Do Corticosteroids Affect UACR?
Yes, corticosteroids can increase UACR, particularly when both systemic and local corticosteroids are used together, though the clinical significance and mechanism remain incompletely understood.
Evidence for Corticosteroid Effects on Albuminuria
The primary evidence comes from a population-based study showing that corticosteroid use is associated with microalbuminuria 1:
- Overall corticosteroid users had a modestly elevated odds ratio (OR 1.21,95% CI 1.03-1.41) for microalbuminuria after adjusting for age and sex 1
- Systemic corticosteroids alone showed minimal association (OR 1.07,95% CI 0.67-1.72) 1
- Local corticosteroids alone also showed minimal association (OR 1.11,95% CI 0.93-1.32) 1
- Combined systemic and local corticosteroids showed the strongest association (OR 1.99,95% CI 1.42-2.77), nearly doubling the risk of microalbuminuria 1
Mechanism and Clinical Interpretation
The mechanism by which corticosteroids affect UACR is not definitively established 1. Two potential explanations exist:
- Direct drug effect: Corticosteroids may directly increase albumin excretion through cardiovascular or renal effects 1
- Underlying disease: The association may reflect the severity of the underlying condition requiring corticosteroid treatment rather than the drug itself 1
Additionally, corticosteroids can increase plasma creatinine concentration without actually decreasing glomerular filtration rate, likely by modifying creatinine production and release 2. This means the creatinine component of UACR may be artificially elevated, potentially affecting the ratio calculation 2.
Clinical Implications for UACR Monitoring
When interpreting UACR in patients on corticosteroids:
- Expect potential elevation: Particularly in patients using both systemic and local formulations simultaneously 1
- Consider confounding factors: The elevated UACR may not purely reflect kidney injury but rather drug effects on both albumin excretion and creatinine metabolism 1, 2
- Maintain standard monitoring: Current diabetes and CKD guidelines recommend annual UACR screening regardless of corticosteroid use 3
- Continue evidence-based treatments: If UACR is elevated (≥30 mg/g), initiate guideline-directed therapies including ACE inhibitors/ARBs, SGLT2 inhibitors, and nonsteroidal mineralocorticoid receptor antagonists as appropriate, regardless of corticosteroid use 3, 4
Important Caveats
The available evidence has significant limitations:
- The association between corticosteroids and microalbuminuria comes from observational data, not randomized trials 1
- Causality cannot be definitively established—the underlying diseases requiring corticosteroids (inflammatory conditions, autoimmune diseases) may themselves contribute to albuminuria 1
- No guidelines specifically address how to adjust UACR interpretation or treatment thresholds in corticosteroid users 3