To determine the agreement and bias of proxy responses to the Quality of Well-Being Scale [QWB] by husbands or partners of women with the Fibromyalgia syndrome.
Methods: Proxies and patient couples [N = 43] were interviewed to determine the agreement and bias of their proxy responses to the QWB and to identify proxy and patient characteristics that affect the bias and agreement between their responses.
Results: Intraclass correlation coefficients and t-tests indicated that there was moderate agreement between the patient and proxy responses overall with poor agreement on the symptoms subscale and good agreement on the social activity, mobility, and physical functioning subscales. Systematic bias was not observed for the measure overall, nor for any of the subscales. Proxies who overestimated the patient's health status did not differ from those who underestimated on demographic or health status variables. A scatter plot of the difference between patient and proxy scores for the overall QWB plotted against the average QWB score for each pair suggested that agreement was best when the health status of the patient was low.
Conclusions: These findings suggest that the spouses of patients with the Fibromyalgia syndrome may be reliable proxies for the measuring of overall QWB. Proxy responses may be most accurate for patients' whose health is poorest. It is in these cases that proxy reporting is most needed.
Source: Journal of Musculoskeltal Pain. 2007, Vol. 15 #3, pp. 9–17. DOI: 10.1300/J094v15n03_03, by Bigatti SM, Cronan TA, Frederick H, Kaplan RM.