Factors Associated With Prescribing Oral Disease Modifying Agents in Multiple Sclerosis: A Real-World Analysis of Electronic Medical Records

ABSTRACT BACKGROUND Little is known about the factors associated with the selection of Disease Modifying Agents (DMA) for the management of Multiple Sclerosis (MS) since the introduction of oral DMAs in 2010. OBJECTIVES To examine the factors associated with prescribing oral DMAs in patients with MS using data from electronic medical records (EMR). METHODS A retrospective longitudinal study was conducted using TriNetX, a federated EMR network of over 38 million patients from the US, data from 2009–2019. Adult (≥18 years) patients with MS from the United States were identified using a MS diagnosis (ICD-9-CM: 340 or ICD-10-CM: G35) and a DMA prescription within a one-year time period. Patients with DMA prescriptions were classified as oral or injectable users based on their index medication. A multivariable logistic regression model was used to determine the predisposing (age category, sex, race, and ethnicity), enabling (time period), and need factors (comorbidities, MS symptoms, symptomatic medication, and healthcare utilization) associated with prescribing of an oral versus injectable DMA. RESULTS The study cohort consisted of 7,511 MS patients, of whom most were 18-44 years old (48.33%), female (75.18%), and white (80.92%). About 42.32% of MS patients were diagnosed with at least one comorbidity (mean±SD: 0.86±1.37). Two thirds (66.32%) of the patients with MS started injectable DMAs, and the remaining one third (33.68%) started oral DMAs. Multivariable regression revealed that middle-aged (45–64 years; Adjusted Odds Ratio [AOR]=0.88; 95% Confidence Interval [CI]: 0.79–0.98) and older adults (≥65 years; AOR=0.67, 95% CI: 0.53–0.84) were associated with a decreased likelihood of receiving oral DMAs. The presence of general symptoms (AOR=1.26, 95% CI: 1.10-1.45) and cerebellar symptoms (AOR=1.56, 95% CI: 1.26-1.93) was associated with an increased likelihood of an oral DMA. However, the presence of sensory symptoms (AOR: 0.72, 95% CI 0.59-0.88) was associated with a decreased likelihood of an oral DMA. Comorbidities such as renal failure (AOR=0.16, 95% 0.04-0.62), obesity (AOR=0.60, 95% CI 0.45-0.80), drug abuse (AOR=0.61, 95% CI: 0.38-0.99), and other neurological disorders (AOR=0.82, 95% CI: 0.69-0.96) were associated with a decreased likelihood of receiving an oral DMA prescription. While the use of analgesics (AOR=0.78, 95% CI: 0.69-0.88) was associated with decreased likelihood, the use of antispasmodics (AOR=1.14, 95% CI: 1.01-1.28) was associated with an increased likelihood of receiving an oral DMA. Relative to the time-period when first oral DMAs entered into the market (2010-11), with time, the likelihood of prescribing oral DMA increased by multiple folds (2012-13, AOR=4.30, 95% CI 3.08-6.00; 2014-15, AOR=19.34, 95% CI 14.10-26.54; 2016-17, AOR=17.63, 95% CI 12.76-24.35; and 2018-19, AOR=20.73, 95% CI 14.64-29.37). CONCLUSIONS Oral DMA use steadily increased over the years, with one in three MS patients receiving oral agents. Both demographic and clinical factors were associated with the selection of oral DMA over injectable DMA.