Prevalence and mortality of transient acute kidney injury within 48 h, as new subtype, following coronary angiography: a cohort study

Background The association of transient acute kidney injury (AKI) with mortality was controversial. Our study aims to investigate the prevalence and impact of transient AKI on mortality in patients following coronary angiography (CAG). Methods Our study retrospectively enrolled 3970 patients with pre-operative serum creatinine (Scr) and twice measurements within 48 h after procedure. Transient AKI defined as the diagnosis of AKI (Scr > 0.3 mg/dL or > 50% from the baseline level) on day 1 when Scr failed to meet the criteria for AKI on the day 2. Maintained AKI was defined as AKI not meeting the definition for transient AKI. The primary outcome was 1-year all-cause mortality. Multivariable logistic regression was used to assess the association between transient AKI and 1-year mortality. Results Among 3,970 participants, 861 (21.7%) occurred AKI, of whom 128 (14.9%) was transient AKI and 733 (85.1%) was maintained AKI. 312 (7.9%) patients died within 1-year after admission. After multivariable analysis, transient AKI was not associated with higher 1-year mortality [adjusted odds ratio (aOR), 1.37; CI 0.68–2.51] compared without AKI. Among AKI patients, transient AKI was associated with a 52% lower 1-year mortality compared with maintained AKI. Additionally, maintained AKI was significantly associated with higher 1-year mortality (aOR, 2.67; CI 2.05–3.47). Conclusions Our data suggested that transient AKI within 48 h was a common subtype of AKI following CAG, without increasing mortality. More attention needs to be paid to the patients suffering from maintained AKI following CAG.