TMP/SMX use was linked to fewer severe infections in IIM

What the study found: Trimethoprim-sulfamethoxazole (TMP/SMX) use was associated with a lower risk of severe infections in patients with idiopathic inflammatory myopathy (IIM) who were receiving remission induction therapy. The reduction was especially seen for respiratory tract infections.
Why the authors say this matters: The authors note that people with IIM are often treated with glucocorticoids and other immunosuppressants, which raise the risk of opportunistic infections. The study suggests TMP/SMX may do more than prevent Pneumocystis jirovecii pneumonia (PJP), as the findings indicate it may also be linked to fewer other severe infections.
What the researchers tested: This was a retrospective, single-center study of 89 patients with IIM who underwent remission induction therapy. After excluding 2 patients who developed PJP, 87 patients remained for analysis, and the team assessed severe infections during follow-up and used Cox regression analysis to look for risk factors.
What worked and what didn't: Sixteen patients developed severe infections other than PJP, and respiratory infections were the most common. Patients who received TMP/SMX had a significantly lower incidence of severe infections and of respiratory tract infections than those who did not, while older age was associated with higher risk in multivariate analysis.
What to keep in mind: This summary is based on a retrospective, single-center study, so the abstract does not describe broader generalizability. The abstract does not provide additional limitations beyond the study size and design.

Key points

• TMP/SMX use was associated with fewer severe infections in patients with idiopathic inflammatory myopathy.
• Respiratory tract infections were the most common severe infections reported.
• Older age increased the risk of severe infection in multivariate analysis.
• The study excluded 2 patients who developed Pneumocystis jirovecii pneumonia, leaving 87 patients for analysis.
• The study was retrospective and conducted at a single center.