Antibiotic-Associated Acute Kidney Injury Among Older Adults: A Case-Crossover Study.

Background and objectives: Drug-related acute kidney injury is quite common in older adults. The associated drugs, including antibiotics, are often co-prescribed. The objective of this study was to ascertain antibiotic-associated acute kidney injury (AKI) in older adults aged 65 years or above in New Zealand using a case-crossover study design.

Methods: The International Statistical Classification of Diseases and Related Health Problems, tenth revision, Australian modification code N17.x was used to identify all individuals aged 65 years and above with a diagnosis of incident AKI on admission between 1 January 2005 and 31 December 2020, from the New Zealand National Minimum Data Set. A case-crossover cohort for antibiotic exposures, with a 3 day case period and two 30 day washout periods, summed up to a 66 day study period, was created. Using conditional logistic regression, the changed odds of AKI due to exposure to an antibiotic was calculated as matched odds ratios and their 95% confidence intervals.

Results: A total of 2399 incident cases of AKI were identified between 2005 and 2020 among older adults. The adjusted odds of consuming sulfamethoxazole/trimethoprim antibiotic during the case period was 3.57 times (95% CI 2.86-4.46) higher than the reference period among the incident AKI cases. Fluoroquinolone utilization was also associated with incident AKI (adjusted OR = 2.56; 95% CI 1.90-3.46).

Conclusion: The potential of sulfamethoxazole/trimethoprim and fluoroquinolones to be associated with AKI raises the significant need for vigilant prescribing of these antibiotics in older adults.