AKI duration tied to CKD, CVD risk

The duration of acute kidney injury (AKI) was associated with the risks of chronic kidney disease (CKD) but not overall cardiovascular disease (CVD*), a population-based Danish cohort study suggests.

“Longer AKI durations were associated with long-term rates of CKD,” reported Dr Simon Kok Jensen from Aarhus University Hospital in Denmark, during his presentation at ERA 2023. “Conversely, AKI duration was not associated with long-term risks of overall CVD; however, the rates of ischaemic heart disease and heart failure increased with longer AKI durations.”

CKD risk

When evaluating the risk of kidney complications, there was a higher risk of CKD among individuals with persistent AKI (23 percent) and acute kidney disease (AKD; 22 percent) compared with those who had rapid reversal AKI (19 percent).

When adjusting for differences and baseline characteristics including comorbidities, prescriptions, and AKI stage, the risk of CKD gradually increased with longer AKI duration, noted Jensen. The adjusted hazard ratios (HRs) for persistent AKI and AKD were 1.15 and 1.47, respectively.

A similar pattern was observed for kidney failure. Risk rates were 1.8, 2.4, and 2.6 percent for the respective rapid reversal AKI, persistent AKI, and AKD groups. The corresponding adjusted HRs were 1.00, 1.09, and 1.50, respectively.

CVD risk

For CV complications, there was no increase in the risk of overall CVD with longer AKI duration, as reflected by the similar rates of rapid reversal AKI, persistent AKI, and AKD (37, 36, and 34 percent, respectively). These corresponded to adjusted HRs of 1.0, 1.02, and 0.98. 

“However, for specific CV conditions ... we did find slight increases in the adjusted HRs with longer AKI duration,” said Jensen. The adjusted HRs were 1.11 for ischaemic heart disease (AKD subgroup) and 1.09 for heart failure (both persistent AKI and AKD subgroups).

A potential risk marker

“It is well established that AKI is associated with CKD, CVD, and death. Furthermore, it has been shown that AKI duration is tied to the risk of death,” said Jensen. “However, the association between AKI duration and CKD and CVD risks remains undefined.”

As such, Jensen and colleagues designed this study to evaluate CKD and CVD risks according to AKI duration, and to examine the impact of AKI duration on the rates of CKD and CVD using Danish national registries. Individuals ≥18 years with AKI who had assessments of baseline kidney function and AKI duration were included.

The study comprised nearly 170K participants. Median age was 72 years, and more than half were female. Mean estimated glomerular filtration rate was 71 mL/min1.73 m². A majority (65 percent) of the participants had AKD (>7 days), 22 percent had rapid reversal AKI (<2 days), while 13 percent had persistent AKI (2–7 days). The most common comorbidities were CKD (37 percent) and hypertension (43 percent).

“The distinct increase in rates of CKD and specific CVDs with longer AKI durations illustrates the potential for using AKI duration as a risk marker when planning nephrology follow-up after AKI,” noted Jensen. “Further studies examining whether interventions to shorten AKI duration prevent outcomes are warranted.”