|Year : 2020 | Volume
| Issue : 2 | Page : 58-65
Thirty-day outcomes among intensive care unit patients with septic shock with versus without preadmission chronic renal disease
Haifa Mesfer Algethamy1, Yasmin Sharton1, Ayman Morish2
1 Department of Anesthesia and Critical Care Medicine, Faculty of Medicine, King Abdulaziz University Hospital, King Abdulaziz University, Jeddah, Saudi Arabia
2 Department of Anesthesia and Critical Care Medicine, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
|Date of Submission||28-Jan-2020|
|Date of Decision||31-Mar-2020|
|Date of Acceptance||06-May-2020|
|Date of Web Publication||1-Jul-2020|
Haifa Mesfer Algethamy
Department of Anesthesia and Critical Care, King Abdulaziz University Hospital, Jeddah
Source of Support: None, Conflict of Interest: None
Background: Considerable research indicates that experiencing acute kidney injury (AKI) during hospitalization from sepsis increases patients' risk of death, but few data exist on whether preexisting renal disease, irrespective of the need for dialysis, also increases mortality. Objectives: The objectives of this study were to identify if preexisting renal disease alters outcomes in patients admitted to a Saudi Arabian, tertiary-care intensive care unit (ICU) for septic shock. Materials and Methods: All patients ≥14 years old admitted to the ICU for septic shock from December 2015 to January 2017 were enrolled prospectively and followed for a minimum of 30 days or until death or hospital discharge. Patients with versus without preexisting renal disease were compared regarding demographic and baseline clinical characteristics, details of their infection and treatment, and outcomes. Results: Among 161 patients (mean age: 61.6; male:female = 1:1), 33 had some documented, preexisting renal disease, among whom 17 required regular dialysis. Among the 128 without preexisting renal disease, 66 (52%) died in hospital, versus 11 of 17 (65%) and 9 of 16 (56%) with kidney disease requiring and not requiring dialysis, respectively. Both the presence of renal dysfunction and the development of new-onset AKI were borderline linked to increased, inhospital mortality (P = 0.051 and 0.080, respectively). However, the presence of preexisting renal disease, with or without the need for dialysis, was nonsignificantly (P = 0.58) linked to increased, inhospital mortality. Conclusions: In our sample of 161 patients with septic shock, the presence of preexisting renal disease was not associated with increased mortality, but new-onset AKI and the presence of renal dysfunction in the ICU both were associated with increased mortality.
Keywords: Acute kidney injury, chronic renal disease, intensive care unit, mortality, sepsis, septic shock
|How to cite this article:|
Algethamy HM, Sharton Y, Morish A. Thirty-day outcomes among intensive care unit patients with septic shock with versus without preadmission chronic renal disease. Saudi Crit Care J 2020;4:58-65
|How to cite this URL:|
Algethamy HM, Sharton Y, Morish A. Thirty-day outcomes among intensive care unit patients with septic shock with versus without preadmission chronic renal disease. Saudi Crit Care J [serial online] 2020 [cited 2020 Sep 20];4:58-65. Available from: http://www.sccj-sa.org/text.asp?2020/4/2/58/288733
| Introduction|| |
Annually, an estimated 18 million people are diagnosed with sepsis worldwide, with up to three million diagnosed each year in the United States of America (USA) alone., Mortality rates among those with sepsis are high, in some studies reaching 30%–50%,,, or even higher, especially among certain subsets of patients.
Two subsets with higher mortality rates are patients diagnosed with septic shock and those who develop acute kidney injury (AKI).,,, Among those who are critically ill, in general, AKI appears to elevate the risk of death, independent of other factors. In a South Korean study of almost 1000 patients admitted to an intensive care unit (ICU) with septic shock, almost six in ten (57%) ultimately developed AKI, and Kaplan–Meier curves revealed significantly elevated mortality in those with AKI versus not, as well as a trend toward increased mortality with increasing stage of AKI. In a second, massive study incorporating 54 ICUs from across Australia, in which more than 120,000 patients were reviewed, AKI was associated with both increased ICU (19.8% vs. 13.4%; odds ratio [OR]: 1.60, 95% confidence interval: 1.5–1.7; P < 0.001) and inhospital (29.7% vs. 21.6%; OR: 1.53, 1.46–1.60; P < 0.001) mortality. Moreover, in a third study of over 29,000 patients admitted to critical care units across 54 hospitals and 23 countries between September 2000 and December 2001, a mortality rate of 60% was documented. Moreover, septic patients with AKI had a statistically higher mortality rate than nonseptic patients with AKI (70% vs. 52%, P < 0.001), a difference that persisted even when adjusted for covariates (OR = 1.48; 95% confidence interval: 1.17–1.89; P = 0.001). Interestingly, among those 29,269 patients, clinically documented acute renal failure was diagnosed in roughly 6% (n = 1738), among whom less than one-third had had any renal dysfunction documented before their admission to intensive care. Moreover, just as AKI appears to influence the course of sepsis, sepsis appears to be a common cause of AKI, especially in developed countries, accounting for roughly 25%–50% of cases.,
A link also appears to exist between end-stage renal disease (ESRD) and sepsis. For example, the US national statistics have revealed 100- to 300-fold higher mortality secondary to sepsis in dialysis patients relative to the general population, as well as a 20-fold higher rate of death in renal transplant recipients. Conversely, in a recently published US study, though both ICU and inhospital mortality were greater in those with sepsis and AKI, relative to those with sepsis but no AKI, the same was not true for ESRD.
Hence, the over-riding aim of the current study was to identify links between chronic renal disease (CRD) and ESRD, and both ICU and inhospital mortality, as well as the rate of new-onset ESRD among septic shock patients in a Saudi ICU. The specific study objective was to identify the association between preadmission CRD, with or without the need for dialysis, and 30-day inhospital mortality. The study also aimed to identify the percentage of patients who develop renal failure, requiring dialysis, in the ICU, to identify the association between new-onset renal failure and 30-day mortality, and to assess whether new-onset AKI in the ICU increases mortality rates or not.
| Materials and Methods|| |
Before data collection, the study protocol was approved by the institution's ethics review board for research and was in full compliance with the second edition of the Declaration of Helsinki.
In this prospective study, all patients referred to the ICU at King Abdulaziz University Hospital in Jeddah for treatment of septic shock over the 14 months between December 1, 2015, and January 31, 2017, were enrolled and followed for a minimum of 30 days. For the purposes of the current analysis, septic shock was defined as per the Third International Consensus Definitions for Sepsis and Septic Shock (Singer); patients recruited early before publication of these consensus definitions who did not meet the criteria for septic shock were excluded from further analysis and will not be further mentioned here.
To be eligible, patients also had to be at least 14 years old and to have not had cultures performed previously which identified any offending organisms. Such patients were followed for either a minimum of 30 inhospital days, hospital discharge, or death.
Patient eligibility for the study was determined by the study team at the time of their admission to the ICU, with all subsequent data either recorded electronically or using a predetermined data collection form.
Patients received standard care for septic shock and sepsis, which included the use of vasopressors, as indicated; fluid resuscitation; supplemental oxygen; mechanical ventilation, as indicated; and the empirical administration of antibiotics. The choice of all treatments was left to the treating team, in response to each patient's individual clinical picture. Standard monitoring included constant monitoring of vital signs, fluid intake and urine output, and regular monitoring of mental status. Standard laboratories included at least daily blood draws to measure serum electrolytes, lactate, creatinine, liver function tests, cell counts, and any other laboratory tests deemed relevant to the individual case.
Data of specific interest included each patient's age, gender and nationality/race, height, weight, calculated body mass index (BMI), route of admission to the ICU, any comorbid conditions, the site and established source of infection, clinical laboratories, culture and sensitivity results and source, antibiotics administered and the timing of initiation relative to ICU admission, other treatments administered, and various clinical outcomes, including complications of sepsis, a general measure of clinical status, and final outcome (e.g., death, continued hospitalization, and discharge home).
As a measure of general clinical status, on ICU day #1 (the day of admission) and day #3, each surviving patient's Sepsis-Related Organ Failure Assessment (SOFA) score was calculated; the SOFA score is a widely used, published instrument that has been validated for such use (Vincent).
Continuous variables were summarized as means with ranges, whereas categorical variables were categorized as proportions. For comparisons involving two groups, continuous variables were compared by Student's t-tests when the data were normally distributed and by Wilcoxon rank-sum tests when not normally distributed. Intergroup comparisons for all categorical variables, whether nominal or ordinal, were compared by Pearson χ2 analysis. When three or more patient groups were compared, analysis of variance, with or without a conservative adjustment of degrees of freedom, was used, again depending on whether the data were normally or nonnormally distributed. Intergroup comparisons for all categorical variables, whether nominal or ordinal, were compared by Pearson χ2 analysis or Fisher's exact test, depending on the number of subjects per cell.
All tests were two-tailed, with P ≤ 0.05 set as the criterion for statistical significance and 0.51< P ≤0.10 set as the criterion for borderline significance. All analyses were performed using the statistical software program SPSS, version 24 (SPSS Inc., NY, USA).
| Results|| |
Characteristics of the overall sample
A total of 161 patients met study criteria and were included in the initial analysis, ranging in age from 14 to 101 years old (mean 61.6), with 4.3% under age 20, 9.9% 20–39 years old, 27.3% 40–59, 41.6% 60–79, and 16.0% 80 or older. Of these 161, an equal number (49.1%) were male as female, with the gender not recorded in the chart for 1.8% (n = 3); 36.3% were Saudi nationals, 43.8% non-Saudi Arabs, and 20.0% non-Arab [Figure 1].
|Figure 1: Survival chart for patients without preexisting kidney disease|
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Physically, the overall mean height across the 161 patients was 161.2 cm (range: 105–190), height 71.3 (31–165), and BMI 27.8 (15.2–90.7), with 5.6% of the sample falling within the range of underweight, 35.0% normal weight, 29.4% overweight, and 30.0% obese. A sizeable majority (70.8%) came to the ICU through either the emergency room or directly from their home, with the vast majority of the remainder either coming from the medicine service (18.8%) or surgery service (8.7%). Almost all (91.9%) had some preexisting comorbidity, with 72.7% having more than one comorbid condition. The most common comorbid conditions were some cardiovascular disease (CVD, 62.1%), most commonly hypertension (55.3%), ischemic heart disease (14.3%), or congestive heart failure (11.2%); 21.1% had more than one CVD. The next most common was diabetes mellitus (58.4%), followed by CRD (20.5%; 10.6% on dialysis), past or current stroke (16.1%), chronic lung disease (11.8%), and cancer (6.2%). Two patients (1.2%) had been previously diagnosed with AIDS. Roughly one in six (17.4%) had been bedridden before their admission to our ICU. The mean baseline SOFA score on ICU day #1 was 9.1/24 (range: 2–19) [Figure 1].
More than half of the patients (57.1%) were deemed to have acquired their infection in the community, with the remainder nosocomial. The most common primary sites of infection were respiratory tract (48.1%), skin or soft tissues (15.6%), urinary tract (9.7%), or intra-abdominal (9.7%). The original source of infection was identified in 55.3% and either unknown or not reported in 44.7%. As with the primary sites of infection, the most common original sources of infection were pulmonary (26.1%; aspiration pneumonia in 17.4%); skin or soft tissues (15.5%); or genitourinary (8.7%), with 6.2% ascribed to some foreign vascular device [Table 1]. The underlying organism was identified by culture in 80.1% and surmised by the clinical picture in 13.7%. The most common organisms were Escherichiacoli (26.1%), Klebsiella (18.6%), Pseudomonas (17.4%), Staphylococcus aureus (16.1%), and Enterococcus (10.6%). Roughly two-thirds of the cultured organisms (64.0%) were Gram negative, with 34.8% Gram positive, and 1.9% anaerobic. Fungi were identified in 6.8% and H1V1 in 2.5%. More than one in four (28.6%) of the bacteria were considered antibiotic resistant [Figure 1].
The most common classes of antibiotic used were β-lactam (in 60.9%); a combination drug, like trimethoprim-sulfamethoxazole or tazobactam -piperacillin (47.8%); a glycopeptide (33.5%); or a macrolide (11.2%), with tazobactam-piperacillin, the most commonly administered drug (46.6%), followed by meropenem (32.3%), vancomycin (31.1%), and ceftriaxone (20.5%). Roughly half of the patients (46.6%) ultimately were administered two antibiotics, 36.6% a single drug, and 16.1% three drugs. Other than vasopressors, the most commonly prescribed other treatments were mechanical ventilation (61.5%), enteral feeding (72.7%), goal-directed therapy (31.7%), dialysis (24.8%), systemic steroids (low dose in 14.9% and high dose in 1.9%), and strict glycemic control (9.3%) [Figure 1].
Of the 161 patients, 128 had no known current or past CRD before their admission to our ICU, whereas 33 did. Of these 33, 17 were undergoing regular dialysis, whereas 16 were not. Ultimately, 58.4% of the patients exhibited either renal failure or compromise in the ICU. Seventy-seven of the original 161 patients (47.8%) died within the ICU, with 9 (5.6%) still in the ICU after 30 days of follow-up, 24 (14.9%) transferred to some other ICU, and 46 discharged from the ICU. Nine of the 70 transferred either to the floor or another unit (5.6% of the total 161) died in hospital, whereas just 36 (22.4%) were discharged to home, 9 (5.6%) remained in some other critical care unit, 22 (13.7%) remained on one of the hospital wards, and 3 (1.9%) were lost to follow-up. Among those who died in the ICU, the mean time to death in the ICU was 10.6 days (range: 0.5–37), whereas the mean ICU stay among those ultimately discharged from the ICU was 14.8 days (2–67). The mean time to death after discharge from the ICU, among the nine who died in hospital, was 14.3 days, whereas the mean length of the hospital stay among those ultimately discharged home was 25.0 days [Figure 1].
[Figure 1] and [Figure 2] document the course of the 161 patients, categorized into those 128 with no preexisting renal disease before their ICU admission [Figure 1], and those 33 with previously documented CRD, further subdivided into the 17 on dialysis and 16 not on dialysis before admission [Figure 2].
Comparing patients with versus without preexisting kidney disease
[Table 2], [Table 3], [Table 4], [Table 5] compare patients with (n = 33) and without (n = 128) previously documented renal disease, further subdividing the former group into those on versus not receiving dialysis (n = 17 and 16, respectively). Demographically, the groups were not statistically different, in mean age; (age group divided into 20-year intervals), gender; mean weight, height or BMI; (weight group; underweight, normal weight, overweight, obese); racial identity; or route of admission to the ICU [Table 2].
|Table 2: Demographic and baseline clinical characteristics of the sample|
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|Table 3: Comparing patients with preexisting kidney to patients with normal kidney function - baseline characteristics|
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|Table 4: Comparing patients with preexisting kidney to patients with normal kidney function - treatment variables|
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|Table 5: Comparing patients with preexisting kidney to patients with normal kidney function - outcomes|
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No statistically significant intergroup differences were identified in the three groups' baseline clinical characteristics, though four variables were borderline significant [Table 3]. The main site of infection differed somewhat (P = 0.06), with patients in the preexisting renal disease without dialysis group tending to have more respiratory or skin/soft-tissue infections than those receiving dialysis (67% vs. 35%). Patients on dialysis before ICU admission also seemed to have more different strains of bacteria cultured than either those not on dialysis and those with no prior renal disease (1.71 vs. 1.13 and 1.22, respectively; P = 0.096). Meanwhile, those with renal disease not on dialysis were borderline more likely to have cancer (19% vs. 0% and 6%, P = 0.06) and those with no prior renal disease borderline more likely to have a history of CVD (88% vs. 59% and 65%, P = 0.08).
[Table 4] compares the treatments given, among which the only intergroup difference pertained to hemofiltration which was, understandably, significantly more common in patients with prior renal disease (18.2%) than those without (1.6%, P < 0.001).
[Table 5] compares outcomes between the three subject groups, among which two statistically significant differences were noted. Understandably, given that patients on dialysis before admission required either hemodialysis or hemofiltration afterward, the three groups differed in the percentage who had dialysis (100% vs. 50% vs. 31%, P = 0.03). However, comparing just the latter two groups, the difference just failed to meet our criterion for borderline significance (χ2 = 2.47; df = 1; P = 0.12).
The other intergroup difference was that those on dialysis before admission averaged fewer major complications (1.2 vs. 2.1 and 1.9, P = 0.004), though this difference disappeared when dialysis was considered a complication, even among those already on dialysis before ICU admission.
Interestingly, the three groups did not differ in the percentage who died either in the ICU or in hospital or in the percentage discharged from the ICU or discharged home. Moreover, the eight patients with prior renal disease who had to commence dialysis in the ICU were no different in their mortality rate than those already on dialysis before admission (63% vs. 65%, respectively).
On the other hand, among those with no prior history of renal dysfunction, the development of AKI in the ICU was borderline associated with increased mortality [Figure 3]; χ2 = 3.00, df 1, P = 0.08]. Moreover, among all 161 patients, the presence of any renal dysfunction, from AKI to ESRD, in the ICU also was borderline statistically associated with increased mortality [Figure 4]; χ2 = 3.80, df 1, P = 0.051].
| Discussion|| |
As documented by others, in our sample of 161 ICU patients with septic shock, the presence of renal dysfunction in the ICU, whether new onset or already established, was at least borderline statistically linked to increased mortality. However, when we looked for an association specifically between already established renal disease and mortality, we failed to identify any link. This finding is consistent with one US study, reported by Jeganathan et al., in which there was no significant difference in mortality among those with sepsis and ESRD and those with sepsis but no ESRD.
It also is consistent with the results of another American study, reported by Lowe et al., in which 137 ESRD patients and 3427 patients without ESRD were prospectively enrolled into an emergency department septic shock treatment pathway registry between January 2014 and May 2016, and their clinical status and outcomes were compared. Septic shock patients with ESRD were observed to have a greater burden of chronic illness than non-ESRD patients but similar admission clinical profiles, whereas their inhospital mortality rate was not significantly higher (20.4% vs. 17.1%, P = 0.31). The patient's age and serum lactate level at admission were independently associated with mortality in ESRD septic shock patients, whereas ESRD was independently associated with a reduced mean volume of intravenous fluid required for resuscitation.
In yet another, even larger study, using an international, multicenter database and retrospectively analyzing data from 800 chronic dialysis patients and 9614 not on dialysis patients admitted to ICUs with septic shock from 1989 to 2013, multivariate time-varying Cox models with and without propensity-score matching again failed to identify any association between ESRD requiring dialysis and inhospital death, with mortality rates of 54.8% and 49.0%, respectively. On the other hand, the isolation of resistant organisms (10.7% vs. 7.1%; P = 0.005) and delays receiving antimicrobials (6.0 vs. 5.0 h, P <0.005) were more common in chronic dialysis than nondialysis patients, and delayed appropriate antimicrobial therapy was associated with an increased risk of death among long-term dialysis patients (P < 0.0001).
How all the above-noted results, and our own, align with US national statistics indicating up to a 300-fold greater risk of mortality from sepsis in dialysis patients relative to the general population is unclear.
Our study was different from the just-described studies, in that we assessed mortality and other outcomes not just in patients with preexisting ESRD, but in patients with any preexisting kidney disease, and detected no difference in mortality rate between either group and those without prior renal disease, or between the two renal disease groups themselves, with overall inhospital mortality rates of 65% and 56%, respectively. Unfortunately, our review of the literature failed to identify similar studies, suggesting that this question – does the existence of any preexisting renal disease increase the risk of death from sepsis or septic shock – warrants replication.
Our study has obvious limitations, the most notable being its relatively small size, in terms of patient numbers, with only 161 patients total, as well as only 17 on dialysis before ICU admission and 16 with renal disease not requiring dialysis. We also, in this analysis, did not look at certain other variables that might be confounders, including certain variables known to impact survival in shock patients, such as serum lactate levels, and the use of and level of resistance to vasopressors. On the other hand, we compared our three patient groups (patients on dialysis before ICU admission, patients with kidney disease not requiring dialysis before ICU admission, and those without prior renal disease) with respect to 75 other baseline and treatment variables and identified very few intergroup differences that would explain away the lack of mortality rate differences we observed. One difference in outcomes that we detected was the lower mean number of complications in those previously on dialysis; however, when dialysis itself was added as a complication, this difference disappeared.
| Conclusions|| |
In our sample of 161 septic shock patients, we identified 33 with preexisting renal disease, 17 of whom required dialysis. Although the development of AKI during the ICU stay was statistically associated with increased mortality, the presence of renal disease, with or without dialysis, before ICU admission was not. These results conflict with US national data indicating a markedly increased risk of death from sepsis among patients on dialysis. The reasons for this discrepancy are unclear.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]