Improvements in certain routine laboratory tests correlate with improved clinical outcomes over a period of 12 months in patients with active systemic lupus erythematosus (SLE), according to study findings published in Lancet Rheumatology.
Researchers conducted a longitudinal multicenter cohort study to study the association between laboratory tests and clinical outcomes in patients with active SLE.
Data were prospectively collected from the Asia Pacific Lupus Collaboration (APLC) from 22 centers across 12 countries including patients with active SLE receiving treatment between May 2013 and December 2019.
At 12 months, the researchers assessed improvements in laboratory values and 5 clinical outcomes, including damage accrual, lupus low disease activity state (LLDAS), Physician Global Assessment (PGA), modified SLE responder index (mSRI), and the number of flares.
Of the 1525 patients with active SLE, 93% were women and 87% were of Asian ethnicity.
The strongest indicators of low levels of SLE disease activity, as measured by LLDAS, and protection against damage accrual included laboratory test improvements in the following:
- Proteinuria (adjusted odds ratio [aOR], 62.48; 95% CI, 18.79-208.31 for LLDAS and OR, 0.22; 95% CI, 0.10-0.49 for damage accrual)
- Albumin (aOR, 6.46; 95% CI, 2.20-18.98 for LLDAS and OR, 0.42, 95% CI, 0.20-1.22 for damage accrual)
- Hemoglobin (aOR, 1.97, 95% CI, 1.09-3.53 for LLDAS and OR, 0.33; 95% CI, 0.15-0.71 for damage accrual)
- Erythrocyte sedimentation rate (ESR; aOR, 1.71; 95% CI, 1.10-2.67 for LLDAS and OR, 0.53; 95% CI, 0.30-0.94 for damage accrual)
- Platelets (aOR, 4.82; 95% CI, 1.54-15.07 for LLDAS and OR, 0.49; 95% CI, 0.20-1.19 for damage accrual)
The researchers found that improvements in the urinary and serologic tests also correlated with both PGA and mSRI clinical outcome measures, which reflected SLE disease activity and likelihood of positive response to treatment.
On the other hand, white cell and lymphocyte count improvements were least likely to predict disease activity improvements.
Limitations included the observational, retrospective nature of the study; the inability to confirm attribution of abnormal laboratory tests, other than urine testing, to active SLE; lack of laboratory data available at the time of clinical testing, which may have affected subjective disease activity measures; lack of standardization of laboratory testing platforms; and risk of associations being driven by laboratory testing.
“Our findings show the utility of readily available laboratory investigations in the assessment of clinical improvement over time and affirm the need to reform the use of laboratory test results in SLE clinical trial endpoints,” the study authors said.
Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.
Connelly K, Kandane-Rathnayake R, Hoi A, et al. Associations of improvement in laboratory tests with clinical outcomes in patients with active systemic lupus erythematosus: a multinational longitudinal cohort study. Lancet Rheumatology. Published online November 7, 2022. doi:10.1016/S2665-9913(22)00307-1