Identifying acute kidney injury in children: comparing electronic alerts with health data

Feb 25 / Lucy Plumb
Electronic (e-)alerts for rising serum creatinine values are increasingly used as clinical indicators of acute kidney injury (AKI). Much epidemiological AKI research has relied on disease surveillance through electronic health record coding. The introduction of the national AKI alert warning system offers an opportunity to describe and compare AKI identified among children using two different methodologies. The aim of this study was to investigate to what degree AKI episodes, identified using e-alerts from the UK Renal Registry data, correlated with coding for AKI in the hospital record for a national cohort of hospitalised children and examine whether coding corresponded with 30-day mortality after an AKI episode.

Methodology and study design

This was an observational study using routinely collected data from the UK Renal Registry and hospital records. A cross-section of AKI episodes based on alerts issued for children under 18 years in England during 2017 were linked to hospital records. Multivariable logistic regression was used to examine patient and clinical factors associated with AKI coding. Agreement between coding and 30-day mortality was examined at hospital level.

Key findings

6272 AKI episodes in 5582 hospitalised children were analysed. Overall, coding was poor (19.7%). Older age, living in the least deprived quintile (odds ratio (OR) 1.4, 95% Confidence Interval (CI) 1.1, 1.7) and higher peak AKI stage (stage 1 reference; stage 2 OR 2.0, 95% CI 1.7, 2.4; stage 3 OR 8.6, 95% CI 7.1, 10.6) were associated with higher likelihood of coding in the hospital record. AKI episodes during birth admissions were less likely to be coded (OR 0.4, 95% CI 0.3, 0.5). No correlation was seen between coding and 30-day mortality.

Implications

The proportion of AKI alert-identified episodes coded in the hospital record is low, suggesting under-recognition and underestimation of AKI incidence. Understanding the reasons for inequalities in coding, variation in coding between hospitals and how alerts can enhance clinical recognition is now needed.

Study limitations and future research

This study was limited to data from laboratories submitting data to the UK Renal Registry at the time of data extraction and therefore represents approximately 66% of all NHS laboratories in England. Analyses used AKI defined by a relative rise in serum creatinine therefore could have missed cases of AKI had other definitions (such as poor urine output) been used; furthermore, children may have been misclassified as having an AKI episode based on spurious creatinine readings.

Conclusions

Hospital records show poor agreement with AKI, as identified using electronic alerts, which may be due to a lack of clinical recognition ad/or poor coding of admission events. We see factors associated with lower likelihood of coding which are important to recognise and understand why this is happening. Given variations on a hospital level in the proportion of AKI-associated hospitalisations that were coded, it may be possible to learn from those with high levels of coding, thus driving improvements in clinical recognition, management and potentially care of children with AKI.

Link and citation for published article

Plumb, L., Savino, M., Casula, A. et al. Identifying acute kidney injury in children: comparing electronic alerts with health record data. BMC Nephrol 26, 75 (2025). https://doi.org/10.1186/s12882-025-03961-3