Outcome study of patients on maintenance hemodialysis complicated with acute respiratory failure: 1-year data from a medical center in central Taiwan

Transcription

1 Original Article 33 Outcome study of patients on maintenance hemodialysis complicated with acute respiratory failure: 1-year data from a medical center in central Taiwan Su-Chuan Chen *, Kuo-Hsiung Shu *,**, Cheng-Hsu Chen *,****, Ming-Yu Wu *,*, Tung-Min Yu *, Ya-Wan Chuang *, Chi-Hung Cheng *,**,*** Background: Taiwan had the highest incidence and prevalence of end stage renal disease (ESRD) patients in the world. However, there were no clinical data on the prognosis of those ESRD patients on maintenance hemodialysis (MHD) who also had acute respiratory failure. The aim of the study was to observe the shortterm and long-term outcome of this patient group so as to provide a better care. Methods: This was a retrospective observational cohort study. Forty-seven patients on MHD > 3 months with acute respiratory failure were included in the analysis and stratified according to their hospital mortality, as either survivors or non-survivors. We collected demographic, clinical and biochemical parameters to examine if there was any significant difference. Results: For the 47 enrolled patients, 18 were in the survivors group and 29 were in the non-survivors group. There was no significant difference in most of the parameters. The patients with sepsis or cardiopulmonary resuscitation (CPR) had a hospital mortality rate of 100%. The survival time was 18 ± 24 days in patients with sepsis and 2.7 ± 5.6 days in patients with CPR. The patients being intubated for CPR had a hazard ratio for hospital mortality of 4.27 (p < 0.05) compared with those having sepsis. Septic patients had a hazard ratio of 3.84 (p < 0.05) compared with those having pneumonia. The overall cumulative proportional hospital survival was only 17% and the 1-year survival for in-hospital survivors was 40%. Conclusion: ESRD patients with various comorbidities and acute respiratory failure had very poor outcome. The pneumonia group had relatively better prognosis compared with those with other causes of respiratory failure. Given the ominous prognosis, a more conservative treatment for this specific patient group might be considered. (Acta Nephrologica 2010; 24: 33-41) Key words: ESRD, hemodialysis, respiratory failure, outcome, mortality Introduction Since the beginning of 21st century, Taiwan has had the highest incidence (418 per million population) and prevalence (2226 per million population) of dialysis patients among 30 countries as reported by the US Renal Data System (USRDS) 1 in A recent study 2 including 462,293 Taiwanese reported that the national prevalence of Stages 1-5 chronic kidney disease (CKD) was 11.93%. The mortality rate increased with each stage of CKD from 16.4 per 1000 patient-year in Stages 1-2 CKD to 89.6 per patient-year in Stage 5 CKD. 3 Although the mortality rate of patient on maintenance hemodialysis (MHD) for the initial 5 years kept declining to per 1000 patient-year, 1 it was still far higher than the CKD group. In Taiwan, the National Health Insurance (NHI) program has been initiated since 1995 and made renal replacement therapy (RRT) more available for all patients with end stage kidney disease (ESRD). The growing burden of ESRD patients would Division of Nephrology, Department of Internal Medicine, Taichung Veterans General Hospital, Taichung, Taiwan* School of Medicine, Chung-Shan Medical University, Taichung, Taiwan** Institute of Medicine, Chung-Shan Medical University, Taichung, Taiwan*** School of Medicine, China Medical University, Taichung, Taiwan**** Received: April, 2009 Revised: May, 2009 Accepted: June, 2009 Correspondence author: Dr. Chi-Hung Cheng, Division of Nephrology, Department of Internal Medicine, Taichung Veterans General Hospital, Taichung, No. 160, Sec. 3, Taichung Port Rd., Situn District, Taichung City 407, Taiwan Tel: Fax: chc@vghtc.gov.tw

2 34 S. C. CHEN, K. H. SHU, C. H. CHEN, et al. Vol. 24, No. 1, 2010 further raise the issue of cost and benefit in health care. The cost of dialysis kept growing up to 8% (NT$35 billion) of the yearly budget of the NHI in Similarly, long-term ventilator support has also been made more available to patients with chronic respiratory failure who consumed about 3% (NT$14 billion) of the yearly budget of the NHI in Furthermore, we observed that when these patients with ESRD receiving MHD had acute respiratory failure, there seemed to be a high rate of weaning failure and also mortality in spite of aggressive treatment. It also seemed that many treatments had only little benefit for some group of patients and made them suffer more. For those patients who survived, whether ventilator-dependent or not, there was no idea as of how long they would survive after discharge. So far, there were no clinical data on the outcome of those patients on MHD who also had acute or chronic respiratory failure. Thus, the aim of this study was to observe the outcome of MHD patients with acute respiratory failure, in order to provide better care for this patient group. We also tried to clarify if there were any variables that could predict the outcome of this patient group and followed up on the survival time if the patients survived the acute illness. We would also discuss the role of more conservative or hospice care in such patient group, as we frequently encounter this problem in the patient s family in daily practice. Materials and Methods Study design and patient selection The study design was a retrospective observational cohort study in a single medical center in central Taiwan, which had about 45,000 inpatients per year. We searched the computerized medical records of admission for the codes representative of hemodialysis (HD) AND on ventilator from January 1 st, 2006 to December 31 st, 2006, to identify the patient group who received HD and ventilator therapy during the same admission. The patients were eligible if they had MHD for at least 3 months, received intubation due to respiratory failure of any causes and required ventilator support. We excluded those patients requiring ventilator support for less than 72 hours due to operation. Only HD is eligible and other forms such as hemoperfusion and plasma exchange (40 patients) were excluded. Those patients receiving continuous veno-venous hemodialysis (CVVHD) due to hemodynamical instability were not excluded. A total of 318 patients were enrolled and had their charts reviewed. Among those enrolled, 190 patients were excluded due to acute or acute on chronic renal failure, 43 due to missing chart data, 11 due to HD time < 3 months, and 27 due to intubation time < 72 hours because of operation. Finally, a total of 47 patients were studied in the research. Methods Demographic data including sex, age, comorbidity, cardiothoracic ratio (CTR) on chest x-ray, admission diagnosis, admission ward type, cause of respiratory failure, cause and duration of HD were reviewed and recorded. The blood sample was collected before or soon after intubation. Their hemogram and biochemical data including blood urea nitrogen (BUN), hematocrit (Hct), serum creatinine (Cr), albumin, calcium (Ca), phosphate (P) and calcium-phosphate product (Ca P), arterial blood gas (ABG, including PaO 2, FiO 2, PaCO 2 and ph) were measured. The Acute Physiology and Chronic Health Evaluation II (APACHE II) score was collected in the first 24 hours of ICU admission after intubation. Comorbidity included diabetes, hypertension, coronary artery disease, heart failure, cerebral vascular disease and coexistence malignancy. Admission ward type was categorized into medical and surgical ward. Cause of respiratory failure included pneumonia, pulmonary edema, sepsis, airway protection for central nervous system (CNS) insult and cardiopulmonary resuscitation (CPR). The survival was calculated from the date of intubation. The patients were categorized into survivors and non-survivors according to the survival status at discharge. Those being recorded as critically against advice discharge (AAD) on charts were categorized as non-survivors. The death was also confirmed by linking to the database recording all deaths of citizens between 2006 and 2008 from Taiwan s Department of Health (DOH). For the survivors, we followed up and recorded their survival status till January 31 st, Statistical analysis Categorical data were reported as proportions. Continuous data were expressed as mean ± standard deviation (SD). We used the Fisher s exact test, Pearson Chi-square test, Yate s continuity correction and Mann- Whitney U test for comparison between the two groups. Mortality, i.e., deaths occurring after intubation or discharge, was presented as Kaplan-Meier survival curve. A Log rank test was employed to compare the survival curves representing each cause of respiratory failure. Cox proportional hazards mode was utilized to analyze the relative risk of hospital mortality and results are presented as hazard ratio (HR) and 95% confidence intervals (CI). We used SPSS for windows (version 15) for statistical analysis and a p value < 0.05 was considered statistically significant.

3 Acta Nephrologica Outcome of HD patients with acute respiratory failure 35 Results We examined the characteristics of survivors and non-survivors to determine whether their characteristics differed. The demographic data of all patients are shown in Table 1. The hemogram, biochemical data, duration of HD, CTR, length of hospital stay, APACHE II score and ABG were listed in Table 2. Among the 47 enrolled patients, including 24 women and 23 men, 18 were in the survivors group and 29 were in the non-survivors group. The mean age was 63.1 ± 11.9 years and the duration of dialysis before intubation was 4.0 ± 4.1 years with a median of 2.7 years. The mean APACHE II score was 24.8 ± 7.1 and hospital stay was 35 ± 38 days. The overall mean survival after intubation in the non-survivors group was 19.0 ± 23.6 days. Among the survivors and non-survivors, there was no difference in age, sex, comorbidity, CTR, cause and duration of HD, admission ward type, main admission diagnosis, APACHE II score, length of hospital stay, hemogram and biochemical data. There was only statistical difference in PaCO 2 and ph of ABG. A statistically significant difference in cause of respiratory failure was found. The hospital mortality rate of patients in groups of pneumonia, pulmonary edema, sepsis, airway protection for CNS insult and CPR were 36%, 57%, 100% 50%, and 100%, respectively. Sixteen patients being intubated due to sepsis or CPR died with a mean and median survival of only 12 and 4.5 days, respectively. Eleven out of 16 patients died in the first weeks after intubation. Further analysis of survival curves representing each cause of respiratory failure was shown in Table 3. The patients being intubated for CPR had the highest mortality rate, which was 4.27 (HR, 95% CI ) times higher than that of sepsis. However, other patients with cause of respiratory failure including pulmonary edema, pneumonia and airway protection for CNS insult had obvious lower mortality (Table 3). The lowest relative risk was seen in the pneumonia group with a HR of 0.26 (95% CI ). In other words, the sepsis group had a mortality rate 3.84 times higher than the pneumonia group. The survival curve of the whole cohort was shown in Fig. 1. Hospital survival after intubation declined rapidly with a cumulative proportional survival of 66% in the first week and 33% in the second month. The Log rank test showed p < when comparing the survival curves of different causes of respiratory failure (Fig. 2). The CPR and sepsis groups had extremely poor survival compared with the pneumonia group, whose survival was around 40% in the second month. Fig. 3 shows the survival curve of survivors after their discharge, who were followed up until January 31 st, The first year displayed a high mortality rate, indicated by a steep fall in the curve. The overall 3-year survival of the survivors was only about 25%. In 18 survivors, 11 patients failed to be weaned from ventilator and received tracheostomy before being transferred to the chronic respiratory care unit while the other 7 were weaned successfully. Ten out of 11 survivors having tracheostomy died during subsequent follow-up with a mean survival after intubation of 10.2 ± 7.2 months (median: 9 months). Three out of seven survivors having successful weaning died with a survival of 1, 2 and 31 months, respectively. As a whole, only 5 out of 47 patients survived at the end of the follow-up. Discussion There had been relatively fewer studies focusing on the outcome of ESRD patients who were admitted to ICU. Some single-center studies 5-7 explored the validity of ICU scoring systems as a predictor of outcome in this patient population. One multi-center study 8 compared the outcome of acute renal failure (ARF, 254 cases) and ESRD (57 cases) who were admitted to ICU. It showed an ICU mortality rate of 11% for patients with ESRD, of whom the APACHE III score was found to overestimate the mortality. Compared with previous studies 5,7-9 showing low hospital mortality (14-34%) of patients with ESRD admitted to ICU, our study showed a relatively high hospital mortality rate of 61.7% (29/47) or a 3-month cumulative proportional survival rate of 17% in this patient group, (Fig. 1). This might be because some previous studies included those patients who did not require mechanical ventilation. Only 20-30% of patients were on mechanical ventilation in these studies, 7,9 compared with 100% in our patient population. Our patients also had high prevalence of comorbidities, such as diabetes (61.7%), hypertension (59.6%), coronary arterial disease (CAD) (42.6%) and heart failure (CTR > 0.5, 96.6%). The mean APACHE II score of our patients was 24.8 ± 7.1. The predicted mortality rate would be 52.5%,10 which was close to but a little lower than that observed (61.7%). We found that the APACHE II score underestimated the overall hospital mortality in our patient group. Although the APACHE II score (p = 0.15) could not differentiate the survivors from the non-survivors, the survivors tended to have lower score (22.9 ± 6.4) than non-survivors (26.0 ± 7.4). The high APACHE II score in both groups implied that our patients were more critically ill. This might be because our hospital was a tertiary hospital and had many patients with very serious complications referred from central Taiwan. Diabetic patients with CKD had higher overall mortality than non-diabetic patients and it was also true for

4 36 S. C. CHEN, K. H. SHU, C. H. CHEN, et al. Vol. 24, No. 1, 2010 Table 1. Demographic data (categorical data) All (n = 47) Survivors (n = 18) Non-survivors (n = 29) p-value Age (years) <50 8 (17.0) 2 (25.0) 6 (75.0) (31.9) 6 (40.0) 9 (60.0) (51.1) 10 (41.7) 14 (58.3) Male sex 23 (48.9) 6 (26.1) 17 (73.9) Comorbidity Diabetes 29 (61.7) 11 (37.9) 18 (62.1) CAD 20 (42.6) 7 (35.0) 13 (65.0) Hypertension 28 (59.6) 12 (42.9) 16 (57.1) CVA 8 (17.0) 3 (37.5) 5 (62.5) Malignancy 6 (12.8) 2 (33.3) 4 (66.7) CTR (95.7) 17 (37.8) 28 (62.2) Ward type Medical 32 (68.1) 14 (43.8) 18 (56.3) Surgical 15 (31.9) 4 (26.7) 11 (73.3) Cause of HD CGN 2 (4.3) 1 (50.0) 1 (50.0) Diabetes 27 (57.4) 9 (33.3) 18 (66.7) Unspecified uremia 16 (34.0) 7 (43.8) 9 (56.3) Lupus 2 (4.3) 1 (50.0) 1 (50.0) Main admission diagnosis Operation 9 (19.1) 3 (33.3) 6 (66.7) Infection 18 (38.3) 7 (38.9) 11 (61.1) Hemorrhagic stroke 4 (8.5) 2 (50.0) 2 (50.0) Ischemic stroke 3 (6.4) 1 (33.3) 2 (66.7) Gastrointestinal bleeding 4 (8.5) 0 (0.0) 4(100.0) Pulmonary edema 4 (8.5) 3 (75.0) 1 (25.0) Others 5 (10.6) 2 (40.0) 3 (60.0) Cause of respiratory failure Pneumonia 22 (46.8) 14 (63.6) 8 (36.4) Pulmonary edema 7 (14.9) 3 (42.9) 4 (57.1) Sepsis 10 (21.3) 0 (0.0) 10(100.0) Airway protection 2 (4.3) 1 (50.0) 1 (50.0) CPR 6 (12.8) 0 (0.0) 6(100.0) CAD: coronary artery disease, CVA: cerebral vascular accident CTR: cardiothoracic ratio, HD: hemodialysis, CGN: chronic glomerulonephritis CPR: cardiopulmonary resuscitation Figures in parentheses are percentages.

5 Acta Nephrologica Outcome of HD patients with acute respiratory failure 37 Tabel 2. Demographic data (continuous data) All (n = 47) Survivors (n = 18) Non-survivors (n = 29) p-value Age (yrs) 63.1 ± 11.9 (65, 34-84) 63.2 ± 11.0 (66, 35-77) 63.0 ± 12.6 (65, 34-84) Duration of HD (yrs) 4.0 ± 4.1 (2.7, ) 3.8 ± 4.0 (2.5, ) 4.1 ± 4.2 (2.7, ) CTR 0.57 ± 0.05 (0.56, ) 0.57 ± 0.05 (0.56, ) 0.57 ± 0.05 (0.56, ) BUN before HD (mg/dl) 66.5 ± 25.5 (62, ) 69.1 ± 28.7 (71, ) 64.8 ± 23.7 (59, ) Cr before HD (mg/dl) 7.5 ± 3.0 (7.0, ) 7.0 ± 3.2 (6.1, ) 7.8 ± 2.9 (7.2, ) Albumin (g/dl) 3.2 ± 0.6 (3.3, ) 3.2 ± 0.6 (3.3, ) 3.2 ± 0.7 (3.3, ) White blood cells ( 1000/cumm) 15 ± 10 (13, ) 14 ± 8 (13, ) 15 ± 11 (13, ) Calcium (mg/dl) 9.2 ± 1.0 (9.2, ) 9.0 ± 1.1 (8.9, ) 9.3 ± 0.9 (9.3, ) Hematocrit (%) 27.6 ± 5.2 (27.8, 18-43) 27.8 ± 4.1 (27.4, 22-36) 27.5 ± 5.9 (28, 18-43) Phosphate (mg/dl) 4.6 ± 3.0 (4.0, ) 5.0 ± 3.7 (3.9, ) 4.4 ± 2.6 (4.2, ) Ca P (mg 2 /dl 2 ) 42.8 ± 27.2 (38, 4-106) 45.3 ± 32.4 (36.6, 4-106) 41.2 ± 23.9 (39, 5-105) Length of hospital stay (days) 35 ± 38 (24, 1-200) 44 ± 49 (27, 4-200) 30 ± 30 (17, 1-102) APACHE II score 24.8 ± 7.1 (25, 9-44) 22.9 ± 6.4 (24, 9-34) 26.0 ± 7.4 (26, 11-44) PaO 2 (mmhg) 144 ± 92 (132, ) 147 ± 51 (156, ) 143 ± 111 (87, ) FiO ± 0.22 (0.4, ) 0.51 ± 0.19 (0.4, ) 0.6 ± 0.24 (0.5, ) PaO 2 /FiO 2 (mmhg) 296 ± 186 (289, ± 133 (375, ) 280 ± 222 (197, PaCO 2 (mmhg) 30 ± 8.7 (28, 16-47) 26 ± 6.6 (24, 18-40) 33 ± 9.1 (33, 16-47) Blood ph 7.40 ± 0.15 (7.4, ) 7.48 ± 0.11 (7.5, ) 7.36 ± 0.15 (7.4, ) HD: hemodialysis, CTR: cardiothoracic ratio, BUN: blood urea nitrogen, Cr: creatinine, Ca P: calcium-phosphate product, PaO 2 : partial pressure of arterial oxygen, PaCO 2 : partial pressure of arterial CO 2, FiO 2 : fraction of inspired oxygen Data are expressed as mean ± SD (median, range) Table 3. Relative risk of hospital mortality Cause of respiratory failure Hazard ratio* p-value Sepsis 1.00 Pulmonary edema 0.45 ( ) Pneumonia 0.26 ( ) Airway protection 0.73 ( ) CPR 4.27 ( ) * Hazard ratio (HR) presented with 95% confidence intervals CPR: cardiopulmonary resuscitation

6 38 S. C. CHEN, K. H. SHU, C. H. CHEN, et al. Vol. 24, No. 1, Cumulative proportion survival (%) n= Time (days) Fig. 1. Overall hospital survival among 47 patients with ESRD and acute respiratory failure dialysis patients. 1,11,12 However, our study failed to show the difference in comorbidity between survivors and non-survivors, including diabetes, CAD, hypertension, cerebral vascular accident (CVA), and malignancy. The hemogram, biochemical data, including albumin, cause of HD and the main admission diagnosis were also similar, except for PaCO 2 and ph of ABG. Regarding the ABG, there was no difference in PaO 2, FiO 2, PaO 2 /FiO 2. The relatively low PaO 2 /FiO 2 (296 ± 186 mmhg) for all patients implied poor oxygenation capacity and severity of underlying disease. Although there was statistical significance in ph and PaCO 2 as the non-survivors had slightly lower PaCO 2 and ph, it was still within acceptable range clinically and might not provide more clinical information. Moreover, there still existed some bias in data collection due to the retrospective nature of our study. The number of patients might be too small to show the difference. The hemogram and biochemical data were collected only during admission in acute ill status and they also fluctuated with the course of disease. It might not reflect the actual value at more stable MHD period. Our patients also had high rate of comorbidities, low serum albumin (3.2 ± 0.6 g/dl), low hematocrit (27.6 ± 5.2%) and high APACHE II score (24.8 ± 7.1), implying their poor clinical condition. This might lead to selection bias, as the patients we included in both groups were generally and equally undernourished. All these could contribute to the statistical insignificance of the parameters. On the contrary, we found statistical difference in cause of respiratory failure; or in other words, the main ICU admission diagnosis, between the two groups. This indicated that the main contributing factor for the high mortality of our patients was the acute illness rather than the underlying chronic disease. Because most of our patients were sicker and had various comorbidities, the small sample size might not show the impact of chronic illness on the outcome. More patients were needed to clarify if comorbidity contributes to mortality. The patients being intubated or diagnosed with sep-

7 Acta Nephrologica Outcome of HD patients with acute respiratory failure 39 sis or cardiac arrest (CPR group) had extremely high hospital mortality (100%). The survival was only less than 30% in the first week, as presented in Fig. 2. Undoubtedly, the CPR group had the poorest prognosis, with a mortality rate 4.27 times higher than that of the sepsis group. The most possible cause of death was cardiovascular disease in these patients. Sepsis was a leading cause of admission to non-cardiological ICUs and the second leading cause of death among ICU patients. 13 Blanco et al.14 reported a hospital mortality rate of 54.3% (169/311 patients) and a mortality rate of 14.8% in the first 48 h for ICU patients with severe sepsis. Similarly, the mortality rate of our patients with sepsis in the first 48 h was 10% (1/10). Because all of our patients had ESRD and respiratory failure, higher mortality could be expected. The pneumonia group had the best prognosis when compared with the other groups, with a hospital mortality rate of 36% (8/22) or a cumulative proportional survival rate of around 40% in the second month, (Fig. 2). The relative risk of hospital mortality for pneumonia was 0.26 (HR, 95% CI ) when compared with that of the sepsis group. Owing to the retrospective nature of our study, the pneumonia patient group might include some patients also having severe sepsis, thus overestimating the mortality in the pneumonia group. The actual mortality might be even lower than that observed. Although not statistically significant, patients with pulmonary edema and airway protection also had lower relative risks of mortality than those in the sepsis group, (Fig. 2 and Table 3). This implied that the underlying chronic illness responsible for acute respiratory failure was the main determinant of prognosis and mortality in our critically ill patients. Furthermore and intuitively, we might think that the pulmonary edema group should have the best prognosis because the fluid overload could be removed by simple ultrafiltration. However, our data did not confirm this belief. While the small number of patients in the pulmonary edema group (7 patients, 4 non-survivors and 3 survivors) had its limitation, the underlying cause of pulmonary edema should explain the unexpected result. The four non-survivors included three patients who died 100 Cumulative proportion survival (%) Airway protection, n = 2 Sepsis, n = 10 Pneumonia, n = 22 Pulmonary edema, n = 7 0 CPR, n = Time (days) Fig. 2. Overall hospital survival, stratified according to the cause of respiratory failure

8 40 S. C. CHEN, K. H. SHU, C. H. CHEN, et al. Vol. 24, No. 1, Cumulative proportion survival (%) n = Time (days) Fig. 3. Long-term survival of the 18 survivors after discharge from cardiogenic shock (CAD-III, acute myocardial infarction), and one who died from ventricular tachycardia. The fact that they all had severe heart dysfunction and pulmonary edema implied just the result but not the cause for death. In contrast, although the three survivors all had congestive heart failure (CHF) and CAD, there were no cardiogenic shock or arrhythmia. Thus, the pulmonary edema represented only the epiphenomenon and more patients were needed for further investigation of different causes of pulmonary edema. In order to prevent missing the diagnosis of CHF, we used CTR instead, although it had some limitations such as patients with diastolic heart failure might not present a large heart silhouette on chest X-ray. CTR had been associated with left ventricular mass, 15 left ventricular systolic dysfunction 16 and mortality in patients with hypertension or chronic cardiovascular disease. 17 Chen et al. 18 reported that CTR was an indicator of inflammation and nutritional status in non-diabetic MHD patients and could predict two-year mortality in these patients. Reducing the CTR to less than 0.5 and treating underlying causes were believed to improve survival. Currently, there was no study regarding the impact of CTR on outcome of diabetic MHD patients. In our study, the prevalence of CTR > 0.5 were 95.7% (45/47) and only two patients had a CTR < 0.5, resulting in statistical insignificance between the two groups. This might be due to the older age and high prevalence of diabetes (61.7%) in our patient group, while diabetes was a risk factor for cardiovascular disease and heart failure. 19 CTR was generally believed to be correlated with fluid status and was used as a guide for determination of dry body weight in MHD patients. 20,21 The high prevalence of CTR > 0.5 indicated that inadequate HD with fluid overload might also affect the outcome of our patients. The survivors, who had successful weaning or were transferred to the chronic respiratory care unit, also had high mortality. The survival rate was around 40% in the first year and 25% in the third year, as shown in Fig. 3. This could be explained by the fact that these survivors

9 Acta Nephrologica Outcome of HD patients with acute respiratory failure 41 still had various comorbidities, which resulted in high mortality. The subgroup analysis showed that patients with chronic respiratory failure had higher crude mortality (10/11, 91%) than those being weaned successfully (3/7, 43%) at the end of follow-up. Given such poor prognosis, palliative care without intubation might be another option for the patients and their family, thus avoiding further suffering in these dying patients. The USRDS1 data in 2008 also revealed a steady increase in the percentage of deceased ESRD patients receiving dialysis withdrawal or hospice care. However, there was no consensus about the hospice care for this group of severely deceased ESRD patients in Taiwan. We provided our experience and opinion here. Our study had several limitations. It was a retrospective study conducted in a single medical center. The results might lack general applicability. Several parameters that are relevant to the prognosis of MHD patients were not collected. They included urea reduction ratio (URR), Kt/Vurea, 22 vascular access type (fistula, catheter, graft) 23 and normalized protein catabolic rate (npcr). 24 These data were either missing or incompletely recorded in the charts. A different result might be obtained after adjusting for these confounding factors. In conclusion, MHD patients complicated with acute respiratory failure were associated with a high mortality rate; not only during hospitalization, but also during subsequent follow-up when discharged from the hospital. Whether hospice care should be considered for these patients remains an open question yet to be addressed. Acknowledgements The authors would like to thank the Biostatistics Task Force, Taichung Veterans General Hospital, Taichung, Taiwan, ROC for their assistance in statistical analyses. References 1. U.S. Renal Data System, USRDS 2008 Annual Data Report: Atlas of End-Stage Renal Disease in the United States, National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, Wen CP, Cheng TYD, Tsai MK, et al: All-cause mortality attributable to chronic kidney disease: a prospective cohort study based on adults in Taiwan. Lancet 2008; 371: Hwang S, Lin M, Chen H, et al: Increased risk of mortality in the elderly population with late-stage chronic kidney disease: a cohort study in Taiwan. Nephrol Dial Transplant 2008; 23: National Health Insurance. Annual Statistical Report Department of Health, Executive Yuan, ROC, Taiwan, Uchino S, Morimatsu H, Bellomo R, Silvester W, Cole L: End-stage renal failure patients requiring renal replacement therapy in the intensive care unit: incidence, clinical features, and outcome. Blood Purif 2003; 21: Manhes G, Heng AE, Aublet-Cuvelier B, Gazuy N, Deteix P, Souweine B: Clinical features and outcome of chronic dialysis patients admitted to an intensive care unit. Nephrol Dial Transplant 2005; 20: Dara SI, Afessa B, Bajwa AA, Albright RC: Outcome of patients with end-stage renal disease admitted to the intensive care unit. Mayo Clin Proc 2004; 79: Clermont G, Acker CG, Angus DC, Sirio CA, Pinsky MR, Johnson JP: Renal failure in the ICU: comparison of the impact of acute renal failure and end-stage renal disease on ICU outcomes. Kidney Int 2002; 62: Rocha E, Soares M, Valente C, et al: Outcomes of critically ill patients with acute kidney injury and end-stage renal disease requiring renal replacement therapy: a case-control study. Nephrol Dial Transplant 2009; [Epub ahead of print]. Available from: Knaus WA, Draper EA, Wagner DP, Zimmerman JE: APACHE II: a severity of disease classification system. Crit Care Med 1985; 13: Foley RN, Culleton BF, Parfrey PS, et al: Cardiac disease in diabetic end-stage renal disease. Diabetologia 1997; 40: Locatelli F, Pozzoni P, Del Vecchio L: Renal replacement therapy in patients with diabetes and end-stage renal disease. J Am Soc Nephrol 2004; 15 Suppl 1: S Martin GS, Mannino DM, Eaton S, Moss M: The epidemiology of sepsis in the United States from 1979 through N Engl J Med 2003; 348: Blanco J, Muriel-Bombín A, Sagredo V, et al: Incidence, organ dysfunction and mortality in severe sepsis: a Spanish multicentre study. Crit Care 2008; 12: R Rayner BL, Goodman H, Opie LH: The chest radiograph. A useful investigation in the evaluation of hypertensive patients. Am J Hypertens 2004; 17: Shah S, Davies MK, Cartwright D, Nightingale P: Management of chronic heart failure in the community: role of a hospital based open access heart failure service. Heart 2004; 90: Kearney MT, Fox KAA, Lee AJ, et al: Predicting sudden death in patients with mild to moderate chronic heart failure. Heart 2004; 90: Chen KH, Lin-Tan DT, Huang WH, et al: Cardiothoracic ratio, malnutrition, inflammation, and two-year mortality in non-diabetic patients on maintenance hemodialysis. Kidney Blood Press Res 2008; 31: Nathan DM: Long-term complications of diabetes mellitus. N Engl J Med 1993; 328: Xiao XC, Tao LJ: Assessment of dry body-weight in hemodialysis patients by plasma cyclic 3'5'-guanosine monophosphate. Hunan Yi Ke Da Xue Xue Bao 2001; 26: Park J, Yang WS, Kim SB, et al.: Usefulness of segmental bioimpedance ratio to determine dry body weight in new hemodialysis patients: a pilot study. Am J Nephrol 2009; 29: KDOQI Clinical Practice Guidelines and Clinical Practice Recommendations for 2006 Updates: Hemodialysis Adequacy, Peritoneal Dialysis Adequacy and Vascular Access. Am J Kidney Dis 2006; 48: S1-S Lacson E, Wang W, Hakim RM, Teng M, Lazarus JM: Associates of mortality and hospitalization in hemodialysis: potentially actionable laboratory variables and vascular access. Am J Kidney Dis 2009; 53: Kalantar-Zadeh K, Supasyndh O, Lehn RS, McAllister CJ, Kopple JD: Normalized protein nitrogen appearance is correlated with hospitalization and mortality in hemodialysis patients with Kt/V greater than J Ren Nutr 2003; 13: