Interprovincial differences in the achievement of K/DOQI targets of mineral metabolism in Canada

Abstract

Abnormalities in mineral metabolism in chronic kidney disease are associated with increased morbidity and mortality. The Kidney Disease Outcomes Quality Initiative (K/DOQI) clinical practice guidelines were established in 2003 to address issues in the management of mineral and bone metabolism. The goal of this study was to compare (i) mineral metabolism control among Canadian haemodialysis (HD) patients with K/DOQI-defined targets and Dialysis Outcomes and Practice Patterns Study II (DOPPS II) data and (ii) the effect of different treatment strategies. A cross-sectional study of 2215 HD patients was conducted. Phosphorus (P), calcium (Ca), intact parathyroid hormone (iPTH) and calcium-phosphate product (CaXP) were analysed. In addition, management was compared between provinces with more or less restricted access to the phosphate binder sevelamer. K/DOQI targets for P, Ca, iPTH and CaXP K/DOQI targets were met by 59.7%, 58.6%, 29.7% and 83.3%, respectively. A greater proportion of patients were within target compared with those in DOPPS II (2002-2004). Targets were more likely to be reached by patients residing in provinces with formularies allowing less restricted access to sevelamer: P: 61.8% vs 55.7% (P = 0.01); CaXP: 85.5% vs 79.1% (P = 0.0006). As expected, patients in provinces with more restrictive formularies were more often receiving doses of elemental calcium > 1.5 g/day than those with more open listings (62.1% vs 14.0%, P < 0.0001) and were less likely to receive sevelamer (14.1% vs 42.4%, P = 0.0001). Mineral metabolism parameters were more frequently within the target range amongst (i) patients in the current study compared with those in the DOPPS II era and (ii) patients in provinces with less restricted access to sevelamer.