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DOI: 10.1160/TH12-05-0368
Psychometric properties of the 8-item Morisky Medication Adherence Scale in patients taking warfarin
Publikationsverlauf
Received:
31. Mai 2012
Accepted after major revision:
05. Juli 2012
Publikationsdatum:
29. November 2017 (online)
![](https://www.thieme-connect.de/media/10.1055-s-00035024/201204/lookinside/thumbnails/10-1160-th12-05-0368-1.jpg)
Summary
There is no patient-reported medication adherence measure that has been validated in Singapore. This study aimed to validate the 8-item Morisky Medication Adherence Scale (MMAS) in patients taking warfarin in Singapore. A cross-sectional survey was conducted in a convenience sample of 151 patients taking warfarin at an anticoagulation clinic in 2011. Respondents completed the MMAS in English or Chinese depending on their preference. The MMAS had a Cronbach′s alpha of 0.56 and good criterion-related validity as the scale scores were associated with warfarin refill rates (p = 0.04). Respondents with higher MMAS scores were found to have a higher percentage of International Normalised Ratios (INRs) within the therapeutic range (p = 0.01), higher adherence to diet recommendations (p = 0.02), and less perceived difficulty in taking all medications (p < 0.001); they were also more likely to take warfarin at the same time every day (p < 0.001). Confirmatory factor analysis showed that the eight items loaded onto one factor (RMSEA = 0.03). The sensitivity, specificity, positive predictive value and negative predictive value of the MMAS for identifying patients with poor INR control were 73.0%, 35.6%, 49.5% and 60.5%, respectively, using the time in the therapeutic INR range as the gold standard. This study shows that the 8-item MMAS has good validity and moderate reliability in patients taking warfarin. Future research is needed to investigate the scale′s psychometric properties in other patient populations and clinical settings.
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References
- 1 Geerts WH. et al. Prevention of venous thromboembolism: the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy. Chest 2004; 126 (Suppl. 03) 338S-400S.
- 2 Albers GW. et al. Antithrombotic and thrombolytic therapy for ischemic stroke: the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy. Chest 2004; 126 (Suppl. 03) 483S-512S.
- 3 Ansell J. et al. The pharmacology and management of the vitamin K antagonists: the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy. Chest 2004; 126 (Suppl. 03) 204S-233S.
- 4 Baglin T P. et al. Guidelines on oral anticoagulation (warfarin): third edition--2005 update. Br J Haematol 2006; 132: 277-285.
- 5 Wittkowsky AK, Devine EB. Frequency and causes of overanticoagulation and underanticoagulation in patients treated with warfarin. Pharmacotherapy 2004; 24: 1311-1316.
- 6 Waterman AD. et al. Effect of warfarin nonadherence on control of the International Normalized Ratio. Am J Health Syst Pharm 2004; 61: 1258-1264.
- 7 Levine MN. et al. Hemorrhagic complications of anticoagulant treatment: the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy. Chest 2004; 126 (Suppl. 03) 287S-310S.
- 8 Merli GJ, Tzanis G. Warfarin: what are the clinical implications of an out-of-range-therapeutic international normalized ratio?. J Thromb Thrombolysis 2009; 27: 293-299.
- 9 Hylek EM. et al. of intensity of oral anticoagulation on stroke severity and mortality in atrial fibrillation. N Engl J Med 2003; 349: 1019-1026.
- 10 Hixson-Wallace JA. et al. Effect of regimen complexity on patient satisfaction and compliance with warfarin therapy. Clin Appl Thromb Hemost 2001; 07: 33-37.
- 11 Kimmel SE. et al. The influence of patient adherence on anticoagulation control with warfarin: results from the International Normalized Ratio Adherence and Genetics (IN-RANGE) Study. Arch Intern Med 2007; 167: 229-235.
- 12 Rose AJ. et al. Epidemiology of subtherapeutic anticoagulation in the United States. Circ Cardiovasc Qual Outcomes 2009; 02: 591-597.
- 13 Glader EL. et al. Persistent use of secondary preventive drugs declines rapidly during the first 2 years after stroke. Stroke 2010; 41: 397-401.
- 14 Osterberg L, Blaschke T. Adherence to medication. N Engl J Med 2005; 353: 487-497.
- 15 Vermeire E. et al. Patient adherence to treatment: three decades of research. A comprehensive review. J Clin Pharm Ther 2001; 26: 331-342.
- 16 Farmer KC. Methods for measuring and monitoring medication regimen adherence in clinical trials and clinical practice. Clin Ther 1999; 21: 1074-1090.
- 17 Morisky DE. et al. Predictive validity of a medication adherence measure in an outpatient setting. J Clin Hypertens 2008; 10: 348-354.
- 18 Morisky DE. et al. Concurrent and predictive validity of a self-reported measure of medication adherence. Med Care 1986; 24: 67-74.
- 19 Korb-Savoldelli V. et al. Validation of a French Version of the 8-Item Morisky Medication Adherence Scale in Hypertensive Adults. J Clin Hypertens. 2012 in press
- 20 Sakthong P. et al. Psychometric properties of the Thai version of the 8-item Morisky Medication Adherence Scale in patients with type 2 diabetes. Ann Pharmacother 2009; 43: 950-957.
- 21 Al-Qazaz H. et al. The eight-item Morisky Medication Adherence Scale MMAS: translation and validation of the Malaysian version. Diabetes Res Clin Pract 2010; 90: 216-221.
- 22 Ttrindade AJ. et al. Are your patients taking their medicine? Validation of a new adherence scale in patients with inflammatory bowel disease and comparison with physician perception of adherence. Inflamm Bowel Dis 2011; 17: 599-604.
- 23 Reynolds K. et al. Psychometric properties of the osteoporosis-specific morisky medication adherence scale in postmenopausal women with osteoporosis newly treated with bisphosphonates. Ann Pharmacother 2012; 46: 659-670.
- 24 Orensky IA, Holdford DA. Predictors of noncompliance with warfarin therapy in an outpatient anticoagulation clinic. Pharmacotherapy 2005; 25: 1801-1808.
- 25 Cortina JM. What Is Coefficient Alpha? An Examination of Theory and Applications. J Appl Psychol 1993; 78: 98-104.
- 26 Hess LM. et al. Measurement of adherence in pharmacy administrative databases: a proposal for standard definitions and preferred measures. Ann Pharmacother 2006; 40: 1280-1288.
- 27 Brown TA. Confirmatory Factor Analysis for Applied Research. The Guilford Press; New York: 2006
- 28 Streiner DL. Health Measurement Scales: A Practical Guide to Their Development and Use. 3rd ed. Oxford University Press; USA: 2003
- 29 Krousel-Wood M. et al. New medication adherence scale versus pharmacy fill rates in seniors with hypertension. Am J Manag Care 2009; 15: 59-66.
- 30 Natarajan N. et al. Family practice patients' adherence to statin medications. Can Fam Physician 2007; 53: 2144-2145.
- 31 Agh T. et al. Factors associated with medication adherence in patients with chronic obstructive pulmonary disease. Respiration 2011; 82: 328-334.
- 32 Ingersoll KS, Cohen J. The impact of medication regimen factors on adherence to chronic treatment: a review of literature. J Behav Med 2008; 31: 213-224.
- 33 Chiquette E. et al. Comparison of an anticoagulation clinic with usual medical care: anticoagulation control, patient outcomes, and health care costs. Arch Intern Med 1998; 158: 1641-1647.
- 34 Cohen AT. et al. Will a once-weekly anticoagulant for the treatment and secondary prevention of thromboembolism improve adherence?. Thromb Haemost 2009; 101: 422-427.