Poverty is associated with an accumulation of lupus damage, which leads to a higher risk of death, a study reports.
The research, “The Relationship between Poverty and Mortality in Systemic Lupus Erythematosus,” was published in the journal Arthritis Care & Research.
The link between socioeconomic status and lupus outcomes has become a hot topic of investigation. A number of studies have linked poverty to worse outcomes.
One found a significant connection between poverty and the amount of damage from lupus. It also showed lower levels of damage when patients climb out of poverty.
No study had addressed the question of why poverty increases lupus death rates, however.
Researchers at the University of California, San Francisco decided to use data from the UCSF Lupus Outcomes Study in 2009 to examine the issue. Most of the information came from interviews that gave researchers a good picture of each patient’s health.
The poverty-and-outcomes analysis covered 807 patients. Researchers classified a patient as living in poverty if their household income was less than 125 percent of what the U.S. government declared to be the Federal Poverty Level in 2009.
Researchers used statistical analysis to search for a link between poverty and patients’ risk of dying from lupus. They adjusted their analysis to account for confounding factors — variables that could distort the relationship between poverty and the risk of dying from lupus.
The confounding factors included patients’ demographics; their lupus status, including the amount of damage their disease had inflicted; their overall health status; their health-related behaviors, such as smoking; and the kind of healthcare they were receiving.
Seventy-one of the 807 had died by 2015. Researchers classified 14 patients, or 12 percent, as poor, and 57, or 88 percent, as non-poor.
When the team adjusted the results to account only for age, poverty more than doubled patients’ risk of death.
But when they adjusted for both age and extent of lupus damage, they discovered that there was no longer a connection between poverty and higher risk of death. This suggested that poverty raised patients’ risk of death by increasing the extent of their damage. The damage-assessment tool the team used was the Brief Index of Lupus Damage (BILD).
When analyzing other variables, researchers found that patients’ overall health, amount of lupus damage, and gender — being a woman — were significant predictors of death. Lupus affects a lot more women than men.
Extent of damage was such a significant predictor of mortality that researchers said a patient’s risk of death rose further with every one-point increase in their BILD score.
Another important — and stark —finding was that the poor patients who died by 2015 lived almost 14 years less than the others who died. The implication was that more lupus damage not only leads to higher risk of death but also earlier mortality.
The key takeaway from the study was that preventing an accumulation of lupus damage is the most important way to keep a poorer patient’s risk of death from rising.
This could require better medical care, of course. But it also could require addressing other concerns that can affect a patient’s health. A major one could be stress arising from worries about affording food, housing, and medical care.
Researchers said helping patients rise out of poverty would be another way to improve their condition.
“Strategies to reduce the impact of poverty” on lupus damage will have the effect “of reducing the disparity in mortality rates between the poor and non-poor,” the team concluded.