Mycoplasma Pneumonia Increases Risk for Rheumatoid Arthritis

Mycoplasma bacteria
Mycoplasma bacteria
Recent data show that patients with mycoplasma pneumonia have an increased risk of developing rheumatoid arthritis.

Patients with mycoplasma pneumonia (MP) have an increased risk of developing rheumatoid arthritis (RA), according to results published online in PLoS ONE. The results indicated that this risk is more pronounced in the first 2 years of MP and for patients aged ≤19 and ≥65 years.

The study included participants hospitalized with MP between 2000 and 2012 from the Taiwan National Health Insurance Research Database (n=116,053) and control patients matched at a 1:4 ratio for age, sex, and index year (n=464,212). The follow-up period lasted from the initial diagnosis of MP to the date of RA diagnosis, censoring of RA, or December 21, 2013. The researchers used the Cox proportional hazard model to analyze the association between MP and incidence of RA.

Among participants with MP, the adjusted hazard ratio (aHR) for incidental RA was 1.37 (95% CI, 0.87-2.16) compared with non-MP control patients.

In a subgroup of participants older than 65 years, the researchers found that the aHR for RA was 3.05 (95% CI, 1.16-7.99, P =.02). In another subgroup of participants with MP aged ≤19 years and ≥65 years, the aHR was 3.19 (95% CI, 1.04-9.76) and 4.14 (95% CI, 1.27-13.4) within the first 2 years of follow-up.

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“Future studies are required to clarify the underlying biological mechanisms of these associations,” the researchers wrote. “We suggest that clinicians should provide appropriate monitoring of RA in patients with MP.”

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Chu K, Chen W, Hsu CY, Hung YM, Wei JC. Increased risk of rheumatoid arthritis among patients with mycoplasma pneumonia: a nationwide population-based cohort study in Taiwan [published online January 14, 2019]. PLoS ONE. doi: 10.1371/journal.pone.0210750