The importance of early referral for the treatment of chronic kidney disease: a Danish nationwide cohort study

BMC Nephrology

Table 1 Characteristics of late versus early nephrology referrals before renal replacement therapy start

	Late referrals^a	Early referrals^b	P value
Incident RRT patients, n	1727	2768
Age, median (IQR)	67 (55–75)	63 (52–73)	<.001
Women, n (%)	653 (38%)	1024 (37%)	.58
Age women, median (IQR)	68 (54–75)	64 (51–73)	<.001
Patients aged ≥70 years, n (%)	720 (42%)	905 (33%)	<.001
Women in patients aged ≥70, n (%)	278 (39%)	340 (38%)	.67
Ethnic origin non-western countries^c, n (%)	65 (4%)	132 (5%)	.11
Ethnic origin western countries^d, n (%)	43 (2%)	68 (2%)	.94
Diabetic end-stage renal disease^e, n (%)	348 (20%)	706 (26%)	<.001
Adult polycystic kidney disease^f, n (%)	57 (3%)	261 (9%)	<.001
Chronic glomerulonephritis^g, n (%)	138 (8%)	346 (13%)	<.001
Comorbidity
Acute myocardial infarction^h, n (%)	99 (6%)	119 (4%)	.03
Strokeⁱ, n (%)	81 (5%)	81 (3%)	.002
Cancer in total^j, n (%)	216 (13%)	156 (6%)	<.001
Cancer in the urinary tract^k, n (%)	49 (3%)	34 (1%)	<.001
Genital cancer^l, n (%)	41 (2%)	43 (2%)	.05
Bacteraemia^m, n (%)	48 (3%)	62 (2%)	.25
Days in hospital, medianⁿ (IQR)	28 (14–52)	16 (5–37)	<.001
Visits in general practice, medianⁿ (IQR)	11 (5–20)	10 (5–19)	.08
Patients 30–69 years, n	924	1748
Primary school only, n (%)	420 (45%)	731 (42%)	.07
Low income^o, n (%)	566 (61%)	1001 (57%)	.05

Abbreviations: RRT, renal replacement therapy; IQR, interquartile range.
^aLate referrals: Course in a nephrology department ≤16 weeks.
^bEarly referrals: Course in a nephrology department >16 weeks.
^cWestern countries: Andorra, Australia, Canada, EU, Iceland, Monaco, New Zealand, Norway, San Marino, Switzerland, USA and the Vatican State.
^dNon-western countries: those not being western countries or Denmark.
^eDiabetic end-stage renal disease (ICD-10 E10–E14).
^fAdult polycystic kidney disease (ICD-10 Q61).
^gChronic glomerulonephritis (ICD-10 N00–N08).
^hAdmitted to hospital within 2 years before RRT start with ICD-10 diagnoses: I21 or I22.
ⁱAdmitted to hospital within 2 years before RRT start with ICD-10 diagnoses: I60, I61, I62, I63 or I64.
^jAdmitted to hospital or course in outpatient clinic within 2 years before RRT start with ICD-10 diagnoses: C00–C43 or C44–C99.
^kAdmitted to hospital or course in outpatient clinic within 2 years before RRT start with ICD-10 diagnoses: C64–68.
^lAdmitted to hospital or course in outpatient clinic within 2 years before RRT start with ICD-10 diagnoses: C51–58 or C61–63.
^mAdmitted to hospital within 2 years before RRT start with ICD-10 diagnoses: A41–42.
ⁿWithin 2 years before RRT start.
^oLow income: ≤30,200 € per year (33.7 % of the Danes with the lowest income 2006, corrected for inflation).

ISSN: 1471-2369