title: Medication barriers and anti-hypertensive medication adherence: the moderating role of locus of control.
abstract: Locus of control as a moderator of the relationship between medication barriers (e.g., side-effects, forgetting to take medication, and keeping track of pills) and anti-hypertensive medication adherence was examined. Baseline data were obtained from 588 hypertensive veterans. In general, fewer medication barriers, higher internal locus of control and lower external locus of control was associated with better hypertensive medication adherence. Furthermore, internal locus of control served as a moderator (beta = -.74, p < .01) for the relationship between medication barriers and medication adherence; effect size was large. Decomposition of the interaction revealed that the relationship between medication barriers and medication adherence was strongest when internal control was high (b = -.24, p < .01). Higher internal locus of control was beneficial when barriers to medication adherence are low, but at high perceived barriers, locus of control plays less of a role in medication adherence. Future efforts to improve medication adherence should consider the patient's perceived level of medication barriers in conjunction with their locus of control.
authors.affiliation: Center for Health Sciences Research in Primary Care, Durham Veterans Affairs Medial Center, North Carolina 27705, USA. tina.hong@duke.edu
authors.forename: Tantina B
authors.initials: TB
authors.lastname: Hong
authors.forename: Eugene Z
authors.initials: EZ
authors.lastname: Oddone
authors.forename: Tara K
authors.initials: TK
authors.lastname: Dudley
authors.forename: Hayden B
authors.initials: HB
authors.lastname: Bosworth
mesh_terms: D000959:Antihypertensive Agents / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000188:drug therapy*; D007389:Internal-External Control; D008297:Male; D008875:Middle Aged; D009657:North Carolina; D010349:Patient Compliance; D012646:Self Administration; D014728:Veterans
chemical_list: D000959:Antihypertensive Agents