Abstract
BACKGROUND: The quality of care received by a growing number of older patients with chronic kidney disease (CKD) has not been adequately examined. OBJECTIVE: The objective of this study was to assess the quality of CKD care among older patients and to clarify its association with the incidence of end-stage renal disease (ESRD). RESEARCH DESIGN: This was a population-based cohort study. SUBJECTS: Older (65 y and above) CKD patients diagnosed between October 2010 and September 2014 from the National Database of Health Insurance Claims of Japan. MEASURES: A composite quality score (QS) of 3 quality measures for CKD care during the 6 months after CKD diagnosis was computed. The validated quality measures included urine testing for proteinuria, nutritional guidance, and nonsteroidal anti-inflammatory drugs avoidance. To assess the association between the QS and ESRD incidence, we used instrumental variable analysis after stratification for the history of diabetes. RESULTS: Among the 890,773 older CKD patients, 2.9% progressed to ESRD (incidence rate of 12.5 per thousand person-years). In total, 59.9% underwent urine testing, 4.5% received nutritional guidance, and 91.2% avoided regular use of nonsteroidal anti-inflammatory drugs. An instrumental variable analysis revealed that a higher QS was associated with-lower ESRD incidence in patients diagnosed with diabetes (hazard ratio: 0.25, 95% confidence interval: 0.24-0.27 for each point higher score) but not in patients without a diagnosis of diabetes (hazard ratio: 0.99, 95% confidence interval: 0.92-1.05). CONCLUSION: Among older CKD patients, quality of CKD care varied between patients, and better quality of CKD care was associated with a lower ESRD incidence in patients with diabetes but not in nondiabetic patients.