[show abstract][hide abstract] ABSTRACT: To estimate the effect of two separate policy changes in the North Carolina Medicaid program: (1) reduced prescription lengths from 100 to 34 days' supply, and (2) increased copayments for brand name medications.
Medicaid claims data were obtained from the Centers for Medicare and Medicaid Services for January 1, 2000-December 31, 2002.
We used a pre-post controlled partial difference-in-difference-in-differences design to examine the effect of the policy change on adults in North Carolina; adult Medicaid recipients from Georgia served as controls. Outcomes examined include medication adherence and Medicaid expenditures. Data COLLECTION/EXTRACTION METHODS: Data were aggregated to the person-quarter level. Individuals in HMOs, nursing homes, pregnant, or deceased in the quarter were excluded.
Both policies decreased medication adherence. The days' supply policy had a much larger effect on adherence than did the copayment increase. Total Medicaid spending declined from the days' supply policy, but the copayment policy resulted in a net increase in Medicaid expenditures.
Although Medicaid costs decreased with the change in days supply policy, these savings were due to reduced adherence to these chronic medications. Additional research should examine the effect of these policy changes from the perspective of Medicaid enrollees.
Health Services Research 02/2011; 46(3):900-19. · 2.29 Impact Factor
[show abstract][hide abstract] ABSTRACT: The purpose of our study is to use Medicaid data to examine the relationship between race and (a) whether youth with schizophrenia or depression diagnoses receive anti-psychotic and antidepressant prescriptions and (b) adherence to anti-psychotics and antidepressants. The analysis is based on claims files from January 1, 2000 through June 30, 2001. To assess adherence, we used the Proportion of Days Covered (PDC) measure. Multivariable logistic regression was used to analyze the data. Black children with schizophrenia were significantly less likely to be adherent to anti-psychotics during a quarter than White children. White children with depression were significantly more likely to receive an antidepressant prescription and they were significantly more adherent during a quarter than Black children. Providers should make sure to investigate both youth and caregiver concerns, fears, and barriers to using these medications and work with the families to develop strategies to improve medication use among youth.
Community Mental Health Journal 06/2010; 46(3):265-72. · 1.03 Impact Factor
[show abstract][hide abstract] ABSTRACT: Multiple measures of adherence have been reported in the research literature and it is difficult to determine which is best, as each is nuanced. Occurrences of medication switching and polypharmacy or therapeutic duplication can substantially complicate adherence calculations when adherence to a therapeutic class is sought.
To contrast the Proportion of Days Covered (PDC) adherence metric with 2 variants of the Medication Possession Ratio (MPR, truncated MPR).
This study was a retrospective analysis of the North Carolina Medicaid administrative claims data from July 1999 to June 2000. Data for patients with schizophrenia (ICD-9-CM code 295.xx) who were not part of a health maintenance organization, not hospitalized, and not pregnant, taking at least one antipsychotic, were aggregated for each person into person-quarters. The numerator for PDC was defined as the number of days one or more antipsychotics was available and the MPR numerator was defined as the total days' supply of antipsychotics; both were divided by the total days in each person-quarter. Adherence rates were estimated for subjects who used only one antipsychotic, switched medications, or had therapeutic duplication in the quarter.
The final sample consisted of 25,200 person-quarters from 7069 individuals. For person-quarters with single antipsychotic use, adherence to antipsychotics as a class was: PDC 0.607, truncated MPR 0.640, and MPR 0.695 (p < 0.001). For person-quarters with switching, the average MPR was 0.690, truncated MPR was 0.624, and PDC was 0.562 (p < 0.001). In the presence of therapeutic duplication, the PDC was 0.669, truncated MPR was 0.774, and MPR was 1.238 (p < 0.001).
The PDC provides a more conservative estimate of adherence than the MPR across all types of users; however, the differences between the 2 methods are more substantial for persons switching therapy and prescribed therapeutic duplication, where MPR may overstate true adherence. The PDC should be considered when a measure of adherence to a class of medications is sought, particularly in clinical situations in which multiple medications within a class are often used concurrently.
Annals of Pharmacotherapy 01/2009; 43(1):36-44. · 2.57 Impact Factor