Disparate outcomes observed within Kidney Disease: Improving Global Outcomes (KDIGO) acute kidney injury stage 1.

The 2012 Kidney Disease: Improving Global Outcomes (KDIGO) clinical practice guideline classifies acute kidney injury (AKI) into 3 stages defined by serum creatinine elevation or urine output decline. We evaluated the potential impact of further categorizing AKI stage 1 into two stages based on serum creatinine criteria, with a focus on how the resulting 4-stage classification would affect the association of AKI stages with clinical outcomes. We defined AKI stage 1a as an absolute increase in serum creatinine of 0.3 mg/dl within 48 hours and stage 1b as a 50% relative increase in serum creatinine within 7 days. We screened all admissions to 5 hospitals from 2012 to 2014 using standardized inclusion and exclusion criteria and included 81,651 admissions in this retrospective cohort study. The incidence of in-hospital AKI was 7.5% for stage 1a, 4.9% for stage 1b, 1.5% for stage 2, and 0.9% for stage 3. Length of stay following the first incidence of AKI was 3.9 days for stage 1a, 6.2 days for stage 1b, 8.8 days for stage 2, and 12.0 days for stage 3. Compared to patients with no AKI, the odds of in-hospital mortality were progressively higher for patients with higher AKI stages (odds ratio 4.3 for patients with stage 1a, 10.9 for stage 1b, 40.6 for stage 2, and 60.0 for stage 3 AKI). Patients with AKI stages 1a and 1b experienced clinically meaningful and statistically significant differences in length of stay and mortality. This study suggests that a modified 4-stage version of the KDIGO AKI classification may provide additional prognostic information.

Optimization of Acute Kidney Injury (AKI) Time Definitions Using the Electronic Health Record: A First Step in Automating In-Hospital AKI Detection.

Kidney Disease: Improving Global Outcomes (KDIGO) acute kidney injury (AKI) definitions were evaluated for cases detected and their respective outcomes using expanded time windows to 168 h. AKI incidence and outcomes with expanded time intervals were identified in the electronic health records (EHRs) from 126,367 unique adult hospital admissions (2012-2014) and evaluated using multivariable logistic regression with bootstrap sampling. The incidence of AKI detected was 7.4% (n = 9357) using a 24-h time window for both serum creatinine (SCr) criterion 1a (≥0.30 mg/dL) and 1b (≥50%) increases from index SCr, with additional cases of AKI identified: 6963 from 24-48 h.; 2509 for criterion 1b from 48 h to 7 days; 3004 cases (expansion of criterion 1a and 1b from 48 to 168 h). Compared to patients without AKI, adjusted hospital days increased if AKI (criterion 1a and 1b) was observed using a 24-h observation window (5.5 days), 48-h expansion (3.4 days), 48-h to 7-day expansion (6.5 days), and 168-h expansion (3.9 days); all are p < 0.001. Similarly, the adjusted risk of in-hospital death increased if AKI was detected using a 24-h observation window (odds ratio (OR) = 16.9), 48-h expansion (OR = 5.5), 48-h to 7-day expansion (OR = 4.2), and 168-h expansion (OR = 1.6); all are p ≤ 0.01. Expanding the time windows for both AKI SCr criteria 1a and 1b standardizes and facilitates EHR AKI detection, while identifying additional clinically relevant cases of in-hospital AKI.