Cardiovascular readmissions and excess costs following percutaneous coronary intervention in patients with chronic kidney disease: data from a large multi-centre Australian registry.

BACKGROUND: Chronic kidney disease (CKD) is a well-established risk factor for adverse events in patients undergoing percutaneous coronary intervention (PCI). However, few data exists on the subsequent healthcare resource use and related incremental costs in this patient subgroup. The present study compares the rates of cardiac-related hospitalisations and the associated direct costs, post-PCI in patients with and without CKD. METHODS: Healthcare costs were estimated for 12,998 PCI patient-procedures from the Melbourne Interventional Group (MIG) registry, collected between February 2004 and October 2010. Information collected included the use of cardiovascular drugs and cardiac-related hospitalisations from those that completed 12-month follow-up. Individual patients were assigned unit costs based on published data from the National Hospital Cost Data Collection for Admissions in Victoria (2008-2009) and the Pharmaceutical Benefit Scheme (PBS) schedule (2011-2012). Bootstrap multiple linear regression was used to estimate the direct excess healthcare costs, adjusting for age and gender and relevant comorbidities. RESULTS: Excess cardiac-related readmissions occurred among patients with "severe CKD or dialysis" (estimated glomerular filtration rate (eGFR): <30 ml/min/1.73 m(2); n = 330; 35%), compared to "moderate CKD" (eGFR: 30-60 ml/min/1.73 m(2); n = 2648; 28%), or the "referent CKD status" (eGFR: ≥ 60 ml/min/1.73 m(2); n = 10,020; 24%). On average, excess (95%CI) overall direct costs were significantly higher in patients with severe CKD or dialysis compared to those with referent CKD status [$AUD 2206 ($AUD 1148 to 3688)]. CONCLUSIONS: From the healthcare payer's perspective, PCI patients with severe CKD compared to no-CKD imposed significantly higher burden on subsequent healthcare resources. Hospitalisations accounted for the majority of these expenditures.