## 5 Conclusions  
Increasing the observation window allows for the comparison of a greater number of SCr assessments which increases the incidence of AKI detected in-hospital. Detection of AKI using a 24-h window may represent a severe form of AKI (even for an absolute increase in SCr by \(\geq\)0.3 mg/dL). Cases of AKI detected using the expanded windows (e.g., \(>\)48 h) identified AKI later during the hospital course and continued to predict prolonged hospital stay and risk for in-hospital death. The importance of this data in clinical practice will be with the relatively simple programming of these AKI definitions into the electronic health record to generate clinical alerts. Electronic health record automated in-hospital expansion of the KDIGO AKI SCr observation time windows to 168 h increases the observed incidence of AKI from 14.9% to 17.3% and these additional patients with AKI experienced a clinically meaningful increased risk of in-hospital death and prolonged LOS.  
The following are available online at [[https://www.mdpi.com/article/10.3390/jcm10153304/s1](https://www.mdpi.com/article/10.3390/jcm10153304/s1)]([https://www.mdpi.com/article/10.3390/jcm10153304/s1](https://www.mdpi.com/article/10.3390/jcm10153304/s1)), Text S1: Applied examples for observation windows and precision levels, Figure S1: Schema for observation window expansions, Figure S2: Histogram of serum creatinine assessments by hour of day (\(n\) = 673,011), Figure S3: Days of hospital care before and after detection of AKI as the observation window increases from 24 to 172 h (\(n\) = 124,566 survivors only), Figure S4: Days of hospital care before and after detection of AKI using only criterion 1a (absolute increase of 0.3 mg/dL) as the observation window increases from 24 to 172 h (\(n\) = 126,367), Figure S5: Days of hospital care before and after detection of AKI using only criterion 1b (50% relative increase) as the observation window increases from 24 to 172 h (\(n\) = 126,367), Figure S6: Adjusted odds ratio of in-hospital mortality by narrowest observation window using only criterion 1a (absolute increase of 0.3 mg/dL), Figure S7: Adjusted odds ratio of in-hospital mortality by narrowest observation window using only criterion 1b (50% relative increase), Table S1: Association between AKI and length of stay (\(n\) = 126,367), Table S2: Association between AKI and in-hospital mortality (\(n\) = 126,367).  
Research idea and study design: J.T.S., L.W.M., H.G.S., A.O.G. and W.N.S.; data acquisition: J.T.S.; data analysis/interpretation: J.T.S., L.W.M., H.G.S., A.E.F., A.O.G. and W.N.S. Each author contributed important intellectual content during manuscript drafting or revision, accepts personal accountability for the author's own contributions, and agrees to ensure that questions pertaining to the accuracy or integrity of any portion of the work are appropriately investigated and resolved. All authors have read and agreed to the published version of the manuscript.  
No direct funding was received for this research. Publication costs were supported by Renal Research Inc., a 501c3 research and education foundation.  
The study was approved by Houston Methodist Hospital Institutional Review Board with a waiver of informed consent.  
The study was approved by the health-system's institutional review board with a waiver of informed consent.  
The data presented in this study are available on request from the first author. The data are not publicly available due to privacy concerns.  
The investigators would like to thank the patients whose data provided the insights described. The support of Renal Research Inc. for the publication of this manuscript is gratefully acknowledged.  
The authors declare no conflict of interest.