In-center hemodialysis absenteeism: prevalence and association with outcomes

Figures & data

Figure 1 Distribution of patient counts by missed treatment rate and cause.

Note: The number of patients who missed treatments for any cause (left panel), due to a documented medical event (including hospitalization, emergency department visit, or outpatient procedure; middle panel) or due to absence (right panel) is presented by the rate of missed treatments per patient-year.

Table 1 Missed treatments by cause during 2012

Variables	All	Hospitalization	ED visit	Procedure	Absence
Events, n	462,028	208,478	8885	546	244,119
Rate per patient-year	15.31	6.91	0.29	0.02	8.09
% of all missed treatments		45.1	1.9	0.1	52.8

Notes: Total time at risk: 30,178 patient-years. Total number of missed treatments per patient was capped at 78.

Abbreviation: ED, emergency department.

Table 2 Comparison of baseline patient characteristics by attendance status: pre-match

Variables	Overall, N = 93,389	Attended, N = 92,107	Absence, N = 1282	Standardized difference (%)	P-value
Age (years)					<0.001
Mean ± SD	62.9 ± 14.5	62.9 ± 14.5	60.5 ± 14.5	−16.9
Gender, n (%)					0.33
Female	41,424 (44.4)	40,838 (44.3)	586 (45.7)	2.8
Race, n (%)					<0.001
White	35,425 (37.9)	34,982 (38.0)	443 (34.6)	−7.1
Black	36,310 (38.9)	35,720 (38.8)	590 (46.0)	14.7
Hispanic	14,843 (15.9)	14,653 (15.9)	190 (14.8)	−3.0
Asian	3043 (3.3)	3028 (3.3)	15 (1.2)	−14.4
Other/unknown	3768 (4.0)	3724 (4.0)	44 (3.4)	−3.2
Vascular access, n (%)					0.05
Arteriovenous fistula	63,831 (68.3)	63,000 (68.4)	831 (64.8)	−7.6
Arteriovenous graft	20,999 (22.5)	20,685 (22.5)	314 (24.5)	4.8
Central venous catheter	8556 (9.2)	8419 (9.1)	137 (10.7)	5.2
Other/missing	3 (0.0)	3 (0.0)	0 (0.0)
Dialysis vintage (months)					0.006
Median [p25, p75]	48 [26, 81]	48 [26, 81]	45 [24, 76]	−10.5
Target weight (kg)					0.34
Mean ± SD	80.7 ± 22.5	80.7 ± 22.5	81.3 ± 22.2	2.7
Etiology of ESRD, n (%)					0.12
Diabetes	41,917 (44.9)	41,323 (44.9)	594 (46.3)	3.0
Hypertension	28,576 (30.6)	28,171 (30.6)	405 (31.6)	2.2
Other	22,896 (24.5)	22,613 (24.6)	283 (22.1)	−5.9
Atrial fibrillation, n (%)	105 (0.1)	104 (0.1)	<10	−1.1	0.71
Diabetes, n (%)	63,728 (68.2)	62,804 (68.2)	924 (72.1)	8.5	0.003
Congestive heart failure, n (%)	13,507 (14.5)	13,306 (14.4)	201 (15.7)	3.4	0.21
Coronary artery disease, n (%)	11,586 (12.4)	11,438 (12.4)	148 (11.5)	−2.7	0.35
Cerebrovascular disease, n (%)	968 (1.0)	956 (1.0)	12 (0.9)	−1.0	0.72
Peripheral vascular disease, n (%)	7588 (8.1)	7487 (8.1)	101 (7.9)	−0.9	0.74
Serum albumin (g/dL)					0.004
Mean ± SD	4.0 ± 0.4	4.0 ± 0.4	3.9 ± 0.4	−8.0
Serum calcium (mg/dL)					0.69
Mean ± SD	9.0 ± 0.7	9.0 ± 0.7	9.0 ± 0.7	−1.1
Creatinine (mg/dL)					0.31
Mean ± SD	8.7 ± 2.9	8.7 ± 2.9	8.6 ± 2.9	−3.0
Ferritin (ng/mL)					0.73
Mean ± SD	759.9 ± 351.8	759.9 ± 351.6	763.3 ± 366.2	1.0
Hemoglobin (g/dL)					0.41
Mean ± SD	10.9 ± 1.1	10.9 ± 1.1	10.9 ± 1.1	−2.3
Serum phosphate (mg/dL)					<0.001
Mean ± SD	4.98 ± 1.39	4.98 ± 1.39	5.11 ± 1.43	9.5
Parathyroid hormone (ng/mL)					0.23
Median [p25, p75]	335 [220, 500]	334 [220, 499]	338 [227, 522]	3.9
Transferrin saturation (%)					0.67
Mean ± SD	31.2 ± 12.3	31.2 ± 12.3	31.0 ± 12.4	−1.2
nPCR (g/kg/day)					<0.001
Mean ± SD	1.04 ± 0.28	1.04 ± 0.28	1.00 ± 0.28	−14.4
Kt/V					<0.001
Mean ± SD	1.64 ± 0.27	1.64 ± 0.27	1.61 ± 0.28	−13.9

Abbreviations: ESRD, end-stage renal disease; K, dialyzer clearance of urea; t, dialysis time; V, volume of distribution of urea; nPCR, normalized protein catabolic rate; p25, 25th percentile; p75, 75th percentile; SD, standard deviation.

Table 3 Comparison of baseline patient characteristics by attendance status: post-match

Variables	Overall, N = 7692	Attended, N = 6410	Absence, N = 1282	Standardized difference (%)	P-value
Age (years)					0.76
Mean ± SD	60.6 ± 14.8	60.6 ± 14.8	60.5 ± 14.5	−0.9
Gender, n (%)					0.62
Female	3564 (46.3)	2978 (46.5)	586 (45.7)	−1.5
Race, n (%)					0.99
White	2646 (34.4)	2203 (34.4)	443 (34.6)	0.4
Black	3539 (46.0)	2949 (46.0)	590 (46.0)	0.0
Hispanic	1151 (15.0)	961 (15.0)	190 (14.8)	−0.5
Asian	95 (1.2)	80 (1.2)	15 (1.2)	−0.7
Other/unknown	261 (3.4)	217 (3.4)	44 (3.4)	0.3
Vascular access, n (%)					0.72
Arteriovenous fistula	4914 (63.9)	4083 (63.7)	831 (64.8)	2.3
Arteriovenous graft	1919 (24.9)	1605 (25)	314 (24.5)	−1.3
Central venous catheter	859 (11.2)	722 (11.3)	137 (10.7)	−1.8
Dialysis vintage (months)					0.97
Median [p25, p75]	46 [25, 75]	46 [25, 75]	45 [24, 76]	−1.1
Target weight (kg)					0.24
Mean ± SD	82.0 ± 23.0	82.2 ± 23.2	81.3 ± 22.2	−3.6
Etiology of ESRD, n (%)					0.99
Diabetes	3568 (46.4)	2974 (46.4)	594 (46.3)	−0.1
Hypertension	2425 (31.5)	2020 (31.5)	405 (31.6)	0.2
Other	1699 (22.1)	1416 (22.1)	283 (22.1)	0.0
Atrial fibrillation, n (%)	<10	<10	<10	−1.0	0.75
Diabetes, n (%)	5588 (72.6)	4664 (72.8)	924 (72.1)	−1.5	0.61
Congestive heart failure, n (%)	1251 (16.3)	1050 (16.4)	201 (15.7)	−1.9	0.53
Coronary artery disease, n (%)	921 (12.0)	773 (12.1)	148 (11.5)	−1.6	0.60
Cerebrovascular disease, n (%)	80 (1.0)	68 (1.1)	12 (0.9)	−1.3	0.69
Peripheral vascular disease, n (%)	615 (8.0)	514 (8.0)	101 (7.9)	−0.5	0.87
Serum albumin (g/dL)					0.73
Mean ± SD	3.9 ± 0.4	3.9 ± 0.4	3.9 ± 0.4	−1.1
Serum calcium (mg/dL)					0.82
Mean ± SD	9.0 ± 0.7	9.0 ± 0.7	9.0 ± 0.7	0.7
Creatinine (mg/dL)					0.84
Mean ± SD	8.6 ± 3.0	8.6 ± 3.0	8.6 ± 2.9	0.6
Ferritin (ng/mL)					0.85
Mean ± SD	765.1 ± 362.3	765.5 ± 361.5	763.3 ± 366.2	−0.6
Hemoglobin (g/dL)					0.92
Mean ± SD	10.9 ± 1.1	10.9 ± 1.1	10.9 ± 1.1	−0.3
Serum phosphate (mg/dL)					0.23
Mean ± SD	5.1 ± 1.4	5.1 ± 1.4	5.1 ± 1.4	3.7
Parathyroid hormone (ng/mL)					0.33
Median [p25, p75]	335 [217, 519]	334 [214, 518]	338 [227, 522]	4.2
Transferrin saturation (%)					0.76
Mean ± SD	31.1 ± 12.3	31.1 ± 12.3	31.0 ± 12.4	−0.9
nPCR (g/kg/day)					0.35
Mean ± SD	1.0 ± 0.3	1.0 ± 0.3	1.0 ± 0.3	−2.9
Kt/V					0.37
Mean ± SD	1.6 ± 0.3	1.6 ± 0.3	1.6 ± 0.3	−2.7

Abbreviations: ESRD, end-stage renal disease; K, dialyzer clearance of urea; t, dialysis time; V, volume of distribution of urea; nPCR, normalized protein catabolic rate; p25, 25th percentile; p75, 75th percentile; SD, standard deviation.

Figure 2 Rates of hospitalization and mortality by attendance status.

Notes: The crude rates (per patient-year) of hospitalization (left panel) and mortality (right panel) within 30 days of the index treatment are presented; the rate for patients who attended the treatment is presented in light gray, whereas the rate for those who were absent from the treatment (ie, did not attend and did not have a documented medical event on the day of the missed treatment) is presented in dark gray. The adjusted IRR (95% CI) referent to patients who did attend the treatment is presented at the top of each panel.
Abbreviations: CI, confidence interval; IRR, incidence rate ratio.

Figure S1 Rates of hospitalization and death by attendance status (180-day outcome period).

Notes: The crude rates (per patient-year) of hospitalization (left panel) and mortality (right panel) within 180 days of the index treatment are presented; the rate for patients who attended the treatment is presented in light gray, whereas the rate for those who were absent from the treatment (ie, did not attend and did not have a documented medical event on the day of the missed treatment) is presented in dark gray. The adjusted IRR (95% CI) referent to patients who did attend the treatment is presented at the top of each panel.

Abbreviations: CI, confidence interval; IRR, incidence rate ratio.

Table S1 Hospitalizations that led to a missed treatment by CCS level 1 categories

Cause of hospitalizationa	Number	Percent
Diseases of the circulatory system	47,030	23.6
Injury and poisoning	36,390	18.3
Diseases of the respiratory system	23,874	12.0
Infectious and parasitic diseases	23,283	11.7
Endocrine, nutritional, and metabolic diseases, and immunity disorders	18,697	9.4
Diseases of the digestive system	17,525	8.8
Symptoms and signs, and ill-defined conditions and factors influencing health status	5057	2.5
Diseases of the skin and subcutaneous tissue	4929	2.5
Diseases of the nervous system and sense organs	4877	2.4
Diseases of the genitourinary system	4509	2.3
Diseases of the musculoskeletal system and connective tissue	4486	2.3
Neoplasms	3308	1.7
Diseases of the blood and blood-forming organs	2295	1.2
Mental illness	2127	1.1
Residual codes, unclassified, all E codes [259 and 260]	857	0.4
Congenital anomalies	125	0.1
Complications of pregnancy, childbirth, and the puerperium	<10	0.0

Note:

a Groupings made using CCS.¹

Abbreviation: CCS, Clinical Classification Software.

Table S2 Overall comparison of short-term (30-day) and long-term (180-day) secondary outcomes by attendance status

Outcome	Attended, mean (95% CI)	Absence, mean (95% CI)	Difference, mean (95% CI)	P-value
30-Day outcomes
Serum potassium	4.73 (4.72, 4.75)	4.73 (4.69, 4.77)	0.00 (−0.04, 0.04)	0.91
Hemoglobin	10.93 (10.90, 10.96)	10.75 (10.69, 10.81)	−0.18 (−0.25, −0.12)	<0.001
Ultrafiltration rate	9.76 (9.59, 9.93)	9.94 (9.12, 10.75)	0.18 (−0.65, 1.00)	0.68
Ultrafiltration volume	2.67 (2.64, 2.70)	2.61 (2.52, 2.70)	−0.06 (−0.15, 0.04)	0.26
Blood pressure	147.3 (146.8, 147.8)	147.6 (146.4, 148.8)	0.3 (−1.0, 1.6)	0.68
ESA administrations	7.85 (7.74, 7.96)	7.68 (7.43, 7.93)	−0.17 (−0.44, 0.10)	0.22
ESA dosea	4594 (4494, 4693)	4775 (4535, 5016)	181 (−77, 439)	0.17
ESA utilizationb	3953 (3859, 4047)	4060 (3835, 4284)	107 (−135, 348)	0.39
180-Day outcomes
Serum potassium	4.75 (4.74, 4.76)	4.75 (4.72, 4.77)	0.00 (−0.04, 0.03)	0.78
Hemoglobin	10.93 (10.91, 10.96)	10.85 (10.8, 10.9)	−0.08 (−0.14, −0.03)	0.003
Ultrafiltration rate	9.72 (9.62, 9.83)	10.03 (9.25, 10.81)	0.31 (−0.48, 1.09)	0.44
Ultrafiltration volume	2.66 (2.63, 2.69)	2.62 (2.54, 2.7)	−0.04 (−0.12, 0.05)	0.39
Blood pressure	147.3 (146.8, 147.8)	147.8 (146.7, 149.0)	0.6 (−0.7, 1.8)	0.37
ESA administrations	45.25 (44.66, 45.83)	42.39 (41.12, 43.67)	−2.85 (−4.25, −1.46)	<0.001
ESA dosea	4583 (4495, 4672)	4862 (4639, 5085)	278 (39, 518)	0.02
ESA utilizationb	4160 (4074, 4246)	4429 (4212, 4646)	269 (37, 502)	0.02

Notes:

a Among patients receiving ESA.

b Among all patients (users and nonusers).

Abbreviations: CI, confidence interval; ESA, erythropoiesis-stimulating agent.

Clinical Classifications Software (CCS) for ICD-9-CM. [webpage on the Internet] Available from https://www.hcup-us.ahrq.gov/toolssoftware/ccs/ccs.jspAccessed November 1, 2016

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