NB. This study has been previously registered with the National Trial Registry (NTR6266) that has been cancelled. The registered trial has been automatically transferred to a new "Landelijk Trial Register", which does not contain all correct information on the current study and where no corrections can be made. Hence, the current study has been registered again with ClinicalTrials.gov.

The goal of this clinical trial is to study the effectiveness of an online self-management intervention in adult patients with hand osteoarthritis and to explore the possibilities to implement the intervention in clinical practice after the study period. An RCT will be performed, in which 70 participants will be randomized to either care-as-usual (hand osteoarthritis care path, including consultation with the rheumatologist and a 1,5-hour consultation with a clinical nurse or occupational therapist, n=35) or care-as-usual plus the online self-management intervention (n=35). The primary effect constitutes of the difference in change in pain coping between patients in the intervention and control condition from baseline to post-intervention. As secondary outcomes, a number of other psychological and physical outcome measures will be assessed (e.g., health-related quality of life, well-being, pain impact on daily life, pain cognitions). Also, cost-effectiveness of the intervention will be measured, by assessing productivity loss and health care use of participants (using iPCQ and iMCQ).

Rationale: Hand osteoarthritis has a high clinical burden, as reflected by considerable pain, decreased strength and mobility, physical disability, and an often-decreased health-related quality of life. Self-management factors related to physical and psychosocial adjustment, such as patients' perceptions about their disease and coping, play an important role in heath-related quality of life and functional ability in patients with chronic diseases, such as osteoarthritis. Improving capacities of patients in managing a chronic condition is increasingly recognized as important in the treatment of (somatic) conditions and is becoming more common in clinical practice and research. In this study, the effect of an online self-management intervention focusing on coping skills related to chronic pain in comparison to care-as-usual is studied.

Objective: To study the effectiveness of the online self-management intervention in patients with hand osteoarthritis and to explore the possibilities to implement the intervention in clinical practice after the study period.

Study design: An RCT will be performed, in which 70 participants will be randomized to either care-as-usual (hand osteoarthritis care path, including consultation with the rheumatologist and a 1,5-hour consultation with a clinical nurse or occupational therapist, n=35) or care-as-usual plus the online self-management intervention (n=35). Baseline, post-intervention, 6-week, and three-month follow-up questionnaires will be used to measure primary and secondary outcomes. To assess implementation possibilities of the online intervention, structured qualitative interviews among patients and health professionals will examine to what extent the intervention suits the needs and skills of patients and to what extent the intervention fits within the current care process.

Study population: All patients ≥18 years with hand osteoarthritis who are referred to the hand osteoarthritis care path at the rheumatology clinic at Leiden University Medical Center with on-going pain complaints during at least three months will be invited to participate in the study. Patients need to be fluent in Dutch, need to be able to give informed consent, and have internet access. Severe psychiatric co-morbidity, on-going psychological treatment elsewhere, difficulties with (written) communication, a lack of internet literacy, and having secondary osteoarthritis are exclusion criteria.

Intervention: The intervention is based on cognitive-behavioral methods. It starts off with a face-to-face introduction consultation. Subsequently, the tailored self- management intervention will be offered via an online program. The intervention consists of six modules containing pain education, practical assignments, relaxation training, and registrations. The first and last modules are an introductory and closure module; in between are four modules aimed at learning how to cope with the consequences of a chronic condition in daily life. The modules focus on (1) activity, (2) mood, (3) thoughts, and (4) the social environment. At least once a week, participants receive feedback on the assignments and motivational support from a psychologist, by means of text messages in a secured mail box in the online program. After finishing the online program, patients will be approached by their treating psychologist for two booster sessions via telephone. In these booster sessions it will be evaluated how the patient further attained his/her pre-set goals for the intervention. Strategies to strengthen the achieved results will be discussed. The booster sessions will take place 1 month and 2,5 months after finishing the online program.

Main study parameters/endpoints: The primary effect constitutes of the difference in change in pain coping between patients in the intervention and control condition from baseline to post-intervention. As secondary outcomes, a number of other psychological and physical outcome measures will be assessed (e.g., health-related quality of life, well-being, pain impact on daily life, pain cognitions). Also, cost-effectiveness of the intervention will be measured, by assessing productivity loss and health care use of participants (using iPCQ and iMCQ).

Nature and extent of the burden and risks associated with participation, benefit and group relatedness: In the control group the usual standard of care is provided. In the intervention group patients will be offered an internet-based self-management intervention, which potentially improves their pain coping and other psychological and physical outcomes. No risk is involved with participation in this study. The only burden for participants is investment of time.

Inclusion Criteria:

• Diagnosed with hand osteoarthritis, following American College of Rheumatology (ARC) criteria (Altman et al., 1990)
• Referred to the hand osteoarthritis care path
• Complaints from hand osteoarthritis including pain, with a minimal duration of 3 months
• Minimum age of 18 years
• Fluent in Dutch language
• Able to give informed consent
• Own a computer with internet access

Exclusion Criteria:

• Difficulties with (written) communication (e.g., due to analphabetism) and lack of internet literacy
• Severe psychiatric comorbidities that interfere with the study protocol
• On-going psychological treatment elsewhere
• Patients with secondary osteoarthritis due to diseases, such as 1) inflammatory rheumatic diseases, such as rheumatoid arthritis, psoriatic arthritis, etc., 2) bone diseases, such as M. Paget, osteochondritis, 3) metabolic diseases associated with joint disease, such as hemochromatosis, acromegaly, 4) severe crystal arthropathies, such as tophaceous polyarticular gout.

Once an article on the study is published, a publication package will be published on DataverseNL. This package includes the manuscript, procedures, raw data files, computer code, and processed data files.

IPD will become available once an article on the study is published on DataverseNL; the statistical analysis plan will be published on ClinicalTrials.gov during registration (before data analysis takes place).

Open access.

Blinding of participants and practitioners is not possible due to the nature of the study. However, the statistician who creates the randomization schedule and performs statistical analyses is blinded to group allocation.