Development and construct validation of the pharmacists' care of migraineurs scale

To develop the pharmacists' care of migraineurs scale (PCMS) and to evaluate its psychometric properties.

Migraine is often managed suboptimally in primary care. Migraineurs frequently come into contact with community pharmacists, who have the opportunity to make a positive impact on migraineur treatment outcomes. A valid and reliable tool that measures and documents the care provided by pharmacists to migraineurs is critical to the development and evaluation of educational programs and interventions.

Relevant domains of pharmacist care and their respective composite items (behaviors) were identified through an extensive literature search and the use of 2 pharmacist and 2 migraineur focus groups sessions. The resultant 45 PCMS items composed a survey questionnaire mailed to a nationwide random sample of 6000 pharmacists. Data were subjected to an exploratory principal axis factoring procedure to discern the factor structure, and as such describe the latent domains composing the pharmacist caring behaviors constructs.

A total of 580 usable responses were returned, with an additional 60 returned as undeliverable, thus yielding a response rate of 9.7%. Exploratory factor analysis using principal axis factoring yielded 9 factors. However, upon examining the scree plot, communalities, and factor loadings, a reanalysis forcing a 7-factor solution yielded a more interpretable and plausible factor structure. The 7-factor solution included the following domains: (1) empathy; (2) prospective drug utilization review for newly diagnosed migraineurs; (3) medication counseling; (4) nonpharmacologic treatment plan; (5) headache sufferer triage; (6) dissemination of public health information; (7) maintenance of knowledge on migraine. Following the application of scale purification procedures, the final instrument is composed of 41 items and demonstrated a Cronbach's alpha reliability of 0.947. Cronbach's alpha reliabilities for the 7 domains ranged from 0.67 to 0.91, indicative of good to excellent internal consistency reliabilities for all the domains.

The PCMS demonstrated very good construct validity and reliability. While additional validity testing is warranted, the PCMS should allow for benchmarking in the evaluation of interventions designed to improve pharmacists' care to migraineurs and for identifying correlates to effective community pharmacist migraineur care.