Low-Dose Methotrexate Carries Higher Risk for Older Patients With CKD

TOPLINE:

The use of low-dose methotrexate among older adults with chronic kidney disease (CKD) was associated with a significantly increased risk at 90 days for serious adverse events requiring a hospital visit, compared with starting treatment with hydroxychloroquine.

METHODOLOGY:

• In a retrospective, population-based cohort study conducted in Ontario, Canada, researchers used linked administrative healthcare data to identify adults aged 66 years and older with CKD who were not undergoing dialysis and were new to medication; CKD was defined as an estimated glomerular filtration rate (eGFR) of less than 60 mL/min/1.73m².

• The study population included 2309 individuals who began treatment with low-dose methotrexate (5–35 mg/wk); they were matched with 2309 individuals who began treatment with hydroxychloroquine (200-400 mg/d). The median age was 76 years, 69% were women, and rheumatoid arthritis was the most common diagnosis (56%).

• The primary outcome was the risk of a hospital visit at 90 days for a composite of serious adverse events that included myelosuppression, sepsis, pneumotoxic effects, or hepatoxic effects.

TAKEAWAY:

• Overall, 3.55% of methotrexate patients and 1.73% of hydroxychloroquine patients met the primary outcome (risk ratio, 2.05); these events occurred at a median of 49 days and 43 days after starting the medications for the two groups, respectively.

• In an analysis by eGFR category, the risk of serious adverse events at 90 days increased among patients with eGFR levels less than 45 mL/min/1.73 m² (risk ratio, 2.79).

• In a secondary comparison, the 90-day risk of serious adverse events was higher among methotrexate patients who began treatment with doses of 15–35 mg/wk in comparison with those whose initial doses were 5 to less than 15 mg/wk.

IN PRACTICE:

"Patients with CKD starting low-dose methotrexate should have active surveillance, including blood tests and chest radiographs performed regularly to monitor for signs of myelosuppression, infection, hepatotoxic effects, and pneumotoxic effects," the researchers write.

SOURCE:

The lead author on the study was Flory T. Muanda, MD, of Western University, London, Ontario, Canada. The study was published online in JAMA Network Open on November 27.

LIMITATIONS:

The observational design and lack of data on patients' adherence to medications were among the limiting factors, as were the focus on older adults with CKD and the lack of assessment of the risk-benefit ratio of low-dose methotrexate.

DISCLOSURES:

The study was supported by the Institute for Clinical Evaluative Sciences. Muanda had no financial conflicts to disclose.