Early Referral of the Chronic Kidney Disease Patient is Good Practice

Abstract & Commentary

By Rahul Gupta, MD, MPH, FACP, Clinical Assistant Professor, West Virginia University School of Medicine, Charleston, WV. Dr. Gupta reports no financial relationships relevant to this field of study.

Synopsis: A meta-analysis demonstrates that earlier nephrologist referral leads to reduced mortality and hospitalization as well as better preparation and dialysis access placement.

Source: Smart NA, Titus TT. Outcomes of early versus late nephrology referral in chronic kidney disease: A systematic review. Am J Med 2011;124:1073-1080.

In the united states, the prevalence of end-stage renal disease (ESRD) is increasing to match its leading causative factors, such as diabetes and high blood pressure, which are responsible for up to two-thirds of the cases. According to the recent United States Renal Data System Annual Report, the number of patients enrolled in the ESRD Medicare-funded program has risen in the past 35 years by more than 50-fold, expanding from approximately 10,000 beneficiaries in 1973 to 547,982 as of December 31, 2008.1 We know that patients with ESRD consume a disproportionate share of health care resources. Thus, it should not come as a surprise to learn that the total cost of the ESRD program in the United States was approximately $39.46 billion in 2008, including overall Medicare costs of approximately $66,000 per person per year. Despite such substantial resource allocation, significant evidence gaps about how best to manage people with chronic kidney disease (CKD) continue to exist. A meta-analysis of data from 1980 through December 2005 compared the differences in mortality and the duration of hospitalization in patients with CKD who were referred early vs late to nephrologists.2 The study demonstrated significantly higher mortality and increased early hospitalization of CKD patients referred late to nephrologists as compared with earlier referrals. Because patients with CKD are at risk from both renal and cardiovascular adverse outcomes, it is conceivable that strategies to improve the management of people with CKD have the potential to offer more efficient, effective, and accountable utilization of our health service resources.

The aim of the study by Smart and Titus was to conduct a broader systematic review, examining the effect of early vs late referral of adult CKD patients to nephrologists not only on mortality and hospitalization, but also whether there was an impact on choice of dialysis modality, placement of relevant dialysis access, and other measures such as serum biochemistry. The authors conducted database searches to identify published studies of outcomes in patients with CKD receiving dialysis, including timing of referral to nephrology services which ranged from 1966 to September 2008. The review was based on prospective and retrospective cohort studies. Only 27 studies met the criteria for data extraction and only four of these studies were prospective cohort in design.

The study results demonstrated that patients who were referred earlier showed a cumulative mortality benefit at 3, 6, and 12 months, and 5 years compared with those referred late to nephrology services. The meta-analysis also demonstrated that those referred earlier to a nephrologist had a shorter hospitalization period (8.8 less days in hospital). When patients were referred earlier, peritoneal dialysis uptake was more common. Similarly, earlier referred patients were less likely to have a temporary vascular access and more likely to obtain a permanent access such as an arteriovenous fistula. In analysis of various blood chemistries, earlier referred patients had higher mean levels of hemoglobin, more erythropoietin usage, and lower levels of serum creatinine at the initiation of dialysis. However, the authors did not find any differences between early and late referred patients in sex distribution, prevalence of coronary artery disease, diabetes mellitus, systolic and diastolic blood pressures, or chronic obstructive airways disease, although the prevalence of cerebrovascular disease was significantly lower in early referrals. Similarly, the serum phosphate, albumin, lipids, and estimated glomerular filtration rate were not significantly different between these two groups. The authors calculated that the number of patients needed to be referred earlier to prevent one death at 1 year was 10 but was only five at 5 years.

Commentary

Results of the above meta-analysis reaffirm that when patients with CKD are referred earlier to a nephrologist, they suffer less mortality and hospitalization. However, this analysis also demonstrates that such benefits may not be related to traditional cardiovascular risk factors such as coronary artery disease, diabetes mellitus, hypertension, dyslipidemia, and abnormal renal biochemistry. Perhaps earlier placement of dialysis access, better hemoglobin, and earlier commencement of dialysis may explain the improved prognosis in earlier referred patients with CKD. Generally, patients with CKD should be referred to a nephrologist before the plasma creatinine concentration exceeds 1.2 and 1.5 mg/dL in women and men, respectively, or the estimated GFR falls below 60 mL/min per 1.73 m2. Along with the growing awareness within primary care practice to identify patients with CKD at an earlier stage in the disease process and initiate treatment strategies in order to delay progression of CKD, early nephrology referral allows the patient to have adequate time required to prepare and place dialysis access and further reduce mortality and hospitalizations. Early referral also allows the primary care physician to play a critical role in assisting with recruitment and evaluation of family members for the renal allograft placement prior to the dialysis need. As also evident by the above study, the role of the primary care physician remains key to managing comorbid conditions as well blood chemistries in the CKD patient.

References

1. United States Renal Data System, USRDS 2010 Annual Data Report: Atlas of Chronic Kidney Disease and End-Stage Renal Disease in the United States, National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, 2010.

2. Chan MR, et al. Outcomes in patients with chronic kidney disease referred late to nephrologists: A meta-analysis. Am J Med 2007;120:1063-1070.