title: Theory of planned behavior and adherence in chronic illness: a meta-analysis.
abstract: Social-cognitive models such as the theory of planned behavior have demonstrated efficacy in predicting behavior, but few studies have examined the theory as a predictor of treatment adherence in chronic illness. We tested the efficacy of the theory for predicting adherence to treatment in chronic illness across multiple studies. A database search identified 27 studies, meeting inclusion criteria. Averaged intercorrelations among theory variables were computed corrected for sampling error using random-effects meta-analysis. Path-analysis using the meta-analytically derived correlations was used to test theory hypotheses and effects of moderators. The theory explained 33 and 9 % of the variance in intention and adherence behavior respectively. Theoretically consistent patterns of effects among the attitude, subjective norm, perceived behavioral control, intention and behavior constructs were found with small-to-medium effect sizes. Effect sizes were invariant across behavior and measurement type. Although results support theory predictions, effect sizes were small, particularly for the intention-behavior relationship.
authors.affiliation: Atlantis Healthcare, Unit 7, 112-118 Talavera Road, North Ryde, NSW, 2113, Australia, antonia.rich@atlantishealthcare.com.
authors.forename: Antonia
authors.initials: A
authors.lastname: Rich
authors.forename: Kim
authors.initials: K
authors.lastname: Brandes
authors.forename: Barbara
authors.initials: B
authors.lastname: Mullan
authors.forename: Martin S
authors.initials: MS
authors.lastname: Hagger
mesh_terms: D001290:Attitude; D002908:Chronic Disease / Q000523:psychology*; D006801:Humans; D033182:Intention; D010349:Patient Compliance / Q000523:psychology*; D011582:Psychological Theory