Background/Purpose: Hypertension predicts poor long-term renal outcomes for patients with lupus nephritis (LN) [1, 2]. We sought to characterize relationships between blood pressure and proteinuria using data from randomized clinical trials.

Methods: We analyzed patient-level data from LUNAR (NCT00282347) [3] and BELONG (NCT00626197) [4], which compared rituximab [3] or ocrelizumab [4] vs. placebo in addition to background therapy for the treatment of LN. Complete renal response (CRR) was defined for LUNAR as urine protein/creatinine (UPCR) levels below 0.5, creatinine levels ≤115% of baseline, and inactive urinary sediment. CRR for BELONG was defined as UPCR <0.5 and creatinine ≤125% of baseline. Data from baseline and 1 year visits were analyzed. Logistic regression was used to estimate the association between change in BP and CRR while adjusting for baseline proteinuria and estimated glomerular filtration rate (eGFR). Linear regression was used to estimate the association between change in BP and change in proteinuria while adjusting for race, treatment received, and baseline eGFR.

Results: Each 10 mmHg increase in baseline systolic BP had an odds ratio (OR) of 0.8 for CRR at 1 year (95% CI 0.74, 0.97). This association did not remain significant after adjusting for baseline proteinuria and eGFR (OR 0.9, 95% CI 0.79, 1.05). Baseline systolic and diastolic BP had a weak correlation with baseline UPCR (r=0.2, p<0.01 for both). Change in systolic and diastolic BP from baseline to 1 year was associated with improvement in proteinuria at 1 year in adjusted regression: each 10 mmHg decrease in systolic BP was associated with a 0.45 g/g (CI 0.3, 0.6, p<0.01) improvement in proteinuria at 1 year; each 10 mmHg decrease in diastolic BP was associated with a 0.44 g/g (CI 0.2, 0.65, p<0.01) improvement in proteinuria. These results were consistent when studies were analyzed separately.

Conclusion: Baseline systolic BP was associated with the probability of CRR at 1 year in univariate analysis. However, this association was explained by baseline proteinuria and eGFR. Changes in systolic or diastolic BP were significantly associated with decreases in proteinuria at 1 year. Further characterization of the relative contributions of BP, disease severity, and immunosuppression are warranted.

1.    Yang et al., Lupus 2015; 24(14):1468.

2.    Contreras et al., Lupus 2005; 14(11):890.

3.    Rovin et al., Arthritis Rheum 2012; 64(4):1215.

4.    Mysler et al., Arthritis Rheum 2013; 65(9):2368.