Table 2.
Adjusted odds ratios of factors associated with discontinuation of subcutaneous interferon β-1a, three times weekly, at 1, 2, and 3 years, respectively
| Adjusted odds ratio (95% confidence interval) |
sc IFN β-1a tiw | ||
|---|---|---|---|
| Discontinuation at 1 year (n = 3975) |
Discontinuation at 2 years (n = 2592) |
Discontinuation at 3 years (n = 1664) |
|
| Female sex (vs. male) | NS | NS | 1.48 (0.98–2.22) |
| Region (vs. unknown) | NS | NS | NS |
| Age in years (continuous) | NS | NS | NS |
| Charlson comorbidity index (≥1 vs. 0) | NS | NS | NS |
| Relapses per year (continuous) | NS | 1.60 (1.11–2.30) | 2.31 (1.27–4.22) |
| High relapses (≥2 relapses) (vs. no)a | NS | NS | NS |
| DMD use history (vs. no) | NS | NS | NS |
| Months of treatment duration (continuous) | NS | NS | NS |
| No persistence (vs. yes) | NS | NS | NS |
| Adherence <80% (vs. ≥80%) | 180.95 (135.84–241.03) | 135.80 (100.10–184.23) | 174.90 (115.27–265.38) |
| Health resource usage | |||
| Hospital visits (1 vs. 0, 2 vs. 0, and ≥3vs. 0) | NS | NS | NS |
| Emergency room visits 1 vs. 0, 2 vs. 0, and ≥3vs. 0) | NS | NS | NS |
| Nurse visits (1 vs. 0, 2 vs. 0, and ≥3vs. 0) | NS | NS | NS |
| Neurologist visits (vs. 10+) | |||
| 1 | 0.84 (0.57–1.25) | NS | NS |
| 2 | 0.67 (0.47–0.97) | NS | NS |
| 3+ | 1.11 (0.84–1.48) | NS | NS |
| Psychologist visits (1 vs. 0, 2 vs. 0, and ≥3vs. 0) | NS | NS | NS |
| Psychiatrist visits (1 vs. 0, 2 vs. 0, and ≥3vs. 0) | NS | NS | NS |
| Speech Therapy visits (1 vs. 0, 2 vs. 0, and ≥3vs. 0) | NS | NS | NS |
| Outpatients (1 vs. 0, 2 vs. 0, and ≥3vs. 0) | NS | NS | NS |
| Increasing number of MRI scans (one additional scan versus no increase in number of MRI scans) | 1.45 (1.26–1.67) | 1.18 (1.06–1.32) | 1.20 (1.07–1.34) |
| Laboratory investigations (vs. 0) | |||
| 1 | 0.61 (0.30–1.25) | NS | NS |
| 2 | 0.93 (0.38–2.26) | NS | NS |
| 3+ | 2.54 (1.20–5.38) | NS | NS |
| Baseline corticosteroid use (No = 0, Yes = 1) | NS | NS | NS |
| Follow-up | |||
| NSAID use (vs. no) | NS | NS | NS |
| Antidepressants use (vs. no) | NS | 1.46 (1.10–1.94) | NS |
| Anxiolitics use (vs. no) | 1.40 (1.06–1.82) | NS | NS |
| Corticosteroid use (vs. no) | NS | NS | NS |
DMD disease-modifying drug, IFN interferon, MRI magnetic resonance imaging, NS no significant association with discontinuation, NSAID non-steroidal anti-inflammatory drug, sc subcutaneous, tiw three times a week
aHigh relapse activity defined as having ≥2 relapses in the first year prior to start of subcutaneous interferon β-1a, three times weekly