Joint replacement rates for New Zealanders with RA have not declined in the last decade, a finding that experts say could reflect the strict eligibility criteria for biologics imposed on its citizens.

The analysis of joint replacement surgery rates between 1999 and 2015 found that with the exception of elbow replacements, rates of hip, knee, shoulder, and ankle replacement for RA remained stable over time.

Writing in the Journal of Rheumatology rheumatologist Professor Lisa Stamp and colleagues the University of Otago in New Zealand said that biologic DMARDs had been funded since 2006 but were not available for people without evidence of radiographic progression until 2017.

“Given the relatively strict eligibility criteria for bDMARD, it is possible that this use of bDMARD (once joints have radiographic damage) may lessen the anticipated decline in rates of joint replacement,” they wrote.

They conceded that overall the rates of joint replacement were low because access to joint replacement in the public system was restricted to people with severe functional limitation.

The figures showed a substantial increase in joint replacement in people with osteoarthritis.