Increased blood pressure visit-to-visit variability in patients with systemic lupus erythematosus: association with inflammation and comorbidity burden.

BACKGROUND: Blood pressure visit-to-visit variability is a novel risk factor for deleterious long-term cardiac and renal outcomes in the general population. We hypothesized that patients with systemic lupus erythematosus (SLE) have greater blood pressure visit-to-visit variability than control subjects and that blood pressure visit-to-visit variability is associated with a higher comorbidity burden. METHODS: We studied 899 patients with SLE and 4172 matched controls using de-identified electronic health records from an academic medical center. We compared blood pressure visit-to-visit variability measures in patients with SLE and control subjects and examined the association between blood pressure visit-to-visit variability and patients' characteristics. RESULTS: Patients with SLE had higher systolic blood pressure visit-to-visit variability 9.7% (7.8-11.8%) than the control group 9.2% (7.4-11.2%), P < 0.001 by coefficient of variation. Additional measures of systolic blood pressure visit-to-visit variability (i.e. standard deviation, average real variation, successive variation and maximum measure-to-measure change) were also significantly higher in patients with SLE than in control subjects. In patients with SLE, blood pressure visit-to-visit variability correlated significantly with age, creatinine, CRP, triglyceride concentrations and the Charlson comorbidity score (all P < 0.05). Hydroxychloroquine use was associated with reduced blood pressure visit-to-visit variability (P < 0.001), whereas the use of antihypertensives, cyclophosphamide, mycophenolate mofetil and corticosteroids was associated with increased blood pressure visit-to-visit variability (P < 0.05). CONCLUSION: Patients with SLE had higher blood pressure visit-to-visit variability than controls, and this increased blood pressure visit-to-visit variability was associated with greater Charlson comorbidity scores, several clinical characteristics and immunosuppressant medications. In particular, hydroxychloroquine prescription was associated with lower blood pressure visit-to-visit variability.

Real-world electronic health record identifies antimalarial underprescribing in patients with lupus nephritis.

Antimalarials (AMs) reduce disease activity and improve survival in patients with systemic lupus erythematosus (SLE), but studies have reported low AM prescribing frequencies. Using a real-world electronic health record cohort, we examined if patient or provider characteristics impacted AM prescribing. We identified 977 SLE cases, 94% of whom were ever prescribed an AM. Older patients and patients with SLE nephritis were less likely to be on AMs. Current age (odds ratio = 0.97, p < 0.01) and nephritis (odds ratio = 0.16, p < 0.01) were both significantly associated with ever AM use after adjustment for sex and race. Of the 244 SLE nephritis cases, only 63% were currently on AMs. SLE nephritis subjects who were currently prescribed AMs were more likely to be followed by a rheumatologist than a nephrologist and less likely to have undergone dialysis or renal transplant (both p < 0.001). Non-current versus current SLE nephritis AM users had higher serum creatinine (p < 0.001), higher urine protein (p = 0.05), and lower hemoglobin levels (p < 0.01). As AMs reduce disease damage and improve survival in patients with SLE, our results demonstrate an opportunity to target future efforts to improve prescribing rates among multi-specialty providers.

Phenome-wide association study identifies dsDNA as a driver of major organ involvement in systemic lupus erythematosus.

In systemic lupus erythematosus (SLE), dsDNA antibodies are associated with renal disease. Less is known about comorbidities in patients without dsDNA or other autoantibodies. Using an electronic health record (EHR) SLE cohort, we employed a phenome-wide association study (PheWAS) that scans across billing codes to compare comorbidities in SLE patients with and without autoantibodies. We used our validated algorithm to identify SLE subjects. Autoantibody status was defined as ever positive for dsDNA, RNP, Smith, SSA and SSB. PheWAS was performed in antibody positive vs. negative SLE patients adjusting for age and race and using a false discovery rate of 0.05. We identified 1097 SLE subjects. In the PheWAS of dsDNA positive vs. negative subjects, dsDNA positive subjects were more likely to have nephritis ( p = 2.33 × 10-9) and renal failure ( p = 1.85 × 10-5). After adjusting for sex, race, age and other autoantibodies, dsDNA was independently associated with nephritis and chronic kidney disease. Those patients negative for dsDNA, RNP, SSA and SSB negative subjects were all more likely to have billing codes for sleep, pain and mood disorders. PheWAS uncovered a hierarchy within SLE-specific autoantibodies with dsDNA having the greatest impact on major organ involvement.

Association of estimated sodium and potassium intake with blood pressure in patients with systemic lupus erythematosus.

Sodium and potassium intake are modifiable determinants of hypertension in the general population but have not been studied in patients with systemic lupus erythematosus (SLE). We examined the relationship between urinary excretion of sodium and potassium, as an estimate of intake, and blood pressure in patients with SLE. We studied 178 SLE patients and 86 controls, matched for age, sex, and race. Urine sodium (Na+) and potassium (K+) were measured by flame photometry. Blood pressure was the average of two resting measurements. The associations between systolic (SBP) and diastolic blood pressures (DBP) and estimated 24-hour urinary Na+, K+, and Na+:K+ ratio were tested. The estimated mean 24-hour urinary K+ excretion was lower, and the Na+:K+ ratio was higher in patients with SLE than controls. There were no significant differences in the estimated 24-hour urinary Na+. In patients with SLE, a higher urinary Na+:K+ ratio was associated with higher SBP (ß coefficient = 4.01, p = 0.023) and DBP (ß coefficient = 4.41, p = 0.002) after adjusting for age, sex, and race. SLE patients had significantly lower estimated 24-hour urinary K+ and higher estimated 24-hour urinary Na+: K+ ratio than controls. The urinary Na+:K+ ratio was significantly associated with SBP and DBP.

Quality of life in patients with systemic lupus erythematosus (SLE) compared with related controls within a unique African American population.

The patient's perspective of how their health affects their function is health-related quality of life (HRQOL). HRQOL is poorer in patients with systemic lupus erythematosus (SLE). Few HRQOL studies in SLE patients have focused on African Americans despite an increased disease burden compared with Caucasians. The African American Gullah population of South Carolina has a homogeneous genetic and environmental background and a high prevalence of multi-patient families with SLE. Demographics, medical history, and Short-Form 36 (SF-36) were measured within a cohort of Gullah SLE cases and related controls. Compared with related controls (n = 37), cases (n = 89) had a lower Physical Component Summary (PCS, 41.8 vs. 52.3, p < 0.01), but not Mental Component Summary (MCS, 55.0 vs. 56.0, p = 0.70). The difference in PCS was no longer significant upon adjustment for working status, disability, and medical conditions. None of the 11 SLE American College of Rheumatology criteria, disease duration, or Systemic Lupus International Collaborating Clinics Damage Index were associated with either PCS or MCS. Cases and controls had similar MCS scores. We hypothesize that this lack of effect of SLE on MCS may be due to disease-coping mechanisms interplaying with cultural factors unique to the Gullah.