- Design
- Single-centre cohort analysis at kidney biopsy
- Population
- 165 patients with biopsy-proven lupus nephritis (50.3% on antimalarials)
- Primary outcome
- Proliferative class, NIH activity and chronicity indices, and IFTA score
- Effect
- No detectable difference with antimalarial exposure; sensitivity analyses at 6 and 12 months similar
A cohort from the University of Toronto Lupus Clinic included 165 patients with biopsy-proven lupus nephritis whose biopsy was at least three months after clinic entry. Half (50.3%) were taking an antimalarial at baseline, defined as use at two or more consecutive visits before biopsy.
After adjustment, antimalarial exposure was not associated with detectable differences in proliferative class, NIH activity index, chronicity index or interstitial fibrosis and tubular atrophy. Requiring six months or one year of continuous use gave similar results.
The authors caution about design and sample size. It is a cross-sectional look at biopsy at one point in time in 165 patients, so it cannot test whether antimalarials prevent nephritis or protect the kidney over years. Other evidence supporting hydroxychloroquine across lupus is not undermined by it, and this should not prompt stopping it.
- Do not stop an antimalarial on the basis of this result.
- Biopsy activity and chronicity scores did not differ by antimalarial exposure.
- A cross-sectional biopsy study cannot test long-term renal protection.
- Continue to follow existing lupus guidance on antimalarial use.
Why it matters
It tests, with histology, a drug whose renal benefit is usually inferred from clinical outcomes.
Don't overread it
Single-centre, cross-sectional and small; it does not address long-term renal outcomes.
The statistics, in plain English
No detectable difference in 165 patients means the study could not show one, and a modest effect could be missed. Absence of an association at the biopsy snapshot does not mean no long-term benefit.
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