Incident hemodialysis patients have the highest mortality in the first several months after starting dialysis. This study evaluated the in-hospital mortality rate after hemodialysis initiation, as well as related risk factors.
We examined in-hospital mortality and related factors in 2,692 patients starting incident hemodialysis. The study population included patients with acute kidney injury, acute exacerbation of chronic kidney disease, and chronic kidney disease. To determine the parameters associated with in-hospital mortality, patients who died in hospital (nonsurvivors) were compared with those who survived (survivors). Risk factors for in-hospital mortality were determined using logistic regression analysis.
Among all patients, 451 (16.8%) died during hospitalization. The highest risk factor for in-hospital mortality was cardiopulmonary resuscitation, followed by pneumonia, arrhythmia, hematologic malignancy, and acute kidney injury after bleeding. Albumin was not a risk factor for in-hospital mortality, whereas C-reactive protein was a risk factor. The use of vancomycin, inotropes, and a ventilator was associated with mortality, whereas elective hemodialysis with chronic kidney disease and statin use were associated with survival. The use of continuous renal replacement therapy was not associated with in-hospital mortality.
Incident hemodialysis patients had high in-hospital mortality. Cardiopulmonary resuscitation, infections such as pneumonia, and the use of inotropes and a ventilator was strong risk factors for in-hospital mortality. However, elective hemodialysis for chronic kidney disease was associated with survival.
The annual mortality rate of hemodialysis (HD) patients exceeds 20%
The most common cause of death in dialysis patients is cardiovascular disease followed by infectious disease. A recent study examining early mortality among incident HD patients during the 1st 120 days versus the subsequent 121–365 days shows cardiovascular diseases were still the most common cause of death during the entire 1st year
Although previous studies have identified several important factors associated with increased mortality in incident HD patients, few have addressed the risk factor patterns and their temporal changes during their 1st few months of dialysis therapy. It is crucial to determine if these risk patterns remain constant or change over time, so that targeted interventions can be used at different periods of time. Therefore, the present study examined the risk factors for in-hospital mortality after the start of HD therapy in incident HD patients who had started treatment.
We reviewed the records of 2,692 new patients who started HD at the Chonnam National University Hospital from January 1, 2007 through December 31, 2011. Patients with acute kidney injury (AKI), acute exacerbation of chronic kidney disease (CKD), or CKD with programmed RRT were included.
The following clinical data were collected: age, sex, body mass index, cause of admission, presence of cardiopulmonary resuscitation (CPR), comorbidity, first mode of HD (i.e., emergency or programmed dialysis), in-hospital medication, vascular access, dialysis frequency (times per week), and mortality during hospitalization.
The following laboratory parameters were recorded at admission and when starting HD: blood gas analysis parameters such as PaO2 and HCO3−; blood parameters such as white blood cell count, hemoglobin, blood urea nitrogen, creatinine, aspartate aminotransferase, alanine aminotransferase, total bilirubin, direct bilirubin, sodium, potassium, calcium, phosphorus, albumin, C-reactive protein (CRP), and low-density lipoprotein cholesterol; and urinalysis parameters such as proteinuria (>30 mg/g creatinine) and hematuria (red blood cells >3/high power field).
To determine the parameters associated with in-hospital mortality, patients who died in hospital (nonsurvivors) were compared with those who survived (survivors). All continuous variables are presented as mean±standard deviation. For univariate analysis, categorical and continuous variables were analyzed with the
The clinical parameters of the study patients are summarized in
The laboratory findings at admission are shown in
Details on in-hospital medications, clinical assistive devices, and vascular access are shown in
The results of the multivariate analysis of risk factors for in-hospital mortality in incident HD patients are shown in
The risk factors for in-hospital mortality after excluding CPR, inotrope administration, ventilator use, ICU care, and vancomycin are shown in
In the present study, the in-hospital mortality rate of patients starting incident HD was 16.8%, which is similar to that in previous studies, ranging 11–26%
A study of the UK Renal National Registry cohort, including patients receiving HD and peritoneal dialysis, that used several models to predict the 3-year survival of incident dialysis patients reports older age, Caucasian ethnicity, diabetes mellitus and other primary causes of end-stage renal disease, history of cardiovascular disease, and smoking as risk factors for increased mortality
In the present study, early mortality did not differ significantly between sexes. Some studies report a lower risk of mortality in women in 1-year survival analyses
A low serum albumin level is reported to be a predictor of mortality in dialysis patients
An interesting finding of the present study is the seemingly paradoxical association between diabetes and lower in-hospital mortality, which has also been reported by Bradbury et al
Among clinical variables, the type of the vascular access was strongly associated with mortality. Central venous catheter insertion is strongly associated with mortality compared with arteriovenous fistula or arteriovenous graft in HD patients
The present study has several limitations. First, the study population included not only CKD but also AKI patients. Thus, the study population might be heterogeneous in terms of the underlying diseases and related risk factors for kidney injury. Second, the possibility of residual confounding factors due to unmeasured confounders or measurement errors in the included factors could not be excluded. Finally, as this was a retrospective, single-center, observational study, it was not possible to demonstrate a causal relationship between dialysis initiation and in-hospital mortality.
In summary, incident HD patients had a high in-hospital mortality rate. CPR, infections such as pneumonia, and the use of inotropes and ventilators were strong risk factors for in-hospital mortality in patients starting incident HD. Meanwhile, elective HD for CKD reduced the risk of in-hospital mortality.
All authors have no conflicts of interest to declare.
This study was supported by the Basic Science Research Program through the National Research Foundation of Korea funded by the
Comparison for clinical risk factors at starting hemodialysis
Variables | Nonsurvivor ( | Survivor ( | |
---|---|---|---|
Age (y) | 64.7±14.9 | 60.2±14.6 | <0.001 |
Sex (male) | 283 (62.7) | 1,367 (61.0) | 0.492 |
Body mass index (kg/m2) | 22.9±3.9 | 23.2±6.4 | 0.412 |
On admission | |||
Via emergency room | 360 (79.8) | 1,644 (73.4) | 0.004 |
After cardiac pulmonary resuscitation | 94 (20.8) | 16 (0.7) | <0.001 |
Comorbidities | |||
Hypertension | 237 (52.5) | 1,630 (72.7) | 0.246 |
Diabetes mellitus | 176 (39.7) | 1,116 (49.8) | <0.001 |
Cardiovascular disease | 63 (14.0) | 335 (14.9) | 0.663 |
Hyperlipidemia | 10 (2.2) | 56 (2.5) | 0.868 |
Solid tumor | 87 (19.3) | 237 (10.6) | <0.001 |
Heart failure | 17 (3.8) | 79 (3.5) | 0.876 |
Hematologic malignancy | 38 (8.4) | 34 (1.5) | <0.001 |
Smoking | 161 (35.7) | 665 (29.7) | 0.035 |
Cause of admission | |||
Chronic kidney disease | 149 (33.0) | 1,565 (69.8) | <0.001 |
Urinary tract infection | 9 (2.0) | 27 (1.2) | 0.180 |
Pneumonia | 78 (17.3) | 112 (5.0) | <0.001 |
Acute myocardial infarction | 31 (6.9) | 83 (3.7) | 0.004 |
Postchemotherapy | 27 (6.0) | 31 (1.7) | <0.001 |
Postbleeding | 107 (23.7) | 218 (9.7) | <0.001 |
Stone | 10 (2.2) | 35 (1.6) | 0.315 |
Postoperation | 17 (3.8) | 58 (2.6) | 0.160 |
Others | 23 (5.1) | 112 (5.0) | 0.612 |
Data are presented as mean ± SD or
Laboratory findings at admission
Variables | Nonsurvivor ( | Survivor ( | |
---|---|---|---|
PaO2 (mmHg) | 96.7±59.2 | 86.5±49.2 | <0.001 |
HCO3 (mmol/L) | 18.3±6.8 | 18.3±6.8 | 0.930 |
White blood cell (103/mm3) | 14.0±17.2 | 9.9±7.5 | <0.001 |
Hemoglobin (g/dL) | 10.6±2.6 | 9.9±3.2 | <0.001 |
AST (U/L) | 240.4±1,760.7 | 106.9±914.0 | 0.118 |
ALT (U/L) | 97.3±371.7 | 59.1±326.2 | 0.043 |
Total bilirubin (mg/dL) | 1.6±3.6 | 0.9±1.5 | <0.001 |
Direct bilirubin (mg/dL) | 1.2±1.8 | 0.8±2.2 | 0.017 |
Albumin (g/dL) | 3.1±1.2 | 3.4±1.1 | <0.001 |
Blood urea nitrogen (mg/dL) | 47.1±35.5 | 71.4±48.5 | <0.001 |
Creatinine (mg/dL) | 3.4±3.0 | 7.8±6.0 | <0.001 |
Sodium (mEq/L) | 135.2±7.9 | 134.8±8.4 | 0.333 |
Potasssium (mEq/L) | 4.5±1.1 | 5.5±4.7 | 0.087 |
PT (INR) | 1.4±0.8 | 1.3±0.5 | 0.338 |
Lactate dehydrogenase (U/L) | 1,311.2±3,036.7 | 704.7±1,430.0 | <0.001 |
C-reactive protein (mg/dL) | 9.5±9.5 | 5.6±17.6 | <0.001 |
Inorganic phosphate (mg/dL) | 4.7±2.3 | 5.6±15.5 | 0.214 |
Total calcium (mg/dL) | 7.2±2.0 | 7.1±2.6 | 0.258 |
Low-density lipoprotein (mg/dL) | 84.6±45.7 | 97.4±40.9 | 0.003 |
Proteinuria | 295 (65.4) | 1,615 (72.1) | <0.001 |
Hematuria | 383 (84.9) | 1,734 (77.3) | 0.263 |
Data are presented as mean ± SD or
AST, aspartate transaminase; ALT, alanine transaminase; INR, international normalized ratio; PT, prothrombin time.
Laboratory findings at initial hemodialysis
Variables | Nonsurvivor ( | Survivor ( | |
---|---|---|---|
PaO2 (mmHg) | 95.3±42.1 | 86.9±55.3 | <0.001 |
HCO3 (mmol/L) | 17.4±6.9 | 18.3±7.0 | 0.006 |
White blood cell (103/mm3) | 13.9±10.8 | 9.7±6.2 | <0.001 |
Hemoglobin (g/dL) | 10.0±2.1 | 9.7±3.0 | 0.015 |
AST (U/L) | 485.7±2,268.1 | 130.0±997.0 | 0.001 |
ALT (U/L) | 205.0±736.0 | 69.5±388.2 | <0.001 |
Total bilirubin (mg/dL) | 2.4±4.3 | 1.0±3.0 | <0.001 |
Direct bilirubin (mg/dL) | 1.9±2.7 | 1.8±25.9 | 0.933 |
Albumin (g/dL) | 2.9±1.1 | 3.3±1.0 | <0.001 |
Blood urea nitrogen (mg/dL) | 71.2±45.9 | 81.1±198.1 | 0.289 |
Creatinine (mg/dL) | 4.5±2.8 | 8.2±6.2 | <0.001 |
Sodium (mEq/L) | 138.0±7.7 | 135.4±7.7 | <0.001 |
Potassium (mEq/L) | 4.7±1.1 | 5.3±1.7 | 0.255 |
Data are presented as mean ± SD or
ALT, alanine transaminase; AST, aspartate transaminase.
Comparison for risk factors associated with medication and dialysis modality
Variables | Nonsurvivor ( | Survivor ( | |
---|---|---|---|
Hemodialysis (h/wk) | 8.4±5.4 | 9.4±3.7 | <0.001 |
In-hospital medication | |||
Loop diuretics | 381 (84.5) | 1,374 (61.3) | <0.001 |
Inotropics | 394 (87.4) | 860 (38.4) | <0.001 |
ACEI | 62 (13.7) | 456 (20.3) | <0.001 |
ARB | 97 (21.5) | 1,040 (46.4) | <0.001 |
Statin | 31 (6.9) | 449 (20.0) | <0.001 |
CCB | 166 (36.8) | 1,328 (59.3) | <0.001 |
Vancomycin | 176 (39) | 296 (13.2) | <0.001 |
Steroid | 123 (27.3) | 290 (12.9) | <0.001 |
Anticoagulation | 145 (32.2) | 1,142 (51.0) | <0.001 |
ICU care | 354 (78.5) | 433 (19.3) | <0.001 |
ICU duration (d) | 18.1±26.0 | 13.4±16.2 | 0.003 |
CRRT | 110 (24.4) | 75 (3.3) | <0.001 |
CRRT duration (d) | 10 (2.2) | 56 (2.5) | 0.541 |
Ventilator | 310 (68.7) | 216 (9.6) | <0.001 |
Access | |||
Femoral venous | 289 (64.1) | 644 (28.8) | <0.001 |
Temporary jugular venous | 43 (9.5) | 243 (10.8) | 0.451 |
Jugular venous, tunneled cuffed jugular catheter | 77 (17.1) | 576 (25.7) | <0.001 |
Arteriovenous fistula or graft | 42 (9.3) | 778 (34.7) | <0.001 |
Data are presented as mean ± SD or
ACEI, angiotensin-converting enzyme inhibitor; ARB, angiotensin receptor blocker; CCB, calcium channel blocker; CRRT, continuous renal replacement therapy; ICU, intensive care unit.
Multivariate analysis for risk factors for in-hospital mortality
Variables | Adjusted hazard ratio | CI | |
---|---|---|---|
Age (y) | 1.031 | 0.264–4.025 | 0.966 |
Sex (male) | 0.812 | 0.311–2.121 | 0.671 |
Body mass index (kg/m2) | 0.589 | 0.148–2.348 | 0.453 |
Via emergency room | 2.157 | 0.868–5.357 | 0.098 |
After cardiac pulmonary resuscitation | 31.474 | 5.766–171.814 | <0.001 |
Hypertension | 0.835 | 0.326–2.141 | 0.708 |
Diabetes mellitus | 1.727 | 0.696–4.288 | 0.239 |
Solid tumor | 4.171 | 1.333–13.023 | 0.014 |
Pneumonia | 6.408 | 2.007–20.454 | 0.002 |
Albumin on HD | 0.545 | 0.279–1.065 | 0.074 |
Inotropics | 11.846 | 3.650–38.440 | <0.001 |
Statin | 0.199 | 0.065–0.610 | 0.005 |
Vancomycin | 2.563 | 1.140–5.762 | 0.023 |
Intensive care unit | 6.021 | 2.093–17.316 | 0.001 |
Ventilator | 7.561 | 2.142–26.686 | 0.002 |
CRRT | 0.597 | 0.168–2.1138 | 0.423 |
Data are presented as mean ± SD or
CI, confidence interval; CRRT, continuous renal replacement therapy; HD, hemodialysis.
Multivariate analysis for risk factors of in-hospital mortality
Variables | Adjusted hazard ratio | CI | |
---|---|---|---|
Age (y) | 1.004 | 0.992–1.015 | 0.548 |
Sex (male) | 0.949 | 0.680–1.325 | 0.760 |
Body mass index (kg/m2) | 0.990 | 0.948–1.033 | 0.635 |
Hypertension | 0.809 | 0.560–1.168 | 0.258 |
Diabetes mellitus | 1.057 | 0.738–1.513 | 0.764 |
Solitary tumor | 1.340 | 0.834–2.155 | 0.227 |
Arrhythmia | 3.253 | 2.179–4.8568 | <0.001 |
Hematologic malignancy | 2.088 | 1.041–4.189 | 0.038 |
Chronic kidney disease | 0.424 | 0.279–0.643 | <0.001 |
Pneumonia | 3.302 | 2.033–5.364 | <0.001 |
Other infections | 1.525 | 1.068–2.176 | 0.020 |
Postbleeding | 2.569 | 1.680–3.928 | <0.001 |
Acute myocardial infarction | 1.337 | 0.645–2.772 | 0.435 |
Creatinine | 7.561 | 2.142–26.686 | 0.002 |
Albumin | 0.993 | 0.860–1.146 | 0.922 |
C-reactive protein | 1.011 | 1.001–1.021 | 0.027 |
CI, confidence interval.