Nearly one in every six patients of systemic lupus erythematosus (SLE) is readmitted to the hospital within a month of being discharged, according to a new study by the University of California, San Francisco.

The researchers said that the readmissions mostly occurred among black and Hispanic SLE patients as compared to their white counterparts. Plus, patients insured by Medicare or Medicaid were also more likely to be readmitted as compared to those covered by private insurance.

"SLE patients have one of the highest hospital readmission rates compared to those with other chronic illnesses," said Jinoos Yazdany from the Division of Rheumatology in a press release. "Our study is the first large-scale examination of early readmissions following hospitalization due to SLE."

Lupus is a systemic, autoimmune disease where an overactive immune system attacks healthy joints and organs. Every year, about 25 percent SLE patients require treatment in the hospital, accounting for more than 140,000 hospitalizations in the U.S.

For the study, the researchers analyzed data of 31,903 lupus patients, 18 years of age or older, readmitted between 2008 and 2009 from 5 states - California, Florida, New York, Utah and Washington.

The researchers found that 4,916 SLE patients were re-admitted for lupus nephritis (kidney inflammation), serositis (inflammation of the lining of the lungs, heart, abdomen, or abdominal organs) and thrombocytopenia (low blood platelet count).

The study also found that risk-adjusted readmission rates were lower in New York and higher in Florida. Plus, hospitals with higher SLE readmissions for SLE did not have higher admissions for other chronic conditions like heart failure or pneumonia.

"The significant geographic and hospital-level variation in readmission rates signals a need for quality improvement efforts in lupus," Yazdany said.

The finding is published in the journal Arthritis & Rheumatology.