title: Using observational analysis of multiple sclerosis relapse to design outcomes-based contracts for disease-modifying drugs: a feasibility assessment.
abstract: OBJECTIVE
  To assess predictors and costs of multiple sclerosis (MS) relapse, a potential outcome measure in payer-manufacturer risk-sharing agreements for disease-modifying drugs (DMDs).
  
  
  METHODS
  A retrospective cohort analysis of medical/pharmacy claims was used. Study patients had ≥1 DMD (interferon beta, glatiramer, natalizumab) claim, without DMD claims in a 6-month pre-period before DMD initiation; were aged 18-64 years and continuously enrolled from the pre-period through a 24-month post-period; and had ≥2 MS medical claims during the 30-month study period. Post-period relapse cohorts included: (1) severe (hospitalization with MS diagnosis); (2) moderate (outpatient services including intravenous methylprednisolone); and (3) none. Poisson regression modeled severe relapse frequency, logistic regression modeled ≥1 severe relapse, and generalized linear modeling predicted healthcare costs. Tested predictors included demographics, insurance type, index DMD, pre-period health status, and DMD medication possession ratio (MPR).
  
  
  RESULTS
  Severe relapse was experienced by 14.5% and moderate relapse by 13.8% of 2291 patients. In logistic regression, severe relapse was predicted by plan type; age (odds ratio [OR] = 1.018, 95% confidence interval [CI] = 1.005-1.031); pre-period Charlson Comorbidity Index (OR = 1.307, 95% CI = 1.166-1.464); pre-period proxy measure indicating impaired activities of daily living (OR = 1.470, 95% CI = 1.134-1.905); pre-period MS hospitalization (OR = 2.174, 95% CI = 1.537-3.074); and DMD non-adherence (MPR OR = 0.101, 95% CI = 0.068-0.151). Poisson regression results were similar. Predicted mean [standard deviation] all-cause healthcare expenditures were tripled for patients with severe compared with moderate relapse ($48,173 [$8665] and $13,334 [$1929], respectively).
  
  
  CONCLUSIONS
  Commercially insured patients from a single payer; use may have been inconsistent with approved indications; proxy relapse measure may have misclassified patients.
  
  
  CONCLUSIONS
  Severe MS relapses requiring hospitalization, although affecting less than 15% of patients initiating DMD treatment, are associated with high medical costs. The only actionable predictor of severe relapse identified in observational analysis was MPR, raising questions about the feasibility of using observational data to guide outcomes-based contracting.
authors.affiliation: Health Metrics Outcomes Research , LLC, Delray Beach, FL, USA.
authors.forename: Maureen J
authors.initials: MJ
authors.lastname: Lage
authors.forename: Cathryn A
authors.initials: CA
authors.lastname: Carroll
authors.forename: Kathleen A
authors.initials: KA
authors.lastname: Fairman
mesh_terms: D000293:Adolescent; D000328:Adult; D061067:Antibodies, Monoclonal, Humanized / Q000191:economics* / Q000627:therapeutic use; D015331:Cohort Studies; D016001:Confidence Intervals; D032982:Contracts / Q000191:economics / Q000706:statistics & numerical data; D005240:Feasibility Studies; D005260:Female; D006760:Hospitalization / Q000191:economics / Q000706:statistics & numerical data; D006801:Humans; D007166:Immunosuppressive Agents / Q000191:economics / Q000627:therapeutic use; D007345:Insurance Claim Review / Q000191:economics; D016899:Interferon-beta / Q000191:economics* / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000175:diagnosis / Q000188:drug therapy* / Q000503:physiopathology; D000069442:Natalizumab; D019370:Observation / Q000379:methods*; D016017:Odds Ratio; D017063:Outcome Assessment, Health Care / Q000191:economics*; D016012:Poisson Distribution; D011237:Predictive Value of Tests; D011379:Prognosis; D012008:Recurrence; D012189:Retrospective Studies; D012308:Risk Management; D012720:Severity of Illness Index; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D007166:Immunosuppressive Agents; D000069442:Natalizumab; D016899:Interferon-beta