Acute Kidney Injury, Intensive Monitoring of Renal Function
Conditions
Brief summary
This study aims to examine the association between monitoring (Intensive and non-intensive) of renal function (urine output, serum creatinine) and outcomes among critically ill patients such as Acute Kidney Injury (AKI) and mortality.
Detailed description
Intensive monitoring of renal function provides an early opportunity to modify or attenuate certain risk factors (e.g., nephrotoxin exposure) for AKI. Intensive monitoring of urine output (UO) provides a real-time continuous assessment of renal function in the ICU. However, the association between intensive monitoring and less-intensive monitoring of urine output, with or without close monitoring of serum creatinine (sCr), on susceptibility to AKI and outcomes from AKI are unknown. Our preliminary data indicates that intensive monitoring of UO is associated with lower hospital mortality as compared to less-intensive monitoring for patients that develop AKI. If intensive monitoring of renal function is associated with lower risk of AKI and improved outcomes from AKI, then such monitoring techniques could be widely used in hospitalized patients including non-intensive care settings to either prevent AKI or progression of AKI. Therefore, this observational retrospective cohort study aims to compare the outcomes of patients undergoing intensive monitoring of renal function (UO and/or sCr) with those of patients undergoing less intensive monitoring. Outcomes will include mortality within 30 days of ICU admission among critically ill patients with and without AKI. Development of severe AKI within 7 days of ICU admission and fluid overload on any ICU day in patients who develop severe AKI (KDIGO stage 3) will also be assessed. This study will utilize a large, heterogeneous cohort (n=\ 54,800) of critically ill patients admitted to the ICU over 8 year period at the University of Pittsburgh Medical Center. The study population will consist of patients who receive intensive monitoring of UO (defined as measured at least every 2 hours within the first 48 hours of ICU admission) and strict creatinine measurement (defined as at least daily). Patients who fail to meet criteria for intensive monitoring will be controls (less-intensive monitoring group). AKI will be diagnosed according to the KDIGO stage 1-3 criteria over a 7-day period. Mortality at 30-days from ICU admission will be ascertained using the social security death master file. In order to account for indication bias, a propensity score for intensive monitoring will be built using various risk factors. Risk and severity of illness-adjusted estimates will be generated for susceptibility to AKI and mortality from AKI between intensive and less-intensive monitoring groups.
Interventions
None listed
Sponsors
C. R. Bard
University of Pittsburgh
Study design
Observational model
OTHER
Time perspective
RETROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Critically ill patient admitted to ICU * Required vasopressor support or mechanical ventilation in the 24 hours from ICU admission
Exclusion criteria
* History of chronic dialysis and/or renal transplant * Baseline serum creatinine \>= 4 mg/dl * Insufficient data to determine AKI stage in the 7 days from ICU admission * Died within 48 hours from ICU admission * ICU duration \<2880 minutes
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Detection of Acute Kidney Injury (AKI) | 7 days from ICU admission | We classified AKI according to the maximum Kidney Disease Improving Global Outcomes criteria met during the 7 days after ICU admission using both SC and UO criteria. Admission creatinine levels were the first creatinine value recorded for the index hospital admission. Reference creatinine level was taken as the baseline creatinine level when available; otherwise, it was the lowest between admission creatinine level or creatinine level recorded in the 24 hours following ICU admission estimated using MDRD equation. For all analyses, we used moderate to severe AKI defined as stage 2-3. For UO criteria, at least every 6 hours data was required to stage AKI regardless of whether the patient had intensive or nonintensive UO monitoring overall.Odds ratio were measured between two groups.Odds ratios were determined using multivariable models for intensive vs non-intensive UO and between intensive vs non-intensive creatinine monitoring groups. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Mortality | 30 days | Hazard Ratios were measured to detect the risk of mortality at 30 days from ICU admission. |
| Length of Stay in ICU | 30 days | Patients with and without AKI were compared among urine output group for duration of stay in ICU and hospital. |
| Hospital Length of Stay | 30 days | Hospital length of Stay was measured among urine output group and reported as median (Inter-Quartile Range). |
Participant flow
Recruitment details
This is an observational study. Hence, no prospective enrollment was performed. Collected data was analysed on patients meeting inclusion criteria for the study periof from year 2000 to 2008.
Participants by arm
| Arm | Count |
|---|---|
| Study Population Undergoing Urine Output and Serum Creatinine We stratified patients into two overlapping cohorts: those who received UO monitoring and those who received SC monitoring. We further subdivided each cohort into an intensive monitoring group and a less intensive monitoring group. UO intensive monitoring was defined as hourly recordings and no gaps of \> 3 hours for the initial 48 hours after ICU admission, whereas less intensive UO monitoring was defined as patients not meeting intensive monitoring criteria regardless of UO information in the 7 days following ICU admission. SC intensive monitoring was defined as having 3 calendar days of SC data (at least one measure per day) after ICU admission, whereas less intensive SC monitoring was defined as patients not meeting intensive monitoring criteria regardless of SC monitoring availability in the 7 days following ICU admission. | 15,724 |
| Total | 15,724 |
Baseline characteristics
| Characteristic | Study Population Undergoing Urine Output and Serum Creatinine |
|---|---|
| Age, Continuous | 60 years |
| Race/Ethnicity, Customized Race African American | 1164 Participants |
| Race/Ethnicity, Customized Race Other | 2284 Participants |
| Race/Ethnicity, Customized Race White | 12276 Participants |
| Region of Enrollment United States | 15724 Participants |
| Sex: Female, Male Female | 6796 Participants |
| Sex: Female, Male Male | 8928 Participants |
Adverse events
| Event type | EG000 affected / at risk |
|---|---|
| deaths Total, all-cause mortality | 0 / 0 |
| other Total, other adverse events | 0 / 0 |
| serious Total, serious adverse events | 0 / 0 |
Outcome results
Primary
Detection of Acute Kidney Injury (AKI)
We classified AKI according to the maximum Kidney Disease Improving Global Outcomes criteria met during the 7 days after ICU admission using both SC and UO criteria. Admission creatinine levels were the first creatinine value recorded for the index hospital admission. Reference creatinine level was taken as the baseline creatinine level when available; otherwise, it was the lowest between admission creatinine level or creatinine level recorded in the 24 hours following ICU admission estimated using MDRD equation. For all analyses, we used moderate to severe AKI defined as stage 2-3. For UO criteria, at least every 6 hours data was required to stage AKI regardless of whether the patient had intensive or nonintensive UO monitoring overall.Odds ratio were measured between two groups.Odds ratios were determined using multivariable models for intensive vs non-intensive UO and between intensive vs non-intensive creatinine monitoring groups.
Time frame: 7 days from ICU admission
Population: All patients receiving UO or SC monitoring
| Arm | Measure | Group | Value (NUMBER) |
|---|---|---|---|
| Intensive vs Non-Intensive UO Monitoring | Detection of Acute Kidney Injury (AKI) | Intensive monitoring urine output | 1.22 Odds Ratio |
| Intensive vs Non-Intensive UO Monitoring | Detection of Acute Kidney Injury (AKI) | Intensive monitoring serum creatinine | 1.11 Odds Ratio |
| Intensive vs Non-Intensive SC Monitoring | Detection of Acute Kidney Injury (AKI) | Intensive monitoring urine output | 1.22 Odds Ratio |
| Intensive vs Non-Intensive SC Monitoring | Detection of Acute Kidney Injury (AKI) | Intensive monitoring serum creatinine | 1.11 Odds Ratio |
Secondary
Hospital Length of Stay
Hospital length of Stay was measured among urine output group and reported as median (Inter-Quartile Range).
Time frame: 30 days
| Arm | Measure | Group | Value (MEDIAN) |
|---|---|---|---|
| Intensive vs Non-Intensive UO Monitoring | Hospital Length of Stay | UO Monitoring AKI | 17 days |
| Intensive vs Non-Intensive UO Monitoring | Hospital Length of Stay | UO Monitoring no AKI | 14 days |
Secondary
Length of Stay in ICU
Patients with and without AKI were compared among urine output group for duration of stay in ICU and hospital.
Time frame: 30 days
Population: Median (Inter-Quartile Range) were reported.
| Arm | Measure | Group | Value (MEDIAN) |
|---|---|---|---|
| Intensive vs Non-Intensive UO Monitoring | Length of Stay in ICU | Uo Monitoring AKI | 8 days |
| Intensive vs Non-Intensive UO Monitoring | Length of Stay in ICU | UO Monitoring No AKI | 5 days |
Secondary
Mortality
Hazard Ratios were measured to detect the risk of mortality at 30 days from ICU admission.
Time frame: 30 days
Population: Intensive monitoring by urine output and serum creatinine among AKI population is reported.
| Arm | Measure | Group | Value (NUMBER) |
|---|---|---|---|
| Intensive vs Non-Intensive UO Monitoring | Mortality | Intensive monitoring Urine Output | 0.90 Hazard Ratio |
| Intensive vs Non-Intensive UO Monitoring | Mortality | Intensive monitoring Serum Creatinine | 1.10 Hazard Ratio |