Is dialysis vintage a perioperative risk for end-stage renal disease patients receiving total knee and hip arthroplasty

Abstract

Background:

End-stage renal disease is an independent risk factor for postoperative mortality and cardiovascular events, but dialysis vintage and its relationship with perioperative complication is not well studied. We did a population-based study to investigate this issue.

Materials and methods:

We identified patients who had total knee arthroplasty (TKA) or total hip arthroplasty (THA) surgeries during 1999–2010 from the National Health Insurance Research Database of Taiwan. Patients who had regular dialysis before surgery were recruited in our analysis. The outcome of interest was mortality, morbidities, intensive care unit admission rate, hospitalization duration, readmission rate, and medical costs. We did multivariate regression to adjust for age, sex, and Charlson comorbidity index (CCI) and to analyze the relationship of dialysis vintage and clinical outcomes.

Results:

A total of 518 patients were enrolled for analysis. A total of 286 patients had TKA surgeries and 232 patients had THA surgeries. Patients who had TKA surgery were older and had more medical comorbidities than patients who had THA. After adjustment for age, sex, and CCI, TKA patients who had dialysis vintage <3 years had significantly higher medical costs (p < 0.05). For THA patients, dialysis vintage is not an independent risk factor for outcomes of interest.

Conclusion:

Perioperative complication is associated with age and medical comorbidities. Longer dialysis vintage is not related to perioperative morbidities and mortalities or higher medical costs in either TKA or THA patients.

Keywords

dialysis end-stage renal disease total hip arthroplasty total knee arthroplasty

Introduction

End-stage renal disease (ESRD) is a well-known risk factor for perioperative complications. In a meta-analysis of elective noncardiac surgeries, patients with chronic renal disease are independent risk factors for postoperative mortality and cardiovascular (CV) events. The incidence of complication is two to five fold higher than those with normal renal function.¹ With the improvement of renal replacement therapy (RRT), survival in dialysis patients increases, together with their chances for receiving other surgeries.

Long-term hemodialysis (HD) patients may develop renal osteodystrophy and β2-microglobulin amyloid deposition in and around joints. For dialysis patients, osteoarthritis is the most common indication for total knee replacement arthroplasty (TKA) or total hip arthroplasty (THA).² The incidence of avascular necrosis or amyloid-related arthropathy is also increased in HD patients.³ In the United States, the cumulative incidence for dialysis patients having THA is six times higher than general population.⁴ Despite higher perioperative risk, TKA or THA does relieve pain and increase function and is considered a valid option with careful medical management.^5,6

Although ESRD is a well-known risk factor for perioperative complications, dialysis vintage was not fully studied as an independent risk factor before. Previous studies on HD patient with TKA or THA had a wide range of HD vintage, ranging from 1 year to 28 years.² Chronic renal failure promotes hypertension and dyslipidemia, causing endothelium damage, and is known to associate with higher CV events.⁷ However, other study showed that the long-term dialysis was only associated with a modest increase in risk of CV mortality.⁸ We wanted to explore whether dialysis vintage is associated with increased perioperative risk of dialysis patients who need TKA or THA through a population-based study.

Materials and methods

Data set and study population

The National Health Insurance Research Database (NHIRD) contains de-identified registration files and original claims data of reimbursements from the Taiwan National Health Insurance (NHI) program. Details regarding the nature of data obtained from the NHIRD were described in our previous study.⁹ In brief, the data set we used was a random sample from all individuals who had kidney diseases or severe neurological diseases between 1997 and 2011, with the sampling fraction being as high as 71%. The quality of NHIRD data is widely recognized, and the data have been used in clinical epidemiology and health service research.¹⁰

Based on this data set consisting of two million patients, we constructed a sample for the current study. Firstly, we screened adult patients (≥20 years old) who received TKA or THA between 1999 and 2010. Secondly, we defined ESRD by maintenance dialysis for >3 months. We recruited TKA and THA patients who fit ESRD definition before surgery in our analysis.

Ethics statement

To keep individual information confidential to satisfy regulations on personal privacy in Taiwan, all personal identification numbers in the data were encrypted by converting the personal identification numbers into scrambled numbers before data processing. This study was exempt from full review by the National Taiwan University Hospital Research Ethics Committee, and the need for informed consent was waived because the data used in this study consisted of de-identified secondary data released for research purposes and were analyzed anonymously, which complies with the regulations of the Department of Health, Executive Yuan, Republic of China.

Variables

To investigate the relationship between vintage duration and perioperative outcome, we divided our patients into two groups by vintage ≤3 years and vintage >3 years. We also did sensitivity tests with cut point of 5-year vintage, and the results were similar to grouping by 3 years. To control for the potential confounding effect resulting from the imbalance in clinical characteristics, we calculated the Deyo’s Charlson comorbidity index (CCI).^11,12 This index is a weighted measure that incorporates 17 different medical categories, all of which affect mortality. For each patient, we identified preexisting comorbidities based on the presence of admission diagnostic codes (i.e., International Classification of Disorders 9th revision-CM codes) in their claims data in the NHIRD. Their diagnosis was acquired by tracking the ambulatory medical care and inpatient records in the NHI database in the year before the index admission surgery. The case ascertainment for these medical comorbidities was defined from ≥1 hospital discharge or ≥3 ambulatory visits with a relevant principal or secondary diagnosis code.

Study outcomes

A 30-day death was the primary outcome of interest. The date of death was defined from the records in the registry of catastrophic illnesses or the discharge status (death or critically ill discharge). The secondary outcomes included pneumonia (ICD-9-CM 480–486), septicemia (ICD-9-CM 038 and 998.5), stroke (ICD-9-CM 430–438), postoperative bleeding (ICD-9-CM 998.0, 998.1, and 998.2), deep wound infection (ICD-9-CM 958.3), acute myocardial infarction (ICD-9-CM 410), pulmonary embolism (ICD-9-CM 415), and urinary tract infection (ICD-9-CM 599.0). We also compared the hospitalization duration, medical costs, intensive care admission rate, readmission rate 90 days after discharge for patients with different dialysis duration.

Statistical analysis

The χ ²test, Fisher’s exact test, and Student’s t-test were used to examine differences in demographic variables, medical comorbidities, and clinical outcomes between the patients with different dialysis duration. Multivariate linear regression analyses and multivariate logistic regression analyses were used to adjust for age, sex, and medical comorbidities (presented by CCI) to reveal the influence of dialysis duration on clinical outcomes. An α level of 0.05 was considered statistically significant for all analyses. The analyses were performed using SAS 9.4 software (SAS Institute, Cary, North Carolina, USA).

Results

The patient selection processes are shown in Figures 1 and 2 for TKA and THA cohort, respectively. In our database, 0.7% of these TKA patients had long-term dialysis and 2.1% of these THA patients had long-term dialysis. The demographic data and clinical characteristics of the dialysis patients who had TKA or THA surgeries are presented in Tables 1 and 2, respectively. The comparison of TKA and THA patients with dialysis are presented in Table 3. TKA patient was about 10 years older (p < 0.001) and had higher CCI score (p < 0.05) than patients who had THA. More THA patients had their surgeries in teaching hospital (p < 0.05).

Figure 1.

Flowchart of total knee arthroplasty patient selection.

Figure 2.

Flowchart of total hip arthroplasty patient selection.

Table 1.

Demographics data of dialysis patients with TKA.

		Total (n = 286, 100%)		Vintage ≤3 years (n = 129, 45.1%)		Vintage >3 years (n = 157, 54.9%)
		n	%	n	%	n	%	p Value
Age, mean (SD)		67.88	8.67	67.61	8.69	68.09	8.67	0.6459
Sex	Male	92	32.17	39	30.23	53	33.76	0.5254
Sex	Female	194	67.83	90	69.77	104	66.24
Low economic status	Yes	155	54.20	70	54.26	85	54.14	0.9834
Low economic status	No	131	45.80	59	45.74	72	45.86
CCI, mean (SD)		3.47	1.70	3.72	1.68	3.25	1.69	0.0207
Physician age, mean (SD)		46.94	8.85	46.56	9.11	47.24	8.65	0.5187
Hospital teaching status	Teaching	248	86.71	112	86.82	136	86.62	0.9609
Hospital teaching status	Nonteaching	38	13.29	17	13.18	21	13.38
Vintage (years), mean (SD)		3.87	2.69

TKA: total knee replacement arthroplasty; CCI: Deyo’s Charlson comorbidity index; SD: standard deviation.

Table 2.

Demographics data of dialysis patients with THA.

		Total (n = 232, 100%)		Vintage ≤3 years (n = 96, 41.4%)		Vintage >3 years (n = 136, 58.6%)		p-Value
		n	%	n	%	n	%	p-Value
Age, mean (SD)		57.60	13.29	58.28	13.76	57.12	12.97	0.5140
Sex	Male	90	38.79	36	37.5	54	39.71	0.7342
Sex	Female	142	61.21	60	62.5	82	60.29
Low economic status	Yes	110	47.41	42	43.75	68	50	0.3477
Low economic status	No	122	52.59	54	56.25	68	50
CCI, mean (SD)		3.18	1.42	3.45	1.48	2.99	1.35	0.0159
Physician age, mean (SD)		45.81	9.41	45.76	8.53	45.85	10.01	0.9427
Hospital teaching status	Teaching	217	93.53	85	88.54	132	97.06	0.0094
Hospital teaching status	Nonteaching	15	6.47	11	11.46	4	2.94
Vintage (years), mean (SD)		4.05	2.65

THA: total hip replacement arthroplasty; CCI: Deyo’s Charlson comorbidity index; SD: standard deviation.

Table 3.

Demographic data and clinical outcomes of dialysis patients who received TKA or THA.

		Total (n = 518, 100%)		TKR (n = 286, 55.2%)		THR (n = 232, 44.8%)
		n	%	n	%	n	%	p Value
Age, mean (SD)		63.27	12.10	67.88	8.67	57.60	13.29	<0.0001
Sex	Male	182	35.14	92	32.17	90	38.79	0.1163
Sex	Female	336	64.86	194	67.83	142	61.21
Low economic status	Yes	265	51.16	155	54.2	110	47.41	0.1246
Low economic status	No	253	48.84	131	45.8	122	52.59
CCI, mean (SD)		3.34	1.59	3.47	1.70	3.18	1.42	0.0388
Physician age, mean (SD)		46.43	9.11	46.94	8.85	45.81	9.41	0.1622
Hospital teaching status	Teaching	465	89.77	248	86.71	217	93.53	0.0109
Hospital teaching status	Nonteaching	53	10.23	38	13.29	15	6.47
Vintage (years), mean (SD)		3.95	2.67	3.87	2.69	4.05	2.65	0.4474
Vintage	Vintage ≤3 years	225	43.44	129	45.1	96	41.38	0.3950
Vintage	vintage >3 years	293	56.56	157	54.9	136	58.62
Clinical outcomes
In-hospital 30 day death or death within 30 days of discharge	Yes	14	2.7	10	3.5	4	1.72	0.2161
	No	504	97.3	276	96.5	228	98.28
Composite complication^a	Yes	25	4.83	16	5.59	9	3.88	0.3651
Composite complication^a	No	493	95.17	270	94.41	223	96.12
Intensive care unit admission	Yes	32	6.18	16	5.59	16	6.9	0.5404
Intensive care unit admission	No	486	93.82	270	94.41	216	93.1
Readmission 90 days after surgery	Yes	147	28.38	71	24.83	76	32.76	0.0464
Readmission 90 days after surgery	No	371	71.62	215	75.17	156	67.24
Hospitalization (days)		9.106178	5.28477	8.912587	4.53556	9.344828	6.08469	0.3695
Medical costs (NT)		143,871.5	46,192	147,469.3	45,323	139,436.3	46,961	0.0489

TKA: total knee replacement arthroplasty; THA: total hip replacement arthroplasty; CCI: Deyo’s Charlson comorbidity index; SD: standard deviation.

^aComposite complication: one of the following diagnosis was made during surgical admission: pneumonia, septicemia, stroke, postoperative bleeding, deep wound infection, acute myocardial infarction, pulmonary embolism, urinary tract infection.

The average age of patients who had TKA was 67.9 ± 8.7 years. Female patients comprise 67.8% of the TKA surgical population; 45.1% of the TKA patients had dialysis vintage <3 years (Table 3), and the CCI was significantly higher in patients who had shorter dialysis vintage (CCI 3.7 ± 1.7 vs. 3.4 ± 1.7; p < 0.05) (Table 1). There was no difference in physician age and operation hospital level in short or long dialysis vintage groups.

THA patients who had long-term dialysis were 57.6 ± 13.3 years. There were more female patients than male (female vs. male = 61.2% vs. 38.8%). CCI was significantly higher in patients who had shorter dialysis vintage (CCI 3.5 ± 1.5 vs. 3.0 ± 1.4; p < 0.05). Patients who had longer dialysis vintage received their operation at teaching hospital more than patients who had shorter dialysis vintage (97.06% vs. 88.54%; p < 0.01; Table 2).

Surgical mortality in TKA and THA was comparable (3.5% vs. 1.72%; p = 0.22), but readmission rate was higher in the THA group (TKA vs. THA = 24.83% vs. 32.76%; p < 0.05). The hospital stay in TKA or THA group was similar, but the costs of hospitalization was higher in TKA patients (p < 0.05; Table 3).

For TKA patients, 30-day mortality, the intensive care unit (ICU) admission rate, and 90-day readmission rate were not different in vintage <3 years or >3 years groups. However, TKA patient with vintage <3 years stayed in the hospital for about one and half more days longer (p < 0.05) and had higher medication costs (p < 0.05) compared with patients who had vintage >3 years (Table 4).

Table 4.

Clinical outcomes for TKA patients with different vintage.

		Total (n = 286, 100%)		Vintage ≤3 years (n = 129, 45.1%)		Vintage >3 years (n = 157, 54.9%)
TKA patients		n	%	n	%	n	%	p Value
In-hospital 30 days death or death within 30 days of discharge	Yes	10	3.5	4	3.1	6	3.82	1.0000
	No	276	96.5	125	96.9	151	96.18
Composite complication^a	Yes	16	5.59	9	6.98	7	4.46	0.3565
Composite complication^a	No	270	94.41	120	93.02	150	95.54
Intensive care unit admission	Yes	16	5.59	8	6.2	8	5.1	0.6855
Intensive care unit admission	No	270	94.41	121	93.8	149	94.9
Readmission 90 days after surgery	Yes	71	24.83	29	22.48	42	26.75	0.4054
	No	215	75.17	100	77.52	115	73.25
		Mean	SD	Mean	SD	Mean	SD
Hospitalization (days)		8.91	4.54	9.67	5.72	8.29	3.13	0.0145
Medical costs (NT)		147,469.3	45,323	154,834.4	57,387	141,417.7	31,128	0.0182

TKA: total knee replacement arthroplasty.

In THA patients, dialysis vintage <3 years or >3 years does not affect the difference in 30-day mortality, complication rate, ICU stay, readmission 90 days, the hospitalization days, and medical costs (Table 5).

Table 5.

Clinical outcomes for THA patients with different vintage.

		Total (n = 232, 100%)		Vintage ≤3 years (n = 96, 41.4%)		Vintage >3 years (n = 136, 58.6%)
THA patients		n	%	n	%	n	%	p Value
In-hospital 30-day death or death within 30 days of discharge	Yes	4	1.72	2	2.08	2	1.47	1.0000
	No	228	98.28	94	97.92	134	98.53
Composite complication^a	Yes	9	3.88	4	4.17	5	3.68	1.0000
Composite complication^a	No	223	96.12	92	95.83	131	96.32
Intensive care unit stay	Yes	16	6.9	5	5.21	11	8.09	0.3939
Intensive care unit stay	No	216	93.1	91	94.79	125	91.91
Readmission 90 days after surgery	Yes	76	32.76	37	38.54	39	28.68	0.1148
Readmission 90 days after surgery	No	156	67.24	59	61.46	97	71.32
		Mean	SD	Mean	SD	Mean	SD
Hospitalization (days)		9.34	6.08	9.82	7.05	9.01	5.30	0.3393
Medical costs (NT)		139,436.3	46,961	143,043	50,380	13,6891	44,403	0.3268

THA: total hip replacement arthroplasty.

We did multiple linear regression and multivariate logistic regression to adjust the effect of age, sex, and CCI (Table 6). In TKA patients, 30-day mortality was associated with older age (odds ratio 1.137, 95% CI 1.021–1.266). Patients with higher CCI had more ICU admission, longer hospitalization, and medical costs. After adjustment for age, sex and CCI, shorter dialysis vintage was associated with longer hospitalization and higher medical costs. In THA patients, 30-day mortality, ICU admission, 90-day readmission, and medical costs were associated with higher CCI score. Dialysis vintage is not affecting the above outcomes in THA patients after adjustment for age, sex, and CCI.

Table 6.

Multivariate regression models for TKA and THA patients.

	TKA			THA
	Odds ratio	95% Confidence interval		Odds ratio	95% Confidence interval
30-Day mortality
Dialysis vintage	1.514	0.393	5.833	1.148	0.138	9.559
Age	1.137	1.021	1.266	1.087	0.981	1.204
Sex	2.567	0.495	13.32	2.302	0.189	28.008
CCI	1.307	0.933	1.83	2.291	1.176	4.463
Composite complication^a
Dialysis vintage	0.645	0.231	1.803	1.044	0.26	4.192
Age	1.012	0.953	1.073	1.048	0.99	1.111
Sex	0.609	0.217	1.713	N.A.	N.A.	N.A.
CCI	1.147	0.892	1.475	1.276	0.781	2.083
ICU admission
Dialysis vintage	0.936	0.333	2.629	2.109	0.674	6.604
Age	1.026	0.962	1.094	1.044	0.998	1.092
Sex	1.247	0.402	3.87	0.758	0.259	2.22
CCI	1.364	1.086	1.714	1.515	1.071	2.144
90-days readmission rate
Dialysis vintage	1.313	0.753	2.288	0.725	0.406	1.293
Age	1.005	0.974	1.037	0.983	0.962	1.005
Sex	0.626	0.357	1.099	0.913	0.507	1.644
CCI	1.124	0.964	1.311	1.427	1.16	1.756
Hospitalization	Pr > \|t\|	95% confidence interval		Pr > \|t\|	95% confidence interval
Dialysis vintage	0.0342	−2.17393	−0.08456	0.5015	−2.12397	1.04229
Age	0.6426	−0.04542	0.07348	0.0011	0.03985	0.15767
Sex	0.5889	−0.80176	1.40959	0.7238	−1.31141	1.88537
CCI	0.0005	0.23877	0.85312	0.2295	−0.21484	0.89103
Medical costs
Dialysis vintage	0.0409	−21325	−453.1474	0.7159	−14327	9855.39213
Age	0.2981	−279.37615	908.36895	0.0159	104.83406	1004.66765
Sex	0.1824	−3545.33945	18545	0.4618	−7640.5334	16,775
CCI	0.001	2106.76783	8243.73427	0.0013	2745.09341	11,191

TKA: total knee replacement arthroplasty; THA: total hip replacement arthroplasty; N.A.: not available; ICU: intensive care unit.

Discussion

In the present study, we showed that longer dialysis vintage did not increase 30-day mortality, complication rate, 90-day readmission rate, ICU admission, hospitalization days, and medical costs in patients who had TKA or THA surgeries.

In Taiwan, the life expectancies of peritoneal and hemodialysis patients after the start of dialysis were reported to be 7.9 and 8.7 years.¹³ With improving medical treatment and survival, patients with ESRD are more likely to keep their life quality while remaining on dialysis for more years than in the past. ESRD is associated with significant alterations in CV function; homeostasis of body fluid, electrolytes, and acid–base equilibrium; bone metabolism, erythropoiesis; and blood coagulation. Thus, despite improvement in RRT, ESRD is associated with higher perioperative CV mortality than non-ESRD patients in either cardiac or noncardiac surgeries.^14
–16

The influence of ESRD on CV events was supposed to increase with ESRD duration. Dialysis vintage with peritoneal dialysis(PD) <2 years is associated with better hydration, nutritional state, and survival, and the benefit was not found in PD patients who had vintage longer than 4 years.¹⁷ A cause-specific mortality study on dialysis vintage demonstrated that longer dialysis vintage is related to a higher risk for infection-related mortality with worse outcome observed with vintage >30 years.⁸ Whether dialysis vintage is associated with higher perioperative CV events or mortality was not fully investigated before. Our results suggested that longer dialysis vintage was not associated with major complications.

Earlier studies showed that long-term dialysis patients had high infection rate and early complications in THA.¹⁸ Furthermore, surgical death was usually not related to the index procedure, but to patients’ medical comorbidities.^9
–11 In our study, longer dialysis vintage did not contribute to higher surgical mortality or composite complication rate. Instead, higher CCI, which was a surrogate for more medical comorbidities, was associated with more ICU stay and medical costs in either TKA or THA. We suggest that to evaluate the perioperative risk of dialysis patients, we should emphasize more on patients’ age and medical comorbidities, but not dialysis vintage.

Since the present study is a population-based study, this enabled us to establish an association between dialysis vintage and perioperative risk. However, several limitations should be addressed. First, the diagnosis of medical comorbidities in our study was entirely determined by the ICD codes from the NHI claim database and there may be concern about the diagnostic accuracy of the database. However, the Bureau of the NHI has formed different audit committees that randomly sample the claim data from every hospital and review charts on a regular basis to verify the diagnostic validity and quality of care. Accordingly, the NHI claim database is an established research database and has been used in various biomedical research fields. Moreover, we used case ascertainment algorithms that required at least two ambulatory medical care visits with a relevant diagnosis code to validate the diagnosis, which might be expected to provide adequate diagnostic accuracy.¹⁹ Second, dialysis patients comprised a complex group of patients who suffered from different etiology of renal failure, and their dialysis conditions vary from person to person. For example, duration of the dialysis procedure is an important element in determining patient mortality,²⁰ but this information is not obtainable in our database. Third, due to the inherent limitations of the NHI database, information was lacking regarding lifestyle factors, such as smoking, alcohol consumption, and obesity, which is important for perioperative risk assessments. Nevertheless, we did multivariate regression to adjust for possible confounding factors. Finally, most inhabitants of Taiwan are of Chinese ethnicity, and it is uncertain whether our findings can be generalized to other ethnic groups. Since it is a retrospective study, we could not exclude the possibility of selection bias. Patients’ fitness, willingness, previous drug therapy, and orthopedic surgeons’ evaluation on dialysis patients may interfere with our interpretation of end-point analysis.²¹

Conclusion

Longer dialysis vintage is not related to perioperative morbidities and mortalities or higher medical costs in patients receiving TKA or THA. Surgical mortality and perioperative complications are associated with advanced age and medical comorbidities for TKA patients and TKA patients are older than THA patients. In contrast, medical comorbidities in patients receiving THA are the main risk factor for surgical mortality.

Footnotes

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

ORCID iD

Yi-Chia Wang

References

Mathew

Devereaux

O’Hare

. Chronic kidney disease and postoperative mortality: a systematic review and meta-analysis. Kidney Int 2008; 73: 1069–1081.

Lieu

Harris

Naylor

. Review article: total hip replacement in haemodialysis or renal transplant patients. J Orthop Surg (Hong Kong) 2014; 22: 393–398.

Sethi

Morgan

Brown

. Dialysis arthropathy: a clinical, biochemical, radiological and histological study of 36 patients. Q J Med 1990; 77: 1061–1082.

Abbott

Bucci

Agodoa

. Total hip arthroplasty in chronic dialysis patients in the United States. J Nephrol 2003; 16: 34–39.

Yen

Chen

. Perioperative complications of total knee arthroplasty in dialysis patients. J Arthroplasty 2018; 33: 872–877.

Toomey

. Hip arthroplasty in chronic dialysis patients. J Arthroplasty 1998; 13: 647–652.

Schiffrin

Lipman

Mann

. Chronic kidney disease: effects on the cardiovascular system. Circulation 2007; 116: 85–97.

Sumida

Yamagata

Iseki

. Different impact of hemodialysis vintage on cause-specific mortality in long-term hemodialysis patients. Nephrol Dial Transplant 2016; 31: 298–305.

Yang

Chen

Chao

. Comparative study of outcomes among patients with polycystic kidney disease on hemodialysis and peritoneal dialysis. Sci Rep 2015; 5: 12816.

10.

Yeh

H-Y

J-C

Haschler

. Taiwan’s National Health Insurance Research Database: administrative health care database as study object in bibliometrics. Scientometrics 2011; 86: 365–380.

11.

Simard

Sirois

Candas

. Validation of the combined comorbidity index of Charlson and Elixhauser to predict 30-day mortality across ICD-9 and ICD-10. Med Care 2018; 56: 441–447.

12.

Charlson

Szatrowski

Peterson

. Validation of a combined comorbidity index. J Clin Epidemiol 1994; 47: 1245–1251.

13.

Kao

Chang

Chen

. Lifetime costs for peritoneal dialysis and hemodialysis in patients in Taiwan. Perit Dial Int 2013; 33: 671–678.

14.

Kanda

Hirasaki

Iida

. Perioperative management of patients with end-stage renal disease. J Cardiothorac Vasc Anesth 2017; 31: 2251–2267.

15.

Johnson

Smith

Golan

. Perioperative and long-term outcomes after radical cystectomy in hemodialysis patients. Urol Oncol 2018; 36: 237 e19–237 e24.

16.

Antoniak

Are

Vokoun

. The relationship between age and chronic kidney disease in patients undergoing pancreatic resection. J Gastrointest Surg 2018; 22(8): 1376–1384.

17.

Hoppe

Schwermer

Olewicz-Gawlik

. Dialysis vintage and cardiovascular injury as factors influencing long-term survival in peritoneal dialysis and hemodialysis. Adv Clin Exp Med 2017; 26: 251–258.

18.

Lieberman

Fuchs

Haas

. Hip arthroplasty in patients with chronic renal failure. J Arthroplasty 1995; 10: 191–195.

19.

Wang

Lin

. Increased risk of ischemic heart disease in young patients with migraine: a population-based, propensity score-matched, longitudinal follow-up study. Int J Cardiol 2014; 172: 213–216.

20.

Held

Levin

Bovbjerg

. Mortality and duration of hemodialysis treatment. JAMA 1991; 265: 871–875.

21.

Juni

Dieppe

Donovan

. Population requirement for primary knee replacement surgery: a cross-sectional study. Rheumatology (Oxford) 2003; 42: 516–521.