TABLE 2.

Adherence to Treatment During First Year of Therapy Based on Proportion of Days Covered

Treatment	Number	Mean PDCa	High Adherence %b	Medium Adherence %c	Low Adherence %d
Cyclobenzaprine	15,388	0.20	5	7	88
Gabapentin	9,605	0.44	22	20	58
Tramadol	9,043	0.27	9	12	79
Duloxetine	8,607	0.59	38	22	40
Pregabalin	5,637	0.47	24	21	55
Milnacipran	2,370	0.43	20	18	62

^aPDC calculated as number of days in the period when the patient had drug supply (i.e., “covered” by medication)/number of days in the period.

^bHigh adherence, PDC ≥ 0.8.

^cMedium adherence, PDC 0.5 to < 0.8.

^dLow adherence, PDC < 0.5.

PDC = proportion of days covered.