UK Renal Registry 12th Annual Report : Chapter 10: Biochemistry profile of patients receiving dialysis in the UK in 2008 : national and centre-specific analyses

Introduction: The UK Renal Association Clinical Practice Guidelines include clinical performance measures for biochemical parameters in dialysis patients [1]. The UK Renal Registry (UKRR) annually audits dialysis centre performance against these measures as part of its role in promoting continuous quality improvement. Methods: Cross sectional performance analyses were undertaken to compare dialysis centre achievement of clinical performance measures for prevalent haemodialysis (HD) and peritoneal dialysis (PD) cohorts in 2008. The biochemical variables studied were phosphate, adjusted calcium, calcium phosphate product, parathyroid hormone, bicarbonate, total cholesterol and HbA1c. In addition, longitudinal analyses were performed (2000–2008) to show changes in achievement of clinical performance measures over time. Results: Serum phosphate was between 1.1 and 1.8 mmol/L in 55% of HD and 64% of PD patients, which was similar to 2007. There was a fall in overall mean phosphate concentration to 1.55 mmol/L. A revised adjusted serum calcium target of 2.2–2.5 mmol/L was achieved by 63% of HD and 65% of PD patients. For comparison, the previous target of 2.2–2.6 mmol/L was achieved by 74% and 78% respectively, a figure little changed since 2005. The downward trend in serum calcium results evident for the previous nine years appears to have halted. The calcium phosphate target of <4.8 mmol2/L2 was achieved by 84% of HD and 87% of PD patients, continuing the steady improvement over the past nine years and reflecting the downward trend in phosphate results. As in previous years, a minority of patients achieved the PTH target range of 16–32 pmol/L and there was considerable heterogeneity between centres. Although analytical and biological variability may have contributed to this, centres achieving the standards relating to one mineral parameter tended to achieve the standards in others suggesting that treatment factors were also relevant. The audit measure for bicarbonate was achieved in 71% of HD and 82% of PD patients. Eighty-five percent of HD patients and 69% of PD patients achieved a value for total cholesterol <5 mmol/L. This was the first year that HbA1c has been audited. Overall, 43% of diabetic dialysis patients exceeded the target of 7.5% HbA1c and there was considerable variation between centres. Conclusion: There is wide variation between centres in attainment of biochemical performance measures. There is some evidence in bone mineral metabolism that centres performing well in one variable are more likely to also meet the other standards. The inter-centre variation may be explained in part by laboratory practices and case mix but probably also represents variation in practice and in effectiveness of processes of care. Apart from glycaemic control there are a number of analytical and clinical factors that affect HbA1c that would be worthy of further investigation as a cause of variability.