The association between adherence to levodopa/carbidopa/entacapone therapy and healthcare utilization and costs among patients with Parkinson's disease: a retrospective claims-based analysis.
BACKGROUND
Suboptimal adherence to long-term therapies is common and may potentially have adverse consequences on patient outcomes and healthcare costs.


OBJECTIVE
To assess the association between adherence to levodopa/carbidopa/entacapone therapy and healthcare utilization and costs in patients with Parkinson's disease.


METHODS
A retrospective historical cohort study, conducted in the US, using a health insurance claims database, with data spanning from 1 January 2000 to 31 December 2005. Subjects included patients with Parkinson's disease who were treated with levodopa (L), carbidopa (C) and entacapone (E) either as separate tablets (LC + E) or as a single-tablet formulation (LCE). The association between satisfactory adherence (defined as 'proportion of days covered' for LCE or LC + E during 1-year follow-up ≥80%) and healthcare utilization and costs was examined using multivariate regression to control for pretreatment adherence to LC and other patient characteristics.


RESULTS
Compared with unsatisfactory adherence (n = 598), satisfactory adherence (n = 617) was associated with 39% fewer Parkinson's disease-related hospitalizations (95% CI 20, 54; p < 0.001), 47% lower all-cause inpatient costs (95% CI 18, 65; p = 0.004) and 18% lower all-cause total costs (95% CI 11, 24; p < 0.001). On an adjusted basis, all-cause total costs were $US3508 less for those with satisfactory versus unsatisfactory adherence. In both the LC + E and LCE groups, satisfactory adherence was associated with significant reductions in all-cause hospitalizations (39% and 46%, respectively), and all-cause total costs (10% and 31%, respectively). The association between adherence and total healthcare costs was stronger for patients receiving LCE.


CONCLUSIONS
Better adherence to levodopa/carbidopa/entacapone therapy is associated with lower healthcare utilization and costs. Non-adherence to LCE is associated with a greater increase in costs than non-adherence to LC + E. Efforts should be made to ensure adherence to both therapies.
PAI (Policy Analysis, Inc.), Brookline, Massachusetts 02445, USA. tdelea@pai2.com
Thomas E
TE
Delea
Simu K
SK
Thomas
May
M
Hagiwara
D000978:Antiparkinson Agents / Q000008:administration & dosage* / Q000191:economics; D002230:Carbidopa / Q000008:administration & dosage / Q000191:economics; D002396:Catechols / Q000008:administration & dosage / Q000191:economics; D015331:Cohort Studies; D003695:Delivery of Health Care / Q000191:economics / Q000706:statistics & numerical data*; D017048:Health Care Costs; D006801:Humans; D007980:Levodopa / Q000008:administration & dosage / Q000191:economics; D009570:Nitriles / Q000008:administration & dosage / Q000191:economics; D010300:Parkinson Disease / Q000188:drug therapy* / Q000191:economics; D010349:Patient Compliance; D012189:Retrospective Studies
D000978:Antiparkinson Agents; D002396:Catechols; D009570:Nitriles; D007980:Levodopa; C071192:entacapone; D002230:Carbidopa