Incidence rate and causes of infection in Thai systemic sclerosis patients

Infection is a common cause of death in systemic sclerosis (SSc) but despite immunosuppressant therapy, there are few reports of opportunistic infection.

To estimate the incidence of infection, to determine the etiologic organism, and to assess the risk factors for infection among Thai SSc patients.

A historical cohort analysis was conducted on patients over 15 years of age, diagnosed with SSc, who attended the Scleroderma Clinic at Srinagarind Hospital, Khon Kaen, Thailand, between January 1, 2005 and December 31, 2006.

The medical records of 117 SSc patients were reviewed. The female-to-male ratio was 1.5 : 1.0. Of the total 310 person-years under observation, 63 events of infection occurred. The incidence rate of infection was 20.3 per 100 person-years (95% CI 15.6-26.0) and the incidence rate of major infection was 11.0 per 100 person-years (95% CI 8.4-16.5). The mean age and mean duration of SSc at the time of infection was 50.1 ± 11.1 years (range, 25.2-76.6) and 12.9 ± 10.4 months (range, 0.5-34.6), respectively. Urinary tract infection was the most common infection (23.8%). Opportunistic infection was found in one case (esophageal candidiasis). Esophageal dysmotility was significantly related to major infection (odds ratio [OR] 3.22). There was a clinical association between aspiration pneumonia and esophageal dysmotility (OR 1.23), as well as non-strongyloidiasis diarrhea and gastrointestinal involvement (OR 2.28). One person died due to severe bacterial aspiration pneumonia.

Infection is not uncommon among SSc patients; however, opportunistic infection is rare, despite immunosuppressant therapy. Esophageal dysmotility increases the risk of major infection, particularly of aspiration pneumonia.