- Osteoarthritis (OA) might increase the rate at which people become more frail by limiting their physical activity but also by other mechanisms.
- It wasn’t known whether OA affecting multiple joints worsens frailty beyond that seen with single-joint OA, prompting this analysis of Canadian patients in a long-term, prospective study of aging.
- Compared with patients with single-joint or no OA followed for 6 years, those with multi-joint OA showed greater and more rapidly progressing frailty even after adjusting for differences in physical activity and other parameters.
Frailty worsened more for individuals with osteoarthritis (OA) affecting two or more joints versus those with single-joint or no OA, data from a long-running, population-based study indicated.
Among more than 1,000 participants in the Canadian Longitudinal Study on Aging (CLSA) with multi-joint OA, their mean degree of frailty started off higher and accelerated further through 6 years of follow-up, even after adjusting for sex, age, body mass index, and, crucially, physical activity, according to Myles O’Brien, PhD, of Sherbrooke University in Quebec, and colleagues.
“Individuals in the two-or-three osteoarthritis joint groups experienced approximately a 40-47% faster rate of frailty progression compared with those without osteoarthritis despite starting at a higher baseline frailty,” the researchers wrote in Arthritis Care & Research.
“These findings reinforce the conceptualization of osteoarthritis as a multi-joint, systemic condition and highlights it as an important determinant of frailty trajectories,” they continued. Clinicians, they added, should pay attention to “frailty in individuals with multi-joint osteoarthritis to support risk stratification and guide supportive care approaches aimed at maintaining function and independence.”
That OA in general contributes to frailty is well known and hardly surprising, but research over the last few decades has suggested that the relationship goes beyond reduced physical activity. “Beyond physical pathways, osteoarthritis-related pain and disability may contribute to depression and social isolation by limiting participation in social and community activities, while greater symptom burden often necessitates increased medication use, raising the risk of polypharmacy, both of which are independently associated with frailty progression,” O’Brien and colleagues observed.
In addition, they noted, the interaction goes the other way too: frailty increases risks for hospitalization and lengthens recovery times, and it may worsen perceived joint pain. But whether the number of joints affected with OA worsened frailty hadn’t been distinguished by prior studies.
To examine this issue, O’Brien’s group drew on the CLSA, which got underway in 2012 and eventually enrolled about 30,000 individuals ages 45-85 at baseline. (This study did not enroll some segments of the Canadian population: people in the three far-northern territories, those with cognitive impairments, members of the military, and the institutionalized.)
About half of CLSA’s total enrollment were excluded from the current analysis because they missed too many follow-up visits to gauge frailty progression adequately. However, O’Brien and colleagues looked at characteristics for those excluded from the analysis and while some differences were statistically significant, they were all minor in absolute terms.
In total, 13,757 individuals’ frailty trajectories were analyzed: 10,193 with no OA, 2,535 with single-joint OA, 806 with two-joint OA, and 223 with three-joint OA.
Frailty scoring included 86 measures of chronic illnesses, overall health (self-rated), mental health and cognition, abilities in activities of daily living, hearing and vision, and respiratory and cardiovascular conditions. CLSA members lacking data on at least 80% of these measures were excluded. Scores were expressed on a 0-1 scale. At baseline, mean frailty scores increased with increasing OA involvement, ranging from about 0.14 for those with no OA to 0.20 for participants with three-joint OA.
All groups became frailer over the 6 years of follow-up, but the rate of progression also generally increased with greater OA involvement. Slopes for progression rates were as follows (in points per year of follow-up):
- No OA: 0.237
- One joint: 0.293
- Two joints: 0.348
- Three joints: 0.330
Combining the two- and three-joint groups as multi-joint OA, their average slope for frailty progression was 0.070 points per year higher than for the single-joint group (95% CI 0.029-0.109).
Notably, these calculations adjusted for self-reported sitting time, light to moderate physical activity, and strenuous physical activity, indicating that the faster progression was not just because individuals lost muscle strength through sedentarism. As well, participants were re-examined every 3 years, so changes from baseline in these and other parameters could be taken into account.
Limitations included reliance on participants’ self-reports for some data and lack of information on OA severity. OA status was set at baseline for statistical analysis, irrespective of whether it developed anew during follow-up or it expanded from one joint to two or more. As well, only OA affecting the hands, hip, or knees was considered. And the study’s conduct in Canada might limit generalizability to other locales.
