New Onset Depression in Newly Diagnosed MS Patients

San Francisco—Patients with multiple sclerosis (MS) are more likely to become depressed than healthy controls and patients with other chronic medical conditions. There are few data regarding the time to onset of depression in newly diagnosed MS patients or the economic implications to payers of comorbid depression in these patients.

The objective of this investigation, reported in a poster session at the AMCP meeting, was to examine variations in the incidence of depression and to determine patterns of all-cause healthcare resource utilization for newly diagnosed MS patients. The poster was titled Economic Implications of New Onset Depression in Newly Diagnosed Multiple Sclerosis Patients: Implications for Managed Care Pharmacy Practice.

Patient records were obtained from the i3 InVision^™ DataMart database, which contains medical, pharmacy, and laboratory claims data for 14 million people. Information that would result in the identities of these patients was removed to ensure HIPAA compliance. Analyses included medical and pharmacy claims data for the 24 months after the MS diagnosis index date (the date of the second of 2 MS-related medical claims). Eligibility criteria were enrollment in a large, national insurance company for 30 consecutive months between January 2006, and March 2011, a new diagnosis of clinically definite MS, no diagnosis or medical claim of depression, and no pharmacy claim for an antidepressant during the 6 months prior to the MS index date.

Outcome measures were a proportion of incident depression in newly diagnosed MS patients, annualized all-cause and MS-related payer expenditures for patients with or without incident depression, and time to new-onset depression from initial disease-modifying therapy (DMT) exposure.

Records for 2823 newly diagnosed MS patients met eligibility criteria. Of those, 670 patients (23.7%) met protocol-defined criteria for depression during the 24-month postindex evaluation period. Average time to new onset of depression was 4 to 5 months.

For total resource utilization, newly diagnosed MS patients with incident depression incurred 25% greater annual expenditures than their peers without incident depression (P<.0001). The greatest incremental costs for patients with depression were associated with more physician (34%; P<.0001) and home visits (46%; P<.0052), outpatient services (41%; P<.0001), and prescription drugs (96%; P<.0001). The proportions of MS-related costs of the total all-cause health expenditures were approximately 18% and 20% in cohorts with and without incident depression, respectively.

For DMT-naïve patients (n = 1859), 21% (n =394) met criteria for incident depression. Prescription drug use was higher across all categories among patients with incident depression (P<.0038). Annualized all-cause payer costs for DMT-naïve patients with incident depression were 73% higher than for their counterparts without depression (P<.0001).

For DMT-exposed patients (n = 964), 29% (n =276) met criteria for incident depression. Initiation of DMT was more rapid for patients with incident depression (P=.02). The only significant predictor of incident depression was the type of DMT used. Patients treated with interferon beta-1a intramuscularly or interferon beta-1b subcutaneously (SC) were at greater risk of incident depression than patients treated with glatiramer acetate, interferon beta-1a SC, or natalizumab. Onset of depression was most rapid (~3 weeks) after beginning treatment with interferon beta-1b or natalizumab.

This study was supported by Teva Pharmaceuticals.