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Calcific uraemic arteriolopathy (CUA), is a devastating complication seen in patients with chronic kidney disease (CKD). Despite an increasing awareness and incidence worldwide, there has been little progress regarding effective therapies. Sodium thiosulfate (STS) continues to prove a controversial topic in the literature and yet is used regularly in some renal units due to a lack of better options. Aside from case reports, there is no published literature looking at CUA in the New Zealand CKD population, which has a high prevalence of CKD in indigenous Māori patients.
This study is a retrospective analysis of all patients diagnosed with CUA in the Counties Manukau catchment area in Auckland, New Zealand, from 2004 to 2020. Demographic, dialysis, CUA-related and medical history factors were collected and compared against treatment received, and against one-year and overall mortality. Furthermore, data from 2004-2012 and 2012-2020 was compared to ascertain trends in the disease burden and changes in clinical practice over time.
64 patients diagnosed with CUA were identified across the study period. These patients were predominantly obese (mean BMI 36.6 kg/m2), female (65%) and diabetic (65%) with the majority undergoing haemodialysis (69%). 45% of patients were of Māori descent, 31% of patients were Pasifika, 20% were NZ European. The overall one-year mortality was 56%. When comparing the period 2012 – 2020 with 2004 – 2012, there were more than double the cases of CUA identified. There were more patients with diabetes and hypertension, fewer patients on warfarin, an increasing use of STS and a decreasing use of parathyroidectomy in the latter period.
In univariable analysis, an older age, the presence of diabetes and increasing comorbidities were found to be independent risk factors for mortality. An increased serum albumin and having had a surgical parathyroidectomy prior to the diagnosis of CUA were associated with a lower mortality risk. In multivariable analysis, dialysis intensification and parathyroidectomy prior to the diagnosis of CUA were the only two treatment modalities found to be associated with reduced mortality. There was no mortality benefit seen with STS alone or when combined with other adjunctive treatments.
This is the largest analysis of patients with CUA in the Australasia-Pacific region to date, and the first in New Zealand. Demographic features such as female sex, age > 60 years old and hypoalbuminaemia identified as associated risk factors are in line with data from other international registries. One-year mortality is similarly comparative. However, this study highlights that Māori patients are disproportionately affected, in part reflecting the high prevalence of CKD in our indigenous population. This study highlights the glaring lack of advancement in treatment options for CUA over the last twenty years. This points to the need towards a greater focus on aggressive control of risk factors such as protein-calorie malnutrition, obesity and CKD-MBD parameters prior to the development of this devastating disease.