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Sudden weather changes may trigger organ-specific lupus flares
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ATLANTA — Atmospheric changes and associated environmental stressors within 10 days of a clinic visit were linked to organ-specific lupus flares among patients with systemic lupus erythematosus, according to a presentation at the 2019 ACR/ARP Annual Meeting.
“Our interest in this topic started in 2012, when we looked at the typical relationship between lupus activity and seasons in the Hopkins Lupus Cohort,” George Stojan, MD, assistant professor of medicine at Johns Hopkins Lupus Center, said during a press conference. “We found that photosensitive rashes were more common between April and September, that arthritis was more common between May and October, that renal flares were significantly less common during summers, and that anti-double stranded DNA levels were significantly elevated during the months of October and November. The question is what was underlying this seasonality.”
He added, “We hypothesized that atmospheric factors like ozone concentration, temperature, wind, humidity, barometric pressure, as well as environmental factors — such as smoke particulate matter pollution — within a 10-day period prior to the patient visit was predictive of an organ-specific flare at their visit.”
To determine whether environmental exposures impacted SLE activity — and if fluctuations in temperature, resultant wind, relative humidity and barometric pressure could predict organ-specific flares — Stojan and colleagues retrospectively examined clinic visits among a cohort of SLE patients (n = 1,628) from 1999 to 2017.
Patients in the study fulfilled four of the 11 American College of Rheumatology/Systemic Lupus Erythematosus International Collaborating Clinics classification criteria for SLE. The researchers noted that disease activity was expressed as Physician Global Estimate (PGA), taken during each patient visit; a flare was defined as a PGA score increase of 1 point or more compared with the previous visit.
In addition, Stojan and colleagues collected environmental and atmospheric data from the U.S. Environmental Protection Agency, including information on fine particulate matter (PM2.5) and ozone concentration, temperature, residual wind, relative humidity and barometric pressure; the average value of each of these factors were measured for 10 days prior to the patient’s visit. Using this data, the researchers built univariate and multivariate models to assess the link between these variables and lupus disease activity, adjusting the models for age, sex, income, racial distribution and rural vs. urban residence.
Stojan and colleagues then used multivariate logistic regression to classify the significant determinants linked to lupus flares and performed regression for each organ flare outcome, basing regression inference on generalized estimating equations to account for the time repeated outcomes.
According to study results, there were multiple statistically significant associations between environmental factors and lupus activity. The researchers reported that rash, serositis, hematologic and joint flares were associated with an increase in temperature (P < .05), whereas renal flares diminished as the temperature and ozone concentration increased (P < .05).
“The average temperature 10 days prior to visit was associated with hematologic and neurologic flares, but was negatively associated with renal flares: The hotter it was, the less likely patients were to have a renal flare,” Stojan said.
Stojan and colleagues also noted that residual wind was directly associated with joint (P < .001), neurologic (P < .001), hematologic (P < .05) and pulmonary (P < .001) flares, and humidity was significantly associated with joint (P < .001) and serositis (P < .05) flares. Lastly, the concentration of PM2.5 was linked to rash (P < .001), joints (P < .001), serositis (P < .001) and hematologic flares (P < .001). However, the researchers reported that changes in barometric pressure had no significant associations with lupus activity.
“We describe strong associations between atmospheric variables and fine particulate matter concentration with organic-specific lupus flares 10 days prior to their visit,” Stojan said. “The main difference compared to previous studies is that all previous studies looked at global disease activity [whereas] we looked at organ-specific activity. None of the atmospheric variables or the smoke particulate pollution were associated with all organ system flares — they had very specific associations.”
“We can speculate that the seasonality that we previously described could be mediated by these atmospheric or environmental factors, but more studies are necessary for this,” he added. “If proven, this may have wide-ranging epidemiological and clinical consequences in the future.”– by Robert Stott
Reference:
Stojan G. Abstract #675. Environmental and atmospheric factors in systemic lupus erythematosus: A regression analysis. Presented at ACR/ARP Annual Meeting, Nov. 8-13, 2019; Atlanta.
Disclosure: Stojan reports no relevant financial disclosures.