Development of the asthma treatment satisfaction measure

Study aims were to develop and assess the measurement properties of a four-part treatment satisfaction measure for patients with asthma. The Asthma Treatment Satisfaction Measure (ATSM) incorporates specific attributes representing patient expectations, treatment preferences, self-reported treatment outcomes, and overall treatment satisfaction. This paper describes patients' ability to detect change in their satisfaction with asthma therapies using the ATSM.

Adult patients with chronic asthma requiring a change in their asthma controller medications were recruited from sites in the US and Canada. Interviews were conducted with 22 patients to elicit areas important to patients in asthma treatment for measurement of satisfaction, providing the basis for the four-part questionnaire that was then tested for clarity. An additional 105 patients participated in the validation study and completed the first two parts of the ATSM (expectations and importance of treatment) at their initial visit (baseline) prior to a change in treatment. Parts 3 and 4 (treatment outcomes and treatment satisfaction) were completed after 4 weeks on the new treatment. A daily diary was completed by patients at home between visits. During clinical visits, patients also completed the Asthma Specific Quality of Life Questionnaire Standardized version assessing HRQL (AQLQ(S)), the Asthma Control Questionnaire 6-item version (ACQ-6), a 9-item asthma symptom checklist, items assessing symptom severity, and a single item overall rating of satisfaction (numerical analog scale between 0 and 10). Derived total satisfaction scores were compared to scores produced by the single global treatment satisfaction item using score variation and distribution plots.

Qualitative results identified 11 key attributes of asthma treatment. Internal consistency for the expectations, outcomes, and satisfaction parts of the measures (11 items each) were 0.73, 0.82 and 0.95, respectively. ATSM scores were able to discriminate between control and lack of control measured by ACQ-6 scores (F = 30.09; p < 0.001); between improvement, no change, or worsening of symptoms using the 4-week diary (F = 7.05; p < 0.001); between mild, moderate and severe levels of self-reported severity of asthma (F = 2.07; p < 0.001); and levels of self-reported health status (F = 5.96; p < 0.001). Compared to the single overall satisfaction item, the ATSM satisfaction score demonstrated a broader and more normal distribution. Irrespective of the variety of treatment regimens being changed from and changed to in the normal care setting, 4 of the 11 attributes still detected statistically significant differences in (p < 0.05) levels of patient satisfaction related to their new asthma treatment regimen.

By augmenting a satisfaction rating with the constructs that help define satisfaction with treatment (expectation, importance and actual treatment experience), the ATSM scores demonstrated greater ability to detect changes in treatment and provide a potentially useful measurement system for pharmacologic evaluation. This study was conducted using a normal care setting to identify patients undergoing a change in treatment. Therefore, the main limitations were the inability to control for efficacy of treatment, and a relatively small sample. Several individual ATSM satisfaction scores were able to detect significant levels of patient satisfaction related to their treatment, while the global satisfaction scores were unable to detect any significant differences.