DAS28 score was calculated using the number of tender and swollen joints (out of 28 counted), erythrocyte sedimentation rate (ESR) level, and the participant's global assessment of disease activity. The calculated range of DAS28 is 0.49 to 9.07, with scores below 3.2 indicating low disease activity. A positive clinical outcome was defined as a DAS28 decrease by 1.2 or more after 3 months of Humira therapy relative to baseline.

Clinical Outcome Analysis Set (COS): all participants in the SES, who had a non-missing assessment of clinical outcome at baseline and not less than one follow-up visit with a non-missing assessment of clinical outcome. In addition, patients with unclear visit schedule were excluded from the COS.

BASDAI score was calculated using a questionnaire with 6 questions that the participant completes by marking answers on a 10-centimeter visual analog scale with responses that range from 0 (none) to 10 (very severe) and measures severity of fatigue, spinal and peripheral joint pain, localized tenderness and morning stiffness. The final BASDAI score ranges from 0 to 10. A positive clinical outcome was defined as a 50% or more decrease in BASDAI score after 3 months of Humira therapy relative to baseline.

Clinical Outcome Analysis Set (COS): all participants in the SES, who had a non-missing assessment of clinical outcome at baseline and not less than one follow-up visit with a non-missing assessment of clinical outcome. In addition, patients with unclear visit schedule were excluded from the COS.

HAQ-DI score was calculated using the standard questionnaire covering 8 category scores: Dressing and Grooming, Rising, Eating, Walking, Hygiene, Reach, Grip, and Activities. Each category score is calculated as the maximum of the scores for the questions within the category. The HAQ-DI is expressed on a scale from 0 (without any difficulty) to 3 (unable to do) representing an average score across the category. Scores for at least 6 categories are needed to compute the HAQ score. Changes to lower scores indicate improvement in physical function.

SES=participants fulfilling both of the following criteria: a primary diagnosis of specified rheumatic disease (RA, PsA, AS); at least one recorded Humira treatment is documented. n=number of participants with evaluable records at given time point.

Participant acceptability of self-injection was assessed by the percentage of participants able to appropriately execute self-injection after initial training in the medical center, per investigator's opinion and documentation of necessity of re-training. Those participants able to self-inject also reported their experience of self-injection as convenient or inconvenient.

Participants in the SES with evaluable values. SES=participants fulfilling both of the following criteria: a primary diagnosis of specified rheumatic disease (RA, PsA, AS); at least one recorded Humira treatment is documented.

Compliance with the Humira therapy was assessed by the number of missed injections among participants. Documentation of injections missed or delayed by more than 7 days was made at each study visit.

Participants in the SES with evaluable values. SES=participants fulfilling both of the following criteria: a primary diagnosis of specified rheumatic disease (RA, PsA, AS); at least one recorded Humira treatment is documented.

Tolerability was evaluated by assessing the mean duration (in weeks) of treatment with Humira until the development of an adverse event leading to treatment discontinuation or until early discontinuation for any other reason.

Participants in the SES who discontinued therapy and had evaluable records. SES=participants fulfilling both of the following criteria: a primary diagnosis of specified rheumatic disease (RA, PsA, AS); at least one recorded Humira treatment is documented.

Tolerability was measured by AEs and SAEs, collected during the course of the study. See the Reported Adverse Event section for details.

SES=participants fulfilling both of the following criteria: a primary diagnosis of specified rheumatic disease (RA, PsA, AS); at least one recorded Humira treatment is documented.