04.06.2015

Ultrasound exams were able to detect which patients with hand osteoarthritis (OA) were likely to have disease progression, according to Norwegian researchers.

A strong and dose-responsive association was seen between the presence of ultrasound-detected inflammatory features and radiographic progression approximately 5 years later in hand OA patients, reported Alexander Mathiessen, MD, of Diakonhjemmet Hospital in Oslo, and colleagues.

In an adjusted analysis, Kellgren-Lawrence (KL) progression after 5 years was strongly predicted by the presence of ultrasound-detected gray-scale synovitis at baseline, at an odds ratio of 3.3 (95% CI 2.4-4.6, P≤0.01) and by power Doppler signals (OR 5.0, 95% CI 2.6-9.4, P≤0.01) compared with joints without ultrasound inflammation at baseline, they wrote in the Annals of the Rheumatic Diseases.

Both gray-scale (GS) and power Doppler (PD) significantly predicted all measures of individual radiographic features, they added.

“This longitudinal study of patients with hand OA demonstrated that ultrasound findings reflecting inflammation could predict future radiographic progression on a joint level,” the authors wrote. “These findings support [the fact] that inflammation is involved in the pathogenesis of hand OA and indicate that … ultrasound [can be used] as a tool to detect patients with hand OA who are likely to progress.”

The Oslo Hand OA cohort consisted of patients with hand OA recruited from the rheumatology outpatient clinic at Diakonhjemmet Hospital. The investigators used data from 2008 to 2009 as their baseline findings and data collected in 2013 as their follow-up data point.

A total of 78 participants (mean age 67.8) who had available ultrasound examinations and conventional x-ray at baseline and 5–year follow-up were included in the analysis.

Each subject had 30 joints imaged, and gray-scale synovitis and power Doppler activity in finger joints were scored according to a semiquantitative scoring system.

One experienced rheumatologist blinded to imaging results performed a clinical examination of soft tissue swelling in all finger joints bilaterally, assessed as absent or present.

“At baseline, 73 (93.6%) and 33 (42.3%) of patients had GS synovitis and PD present in one or more joints, respectively,” the authors observed.

GS synovitis was associated with erosive development (OR 6.0, 95% CI 3.6-10.2, P≤0.01), joint space narrowing (JSN) progression (OR 4.0, 95% CI 2.9-5.6, P≤0.01), and radiographic osteophyte progression (OR 3.8, 95% CI 2.7-5.4).

Power Doppler signals most strongly predicted osteophyte progression (OR 7.6, 95% CI 4.5-12.6, P≤0.01), followed by erosive development (OR 7.0, 95% CI 2.8-17.8, P=0.003), and JSN (OR 5.2, 95% CI 2.7-10.1, P≤0.01).

All differences between comparator groups were significant unless otherwise stated.

Omitting some 232 joints with baseline features that had no potential for progression, progression of KL grade was found in almost 18% of the remaining joints.

JSN and osteophytes developed or progressed in approximately 12% of remaining joints, while erosions developed or progressed in 4.5% of the joints.

“Joints with severe GS synovitis (grade 3) at baseline had two to five times higher risk of radiographic progression than joints with moderate synovitis (grade 2) and similarly for moderate versus mild synovitis,” the authors noted.

A similar dose-response association was seen between levels of moderate and severe power Doppler signals and progression of radiographic KL grade, osteophytes, and JSN, they added.

With additional adjustment for KL grade, both gray-scale and power Doppler remained significant and dose-responsive predictors for all radiographic features except for erosive development in joints with power Doppler signals grades 2 to 3, the authors stated.

They noted that baseline gray-scale synovitis was a weaker predictor for KL progression in patients with the lowest OA loading, although it remained a strong predictor among patients with a higher loading of OA.

Presence of soft tissue swelling by clinical examination at baseline also predicted radiographic progression of hand OA, with the strongest association for erosion (OR 5.3, 95% CI 3.6-7.8) and JSN (OR 3.0, 95% CI 2.0-4.5).

Study limitations include the fact that the reader knew the order the radiographs had been taken, which could have led to an overestimation of radiographic progression.

Also, the current available ultrasound atlas on inflammation is also based on patients with RA so whether the scoring system is transferable to patients with hand OA needs to be explored, the authors stated.

Finally, a reliability exercise of the clinical examination of soft tissue swelling of the hand was not performed.

“This study confirmed with ultrasound that both GS synovitis and PD activity are risk factors for radiographic progression in hand OA,” the investigators concluded. “Thus, by detecting inflammation, ultrasound could prove beneficial in predicting future radiographic progression and be used in prospective medical trials of hand OA.”

• Reviewed by Robert Jasmer, MD Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, BSN, RN, Nurse Planner

LAST UPDATED 04.07.2015