Organ damage, joint pain, muscle ache, rash and intense fatigue are not the only problems that lupus patients locally can suffer from. They also have a greater chance of catching tuberculosis (TB), according to a Singapore General Hospital (SGH) study published in the Rheumatology International journal in March 2017.
It is double whammy for patients with this rheumatological disease, which has only four approved medications but no cure. However, the finding isn’t a surprise. Numerous studies overseas have associated lupus or systemic lupus erythematosus with an increased risk of contracting TB but little had been known about the extent and possible risk factors of TB among lupus patients in Singapore.
“Patients with lupus face the possibility of irreversible damage to vital organs like the kidney, lungs, heart, joints and other organs. These can weigh heavily on their minds. And now, they also have to worry about getting tuberculosis that can be fatal if not treated. We hope the finding will prompt doctors and patients themselves to be watchful of unexplained chronic cough, weight loss or fever, and consider active screening if needed,” said Professor Julian Thumboo, an author of the study and Senior Consultant, Department of Rheumatology and Immunology, SGH.
To quantify the risk of TB in lupus patients, researchers from SGH’s Departments of Epidemiology, Rheumatology and Immunology, and Infectious Diseases, examined the data of more than 301,000 patients admitted to the Hospital between 2004 and 2011. They found that 840 patients had lupus and close to 20 of them or 2 per cent also had TB. This is about 5 times higher than hospitalised patients without lupus. The risk doubles to 10 times if lupus patients also have chronic conditions such as diabetes and hypertension. In comparison, the incidence of TB among Singapore residents is between 0.035 and 0.045 per cent. This highlights the need for vigilance and early assessment for lupus patients.
The immune system of people suffering from lupus becomes hyperactive and attacks normal, healthy tissue. This results in inflammation, swelling and damage to skin, joints, heart, lung, kidneys and nervous system. The cause of lupus, however, remains unclear.
Treatment for lupus affecting the organs involves high doses of corticosteroids and other medications that suppress the immune system. This inevitably puts them at risk of acquiring infections such as TB. Once infected, lupus patients in remission have a higher rate of relapse and death as TB mimics certain lupus symptoms, making it more difficult to diagnose and treat.
Lupus is more common and severe in Asians where the prevalence is reported to be about two to three times higher than in Caucasians. There are about 4,000 to 5,000 patients with lupus in Singapore alone. It tends to affect women of child-bearing age but is seen in men and children too.