Changes in Hemoglobin Levels Over Time among Patients with RA

A registry-based study investigated the change in hemoglobin (Hb) levels progression over time among patients with rheumatoid arthritis and assessed the relationship between Hb levels and arthritis treatment. This study, which utilized data from the Brigham and Women’s Hospital Rheumatoid Arthritis Sequential Study (BRASS) registry, was presented at the American College of Rheumatology (ACR) Convergence 2021.

The BRASS study is a prospective observational study of more than 1,500 patients with RA who were treated at the Robert Breck Brigham Arthritis Clinic in Boston, MA. Enrollment began in 2003, with a four-year average follow-up rate of 80%. Some patients have follow-up data of up to 18 years.

Using these data, the investigators of this study evaluated Hb levels and total Sharp scores (TSS) in this population. Hb levels were categorized as low (Hb <120 g/L for women and <130 g/L for men) or normal (Hb ≥120 g/L for women and ≥130 g/L for men). Assessment variables included the distributions of Hb at baseline in the overall cohort and between current medication subgroups (anti-tumor necrosis factor [TNF], biologic disease-modifying antirheumatic drug [DMARD], non-biologic DMARD) and patients demographics and disease characteristics overall and according to Hb level. Other variables included changes over time in Hb and TSS, overall, according to Hb level, and according to current medication.

In total, 224 patients had low Hb at baseline. These patients tended to have longer disease duration, increased disease activity, and more pain compared to those with normal Hb. Additionally, patients with low Hb levels were also more likely to be at lower income levels, have less education, and identify as a race/ethnicity other than Caucasian.

Regarding current medication, patients with low Hb were less frequently methotrexate (MTX)-experienced or receiving anti-TNF plus MTX or biologic DMARDs compared with those patients with normal Hb. Baseline use of non-biologic DMARDs and non-steroidal anti-inflammatory drugs were more common in the low versus normal Hb groups.

For patients with ten-year observation data, patients with low Hb at baseline had consistently lower levels of compared with the normal Hb group. However, the average Hb levels in the low Hb groups showed a study increase over time, across all treatment subgroups. The researchers also reported a greater increase in TSS over time for patients with low versus normal Hb.

“Patients with low Hb who were treated with anti-TNFs, biologic DMARDs, or non-biologic DMARDs experienced sustained improvements in Hb levels over time. Patients with lower Hb levels at baseline tended to have increased radiographic progression as measured by TSS compared to RA patients with normal Hb levels. Future analyses may evaluate constant therapy and non-constant therapy cohorts and disease severity cohorts.”