A new measure to assess asthma's impact on quality of life from the patient's perspective.

BACKGROUND: The Asthma Impact on Quality of Life Scale (A-IQOLS) assesses the negative effect of asthma on quality of life (QoL) from the patient's perspective, using dimensions of Flanagan's Quality of Life Scale (QOLS), a measure of current QoL.

OBJECTIVES: To determine and compare the psychometric properties of the A-IQOLS and QOLS, including their sensitivities to differences and changes in asthma status.

METHODS: In a test-retest design (3-5 week interval), adults with persistent asthma underwent spirometry and were administered the A-IQOLS, other asthma outcome measures (ACT, ASUI, Marks and Juniper AQLQs), and QOLS.

RESULTS: Participants' (n = 147) mean age was 49 yrs.; 76% were White; 12% Hispanic; 65% female. A-IQOLS and QOLS scores were significantly correlated with other asthma outcomes scores except FEV1, but shared relatively low common variance with these measures. A-IQOLS, but not QOLS, score changes were significantly correlated with changes in asthma outcomes. The A-IQOLS SEM = 0.27 implies that a within-person score change of ≥ ±0.73 constitutes a true change. The QOLS SEM = 0.43.

CONCLUSIONS: A-IQOLS provides a reliable, valid, and unique assessment of the patient-perceived negative effect of asthma on their QoL, suitable for use in asthma clinical research and potentially in clinical care. Further studies are needed in diverse patient populations. QOLS, a measure of current QoL, is less sensitive to disease status changes but may be useful in characterizing study populations, in treatment adherence research, and as a clinical and research tool in patients with multiple, severe, and/or life-limiting chronic conditions.