Comparing Infection-Related Outcomes By Sex in Patients with Multiple Sclerosis and Matched Controls Using Administrative Claims Data

Background: Few population-level sex-based risk estimates of specific infections exist for US patients with multiple sclerosis (MS).

Objectives: To quantify the sex-based relative risk (RR) of specific infections in MS vs. controls using IQVIA™ RWD Adjudicated Claims–US data (1/1/2010–6/30/2019).

Methods: The MS cohort had ≥2 diagnoses (ICD-9-CM/ICD-10-CM: 340.xx/G35) ≥30 days apart. The control cohort had 2 diagnoses for any other condition. Index date was a randomly selected office visit. Inclusion criteria were age 18–64, continuous 12-month eligibility pre-/post‑index, no antibiotic/antiviral claim 60 days prior, and no pregnancy/inpatient residential care/end-stage renal disease facility/HIV/HCV claims. Cohorts were matched 1:1 on age, sex, payer type, Census region, and index year. RR was estimated for presence of outpatient claim and inpatient hospitalization for urinary/kidney, pneumonia/influenza, other respiratory/throat, and viral infections during 12-months post-index.

Results: The MS and control cohorts included 87,755 patients (mean [SD] age 47.3 [10.5] years, 75.7% women). For women with MS vs. controls, significant differences in infection-related outpatient claims (RR [95% confidence interval {CI}]) were observed for urinary/kidney (1.75 [1.70–1.81]), pneumonia/influenza (1.18 [1.11–1.26]), and viral infections (1.19 [1.15–1.24]). For men with MS vs. controls, significant differences in infection-related outpatient claims were observed for urinary/kidney (2.79 [2.50–3.11]) and viral infections (1.17 [1.08–1.27]). For infection-related inpatient hospitalizations, for women with MS vs. controls, significant differences were observed for urinary/kidney (3.93 [3.44–4.47]), pneumonia/influenza (2.27 [1.94–2.66]), other respiratory/throat (2.35 [1.90–2.91]), and viral infections (2.81 [2.06–3.84]). For men with MS vs. controls, significant differences for infection-related inpatient hospitalizations were observed for urinary/kidney (9.47 [6.58–13.62]), pneumonia/influenza (2.08 [1.61–2.70]), other respiratory/throat (2.42 [1.64–3.56]), and viral infections (2.04 [1.24–3.36]). The only salient interaction between cohort type (MS vs. controls) and sex was among patients with urinary/kidney infections.

Conclusions: Compared to the control cohort, both women and men with MS had increased risk of infection-related outpatient claims and inpatient hospitalizations. A higher relative risk of urinary/kidney infections was observed in men with MS vs. controls.