Acute kidney injury in patients with nephrotic syndrome undergoing contrast-enhanced CT for suspected venous thromboembolism: a propensity score-matched retrospective cohort study

Abstract

Objectives

To determine whether intravenous iodinated contrast material administration increases the risk of acute kidney injury (AKI) in patients with nephrotic syndrome undergoing contrast-enhanced CT.

Methods

Patients with nephrotic syndrome undergoing contrast-enhanced CT were retrospectively identified (n = 701). Control group consisted of patients with nephrotic syndrome receiving non-contrast CT (n = 1053). Two different 1:1 propensity score matching models using three or 10 variables were developed for each estimated glomerular filtration (eGFR) subgroup. Incidence of post-CT AKI for the two groups was assessed and compared by standard AKI criteria and Acute Kidney Injury Network (AKIN) criteria.

Results

After matching with three variables, the AKI incidence in the contrast-enhanced CT and non-contrast CT groups was 2.7% vs 2.5% (standard AKI criteria) and 4.2% vs. 6.7% (AKIN criteria) (p = 1.00 and 0.05), respectively. After matching with 10 variables, AKI incidences were 3.1% vs. 2.6% (standard AKI criteria) and 4.1% vs. 7.4% (AKIN criteria) (p = 0.72 and 0.03), respectively. AKI incidences of each eGFR subgroup in the contrast-enhanced CT group were not higher than in the non-contrast CT group (lowest p = 0.46).

Conclusion

Intravenous contrast material administration during CT was not found to be a risk factor for AKI in this large cohort of patients with nephrotic syndrome.

Key points

• AKI incidence of contrast-enhanced CT and non-contrast CT had no difference.

• AKI incidences of eGFR subgroup in contrast-enhanced CT were not increased.

• Studies without a non-contrast CT control group may overestimate CIN incidence.