Adherence to changing from brand-name to generic atorvastatin in newly treated patients: a retrospective cohort study using health insurance claims

Table 2 Proportion of days covered in pre- and post-index date for the changed and continued cohorts

PDC	Changed to generic	Continued brand	P value	Odd ratio ^a (95 %CI)
PDC	Changed to generic	Continued brand	P value	Unadjusted	Adjusted ^b
Pre-index date
PDC, %, median (range)	97.7 (34.1 ~ 100)	92.4 (22.9 ~ 100)	<0.01
Patients achieving adherence (PDC≧80%) (number, (%))	116 (85.9)	108 (73.5)	< 0.05
Post-index date
PDC, %, median (range)	92.2 (7.8~100)	89.4 (15.6~100)	0.058
Patients achieving adherence (PDC≧80%) (number, (%))	96 (71.1)	93 (63.3)	0.162	1.43 (0.87-2.36)	0.84 (0.46-1.52)
PDC difference from pre- to post-index date (%)	- 8.6^**	- 10.3^**	0.443

Median of proportion of days covered (PDC) and proportion of patients achieving adherence (PDC ≧ 80%) in the pre- and post-index date, and odds ratio of achieving adherence (PDC ≧ 80%) for the changed and continued cohorts.
^aLogistic regression model analysis.
^bAdjusted baseline covariates included adherence in pre-index date (baseline adherence) (PDC≧80 %), duration of use of atorvastatin prior to index date, prescribing medical establishment, and comorbidities, such as hypertension, arrhythmia, and calcium channel blocker.
**:Significant difference in PDC change from pre- to post-index date for the changed and continued cohorts (P < 0.01).

ISSN: 2055-0294