The Disease Activity Score 28-joint Count (DAS-28) is a validated measure of Rheumatoid Arthritis (RA) disease activity frequently used in pharmaceutical trials. The Erythrocyte Sedimentation Rate (ESR) is a blood test measuring how quickly red blood cells sink in a tube; higher rates indicate more inflammation. The DAS-28 incorporates the 28 tender joint count (TJC; 0-28), 28 swollen joint count (SJC; 0-28), ESR, and patient global assessment (PGA; 0-10). It is calculated via: 0.56* √ (TJC28) + 0.28* √ (SJC28) + 0.70*ln (ESR) + 0.014* (PGA). For all components and the total 0-9.4 score, higher values indicate worse disease activity. Thresholds are: Remission (< 2.6), Low (2.6 to <= 3.2), Moderate (> 3.2 to <= 5.1), and High (> 5.1) Disease Activity. The reported outcome is the change in DAS-28 score from baseline to 8 weeks. This is an exploratory outcome as the study is not powered to assess whether MBSR-RD is effective for improving clinical outcomes.

The Modified Rheumatoid Arthritis Disease Activity Index, 5-item (RADAI-5) is a validated patient-reported assessment of RA disease activity that comprises five questions on a Likert scale from 0 to 10. A higher score on the scale of 0-10 indicates worse disease activity. Remission is defined as less than 1.5, Low Disease Activity is between 1.6 and 3.0, Moderate Disease Activity is between 3.2 and 5.4, and High Disease Activity is a score greater than 5.6. We used a modified version of the Modified Rheumatoid Arthritis Disease Activity Index, 5-item (RADAI-5) in which the period of recall is 2 weeks instead of 6 months. This is an exploratory outcome measure as the current study is not adequately powered to assess whether MBSR-RD is effective for improving clinical outcomes. The reported outcome is the change in RADAI-5 score from baseline to 8 weeks.

The Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Interference scale measures the extent to which pain hinders an individual's engagement with physical, mental, cognitive, emotional, recreational, and social activities. The scores are converted to T-scores (mean = 50, SD = 10), with higher scores indicating worse pain interference. A T-score less than or equal to 55 is described as within normal limits, between 55 to 60 is considered mild pain interference, 60 to 70 is considered moderate pain interference, and above 70 is considered severe pain interference. This is an exploratory outcome measure as the current study is not adequately powered to assess whether MBSR-RD is effective for improving clinical outcomes. The reported outcome is the change in PROMIS Pain Interference T-score from baseline to 8 weeks.

The Patient-Reported Outcomes Measurement Information System (PROMIS) Fatigue scale measures the experience of fatigue and associated impact on daily life. This scale is converted to a T-score (mean = 50, SD = 10), with higher scores indicating worse fatigue. A T-score less than or equal to 55 is considered within normal limits, between 55 to 60 is considered mild fatigue, 60 to 70 is considered moderate fatigue, and above 70 is considered severe fatigue. This is an exploratory outcome measure as the current study is not adequately powered to assess whether MBSR-RD is effective for improving clinical outcomes. The reported outcome is the change in PROMIS Fatigue T-score from baseline to 8 weeks.

The Patient-Reported Outcomes Measurement Information System (PROMIS) Mindfulness scale measures the capacity for present moment awareness. This is an exploratory outcome measure that will be used in future larger trials to determine whether mindfulness mediates improvements in clinical outcomes such as pain among participants in the active treatment group. We are reporting raw scores rather than T-scores for this PROMIS measure as the PROMIS Assessment Center has not yet released the scoring algorithms required for conversion to T-scores. The range for raw scores is 13-65, with higher scores indicating higher levels of mindfulness. The reported outcome is the change in PROMIS Mindfulness score from baseline to 8 weeks.

Change in Perceived Stress Scale total score. Range is 0 to 40. Higher scores indicate more perceived stress. The reported outcome is the change in Perceived Stress Scale score from baseline to 8 weeks.

The Brief Resilience Scale measures the perceived ability to bounce back or recover from psychological stress. The scale is scored from 1-5, where a higher score reflects a higher level of resilience to stress. This is an exploratory outcome measure and will be used to determine whether stress resilience mediates improvements in clinical outcomes such as pain among participants in the active treatment group. The reported outcome is the change in the Brief Resilience Scale score from baseline to 8 weeks.

Sleep disturbance was measured using the Patient-Reported Outcomes Measurement Information System (PROMIS) Sleep Disturbance 8-item short form, a validated self-report measure of sleep quality and sleep-related difficulties over the past 7 days. Scores are converted to standardized T-scores (mean = 50, SD = 10), with higher scores indicating worse sleep disturbance. A T-score less than or equal to 55 is described as within normal limits, between 55 to 60 is described as mild sleep disturbance, 60 to 70 is described as moderate sleep disturbance, and above 70 is described as severe sleep disturbance. The reported outcome is the change in PROMIS Sleep Disturbance T-score from baseline to 8 weeks.

Depressive symptoms will be measured using the Patient-Reported Outcomes Measurement Information System (PROMIS) Depression 8-item short form, a validated self-report measure assessing depressive symptoms over the past 7 days. Scores are converted to standardized T-scores (mean = 50, SD = 10), with higher scores indicating worse depressive symptoms. A T-score less than or equal to 55 is described as within normal limits, between 55 to 60 is described as mild depression, 60 to 70 is described as moderate depression, and above 70 is described as severe depression. The reported outcome is the change in PROMIS Depression T-score from baseline to 8 weeks.

Individuals in the TAU group will continue engaging in routine care and be asked to refrain from participating in mindfulness programs during the trial.

Total of all reporting groups

All participants were randomized to the MBSR-RD and TAU arms.

All participants were randomized to the MBSR-RD and TAU arms.

All participants were randomized to the MBSR-RD and TAU arms.

All participants were randomized to the MBSR-RD and TAU arms.

All participants were randomized to the MBSR-RD and TAU arms.

All participants were randomized to the MBSR-RD and TAU arms.

This is a biologic measure of the presence of antibodies against rheumatoid factor (RF). These antibodies are associated with a diagnosis of rheumatoid arthritis and while they are not required for the diagnosis, they confer prognostic information, including increased risk of extra-articular disease.

All participants were randomized to the MBSR-RD and TAU arms.

This is a biologic measure of the presence of antibodies against cyclic citrullinated peptide (CCP). Though CCP positivity has low sensitivity for a diagnosis of RA, it is highly specific. CCP positivity also confers clinical prognostic value, including increased risk of extra-articular disease.

All participants were randomized to the MBSR-RD and TAU arms.

The Clinical Disease Activity Index (CDAI) is a validated measure of Rheumatoid Arthritis (RA) disease activity recommended by the American College of Rheumatology. It sums the 28 swollen joint count (SJC; 0-28), 28 tender joint count (TJC; 0-28), patient global assessment (PGA; 0-10), and provider global assessment (PrGA; 0-10) via: SJC + TJC + PGA + PrGA. For all individual components and the total score from 0-76, higher values indicate worse disease. Thresholds are Remission (< 2.8), Low (<=10), Moderate (10-22), and High (> 22) Disease Activity. It is used in clinical trials and practice.

All participants were randomized to the MBSR-RD and TAU arms.

All participants were randomized to the MBSR-RD and TAU arms.

All participants were randomized to the MBSR-RD and TAU arms.

Intervention adherence will be operationalized as the percentage of participants who were randomized to the mindfulness group and attended at least six of the eight group sessions.

All participants randomized to MBSR-RD arm.

Study retention will be operationalized as the number of participants who completed assessments (questionnaires and physician disease activity assessments) at the follow-up time-point divided by the number of participants who enrolled in the study, multiplied by 100.

All participants were randomized to the MBSR-RD or TAU arms. The total number of participants in the MBSR-RD arm who completed both final follow-up questionnaire assessments and in-person assessments was 18 as one participant completed the final questionnaires but did not return for the final in-person study visit. Study completion was 100% (38/38) for remote data collection and 97.4% (37/38) for in-person data collection.

The Clinical Disease Activity Index (CDAI) is a validated measure of Rheumatoid Arthritis (RA) disease activity recommended by the American College of Rheumatology. It sums the 28 swollen joint count (SJC; 0-28), 28 tender joint count (TJC; 0-28), patient global assessment (PGA; 0-10), and provider global assessment (PrGA; 0-10) via: SJC + TJC + PGA + PrGA. For all individual components and the total 0-76 score, higher values indicate worse disease. Thresholds are: Remission (< 2.8), Low (<=10), Moderate (10-22), and High (> 22) Disease Activity. It is used in RA clinical trials and recommended for use in routine rheumatologic care. This assessment serves as an exploratory outcome in the current trial, as the study is not powered to test efficacy. The outcome reported for this variable is the change in CDAI score from baseline to post-intervention at 8 weeks.

All participants were randomized to the MBSR-RD and TAU arms.

The Disease Activity Score 28-joint Count (DAS-28) is a validated measure of Rheumatoid Arthritis (RA) disease activity frequently used in pharmaceutical trials. The Erythrocyte Sedimentation Rate (ESR) is a blood test measuring how quickly red blood cells sink in a tube; higher rates indicate more inflammation. The DAS-28 incorporates the 28 tender joint count (TJC; 0-28), 28 swollen joint count (SJC; 0-28), ESR, and patient global assessment (PGA; 0-10). It is calculated via: 0.56* √ (TJC28) + 0.28* √ (SJC28) + 0.70*ln (ESR) + 0.014* (PGA). For all components and the total 0-9.4 score, higher values indicate worse disease activity. Thresholds are: Remission (< 2.6), Low (2.6 to <= 3.2), Moderate (> 3.2 to <= 5.1), and High (> 5.1) Disease Activity. The reported outcome is the change in DAS-28 score from baseline to 8 weeks. This is an exploratory outcome as the study is not powered to assess whether MBSR-RD is effective for improving clinical outcomes.

DAS28-ESR requires laboratory data. Laboratory assessments were implemented during the second of two waves of the study, thus DAS28-ESR is available on the 18 people randomized to the second wave.

The Modified Rheumatoid Arthritis Disease Activity Index, 5-item (RADAI-5) is a validated patient-reported assessment of RA disease activity that comprises five questions on a Likert scale from 0 to 10. A higher score on the scale of 0-10 indicates worse disease activity. Remission is defined as less than 1.5, Low Disease Activity is between 1.6 and 3.0, Moderate Disease Activity is between 3.2 and 5.4, and High Disease Activity is a score greater than 5.6. We used a modified version of the Modified Rheumatoid Arthritis Disease Activity Index, 5-item (RADAI-5) in which the period of recall is 2 weeks instead of 6 months. This is an exploratory outcome measure as the current study is not adequately powered to assess whether MBSR-RD is effective for improving clinical outcomes. The reported outcome is the change in RADAI-5 score from baseline to 8 weeks.

All participants were randomized to the MBSR-RD and TAU arms.

The Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Interference scale measures the extent to which pain hinders an individual's engagement with physical, mental, cognitive, emotional, recreational, and social activities. The scores are converted to T-scores (mean = 50, SD = 10), with higher scores indicating worse pain interference. A T-score less than or equal to 55 is described as within normal limits, between 55 to 60 is considered mild pain interference, 60 to 70 is considered moderate pain interference, and above 70 is considered severe pain interference. This is an exploratory outcome measure as the current study is not adequately powered to assess whether MBSR-RD is effective for improving clinical outcomes. The reported outcome is the change in PROMIS Pain Interference T-score from baseline to 8 weeks.

All participants were randomized to the MBSR-RD and TAU arms.

The Patient-Reported Outcomes Measurement Information System (PROMIS) Fatigue scale measures the experience of fatigue and associated impact on daily life. This scale is converted to a T-score (mean = 50, SD = 10), with higher scores indicating worse fatigue. A T-score less than or equal to 55 is considered within normal limits, between 55 to 60 is considered mild fatigue, 60 to 70 is considered moderate fatigue, and above 70 is considered severe fatigue. This is an exploratory outcome measure as the current study is not adequately powered to assess whether MBSR-RD is effective for improving clinical outcomes. The reported outcome is the change in PROMIS Fatigue T-score from baseline to 8 weeks.

All participants were randomized to the MBSR-RD and TAU arms.

The Patient-Reported Outcomes Measurement Information System (PROMIS) Mindfulness scale measures the capacity for present moment awareness. This is an exploratory outcome measure that will be used in future larger trials to determine whether mindfulness mediates improvements in clinical outcomes such as pain among participants in the active treatment group. We are reporting raw scores rather than T-scores for this PROMIS measure as the PROMIS Assessment Center has not yet released the scoring algorithms required for conversion to T-scores. The range for raw scores is 13-65, with higher scores indicating higher levels of mindfulness. The reported outcome is the change in PROMIS Mindfulness score from baseline to 8 weeks.

All participants were randomized to the MBSR-RD and TAU arms.

Change in Perceived Stress Scale total score. Range is 0 to 40. Higher scores indicate more perceived stress. The reported outcome is the change in Perceived Stress Scale score from baseline to 8 weeks.

All participants were randomized to the MBSR-RD and TAU arms.

The Brief Resilience Scale measures the perceived ability to bounce back or recover from psychological stress. The scale is scored from 1-5, where a higher score reflects a higher level of resilience to stress. This is an exploratory outcome measure and will be used to determine whether stress resilience mediates improvements in clinical outcomes such as pain among participants in the active treatment group. The reported outcome is the change in the Brief Resilience Scale score from baseline to 8 weeks.

All participants were randomized to the MBSR-RD and TAU arms.

Sleep disturbance was measured using the Patient-Reported Outcomes Measurement Information System (PROMIS) Sleep Disturbance 8-item short form, a validated self-report measure of sleep quality and sleep-related difficulties over the past 7 days. Scores are converted to standardized T-scores (mean = 50, SD = 10), with higher scores indicating worse sleep disturbance. A T-score less than or equal to 55 is described as within normal limits, between 55 to 60 is described as mild sleep disturbance, 60 to 70 is described as moderate sleep disturbance, and above 70 is described as severe sleep disturbance. The reported outcome is the change in PROMIS Sleep Disturbance T-score from baseline to 8 weeks.

All participants were randomized to the MBSR-RD and TAU arms.

Depressive symptoms will be measured using the Patient-Reported Outcomes Measurement Information System (PROMIS) Depression 8-item short form, a validated self-report measure assessing depressive symptoms over the past 7 days. Scores are converted to standardized T-scores (mean = 50, SD = 10), with higher scores indicating worse depressive symptoms. A T-score less than or equal to 55 is described as within normal limits, between 55 to 60 is described as mild depression, 60 to 70 is described as moderate depression, and above 70 is described as severe depression. The reported outcome is the change in PROMIS Depression T-score from baseline to 8 weeks.

All participants were randomized to the MBSR-RD and TAU arms.

Individuals in the TAU group will continue engaging in routine care and be asked to refrain from participating in mindfulness programs during the trial.