Equity of publicly-funded hip and knee joint replacement surgery in New Zealand: results from a national observational study.

Aim: This study examines equity in the provision of publicly-funded hip and knee total joint replacement (TJR) surgery in New Zealand between 2006 and 2013 to: 1) investigate national rates by demographic characteristics; 2) describe changes in national rates over time; and 3) compare rates of provision between District Health Boards (DHBs).

Methods: Hospital discharge data for people aged 20 years or over who had at least one hip or knee TJR between 2006 and 2013 was obtained from the Ministry of Health's National Minimum Dataset.

Results: Higher TJR rates were observed among those aged 75-84 years, females, those of Māori ethnicity, those not living in rural or main urban areas and those in the most deprived socio-economic groups. TJRs increased from 7,053 in 2006 to 8,429 in 2013, however the rate was highest in 2007. In 2012-13, age-ethnicity-standardised rates varied between DHBs from 196 to 419/100,000 person years, with larger DHBs having lower rates than smaller DHBs.

Conclusion: There was evidence of geographic inequity in TJR provision across New Zealand. Despite increased numbers of procedures, rates of publicly-funded TJR surgery are barely keeping up with population increases. Reasons behind differences in provision should be examined.