Certain inflammation markers may predict advanced knee OA years before onset

CHICAGO — High effusion-synovitis volume levels and the presence of infrapatellar fat pad signal intensity alteration were predictive of advanced knee osteoarthritis up to 2 years before disease onset, according to data presented at the ACR/ARHP 2018 Annual Meeting.

Julie Davis, BS, MPH candidate at The George Washington University, defined advanced knee OA (AKOA) as “a unique subset of KOA characterized by sudden onset and progression to advanced-stage disease in 48 months, and often in less than 12.”

“These individuals experience greater symptoms, including greater pain and dysfunction, than those with commonly progressing OA,” she said during a presentation.

Data from the Osteoarthritis Initiative (OAI) showed that more than one in five adults with KOA were later diagnosed with AKOA. In addition, one in 14 knees of patients with AKOA were replaced within 2.5 years of initial evidence of radiographic progression, “leaving a very small window of opportunity to intervene with these patients,” Davis said.

“Therefore, it’s crucial to recognize the early signs of AKOA,” she added.

In magnetic resonance (MR) images, markers of inflammation, particularly effusion-synovitis — which is a combined measure of effusion and synovitis volume — and infrapatellar fat pad (IFP) signal intensity alteration — the measure of changes in signal intensity — have been previously linked to radiographic KOA, bone marrow lesions, histological chronic synovitis and pain, according to Davis.

“That being said, these may be early markers of AKOA given their greater pre-radiographic pain, dramatic onset and progression,” she said. “However, it’s unclear if either of these are associated with AKOA. Therefore, we aimed to determine whether greater effusion-synovitis and/or IFP signal intensity alteration over time are predictive of AKOA compared to gradual onset of KOA or no KOA.”

Davis and colleagues used data from the OAI to further investigate the impact of effusion-synovitis and IFP signal intensity alteration on AKOA development over a 48-month period. Their analysis included 125 patients with AKOA, which was defined as an increase in a Kellgren-Lawrence (KL) grade from 0 or 1 to 3 or 4.

“So, that’s going from a completely normal appearance to end-stage within that 48-month time period,” Davis said.

Patients diagnosed with AKOA were matched with 125 participants with common KOA and 125 participants who had no change in KL grade from baseline to the end of the observation period.

At baseline, patients with AKOA were more likely to be older, with a mean age of 62.5 years vs. 58.4 years for KOA and 57.3 years for no KOA. They also had a slightly elevated BMI of 29.7 kg/m² vs. 28.1 kg/m² for KOA and 26.9 kg/m² for no KOA.

Up to 2 years before onset, patients with AKOA had significantly higher levels of effusion-synovitis volume than patients with common KOA and no KOA. This finding persisted up to 2 years after AKOA onset.

Patients with AKOA also had more than twice the odds of presenting with IFP signal intensity alteration up to 2 years before onset compared with patients with no KOA. Up to 2 years after onset, the odds for IFP signal intensity were greater in the AKOA group than both the KOA and no KOA group.

There were no significant differences in either inflammation measure among patients with KOA and no KOA at any point. Findings from five sensitivity analyses adjusted for factors such as age, BMI and injury yielded similar results.

“More than 2 years prior to [onset], more than 50% of the adults with AKOA had IFP signal intensity alteration and an average of about 44% greater effusion-synovitis volume than their counterparts,” Davis said. “Because of this, clinicians should consider the implications of early interventions among these patients, including increasing the frequency of the visits, more MRIs for the KOA patients and the potential for earlier knee replacements. Additionally, it may be helpful for future studies to test whether modifying local evidence of inflammation would reduce an overall risk for AKOA.” – by Stephanie Viguers

Reference:

Davis JE, et al. Abstract 952. Presented at: ACR/ARHP Annual Meeting, Oct. 20-24, 2018; Chicago.

Disclosure : Davis reports no relevant financial disclosures.