Few population-level risk estimates of infections in patients with multiple sclerosis (MS) exist in the United States.
To evaluate the odds of infections associated with MS using the IQVIA™ RWD Adjudicated Claims–US database (1/1/2010–6/30/2019).
Patients with MS with ≥2 diagnoses (ICD-9-CM/ICD-10-CM: 340.xx/G35) ≥30 days apart were identified. Individuals in the non-MS cohort were required to have 2 diagnoses for any condition. A randomly selected index office visit date meeting the following criteria was selected: index age 18-64, continuous 12-month eligibility pre/post, no pregnancy claims, no antibiotic/antiviral claim 60 days prior, no inpatient residential care/end-stage renal disease facility, and no HIV/HCV. Patients with and without MS were matched 1:1 on age, sex, payer type, Census region, and index year. Infections were defined as likelihood of presence of antibiotics/antivirals claims and inpatient hospitalizations in the 12-month post-index period. Multivariable logistic regression models were used to measure the association of MS diagnosis with presence of antibiotic/antiviral claims and inpatient hospitalizations for infections. Explanatory variables were: age group, sex, payer type, region, index year (2011-2018), and select comorbidities.
A total of 87,755 patients with MS met study inclusion criteria and were matched to 87,755 patients without MS. Mean (SD) age was 47.3 (10.5) years, 75.7% were female, 65.7% had commercial insurance, and 34.3% had self-insured employer insurance. Patients were from the South (32.7%), Midwest (31.3%), Northeast (25.5%) or West (10.5%) regions. Most common outpatient diagnoses of infections in both cohorts were urinary tract infection, acute sinusitis, acute upper respiratory tract infections, acute pharyngitis, and mycoses. A greater proportion of patients with MS vs. without MS had presence of antibiotic/antiviral claims (53.8% vs. 48.2%; p<0.0001) and inpatient hospitalization for infections (3.2% vs. 1.3%; p<0.0001). Compared with the non-MS cohort, patients with MS had significantly higher odds of an antibiotic/antiviral claim (adjusted odds ratio [AOR], 95% confidence interval [CI]: 1.18 [1.16, 1.20]) and significantly higher odds of inpatient hospitalization (AOR, 95% CI: 2.00 [1.86, 2.15]).
These findings highlight the increased odds of infection among the commercially and self-insured patients with MS in the US.