Glatiramer acetate and interferon beta-1b: a study of outcomes among patients with multiple sclerosis.
BACKGROUND
To study the medical cost and probability of relapse in patients with multiple sclerosis (MS) treated with either glatiramer acetate (GA) or interferon beta-1b (IFN beta.1b).


METHODS
Data were obtained from the i3 InVision Data Mart Database from July 2001 to June 2006. We established an "intent-totreat" (ITT) cohort (n=842) of patients diagnosed with MS who began treatment with either GA or IFN beta-1b and had continuous insurance coverage from 6 months before to 2 years after the date when they began taking the medication. We also created a "continuous use" (CU) cohort (n=418) of individuals who, in addition to the criteria listed above, used either GA or IFN beta-1b within 28 days of the end of the 2-year postperiod. Using multivariate regressions, we examined both the 2-year total average direct medical costs and the likelihood of relapse within this period associated with the use of each of these MS medications. We defined relapse as being either hospitalization with a principal diagnosis of MS or having an outpatient visit with a diagnosis of MS and then prescribed steroids within a 7-day period. All regression analyses controlled for a wide range of factors that may potentially affect outcomes.


RESULTS
In the ITT cohort, patients who started treatment with GA had a significantly lower 2-year estimated risk of relapse (13.54% vs. 5.31%; P=0.0006). In the CU cohort, patients who used GA also had a significantly lower 2-year estimated risk of relapse (10.91% vs. 2.09%; P=0.0018), as well as significantly lower average total medical costs ($53,157 vs. $48,130; P=0.0345).


CONCLUSIONS
Results from this study indicate that users of GA have a significantly lower probability of 2-year relapse than users of IFN beta-1b. In addition, among continuous users, the 2-year total average direct medical costs are significantly lower for users of GA than for users of IFN beta-1b.
Castelli-Haley
Jane
J
Teva Neuroscience, Kansas City, MO 64131, USA.
Oleen-Burkey
MerriKay A
MA
Lage
Maureen J
MJ
Johnson
Kenneth P
KP
D000276:Adjuvants, Immunologic / Q000191:economics / Q000627:therapeutic use; D000328:Adult; D003362:Cost-Benefit Analysis; D016527:Drug Costs / Q000706:statistics & numerical data; D005260:Female; D000068717:Glatiramer Acetate; D017048:Health Care Costs / Q000706:statistics & numerical data*; D006302:Health Services Research; D006801:Humans; D007344:Insurance Claim Reporting / Q000706:statistics & numerical data; D000068576:Interferon beta-1b; D016899:Interferon-beta / Q000191:economics / Q000627:therapeutic use; D016018:Least-Squares Analysis; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000188:drug therapy / Q000191:economics; D015999:Multivariate Analysis; D010455:Peptides / Q000191:economics / Q000627:therapeutic use; D012008:Recurrence; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D016896:Treatment Outcome
D000276:Adjuvants, Immunologic; D010455:Peptides; D000068576:Interferon beta-1b; D000068717:Glatiramer Acetate; D016899:Interferon-beta