The safety and tolerability of adalimumab was assessed at each study visit. The overall number of participants experiencing serious adverse events (SAEs), non-serious adverse events (AEs) and AEs that led to discontinuation are presented. The number of participants presenting with any serious or non-serious event at each particular study visit is also reported. Note that for the incidence data participants were counted multiple times if they experienced an adverse event at more than 1 visit. For additional information see Reported Adverse Events.

This analysis was performed in the safety population of all participants who took at least 1 dose of adalimumab (675 participants).

The DAS 28 index measures disease activity in rheumatoid arthritis and is derived from the number swollen/tender joints, laboratory tests of inflammation, and participant assessment of global health (by marking a 10 cm line from "very good" to "very bad"). Ranges were used to classify participants, with a higher score indicating worse control of disease: Remission (<= 2.6), Low Disease Activity (>2.6 to <=3.2), Moderate Disease Activity (>3.2 to <= 5.1) and High Disease Activity (>5.1). The mean change in DAS 28 score from baseline to final is presented.

Mean change from baseline to 12 months included the ITT population of 310 de novo and 281 participants treated greater than 4 months.

The DAS 28 index measures disease activity in rheumatoid arthritis and is derived from the number swollen/tender joints, laboratory tests of inflammation, and participant assessment of global health (by marking a 10 cm line from "very good" to "very bad"). Ranges were used to classify participants, with a higher score indicating worse control of disease: Remission (<= 2.6), Low Disease Activity (>2.6 to <=3.2), Moderate Disease Activity (>3.2 to <= 5.1) and High Disease Activity (>5.1). The percentage reduction of baseline values is presented.

Mean reduction from baseline to 12 months was calculated for the ITT population of 310 de novo and 279 participants treated greater than 4 months.

The treating physician was to clinically assess each participant at each study visit and report the number of painful and swollen joints. The mean number of painful or swollen joints for participants evaluated at each time point are presented by subgroup. The number of participants evaluated in each subgroup at each time point are also reported.

This analysis was conducted in the ITT population of 591 participants who had assessments at each time point. The number of de novo participants and participants treated greater than 4 months who were analyzed at each time point are given in parentheses.

Quality of life was assessed using the Health Assessment Questionnaire (HAQ). The HAQ is a self-reported scale used in studies of rheumatoid arthritis to assess areas such as dressing/grooming arising, eating, walking, reach, grip, maintaining hygiene, and daily activities. The global HAQ questionnaire was scored as follows: <1 = no/mild disability, 1 to 2 = moderate disability, and >2 = severe disability. An increased score indicates a worsening of the disability. The mean change in global HAQ score from baseline to 12 months is reported (baseline value - final value).

The analysis was conducted for participants who had both baseline and 12-month global HAQ assessments.

Quality of life was assessed using the Health Assessment Questionnaire (HAQ). The HAQ is a self-reported scale used in studies of rheumatoid arthritis to assess areas such as dressing/grooming arising, eating, walking, reach, grip, maintaining hygiene, and daily activities. The global HAQ questionnaire was scored as follows: <1 = no/mild disability, 1 to 2 = moderate disability, and >2 = severe disability. An increased score indicates a worsening of the disability. The percentage change from baseline to 12 months (12-month score minus baseline score divided by baseline score) is presented.

The analysis was conducted for participants who had both baseline and 12-month global HAQ assessments.

Treating physicians were asked to obtain a structural damage assessment by performing x-rays of the hands and feet approximately 1 year after the previous structural damage assessment that was done prior to the participant entering the study. The number of participants with radiological erosions evaluated at baseline and the 12-month visit are summarized by subgroup.

This analysis was conducted in the intent-to-treat population (591 participants total).