Timely Referral to Outpatient Nephrology Care Slows Progression and Reduces Treatment Costs of Chronic Kidney Diseases

Abstract

Introduction: We present a new approach to evaluate the importance of ambulatory nephrology care in patients with chronic kidney disease (CKD).

Methods: An anonymized health claims database of German insurance companies was searched in a retrospective analysis for patients with CKD using the codes of the International Classification of Diseases, 10th German modification. A total of 105,219 patients with CKD were identified. Patients were assigned to the group "timely referral," when nephrology care was present in the starting year 2009, or initiated during the following 3 years in CKD1-4. Using frequency matching for age and gender, 21,024 of the late referral group were matched with the equal number of patients in the timely referral group. Hospital admission rates, total treatment costs, and kidney function (change in CKD stages, start of dialysis, mortality) were documented each year during the 4-year follow-up.

Results: Hospital admission rates (110%-186%) and total treatment costs (119%-160%) were significantly higher (P < 0.03) in late referral compared with timely referral. In the timely referral group, significantly more patients did not change their CKD stage (65%-72.9% vs. 52%-64.6%, P < 0.05) compared with late referral. Starting in CKD3 more patients tended to start dialysis in 1 year in timely referral (1.9 ± 0.6 vs. 1.0 ± 0.4, P = 0.1). In contrast, death rates were significantly higher in the late referral group (18.8 ± 1.8% vs. 6.7 ± 0.4%, P = 0.0001).

Discussion: Timely referral to outpatient nephrology care is associated with slowed disease progression, less hospital admissions, reduced total treatment costs, and improved survival in patients with CKD.

Keywords: chronic kidney diseases; hospital admission rates; mortality; progression of renal insufficiency; timely referral to nephrology care; treatment costs.

Figure 1

Frequency matching for gender and age using 5-year intervals. The paired bars represent the percentage of patients in the particular age group. Total numbers of women and men and mean ages ± SD are given.

Figure 2

Hospital admission rates per patient per year. Bars represent the median (min/max) of n = 4 years (2009–2012) for patients with CKD3–5 and dialysis treatment. P values are given for comparison of the paired bars. The median (min/max) numbers of patients timely versus late were, for CKD3, n = 6724 (5759/8151) versus n = 5137 (4219/6128); for CKD4, n = 1682 (1395/1988) versus n = 1064 (728/1392); for CKD5, n = 447 (361/548) versus n = 259 (181/316); and for hemodialysis, n = 2593 (2521/2695) versus n = 778 (616/909). CKD, chronic kidney disease.

Figure 3

Total costs per patient per year in Euro (€). Bars represent the median (min/max) of n = 4 years (2009–2012) for patients with CKD3–5 and dialysis treatment. P values are given for comparison of the paired bars. For numbers of patients in the analyzed groups, see the legend of Figure 2. CKD, chronic kidney disease.

Figure 4

Total number of patients with stable kidney function in transition from one year to the next. Mean percentages of patients with stable disease in the 2 groups are given in the table underneath. P values are depicted. CKD, chronic kidney disease.

Figure 5

Stability of kidney function, start of dialysis, and mortality in patients starting with CKD stage 3. The bars represent the means ± SD of n = 3 transitions from one year to the next (2009/2010, 2010/2011, 2011/2012). P values for significant changes are given, for comparison of the paired bars. The numbers of patients timely versus late were 3934 versus 2337, 4830 versus 2600, and 6132 versus 3437 for the 3 time points. CKD, chronic kidney disease.

Figure 6

Kaplan-Meier analysis on the probability of patient survival in patients with CKD3 starting in 2009. The numbers at risk are depicted in the table underneath. The log rank is highly significant with P = 0.0001. CKD, chronic kidney disease.