features accessed per log-in	Descriptive statistics
	Duration of engagement	How do the average minutes spent at each login as well as the total time spent with the app per week vary after treatment?	1. Average minutes spent at each login. 2. Total time spent with the app	Descriptive statistics
	Active engagement with Insight Cards	To what extent will the number of created Insight Cards increase or decrease after treatment?	Number of Insight Cards created	Descriptive statistics
	Active engagement with VBGm	To what extent will the number of created VBG cards increase or decrease after treatment?	1. Number of VBGs created. 2. Number of steps created	Descriptive statistics

^aIMPT: interdisciplinary multimodal pain therapy.

^bPDI: Pain Disability Index.

^cOutcome measure is part of routine care.

^dGPE: global perceived effect.

^et₁: immediately postintervention.

^fOutcome measures will be obtained with an additional electronic survey.

^gSF-12: 12-item short-form health survey.

^hiPCQ: iMTA Productivity Cost Questionnaire.

ⁱIPQ-K DLV: Dutch language version of the Illness Perception Questionnaire.

^jPSEQ: Pain Self-Efficacy Questionnaire.

^kNRS: numeric rating scale.

^lt₄: 12 months postintervention.

^mVBG: Value-Based Goals.