ArticleArthritis & rheumatology (Hoboken, N.J.)2021
Association of Higher Hydroxychloroquine Blood Levels With Reduced Thrombosis Risk in Systemic Lupus Erythematosus.
Article in Arthritis & rheumatology (Hoboken, N.J.), 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 34 papers, 4 of them syntheses that pooled it.
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
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Who cites it
34 citing papers in PubMed, 4 syntheses or guidelines pooled it, 61 citations in OpenAlex.
- The 2026 British Society for Rheumatology guideline for the management of children, young people and adults with systemic lupus erythematosus.Rheumatology (Oxford, England) · 2026Guideline
- Risk factors for adverse maternal and fetal outcomes in SLE patients: a systematic review and meta-analysis.Frontiers in medicine · 2025Pooled it
- II Brazilian Society of Rheumatology consensus for lupus nephritis diagnosis and treatment.Advances in rheumatology (London, England) · 2024Guideline
- A multianalyte assay panel with cell-bound complement activation products demonstrates clinical utility in systemic lupus erythematosus.Lupus science & medicine · 2021Pooled it
- Comparison of flares in 85 patients with SLE who maintained, discontinued or reduced dose of hydroxychloroquine during a prospective study of ophthalmological screening for retinopathy (PERFOCTAPS Study).Lupus science & medicine · 2025Trial
- Neutrophil extracellular traps in thrombosis of hematologic malignancies: Underlying mechanisms and therapeutic opportunities (Review).International journal of molecular medicine · 2026Review
- Real-World Longitudinal Data on the Impact of Hydroxychloroquine Blood Level Monitoring on Lupus Outcomes: Results of a Prospective Longitudinal Cohort Study.Arthritis care & research · 2026Article
- Uncommon clinical presentations and diagnostic difficulties of antiphospholipid syndrome associated withMedical mycology case reports · 2026Article
- Toward Optimal Dosing in Systemic Lupus Erythematosus: The Case for Hydroxychloroquine Blood Level Monitoring.Arthritis care & research · 2026Article
- Associations between hydroxychloroquine dose and risk of flares in systemic lupus erythematosus.BMC rheumatology · 2025Article
- Role of antimalarials in lupus nephritis: a narrative review.Clinical rheumatology · 2025Review
- Article
- A Case Series and Review of Hydroxychloroquine Toxicity and Monitoring: How Do We Dose Hydroxychloroquine?Cureus · 2025Article
- Safety of Hydroxychloroquine: What a Dermatologist Should Know.American journal of clinical dermatology · 2025Review
- Refining lupus management: a comprehensive review of HCQ blood levels.Rheumatology advances in practice · 2025Review
- Therapeutic Hydroxychloroquine Blood Levels Are Associated With Fewer Hospitalizations and Possible Reduction of Health Disparities in Lupus.Arthritis care & research · 2024Article
- Hydroxychloroquine Improves Low Complement Levels.Arthritis care & research · 2024Article
- Review
- Reference Range of Hydroxychloroquine Blood Levels That Can Reduce Odds of Active Lupus and Prevent Flares.Arthritis care & research · 2024Article
- Therapeutic Drug Monitoring in Patients with Systemic Lupus Erythematosus: Utility and Gaps.Journal of clinical medicine · 2024Review
Corrections and comments
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Authors and funding
4 authors at 1 institution in 1 country.
Funding
Abstract
objectiveHydroxychloroquine (HCQ) has a primary role in the prophylaxis and treatment of systemic lupus erythematosus (SLE) and may be protective against thrombosis in SLE. Optimal weight-based dosing of HCQ is unknown. This study was undertaken to examine the usefulness of HCQ blood monitoring in predicting thrombosis risk in a longitudinal SLE cohort.
methodsHCQ levels were serially quantified from EDTA whole blood by liquid chromatography-tandem mass spectrometry. The mean HCQ blood levels calculated prior to thrombosis or until the last visit were compared using t-tests between patients with and those without thrombosis. Pooled logistic regression was used to analyze the association between rates of thrombosis and HCQ blood level. Rate ratios (RRs) and 95% confidence intervals (95% CIs) were calculated.
resultsIn 739 patients with SLE, thrombosis occurred in 38 patients (5.1%). The mean ± SD HCQ blood level was lower in patients who developed thrombosis versus those who did not develop thrombosis (720 ± 489 ng/ml versus 935 ± 580 ng/ml; P = 0.025). Thrombosis rates were reduced by 13% for every 200-ng/ml increase in the most recent HCQ blood level (RR 0.87 [95% CI 0.78-0.98], P = 0.025) and by 13% for mean HCQ blood level (RR 0.87 [95% CI 0.76-1.00], P = 0.056). Thrombotic events were reduced by 69% in patients with mean HCQ blood levels ≥1,068 ng/ml versus those with levels <648 ng/ml (RR 0.31 [95% CI 0.11-0.86], P = 0.024). This remained significant after adjustment for confounders (RR 0.34 [95% CI 0.12-0.94], P = 0.037).
conclusionLow HCQ blood levels are associated with thrombotic events in SLE. Longitudinal measurement of HCQ levels may allow for personalized HCQ dosing strategies. Recommendations for empirical dose reduction may reduce or eliminate the benefits of HCQ in this high-risk population.
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Registered trials
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