Aminoglycoside-associated acute kidney injury in elderly patients with and without shock.

Objectives: Multiresistant Gram-negative pathogens pose major healthcare concerns with a limited therapeutic armamentarium. Aminoglycosides (AG) are under-utilized due to nephrotoxicity. We aimed to evaluate AG-associated acute kidney injury (AG-AKI) in elderly inpatients, with and without shock.

Methods: We examined the incidence and predictors of AG-AKI by KDIGO criteria and extended renal dysfunction (ERD) in patients aged >60 years. ERD represented a composite of hospital mortality or absence of renal recovery over 6 months following AG-AKI.

Results: Two hundred and seventy-eight patients (aged 74 ± 8 years) were studied; 43% and 19% received >7 and >10 days of AG therapy, respectively, and 70% gentamicin (versus amikacin). Thirteen per cent had shock and 17% developed AG-AKI. Comparing all patients with shock versus no shock, AG-AKI developed in 33% versus 14%, respectively (P = 0.005); correspondingly among 47 patients with AG-AKI, more with shock had stage 2/3 AKI (92% versus 43%) and dialysis (50% versus 9%) (P < 0.01), but more had other strong AKI confounders than AG therapy alone (83% versus 40%, P = 0.02). Multivariate analyses identified mechanical ventilation, frusemide administration and AG therapy >10 days as predictors of AG-AKI (P < 0.05), whereas shock, pneumonia and frusemide administration predicted more severe stage 2/3 AG-AKI (P < 0.05). Hospital mortality was 30% versus 7% with AG-AKI versus none (P < 0.001). Twenty-three of 211 (11%) patients with extended analysis had ERD, with 47% experiencing renal recovery following AG-AKI. Mechanical ventilation and contrast administration during index hospitalization predicted ERD (P < 0.05).

Conclusions: AG-AKI is common in the elderly, with a significant risk of ERD, but the cause and severity are greatly influenced by critical illness and shock, more so than AG therapy alone.