Design and evaluation of the psychometric properties of a self-questionnaire on patient adherence to wearing elastic compression stockings
Franc¸ois-Andre ´ Allaert, Didier Rastel, Anne Graissaguel, Delphine Sion and Claudine Hamel-Desnos. Phlebology 2018
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Design and evaluation of the psychometric properties of a self-questionnaire on patient adherence to wearing elastic compression stockings
Franc¸ois-Andre ´ Allaert, Didier Rastel, Anne Graissaguel, Delphine Sion and Claudine Hamel-Desnos. Phlebology 2018
Background: Patients’ adherence to elastic compression stockings is difficult to evaluate, and therefore we create a short self-questionnaire and validate its psychometric properties.
Methods: We reduce the questions with Varimed rotation analysis, evaluate its internal consistency using Cronbach’s alpha test and its external validity by comparison to electronic thermic captors. Receiver operating characteristic (ROC) analysis was used to determine a threshold and determine its sensitivity and specificity. Results: The initial questionnaire was reduced from 22 to 5 questions rated from 0 to 4. The internal consistency and its external validity are good, and the ROC analysis shows that values>3 correspond to poor compliance with a sensitivity of 88.1% and a specificity of 63.1%.
Conclusion: The adherence score is valid for the detection of patients poorly compliant to the wearing of elastic compression. Its small number of questions makes it a suitable for a screening in everyday practice.
Main findings
- This clinical trial was intended to produce a short questionnaire of patient adherence to medical compression stockings that could readily be used in day-to-day practice. This was to be done by reducing the number of questions by objective mathematical methods based on an initial questionnaire drawn up by means of Delphi type qualitative interviews. The aim was also to validate the final questionnaire’s psychometric properties against the current gold standard of measuring observance via temperature sensors.
- The adherence questionnaire that was to be shortened was specifically devised beforehand. This qualitative phase was based primarily on Delphi-type interviews to ascertain what adherence to compression stockings was for patients with venous insufficiency and to identify the features to be measured as they were reported in patients’ own words. The questionnaire was put together from interviews of 30 patients in total.
- The qualitative phase of development produced a questionnaire with 22 questions that was used for the clinical trial.
- Wymesure temperature sensors were used to measure whether compression stockings were worn by recording the ambient temperature every 30min. The sensors were sewn into the top edge of the stocking and temperatures higher than 35 C were taken to indicate that the compression stockings in which they were fitted were actually being worn.
- Over the four weeks of the study, all the patients had to wear the compression stockings given to them and for which the protocol measured observance. Each patient was given two pairs of class II Sigvaris stockings, exerting a pressure of 15–20mmHg on the ankle.
- The questionnaire was reduced to 5 questions.
- With just five questions requiring about 1-min at most to answer, this questionnaire can be considered in day-to-day practice, so that it could become not just an instrument of clinical research but a tool of day-to-day clinical evaluation.
- The questionnaire was externally validated against the observance index which was obtained from the results of the sensors.
- The questionnaire was named the Adhesig adherence and it combines the psychometric characteristics required to ensure its validity for identifying patients who adhere poorly to wearing compression stockings. The reduced number of questions and its detection level aimed at sensitivity while providing good specificity make it a suitable tool for such testing in day-to-day practice.
