In Minnesota, Rates of Lupus Nephritis and Poor Health Outcomes Highlight Need for Advancements in Lupus Research and Care

Data from the Lupus Midwest Network (LUMEN) in Minnesota show that incidence and prevalence rates of lupus nephritis (LN, lupus-related kidney disease) have increased over the last 40 years. The findings also highlight the serious health risks associated with LN, and that people with LN have rates of end-stage renal disease and mortality rates that are six times higher than the general population.

Incidence is a measure of disease risk, and it indicates the number of new disease cases within a certain time period (out of the total at-risk population). Prevalence is a measure of disease burden, and it reflects the number of people with a disease during a certain time period out of the general population.

Researchers looked at LN cases in Minnesota between 1976 and 2018 and found that there was one new case per 100,000 at-risk people per year during that time frame. However, when comparing rates of annual new cases between 1976-1989 and 2000-2018, incidence rates nearly doubled, going from 0.7 to 1.3 per 100,000 people in the at-risk population. Additionally, prevalence rates increased between 1985 to 2015, rising from 16.8 cases to 21.2 cases per 100,000 people in the general population.

Researchers also observed no improvement in mortality rates during the 40-year study period. At the 10-year follow-up point, the survival rate was 70%, and 13% of the people with LN had end-stage renal disease. LN also occurred in women at three-times the rate of men.

Notably, these estimates are lower than previously reported incidence and prevalence rates reported in the adult Medicaid population (1.0 vs. 6.9 per 100,000 for incidence rates and 16.8-21.2 vs. 30.9 per 100,000 for prevalence rates). The researchers note this likely reflects differences in socioeconomic and racial backgrounds of the study populations, as the LUMEN group in southeast Minnesota was largely made up of non-Hispanic White people.

At the same time, the researchers also speculate that the increase in racial and ethnic diversity within the Minnesota study population may help explain the increase in LN rates. Lupus and LN disproportionately affect Hispanic and Asian American populations, among other racial and ethnic groups, and as the number of Hispanic and Asian American people increased in Minnesota, LN rates also increased.

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