Introduction: Comorbidities are significant predictors of mortality and other adverse outcomes. Case-mix adjustment is integral to quality reporting, risk adjustment in clinical research, resource allocation and management of patients with comorbid conditions in day to day practice such as dialysis access formation and transplant wait-listing. This study describes the comorbidity data submitted to the UK Renal Registry (UKRR) in incident renal replacement therapy (RRT) patients and examines the association between these comorbidities and early mortality.
Methods: Incident patients reported to the UKRR with comorbidity data in 2011 and 2012 (n = 7,085) were included in analyses exploring the association of comorbidities with patient demographics and treatment modality. For analyses examining the association between comorbidities and survival, adult patients starting RRT between 2007 and 2012 in centres reporting to the UKRR with comorbidity data were included. The relationship between comorbidities and mortality at 90 days and one year after 90 days from start of RRT were explored using Cox regression.
Results: Completeness of comorbidity data was 55% in 2012 compared with 56% in 2007. Of patients with data, 52.9% had one or more comorbidities. Diabetes mellitus and ischaemic heart disease were the most common conditions, observed in 35% and 19% of patients respectively. Fourteen percent of incident RRT patients in the 2-year period were recorded as current smokers. The prevalence of comorbidity increased with increasing age across all ethnic groups. In multivariable survival analysis, malignancy and liver disease were strong independent predictors of poor survival at 1-year after 90 days from the start of RRT in patients <65 years.
Conclusions: Continuing efforts from renal centres to improve data capture in addition to the use of data linkage and statistical techniques such as multiple imputation by the UKRR are likely to lead to enhanced case mix adjustment in the future.
© 2014 S. Karger AG, Basel.