Intensive Monitoring of Renal Function

Study Overview
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Brief Summary
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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
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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.

Official Title
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Association Between Intensive Monitoring of Renal Function and Outcomes in Critically Ill Patients

Conditions
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Intensive Monitoring of Renal Function, Acute Kidney Injury

Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Intensive Monitoring of Renal Function<br>Urine output measurements recorded at least every 2 hours within the first 48 hours of ICU admission and serum creatinine measurements recorded daily for 3 days following ICU admission. | |
| Less-Intensive Monitoring of Renal Function<br>Urine output measurements with gaps of more than 3 hours recorded during the first 48 hours of ICU admission and fewer than 3 days of serum creatinine measurements after ICU admission. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 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. | 7 days from ICU admission | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Mortality | Hazard Ratios were measured to detect the risk of mortality at 30 days from ICU admission. | 30 days | 
| Length of Stay in ICU | Patients with and without AKI were compared among urine output group for duration of stay in ICU and hospital. | 30 days | 
| Hospital Length of Stay | Hospital length of Stay was measured among urine output group and reported as median (Inter-Quartile Range). | 30 days |