title: Validation of the Osteoporosis-Specific Morisky Medication Adherence Scale in long-term users of bisphosphonates.
abstract: OBJECTIVE
  To examine the psychometric properties and validity of the 8-item Osteoporosis-Specific Morisky Medication Adherence Scale (OS-MMAS-8) in postmenopausal women prescribed bisphosphonates (BPs) for at least 15 months.
  
  
  METHODS
  A random sample of women aged ≥55 years with osteoporosis prescribed daily or weekly BPs was identified. Pharmacy fill data were extracted to calculate the medication possession ratio (MPR). Eligible women were stratified by low (<0.50), medium (0.50-0.79), or high (≥0.80) MPR, with the a priori goal of recruiting 133 participants in each group. OS-MMAS-8 scores can range from 0 to 8 and were categorized as low (<6), medium (6 to <8), and high (8) adherence. Internal consistency reliability (Cronbach's alpha), test-retest reliability [intraclass correlation coefficients (ICCs)] and convergent validity (correlating OS-MMAS-8 with MPR and other self-reported measures) were assessed.
  
  
  RESULTS
  A total of 400 women out of 449 respondents reported that they were still taking their BPs at the time of the survey and completed OS-MMAS-8. Overall, 38.5, 34.3, and 27.3% of participants had low, medium, and high OS-MMAS-8 scores, respectively. The mean (SD) MPRs according to OS-MMAS-8 scores (<6, 6 to <8 and 8) were 56.9 (22.6), 69.0 (24.9), and 76.7 (26.4), respectively. The correlation between OS-MMAS-8 and MPR was 0.36; p < 0.0001. Cronbach's alpha was 0.74, and the ICC was 0.83 (95% CI 0.76-0.88).
  
  
  CONCLUSIONS
  OS-MMAS-8 has acceptable psychometric properties for assessing medication adherence in postmenopausal women prescribed therapy for osteoporosis. Additional studies are needed to investigate the psychometric properties of OS-MMAS-8 in other settings and populations.
authors.affiliation: Department of Research & Evaluation, Kaiser Permanente Southern California, 100 S. Los Robles, 2nd Floor, Pasadena, CA, 91101, USA, Kristi.Reynolds@kp.org.
authors.forename: Kristi
authors.initials: K
authors.lastname: Reynolds
authors.forename: Hema N
authors.initials: HN
authors.lastname: Viswanathan
authors.forename: Paul
authors.initials: P
authors.lastname: Muntner
authors.forename: Teresa N
authors.initials: TN
authors.lastname: Harrison
authors.forename: T Craig
authors.initials: TC
authors.lastname: Cheetham
authors.forename: Jin-Wen Y
authors.initials: JW
authors.lastname: Hsu
authors.forename: Deborah T
authors.initials: DT
authors.lastname: Gold
authors.forename: Stuart
authors.initials: S
authors.lastname: Silverman
authors.forename: Andreas
authors.initials: A
authors.lastname: Grauer
authors.forename: Donald E
authors.initials: DE
authors.lastname: Morisky
authors.forename: Cynthia D
authors.initials: CD
authors.lastname: O'Malley
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D050071:Bone Density Conservation Agents / Q000627:therapeutic use*; D004164:Diphosphonates / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D055118:Medication Adherence / Q000523:psychology; D008875:Middle Aged; D015663:Osteoporosis, Postmenopausal / Q000188:drug therapy* / Q000523:psychology; D011594:Psychometrics; D015203:Reproducibility of Results; D057566:Self Report; D011795:Surveys and Questionnaires; D016903:Drug Monitoring
chemical_list: D050071:Bone Density Conservation Agents; D004164:Diphosphonates