Prevalence, Incidence, and Progression of Radiographic and Symptomatic Hand Osteoarthritis: The Osteoarthritis Initiative.

Objective: To describe the prevalence, incidence, and progression of radiographic and symptomatic hand osteoarthritis (OA), and to evaluate differences according to age, sex, race, and other risk factors.

Methods: Participants were assessed for radiographic and symptomatic hand OA at baseline and year 4 to determine incident disease. A modified Poisson regression with a robust variance estimator was used to account for clustering of joints within fingers within persons to estimate the prevalence ratios and relative risk estimates associated with participant characteristics.

Results: Among 3,588 participants, the prevalence of radiographic hand OA was 41.4%, and the prevalence of symptomatic hand OA was 12.4%. The incidence over 48 months was 5.6% for radiographic hand OA and 16.9% for symptomatic hand OA. Over 48 months, 27.3% of the participants exhibited OA progression. We found complex differences by age, sex, and race, with increasing rates of prevalent hand OA with older age in both men and women, but with rates of incident disease peaking at ages 55-64 years in women. Women had higher rates of symptomatic hand OA, but only nonsignificantly higher rates of incident radiographic hand OA, than men. Women more frequently had distal interphalangeal joint disease, while men more frequently had metacarpophalangeal joint OA. Black men and women had lower rates of hand OA than White participants, but Black men had higher rates of prevalent hand OA than Black women at younger ages.

Conclusion: Hand OA is a heterogeneous disease with complex differences by age, sex, race, hand symptoms, and patterns of specific joints affected. Further research investigating the mechanisms behind these differences, whether mechanical, metabolic, hormonal, or constitutional, is warranted.