Validation of an instrument to measure patients' experiences of medicine use: the Living with Medicines Questionnaire.

BACKGROUND

Medicine-related burden is an increasingly recognized concept, stemming from the rising tide of polypharmacy, which may impact on patient behaviors, including nonadherence. No instruments currently exist which specifically measure medicine-related burden. The Living with Medicines Questionnaire (LMQ) was developed for this purpose.

OBJECTIVE

This study validated the LMQ in a sample of adults using regular prescription medicines in the UK.

METHODS

Questionnaires were distributed in community pharmacies and public places in southeast England or online through UK health websites and social media. A total of 1,177 were returned: 507 (43.1%) from pharmacy distribution and 670 (56.9%) online. Construct validity was assessed by principal components analysis and item reduction undertaken on the original 60-item pool. Known-groups analysis assessed differences in mean total scores between participants using different numbers of medicines and between those who did or did not require assistance with medicine use. Internal consistency was assessed by Cronbach's alpha. Free-text comments were analyzed thematically to substantiate underlying dimensions.

RESULTS

A 42-item, eight-factor structure comprising intercorrelated dimensions (patient-doctor relationships and communication about medicines, patient-pharmacist communication about medicines, interferences with daily life, practical difficulties, effectiveness, acceptance of medicine use, autonomy/control over medicines and concerns about medicine use) was derived, which explained 57.4% of the total variation. Six of the eight subscales had acceptable internal consistency (α>0.7). More positive experiences were observed among patients using eight or fewer medicines compared to nine or more, and those independent with managing/using their medicines versus those requiring assistance. Free-text comments, provided by almost a third of the respondents, supported the domains identified.

CONCLUSION

The resultant LMQ-2 is a valid and reliable multidimensional measure of prescription medicine use experiences, which covers more diverse domains than existing questionnaires. However, further validation work is necessary.