Early referral to nephrological care improves long-term survival and hospitalization after dialysis initiation, independent of optimal dialysis start – a call for harmonization of reimbursement policies

Figures & data

Figure 1. Outline of the study.

Table 1. Baseline characteristics all patients and by predialysis care.

	All patients		Late referral		Early referral
	N	Median (25–75%)	N	Median (25–75%)	N	Median (25–75%)	p
Age at RRT initiation (years)	254	65 (54–72)	157	65 (54–74)	97	64 (56–70)	0.5
Charlson Comorbidity Index	247	6 (4–7)	150	6 (4–8)	97	6 (4–7)	0.3
Hemoglobin (g/dL)	242	9.0 (8.0–10.1)	145	8.4 (7.6–9.3)	97	9.8 (9.0–10.5)	<0.001
Ferritin (ng/mL)	237	302.5 (184.0–516.8)	144	319.6 (178.7–557.0)	93	300.0 (205.0–457.9)	0.4
Transferrin saturation (%)	228	19 (14–25)	142	18 (12–24)	86	22 (17–26)	0.002
Calcium (mg/dL)	239	8.5 (7.9–8.9)	143	8.2 (7.8–8.7)	96	8.8 (8.2–9.3)	<0.001
Phosphate (mg/dL)	241	5.2 (4.1–6.4)	144	4.7 (3.6–6.0)	97	5.6 (4.8–6.7)	<0.001
iPTH (pg/mL)	227	261 (157–432)	143	276 (168–510)	84	230 (137–359)	0.03
Bicarbonate (mEq/L)	232	21 (19–22)	145	21 (19–23)	87	20 (19–22)	0.4
Albumin (g/dL)	225	3.5 (3.1–3.9)	140	3.4 (3.0–3.7)	85	3.5 (3.2–4.2)	<0.001
		N (%)		N (%)		N (%)
Sex (female)	254	103 (40.6)	157	61 (38.9)	97	42 (43.3)	0.5
Sub-optimal dialysis start	254	203 (79.9)	157	153 (97.5))	97	50 (51.5)	<0.001
Diabetes mellitus	254	84 (33.1)	157	53 (33.8)	97	31 (32.0)	0.8
Anti-HTN treatment	254	227 (89.4)	157	142 (90.4)	97	85 (87.6)	0.5

RRT: renal replacement therapy; AVF: arteriovenous fistula; HTN: hypertension.

Figure 2. Kaplan–Meier curves for survival after dialysis initiation.

Table 2. Cox regression analysis of predictors of 3-year mortality after dialysis initiation.

	Hazard ratio (95% CI)	p
Age at RRT initiation (year)	1.044 (1.023–1.066)	<0.001
Sex (male)	1.215 (0.819–1.801)	0.3
Early referral	0.587 (0.351–0.987)	0.04
Charlson Comorbidity Index	1.102 (0.981–1.238)	0.1
Diabetes mellitus	1.113 (0.697–1.778)	0.7
Phosphate (mg/dL)	1.091 (0.967–1.232)	0.2
Albumin (g/dL)	0.776 (0.542–1.111)	0.2
Sub-optimal dialysis start	1.112 (0.582–2.124)	0.7

CI: confidence interval; RRT: renal replacement therapy.

Figure 3. Annual hospitalization rates in patients followed up to 3 years after RRT initiation.

Table 3. Logistic regression model of predictors of frequent hospitalizations after dialysis initiation.

	Odds ratio (95% CI)	p
Age at RRT initiation (year)	1.030 (1.0–1.062)	0.05
Sex (female)	0.769 (0.406–1.458)	0.4
Early referral	0.144 (0.051–0.402)	<0.001
Charlson Comorbidity Index	1.086 (0.906–1.303)	0.3
Diabetes mellitus	1.105 (0.524–2.329)	0.8
Sub-optimal dialysis start	2.39 (0.757–7.54)	0.1
Hemoglobin (10–12 g/dL)	0.516 (0.233–1.139)	0.1
Albumin (g/dL)	0.676 (0.372–1.226)	0.2
Constant	0.078 (0.005–1.226)	0.08

CI: confidence interval; RRT: renal replacement therapy.

Table 4. Predictors of 3-year mortality and frequent hospitalizations in early referral patients.

A. Cox regression model for predictors of mortality
	Hazard ratio (95% CI)	p
Age at RRT initiation	1.046 (1.007 − 1.086)	0.02
Sex (male)	1.621 (0.749 − 3.509)	0.2
Diabetes mellitus	2.818 (1.321 − 6.013)	0.002
Body mass index	0.892 (0.824 − 0.965)	0.005
Transferrin saturation (%)	1.015 (0.964 − 1.064)	0.6
Phosphate (mg/dL)	0.911 (0.715 − 1.161)	0.5
Iron supplements	1.6 (0.741 − 3.455)	0.2

Table

B. logistic regression model for predictors of frequent hospitalizations after RRT initiation
	Odds ratio (95% CI)	p
Age at RRT initiation	1.116 (1.014 − 1.229)	0.03
Sex (male)	0.403 (0.079 − 2.057)	0.3
eGFR at RRT initiation (mL/min (1.73 m^2)	1.166 (0.971 − 1.399)	0.1
Albuminuria (g/day)	1.371 (0.923 − 2.035)	0.1
Serum transferrin saturation (%)	1.073 (0.948 − 1.214)	0.3
Constant	0.000 (0.000 − 0.029)	0.004

Data availability statement

Data will be made available on reasonable request.