Increased Risk of Infection Seen in
Patients With MS

Jake Remaly

February 28, 2020

WEST PALM BEACH, Florida — Patients with multiple sclerosis (MS) are at increased risk for most types of infection, with the highest risk associated with renal tract infections, according to an analysis of Department of Defense data.

Susan Jick, DSc, director of the Boston Collaborative Drug Surveillance Program and professor of epidemiology and biostatistics at Boston University, and colleagues sought to understand the rates at which infections occur because they are known to be a common cause of comorbidity and death in patients with MS.

At the meeting held by the Americas Committee for Treatment and Research in Multiple Sclerosis, Jick and colleagues presented rates of infection in patients with MS after MS diagnosis, compared with a matched population of patients without MS.

The MS cohort included patients who had MS diagnosed and treated between January 2004 and August 2017. Patients had medical history available for at least 1 year before MS diagnosis and at least one prescription for an MS disease-modifying treatment.

Patients without MS were matched 10:1 to patients with MS based on age, sex, geographic region, and cohort entry date. For each patient, the researchers identified the first diagnosed infection of each type after cohort entry. They followed patients until loss of eligibility, death, or end of data collection.

In all, the study included 8,695 patients with MS and 86,934 matched patients without MS. The median age at cohort entry was 41 years, and 71% were female. Median duration of follow-up after study entry was about 6 years. Patients with MS were more likely to have an infection in the year before cohort entry, compared with non-MS patients (43.9% vs. 36.3%).

After cohort entry, the incidence rate (IR) of any infection was higher among patients with MS, compared with non-MS patients (4,805 vs 2,731 per 10,000 person-years; IR ratio, 1.76). In addition, the IR of hospitalized infection was higher among MS patients (125 vs. 51.3 per 10,000 person-years; IRR, 2.43).

The IR also was increased for several other types of infections, including renal, skin, fungal, pneumonia or influenza, and other infections (such as rickettsial and spirochetal diseases, helminthiases, and nonsyphilitic and nongonococcal venereal diseases). Eye or ear, respiratory or throat, and viral IRRs "were marginally elevated," the investigators wrote.

In both cohorts, females had a higher risk of infection than males did. The rate of renal tract infection was more than fourfold higher among females, compared with males, in both cohorts. Relative to non-MS patients, however, men with MS had a higher IRR for renal tract infection than women with MS did (2.47 vs. 1.90).

"The risk for any opportunistic infection was slightly increased among MS patients," the researchers wrote (520 vs. 338 per 10,000 person-years; IRR, 1.54).

This was particularly true for candidiasis (252 vs 166 per 10,000 person-years; IRR, 1.52) and herpes virus infection (221 vs. 150 per 10,000 person-years; IRR, 1.47).

"There were few cases of tuberculosis, hepatitis B infection, or hepatitis C infection," they noted.

The study was funded by a grant from Celgene, a subsidiary of Bristol-Myers Squibb. Four authors are employees of Bristol-Myers Squibb, and one author works for a company that does business with Celgene.

Source: 5th annual Americas Committee for Treatment and Research in Multiple Sclerosis (ACTRIMS) Forum 2020. Abstract P086.

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