Colistin treatment in older adults: why should we know more?

We aimed to investigate the risk factors of colistin-associated nephrotoxicity in patients older than 65 years treated in the palliative care unit.

119 palliative care patients who received intravenous colistimethate for at least 7 days were included in the study. The estimated glomerular filtration rate (GFR) was calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) 2021 equation. Data were obtained from the hospital information system.

The mean age of the participants was 76.7 ± 9.9 years and 49.4% were female. Of the 119 patients, 57 had colistin-induced nephropathy (CIN) according to Kidney Disease: Improving Global Outcomes (KDIGO) criteria. The rate of CIN was higher in women than in men. The baseline phosphate level was higher in the CIN (+) group than in the CIN (-) group. The lower GFR values in patients with pneumonia persisted at days 14 and 30, whereas the lower GFR in patients without pneumonia did not. According to multivariate logistic regression, female gender and baseline phosphate level ≥ 4.5 mg/dl were found as independent variables for the development of nephropathy.

The creatinine levels of the patients with pneumonia and CIN did not improve after nephrotoxicity, whereas the creatinine levels of the other patients without pneumonia and CIN did. Female gender and baseline phosphate were independent risk factors for CIN. Prolonged kidney failure may lead to a more difficult clinical follow-up process for clinicians. Therefore, clinicians should be aware of persistent renal insufficiency in older patients with pneumonia receiving colistimethate.