Validation and psychometric properties of the 8-item Morisky Medication Adherence Scale (MMAS-8) in Type 2 diabetes patients in sub-Saharan Africa.

OBJECTIVES: Research in the field of adherence to medications has not been explored in sub-Saharan Africa. The goal of this manuscript is to (1) validate the use of an adherence tool: a translated 8-item Morisky Medication Adherence Scale (MMAS-8) for Type 2 diabetes and (2) assess association between levels of adherence and psychometric properties. METHODS: 154 Type 2 diabetic patients being chronically treated were surveyed from Togolese Diabetes Association using a demographic survey, 4-item Morisky Medication Adherence Scale (MMAS-4) and MMAS-8 from January to March 2012. RESULTS: Internal reliability for the 8-item scale showed the Cronbach alpha being 0.47. The MMAS-8 and MMAS-4 showed a Pearson's correlation of 0.6851. For known groups validity, the chi-square (χ(2)) tests of proportions showed a significant relationship between blood glucose control and MMAS-8 (χ(2)=12.17; p=0.002). The sensitivity, specificity, positive predictive value and negative predictive value were 75%, 48.39%, 56.76%, and 68.18% respectively. CONCLUSIONS: Psychometric analyses showed that the MMAS-8 was a suitable way of measuring medication adherence in the study population given its low cost, ease of use, and the low income status of the country.

Comparative performance of two methods that assess the quality of international normalized ratio measures.

OBJECTIVES: Two methods, Petersen's error grid analysis and Shermock's method to detect clinically important differences, were recently developed to advance the assessment of analytic performance of point-of-care INR devices. Both methods predict when alternate INR measures lead to different clinical decisions. Our goal was to compare their performance characteristics. DESIGN AND METHODS: Performance characteristics were assessed by comparing the models' predictions to clinical decisions that were directly measured in a previous experiment. RESULTS: Shermock's method (82% of predictions correct) demonstrated superior predictive performance compared with the error grid analysis (75% of predictions correct, p=0.008). Shermock's method was particularly superior at identifying the clinical decisions that actually disagreed (79% for Shermock's method vs. 47% for error grid). Consequently, Shermock's method was superior at identifying a POC device with poor performance (79% accuracy vs. 70%, p=0.006). CONCLUSION: Shermock's method had superior performance characteristics and should be integrated into analytic strategies to assess POC INR devices.