Erosive hand osteoarthritis linked to greater radiographic progression, structural damage
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Erosive hand osteoarthritis tends to target older adults and women with preexisting OA, and is associated with severe articular structural damage and radiographic progression, according to data published in Arthritis & Rheumatology.
“The distinguishing characteristics of [erosive hand OA (EHOA)] suggest that pathological processes differ from those of typical [hand OA (HOA)],” Timothy E. McAlindon, MD, MPH, of Tufts Medical Center, in Boston, and colleagues wrote. “Better understanding the fundamental nature of EHOA could help clarify these processes and uncover potential therapeutic targets. In fact, the hypothesis that EHOA represents an inflammatory subtype has already predicated clinical trials of anti-cytokine therapy, however these have had mostly negative results, raising questions about the validity of the heuristic of EHOA as an inflammatory polyarthritis.”
“Moreover, scrutiny of erosions in osteoarthritic finger joints reveals heterogeneity in their localization (central vs. marginal) introducing potential for misclassification among joint diseases,” they added. “These considerations underscore the need to understand the nature of EHOA and its relationship with HOA, including the fundamental question as to whether it represents a separate entity or is simply a more severe manifestation of HOA. The identification of its risk factors and processes involved in its pathogenesis could also form a basis for discovery of potential therapeutic targets.”
To analyze the roles of age, sex, race, OA severity, metabolic factors and bone health in the risk for EHOA, both at baseline and over a 48-month period, McAlindon and colleagues studied a longitudinal cohort of participants from the Osteoarthritis Initiative (OAI). The OAI is a multicenter cohort study of 4,796 U.S. adults with, or at risk for, knee OA. For their own study, the researchers identified 3,365 OAI participants with complete hand radiographs at baseline and 48-month visits, and without prevalent EHOA at baseline.
The researchers defined EHOA as a Kellgren‐Lawrence (KL) grade of 2 or greater in at least one interphalangeal joint on two different fingers, and central erosion in at least one joint.
According to the researchers, a total of 86 included participants developed EHOA during the 48-month study period. Risk factors for incident EHOA were older age (relative risk [RR] per standard deviation = 0.76; 95% CI, 0.59-0.98), female sex (RR = 1.73; 95% CI, 1.05-2.85), greater OA severity (P < .001) and less cortical width (P < .001).
Following the 48-month period, patients who demonstrated EHOA were commonly characterized by greater progressions of radiographic osteoarthritis. This included joint space narrowing, KL grade progression (RRs = 1.35-1.9) and loss of cortical thickness (RR = 1.23), all adjusted for age, sex, race and BMI. EHOA was also characterized by baseline osteoarthritis severity, as measured by sum KL scores.
“Viewed in aggregate, our findings present a perspective of EHOA as a disorder of aging with a female predominance that occurs in the setting of preexisting osteoarthritis, and is strongly associated with both the severity of articular structural damage and its progression,” McAlindon and colleagues wrote. “Individuals who develop EHOA have thinner bones prior to its development and lose more bone and cartilage (even in joints without OA) as the disorder progresses. These observations, together with lower levels of physical activity and lower BMI (in women), paint a picture suggestive of musculoskeletal frailty and accelerated aging.”
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