Digitally Delivered First-line Osteoarthritis Treatment - Effects on Pain and Function in Different Age Groups.
Conditions: Pain, Physical Function, Age
Sponsor: Joint Academy

Digitally Delivered First-line Osteoarthritis Treatment - Effects on Pain and 
Function in Different Age Groups.  
 
2022-01-10 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Study questions: 
Primary:  
Do the mean outcomes for these 3 age groups differ (as they are, unadjusted, and using JA ‘as 
prescribed’ by the Swedish national Board of Health and Welfare (Socialstyrelsen)?  
To what extent does adherence and other covariates explain the potential differences in outcomes?  
Secondary:  
Does the adherence to JA treatment differ across age groups? 
Does the JA uptake differ by age when comparing age distribution of JA participants with age distribution 
of OA in the Skåne population? 
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Background 
Osteoarthritis (OA) is among the leading causes of disability worldwide and due to its rising prevalence, 
the identification of appropriate care and care delivery modalities is a priority for the health care 
systems. Exercise and education constitute the first-line intervention for people with knee and hip OA 
and are effective regardless of symptoms and disease severity. This first-line intervention is available as 
face-to-face programs, or digital programs via eHealth apps. No published studies have yet examined if, 
among the OA population, the uptake, or the outcomes of the program, differ between younger or older 
participants in a digital first-line OA intervention. Our understanding of how background (demographic) 
factors interact with uptake and outcomes is incomplete. 
 
Methods 
This is an observational, retrospective register-based study of participants in a digital osteoarthritis self-
management program. 
All participants signed informed consent digitally upon registration. The regional ethics committee of 
Lund University and the Swedish Ethical Review Authority provided ethical approval (Dnr: 2018/650, 
2019-02232 and 2020-05431). The study adheres to the STROBE guidelines for observational studies. 
Setting and participants  
Participants joined the digital OA self-management and education program (see Intervention below for 
details), through recommendation by their local orthopaedic surgeon or physiotherapist, and via online 
advertisements and campaigns placed on search engines and social networks. Included participants had 
a radiographic and or clinical diagnosis of hip or knee OA from a physical therapist or physician (95% of 
all patients at the date of data extraction). Individuals without a prior diagnosis had clinical OA confirmed 
by an orthopaedic surgeon or physiotherapist via telephone (diagnosis according to NICE UK criteria and 
Swedish National Guidelines, and confirming the absence of any red flag symptoms), or if deemed 
necessary were recommended to seek face-to-face care before inclusion in the program. 

All data for the present study were extracted from the digital self-management program data registry on 
the 22nd of March 2021. Criteria for inclusion in the primary data extraction were: 
● Having registered in the program and had the first telephone contact with the 
physiotherapist assigned to the patient, and enrolled between March 1, 2018 and 
November 30, 2020.  
● Having reported hip or knee as most symptomatic (index) joint 
● Having provided 3-month follow-up data on or before February 28, 2021 
These selection criteria resulted in 14006 eligible participants. 
Adherence was defined as the percentage of completed activities (exercises, and text or video lessons on 
OA, with quizzes on lesson material) per the pre-defined period of 12 weeks. A cut-off of 80% or higher 
adherence corresponds to the National Recommendations for first-line knee and hip OA treatment by 
the Swedish National Board of Health and Welfare (1).  
Intervention  
The intervention consisted of a digital, structured and individualized first-line treatment program for 
people with hip or knee OA (Joint Academy®; www.jointacademy.com ). The physiotherapist-led 
program consists of instructions for neuromuscular exercises appropriately adjusted to each patient in 
regard to degrees of complexity and difficulty. Exercises are distributed daily during the whole 
participation period, in general two per day, for a total of 163 exercise sessions over 12 weeks. While 
rating perceived difficulty and adding comments, patients also indicate when exercises are completed. 
Program progression is halted until all exercises for the day are marked as completed. Information 
(based on current national OA management guidelines and research) in the form of text or video lessons 
(with quizzes on the material after each episode) on subjects related to OA, OA symptoms and 
management is also distributed to each participant. The lessons come packed in themes, with each 
theme containing 1–5 lessons where participants receive one theme per week the first six weeks, and 
then every other week, for a total of 31 lessons over 12 weeks. Completion of a lesson is indicated by the 
patient answering the quiz correctly. Additionally, continuous access to, and dialogue with, is provided 
by a physiotherapist through an encrypted chat function and telephone. 
 
Main exposure & outcomes 
Exposure 
Age (categorized in 3 groups) is the main exposure of the interest.  
Outcomes 
For research question 1:  
1. Joint pain will be assessed at baseline and at week 12 using the Numerical Rating Scale (NRS, 
discrete boxes 0–10) with the instruction: “Mark on this scale how much pain you had the last 
week in your hip/knee”, followed by a 0–10 scale where 0 was defined as No pain and 10 was 
defined as Maximum pain. 

2. As a measure of physical function, the 30 second chair rise will be measured at baseline and 
week 12, performed by the participant with the help of an instruction video with a coupled visual 
timer. The patient enters the performed number of repetitions after each test. 
3. Among other outcomes to be reported are changes between baseline and 12 weeks follow-up in 
self-reported KOOS-12 and HOOS-12, KOOS-PS, HOOS-PS, response to anchor questions, 
response to questions on satisfaction or not with treatment, fear of movement, and walking 
difficulties (Table 1). 
All outcomes will be self-assessed and self-entered using the digital program interface and selected 
based on the International Consortium for Health Outcomes Measurement Standard Set for Hip & Knee 
Osteoarthritis (ICHOM) (2).  
For research question 2: 
Adherence as measured (between 0 to 100%) and desirable adherence ≥80% (i.e. ≥80% completed 
exercises, text or video lessons on OA, with quizzes on lesson material offered in the digital program) 
between 0 and 12 weeks of first-line OA treatment delivered digitally. 
For research question 3: 
Registration in JA is the outcome of interest.  
 
Endpoints 
Main endpoints 
a) Self-reported change in index joint (knee or hip) pain on the NRS-scale between baseline and 12 
weeks of follow-up for the three age groups <=59, 60-69, and >=70 
b) Self-reported change between baseline and 12 weeks in 30-second chair rise test for the three age 
groups <=59, 60-69, and >=70 
Other endpoints 
Outcomes will be compared for the three age groups >=59, 60-69, and >=70 for the following  
KOOS-12 questionnaire 
HOOS-12 questionnaire 
KOOS-PS questionnaire 
HOOS-PS questionnaire 
Physical activity 
Responder criteria and patient responses to questions on satisfactory health state and treatment failure. 
 
Covariates  
We will examine to what extent the potential differences across age groups in research questions 1 & 2 
can be explained by the baseline demographic, socioeconomic (employment status and education level) 
and clinical (BMI, co-morbidity, overall health status, index joint) characteristics. 

Sample size 
This being a registry-based study of prospectively collected data, no formal power calculation will be 
provided. However, with the number of patients providing data, statistical power will be more than 
sufficient to analyze conclusively relevant group differences for the main endpoints. 
 
Statistical analysis 
Data description 
Summary data by age groups will be described by the mean value, standard deviation and number of 
observations or the number and percent of the categories of interest.  
For research question 1, we perform ordinary least squares (OLS) regressions of the outcome of interest 
on age group and the baseline value of that outcome. Next, we adjust for all other covariates including 
adherence. Finally, we will employ the Oaxaca-Blinder (OB) decomposition technique to understand the 
reasons for potential differences across age groups in the outcome of interest. OB decomposition 
decomposes differences between groups into “explained” and “unexplained” portions. The explained 
part estimates the amount of the differences in the outcome attributable to age group differences in the 
means of explanatory variables. The unexplained part originates from the differences in the associations 
between the outcome and explanatory variables across age groups. This latter part represents the 
magnitude of difference which will remain even if the age groups had identical means of covariates. In 
addition to decomposition of mean differences between age groups, we will also decompose the 
difference in variance of the outcome using OB technique. In interpreting the findings, we will take into 
account the minimal clinically important difference for each outcome (e.g. differences above 10 (scale 0-
100), or 1 (scale 0-10) in pain). 
For research question 2, we will use OLS regression (with adherence as measured) and logistic regression 
(for desirable adherence: adherence≥80%) to investigate age group differences in these outcomes. 
Similar to research question 1, we will use OB technique to decompose the potential gap between age 
groups in these two outcomes. In interpreting the findings, we will take into account the minimal 
clinically important difference of 2.0 in repetitions" 
For research question 3, we will obtain data on doctor-diagnosed knee and/or hip OA among the Skåne 
population by age group and contrast this with the JA participants resident in the Skåne. This comparison 
will reflect what proportion of people with doctor-diagnosed OA in each age group registered in JA.  
In all studies we will conduct subgroup analyses by index joint (knee & hip) if data allows. Moreover, 
since the rate of dropout between the baseline and 3 months follow up might be different across age 
groups, we will apply inverse probability weighting to account for this.  
 
 

References 
1. https://www.socialstyrelsen.se/en/regulations-and-guidelines/national-guidelines/ 
2. https://www.ichom.org/standard-sets/#musculoskeletal 
 
 
 
 

Table 1 
Reported only at follow-up 
 
 
 
Reported at both baseline and 
follow-up 
 
 
 
  
  
 
 
 
  
JA-ages-usage-outcomes 
 
QUESTIONS 
Baseline 
3 months  
 
Total number of participants 
14006 
14006 
Demographics 
work_situation                                         
14006 
0 
 
educational_level                                      
14006 
0 
Comorbitities 
other_health_problems.diabetes                         
14006 
0 
 
other_health_problems.lung_disease                     
14006 
0 
 
other_health_problems.balance_troubles                 
14006 
0 
 
other_health_problems.rheumatoid_arthritis           
14006 
0 
 
other_health_problems.cardiovascular_disease       
14006 
0 
 
other_health_problems.causing_walking_difficul
ties     
14006 
0 
Health 
overall_health                                         
14006 
14006 
 
specific_joint                                         
14006 
14006 
 
specific_joint_pain                                    
14006 
14006 
 
pain_in_other_joints                                   
14006 
0 
 
pain_improved                                      
0 
4329 
 
pain_locations                                     
0 
 
 
exercise_choice                                        
14006 
14006 
 
physical_activity_choice                               
14006 
14006 
 
difficulty_walking                                     
14006 
14006 
 
afraid_to_get_hurt_by_movement                         
14006 
14006 
 
patient_acceptable_symptom_state                       
14006 
14006 
 
motivation_readiness                                   
14006 
0 
 
overall_health_improved                            
0 
4329 
 
physical_function_improved                         
0 
4329 
 
considers_treatment_failed                         
0 
8857 
Willingness for surgery 
wants_operation                                        
14006 
14006 
 
invasive_operation_scheduled                            
2337 
2176 
 
arthroscopy_performed_on_specific_joint                
14006 
0 
 
invasive_operation_type_scheduled                        
299 
0 
 
invasive_operation_cancelled                        
0 
1571 
Medication 
invasive_medicines_selections                       
 
 
 
invasive_medicines_changed                         
 
 
EQ-5D 
eq5d.mobility                                          
14006 
14006 
 
eq5d.self_care                                         
14006 
14006 

 
eq5d.pain_discomfort                                   
14006 
14006 
 
eq5d.usual_activities                                  
14006 
14006 
 
eq5d.anxiety_depression                                
14006 
14006 
HOOS-PS 
hoos.running_difficulty                                
 
 
 
hoos.sitting_difficulty                                
 
 
 
hoos.descending_stairs_difficulty                      
 
 
 
hoos.getting_out_of_bath_difficulty                    
 
 
 
hoos.pivoting_loaded_leg_difficulty                    
 
 
KOOS-PS 
koos.squatting_difficulty                              
 
 
 
koos.sitting_up_difficulty                             
 
 
 
koos.bending_over_difficulty                           
 
 
 
koos.twisting_knee_difficulty                          
 
 
 
koos.laying_on_knee_difficulty                         
 
 
 
koos.putting_on_socks_difficulty                       
 
 
 
koos.rising_out_of_bed_difficulty                      
 
 
Work productivity 
wpai.employed                                          
 
 
 
wpai.hours_actually_worked                             
 
 
 
wpai.oa_productivity_effect                            
 
 
 
wpai.oa_regular_activities_effect                      
 
 
 
wpai.missed_working_hours_due_to_oa                   
 
 
 
wpai.missed_working_hours_due_to_other_reas
ons         
 
 
JA 
ja_like                                            
 
 
 
recommend_others                                   
 
 
 
therapist_appreciation                             
 
 
Other 
free_text_medical_information                          
 
 
HIP new 
hip_satisfaction_now 
0 
3956 
 
hip_satisfaction_quality 
0 
3956 
 
hip_satisfaction_performance 
0 
3956 
 
hip_satisfaction_symptoms_now 
0 
3956 
 
hip_satisfaction_sports_performance 
0 
3956 
HOOS-12 new 
hoos.standing 
3541 
3956 
 
hoos.in_out_car 
3541 
3956 
 
hoos.hip_aware 
3541 
3956 
 
hoos.going_stairs 
3541 
3956 
 
hoos.sitting_lying 
3541 
3956 
 
hoos.rising_sitting 
3541 
3956 
 
hoos.hip_confidence 
3541 
3956 
 
hoos.hip_difficulty 
3541 
3956 
 
hoos.hip_pain_duration 
3541 
3956 
 
hoos.walk_flat_surface 
3541 
3956 
 
hoos.modified_lifestyle 
3541 
3956 

 
hoos.walk_uneven_surface 
3541 
3956 
KNEE new 
knee_satisfaction_now 
0 
5721 
 
knee_satisfaction_quality 
0 
5721 
 
knee_satisfaction_performance 
0 
5721 
 
knee_satisfaction_symptoms_now 
0 
5721 
 
knee_satisfaction_sports_performance 
0 
5721 
KOOS-12 new 
koos.standing 
5026 
5721 
 
koos.in_out_car 
5026 
5721 
 
koos.knee_aware 
5026 
5721 
 
koos.going_stairs 
5026 
5721 
 
koos.sitting_lying 
5026 
5721 
 
koos.rising_sitting 
5026 
5721 
 
koos.knee_confidence 
5026 
5721 
 
koos.knee_difficulty 
5026 
5721 
 
koos.knee_pain_duration 
5026 
5721 
 
koos.walk_flat_surface 
5026 
5721 
 
koos.modified_lifestyle 
5026 
5721 
 
koos.twisting_injured_knee 
5026 
5721 
 
 
 

Fig. 1 Flowchart  
 
 
 
Having registered in the program and had 
the first telephone contact with the 
physiotherapist assigned to the patient, and 
enrolled between March 1, 2018 and November 
30, 2020 
Having reported hip or knee as most 
symptomatic (index) joint 
Having provided 3-month follow-up data on 
or before February 28, 2021 
With program adherence of 80% or 
higher 
 
(n = 9738) 
Analyses  
b,c,d,e  
Analyses  
a