James MT, et al. - Researchers formulated this trial in order to derive and validate predictive models for the progression of acute kidney injury to advanced chronic kidney disease. It was reported that advanced chronic kidney disease following hospitalization with acute kidney injury, was speculated via a multivariable model using routine laboratory data. In order to determine the utility of this model in clinical care, additional analyses were warranted.

Methods

• An analysis was performed of the data from 2 population-based cohorts of patients with a prehospitalization estimated glomerular filtration rate (eGFR) of more than 45 mL/min/1.73 m² and who had survived hospitalization with acute kidney injury (defined by a serum creatinine increase during hospitalization > 0.3 mg/dL or > 50% of their prehospitalization baseline).
• These findings were used to derive and validate multivariable prediction models.
• The risk models were derived from 9,973 patients hospitalized in Alberta, Canada (April 2004-March 2014, with follow-up to March 2015).
• These models underwent external validation with data from a cohort of 2,761 patients hospitalized in Ontario, Canada (June 2004-March 2012, with follow-up to March 2013).
• Demographic, laboratory, and comorbidity variables measured prior to discharge served as the exposures.
• The main outcome included defining of the advanced chronic kidney disease by a sustained reduction in eGFR less than 30 mL/min/1.73 m² for at least 3 months during the year after discharge.
• The follow-up of enrollees was carried out for up to 1 year.

Results

• The eligible candidates (mean [SD] age, 66 [15] years in the derivation and internal validation cohorts and 69 [11] years in the external validation cohort; 40%-43% women per cohort) presented with a mean (SD) baseline serum creatinine level of 1.0 (0.2) mg/dL and more than 20% had stage 2 or 3 acute kidney injury.
• The development of advanced chronic kidney disease was reported in 408 (2.7%) of 9,973 patients in the derivation cohort and 62 (2.2%) of 2,761 patients in the external validation cohort.
• In the derivation cohort, 6 variables illustrated an independent link with the outcome: Older age, female sex, higher baseline serum creatinine value, albuminuria, greater severity of acute kidney injury, and higher serum creatinine value at discharge.
• A multivariable model including these 6 variables exhibited a C statistic of 0.81 (95% CI, 0.75-0.86) and improved discrimination and reclassification compared with reduced models which comprised of age, sex, and discharge serum creatinine value alone (integrated discrimination improvement, 2.6%; 95% CI, 1.1%-4.0%; categorical net reclassification index, 13.5%; 95% CI, 1.9%-25.1%) or included age, sex, and acute kidney injury stage alone (integrated discrimination improvement, 8.0%; 95% CI, 5.1%-11.0%; categorical net reclassification index, 79.9%; 95% CI, 60.9%-98.9%), in the external validation cohort.