Reliability and validity of an instrument for assessing patients’ perceptions about medications for diabetes: the PAM-D
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To evaluate the reliability and validity of the Perceptions About Medications for Diabetes (PAM-D) instrument.
The item pool was generated from a literature review and 18 focus groups of Type 2 diabetes patients. Surveys were mailed to 1,000 low-income diabetes patients; 362 were returned; 65 of 100 re-test surveys were returned.
This paper uses data from 343 Type 2 respondents. Mean age and age diagnosed were 59 and 48, respectively; 72% female; 52% African American; 51% were taking oral antihyperglycemic agents [OHA] monotherapy, 18% insulin monotherapy, and 28% insulin plus OHA. The initial 66 items were reduced to 37 across nine scales: scheduling flexibility, portability convenience, regimen inconvenience, medication effectiveness, difficulty remembering medications, gastrointestinal, hypoglycemia-related, and weight/edema physical side effects, and emotional side effects. Scale reliabilities ranged from 0.71 to 0.92 (coefficient alpha) and from 0.54 to 0.83 (test–retest coefficient, 37–81-day interval); factor loadings ranged from 0.35 to 0.86 (median, 0.67); significant scale differences across medication groups (insulin, OHA, insulin plus OHA) were consistent with a priori hypotheses.
The PAM-D has substantial reliability and validity in a low-income, inner-city population of Type 2 diabetes patients and may be valuable for understanding multidimensional perceptions driving patients’ treatment preferences.
KeywordsDiabetes Medication perceptions Patient satisfaction Patient-reported outcomes Psychometrics Validation studies
This research was funded with support from Eli Lilly & Company. Dr. Hayes is a full-time employee of and owns stock in Eli Lilly & Company, maker of diabetes treatments. This work was initially led by Dr. McHorney when she was Professor of Medicine at the Indiana University School of Medicine. Dr. McHorney is now a Senior Director in U.S. Outcomes Research, Merck & Company Inc. Dr. McHorney is a full-time employee of and owns stock in Merck & Co., Inc., maker of diabetes treatments. We thank the IU Medical Group (IUMG); ResNet, IUMG’s Primary Care Practice-Based Research Network, their staff for creating our data base and mailing the survey; staff of the Regenstrief Medical Record System; and Jackie Baker for coordinating returned surveys. Portions of this manuscript were presented as posters at the annual meetings of International Society of Quality of Life (2006) and International Diabetes Foundation (2006).
- 2.Rubin, R. R., & Peyrot, M. (2004). Quality of life, treatment satisfaction, and treatment preference associated with use of a pen device delivering a premixed 70/30 insulin aspart suspension (aspart protamine suspension/soluble aspart) versus alternative treatment strategies. Diabetes Care, 27(10), 2495–2497. Erratum in Diabetes Care. 2004 Dec;2427(2412):3032.PubMedCrossRefGoogle Scholar
- 10.Brod, M., Cobden, D., Lammert, M., Bushnell, D., & Raskin, P. (2007). Examining correlates of treatment satisfaction for injectable insulin in Type 2 diabetes: Lessons learned from a clinical trial comparing biphasic and basal analogues. Health and Quality of Life Outcomes, 5, 8.PubMedCrossRefGoogle Scholar
- 16.McHorney, C. A., Hayes, R., Bowman, L., & Myers, J. (2004). Drivers of treatment preference among patients with Type 2 diabetes. Paper presented at: ISPOR ninth annual international meeting, Arlington, VA, USA, May 16–19. Available at http://www.biostat.iupui.edu/Faculty/monahan.aspx.
- 17.Berelson, B. (1954). Content analysis. In G. Lindzey (Ed.), Handbook of social psychology (pp. 488–518). Reading, MA: Addison-Wesley.Google Scholar
- 18.Aday, L. A., & Cornelius, L. J. (2006). Designing and conducting health surveys: A comprehensive guide (3rd ed.). San Francisco: Jossey-Bass.Google Scholar
- 25.Nunnally, J. C., & Bernstein, I. H. (1994). Psychometric theory (3rd ed.). New York: McGraw-Hill.Google Scholar
- 26.Stewart, A. L., & Ware, J. E. (1992). Measuring functioning and well-being: The medical outcomes study approach. Durham, NC: Duke University Press.Google Scholar
- 30.Hayes, C., & Bowman, L. (2003). Reliability and validity of the treatment flexibility scale. Quality of Life Research, 12, 863.Google Scholar
- 34.Howorka, K., Pumprla, J., Wagner-Nosiska, D., Grillmayr, H., Schlusche, C., & Schabmann, A. (2000). Empowering diabetes out-patients with structured education: Short-term and long-term effects of functional insulin treatment on perceived control over diabetes. Journal of Psychosomatic Research, 48(1), 37–44.PubMedCrossRefGoogle Scholar
- 38.Marra, G., & DIAB. & TE.S Project Study Group. (2004). The DIAB. & TE.S Project: How patients perceive diabetes and diabetes therapy. Acta Bio-Medica: Atenei Parmensis, 75(3), 164–170.Google Scholar
- 40.Cowie, C. C., & Eberhardt, M. S. (1995). Sociodemographic characteristics of persons with diabetes. In National Diabetes Data Group, National Institutes of Health, & National Institute of Diabetes and Digestive and Kidney Diseases (Eds.), Diabetes in America (pp. 85–116, 2nd ed.).Google Scholar