Knee OA predicts incident hand OA; more common in older age, female sex
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In patients with or at risk for knee osteoarthritis, older age is strongly associated a three-to-fivefold increase in prevalent radiographic hand OA, compared with younger ages, with significant age, sex and race interactions, according to data.
The researchers noted significant age-by-sex and age-by-sex-by-race interactions in their findings, with prevalent and incident hand OA particularly common in older age and female patients, and a strong inverse relationship among Black patients for prevalent radiographic and symptomatic hand OA, incident symptomatic hand OA and radiographic hand OA progression compared with whites.
“The prevalence and incidence of hand OA varies greatly depending upon the definition used, population analyzed and whether symptomatic hand OA is analyzed compared to radiographic hand OA,” Charles B. Eaton, MD, MS, of the Alpert Medical School of Brown University, in Providence, Rhode Island, and colleagues wrote. “Previous studies are limited by small sample sizes, single race, single sex, limited ages and only focusing on radiographic hand OA or symptomatic hand OA. Thus, prior studies leave an incomplete picture of the descriptive epidemiology of hand OA.
“Unresolved questions include to what extent do women have more hand OA than men adjusting for age and age by sex interactions, is the pattern of hand OA different for men and women, do Blacks have more or less hand OA than whites, are the risk factors for prevalent, incident and progression of radiographic hand OA similar for symptomatic hand OA,” they added. “Obtaining a comprehensive picture of the epidemiology of hand OA will allow for better understanding of the extent to which hand OA may be related to mechanical etiologies versus metabolic or systemic etiologies.”
To analyze the prevalence, incidence and progression of radiographic and symptomatic hand OA, as well as differences in age, sex and race risk factors, Eaton and colleagues examined data from the Osteoarthritis Initiative (OAI), a multicenter cohort study of 4,796 adults with, or at risk for, symptomatic knee OA. The researchers included 3,588 OAI participants with available hand radiographs at baseline and 48-month follow-up.
Eaton and colleagues examined radiographic and symptomatic hand OA at baseline and month 48 for incidence disease. For their analysis, they used a modified Poisson regression with a robust variance estimator to account for clustering of joints within fingers within persons, and estimated prevalence ratios and RR estimates associated with participant characteristics.
According to the researchers, prevalence figures were 41.4% for radiographic and 12.4% for symptomatic hand OA. Meanwhile, incidences over 48 months were 5.6 % for radiographic and 16.9% for symptomatic hand OA. In all, 27.3% included participants demonstrated OA progression over 48 months.
Eaton and colleagues reported finding complex differences by age, sex and race, with male and female sex associated with increasing prevalent hand OA with age. However, prevalence peaked at age 55 to 65 years with female sex. Additionally, female sex was associated with more symptomatic hand OA, compared with male sex, but only non-significantly higher rates for incident radiographic hand OA. Female sex was also associated with more distal interphalangeal (DIP) joint disease, while male sex was linked to more metacarpal joint OA.
Black participants demonstrated less hand OA than whites. Additionally, among Black participants, male sex was associated with more hand OA compared with female sex at younger ages.
“Our findings that knee OA predicts incident hand OA, and differences noted by sex and race, and the strong association with aging suggests a non-mechanical etiology for hand OA particularly in the DIP joints such as altered metabolic pathways, genetic or epigenetic factors may be operative,” Eaton and colleagues wrote. “Pathologic aging associated with chronic oxidative stress and chronic low levels of inflammation, may play an important role in the development of hand OA.
“Indeed, we and others have previously shown an association of shortened telomere length known to be a measure of pathologic aging was associated with incident radiographic hand OA,” they added. “Future work further exploring pathomechanistic pathways for hand OA appear indicated.”
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