Achievement of lupus low disease activity state (LLDAS) in a New Zealand cohort: a prospective study of ethnic differences in outcomes.

Objectives: To examine ethnic differences in LLDAS attainment and lupus nephritis (LN) in SLE patients from the Auckland, New Zealand (NZ) cohort of the Asia Pacific Lupus Collaboration (APLC) treat-to-target (T2T) Lupus Low Disease Activity State (LLDAS) study. Secondary outcomes were to explore ethnic differences in medication use, SLE damage and patient-reported health outcomes.

Methods: All patients fulfilled either the 1997 American College of Rheumatology classification criteria for SLE or Systemic Lupus International Collaborating Clinics 2012 classification criteria. At each study visit, patients were assessed for LLDAS attainment, flares and medication use and assessed annually for SLE damage and patient-reported health outcomes.

Results: A total of 141 patients from three Auckland tertiary hospitals were analysed during 2018-2020. Seventy-five percent (n = 106) of patients achieved LLDAS on at least one occasion. There was a statistically significant difference in attainment of LLDAS across the three sites in Auckland, where patients from South Auckland exhibited significantly lower LLDAS rates [37% (n = 14)] compared with the other two sites (88-90%; P < 0.0001). Forty of 141 (28%) had LN. Non-NZ European patients had proportionally more proliferative (class III/IV) LN compared with NZ European patients [n = 28/34 (82%) and 2/6 (33%), respectively; P = 0.01]. A total of 55% (n = 78) of the cohort had ever used prednisone.

Conclusion: This is the first NZ study to provide prospective data on SLE disease outcomes. The majority of patients were able to achieve LLDAS. There were ethnic differences in proliferative LN with overrepresentation in non-NZ European ethnic groups.