"What's Sex and Gender Got to Do With It?" A Scoping Review of Sex- and Gender-Based Analysis in Pharmacoepidemiologic Studies of Medication Adherence

Abstract

Objectives: Medication taking is a complex multidimensional behavior that may be impeded by a range of biological and psychosocial factors, including sex and gender. We aimed to synthesize how sex and gender have been reported and analyzed in pharmacoepidemiologic studies of medication.

Methods: We searched for English-language peer-reviewed articles of observational studies (eg, cross-sectional, cohort, and case-control) that examined medication adherence among adults and included sex or gender in their reporting.

Results: We included 937 studies among 530 537 287 participants published between the year 1979 and 2021. Most studies were cross-sectional (47%), lasted ≤ 1 year (35%), examined self-reported adherence (53%), did not assess specific adherence problem(s) (40%), and included medications for cardiovascular conditions (24%) or systemic infections (24%). A quarter of studies (25%) used sex and gender interchangeably, more than one third of studies (36%) that reported gender data likely collected data on sex, and < 1% of studies described sex and gender as distinct variables. Studies of cisgender participants more often reported that females/women experienced greater adherence problems often than males/men (31% vs 20%), particularly discontinuation and cost-related nonadherence. Only 21 studies (2%) reported on transgender individuals, and these predominantly examined antiretroviral medications for HIV.

Conclusions: Our review revealed substantial conflation of sex and gender in studies of medication adherence and a paucity of research among transgender individuals. Moreover, our synthesis showed sex/gender disparities in medication taking with studies reporting greater medication adherence problems among cisgender women and transgender participants than cisgender men.

Keywords: medication adherence; observational studies; pharmacoepidemiology; scoping review; sex- and gender-based analysis.