TABLE 2.

Sampling of antidepressant adherence studies in primary care populations over the past 10 years

FIRST AUTHOR/YEAR OF PUBLICATION	COUNTRY OF ORIGIN	SAMPLE TYPE/METHODOLOGY	SUBJECT NUMBER	DEFINITION OF NONADHERANCE	PREVALENCE OF NONADHERENCE
Demyttenaere/200110	Belgium	Primary care sample/prospective study	272	6-month ATD nonadherence	53.0%
Hansen/200411	Denmark	Primary care sample/ retrospective review	4860	No ATD prescription filled for first 6 months	33.6%
Cantrell/200612	United States	Managed care sample/ retrospective study	22,947	6-month ATD nonadherence	57.0%
Akincigil/200713	United States	Health plan pharmacy claims/retrospective study	4312	4-month ATD nonadherence	49.0%
Bambauer/20075	United States	Primary care enrollees in healthcare plan/retrospective review	7982	Immediate ATD nonadherence 6-month ATD non-adherence	Immediate: 18.0% 6-month: 53.0%
Hansen/200714	Denmark	National registry/retrospective study	Unknown	6-month ATD nonadherence (no refill after 6 months)	25.2%
Sheehan/200815	United States	Managed care sample/retrospective study	266,665	6-month ATD nonadherence	67.4-87.6% depending on ATD type
Vanelli/200816	United States	Pharmacy records/retrospective study	211,565	First 30-days ATD nonadherence	38.8% in those without previous ATD exposure
Kennedy/200817	United States	Medicare beneficiaries/ retrospective study	Unknown	Failure to fill/refill at least one ATD prescription	5.4%
Hrique/200918	France	Primary care sample/retrospective clinical interview	632	6-month ATD nonadherence, patient's initiative	58.1%
Bulloch/201019	Canada	General population sample/survey	2497	Inadequate or missed doses during a typical treatment month with ATDs	45.9%
Serna/201020	Spain	Prescription database/retrospective review	7525	4-month ATD nonadherence	56.0%
Fortney/201121	United States	Primary care VA sample/prospective study	395	Never filled prescription 6-month ATD nonadherence	4.8% 12.2%

Note: ATD = antidepressant; VA = Veterans Affairs