In this issue of Journal of Neuroscience Nursing, the article by de Souza Oliveira-Kumakura et al1 is an excellent example of challenges in using tools to measure outcomes. The purpose of this study was to measure a self-reported measure of adherence and the relation between adherence and warfarin use, demographic and clinical variables, and satisfaction with treatment in patients affected by stroke. Measuring accurately to find outcomes is the backbone of any research study.

In nursing, it is easy to take our measuring tools for granted, such as temperature scanners, blood pressure cuffs, and fingerstick point-of-care testing. What if one day you came to work and discovered the glucometers had stopped measuring glucose but were strangely reporting the hematocrit, and the blood pressure machines were only correct in 1 of 5 tests; otherwise, the measures were worthless? A good nurse would start up the chain of command to central supply while rummaging through other units for working equipment.

Having a tool that accurately captures true negative measures is said to be specific (such as measuring a normal temperature), and if a tool is excellent at capturing a true positive reading, it is sensitive (like measuring a fever). These are concepts we operationalize each day in our practice; we just fail to think about them concretely. However, in research, it is essential to make a statement of specificity and sensitivity when using an instrument.

We have an excellent example of this critical point in the article "Relationship Between Anticoagulant Medications Adherence and Satisfaction in Patients With Stroke."1 Despite the popularity of the non-vitamin K agonist agents, such as dabigatran, apixaban, and rivaroxaban, many patients all over the world still use warfarin for secondary stroke prevention. Most often, the rationale for warfarin is atrial fibrillation, but many other indications exist, so this therapy is not going extinct anytime soon. Preparing nurses to optimize warfarin for patient safety and therapeutic uses remains a priority.

The study used the Measurement of Treatment Adherence (MTA) to measure patient behavior and the Duke Anticoagulation Satisfaction Scale to test patient satisfaction and quality of life.

The results report that the MTA scale, in relation to the international normalized ratio (INR), showed a sensitivity of 77.2%, meaning an almost 23% uncertainty of this relationship, and a specificity of 26.2%,1 meaning if the MTA is scored low, it is not reliable in predicting that the warfarin user is adherent as implied. This dichotomy of results is typical, as tools that have a high sensitivity often have a low specificity. The MTA is thus a good tool to measure adherence to warfarin therapy, which is critical to its therapeutic application of stroke prevention. The results also teased out, that despite high adherence rates in relation to the INR, this factor was not related to patient satisfaction. This finding makes the point that research is also humbling; we often learn things we did not expect.

The role of the nurse in warfarin management cannot be understated, as emphasized in the article. Persons not taking their vitamin K agonist medication create a window for formation of a clot that can lead to a thrombosis event, most often stroke. On the other hand, with any anticoagulant, the risk for bleeding is inherent, so safe use is critically important. The results support that nurses are impactful to adherence to oral anticoagulant therapy and satisfaction in secondary stroke prevention.

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