Response to the Commentary by Furlong & Barr on Cox CL, Lensing S, Rai SN et al.

The commentary by Furlong and Barr [1] suc cinctly, and we believe, accurately addresses the issues that can arise when a proxy respondent (a) does not have regular opportunity to interact with the child or adolescent for whom the proxy is estimating health-related quality of life (HRQoL) or functional status, or (b) is limited by study de sign to rely upon his/her clinical assessment as the basis of completing the proxy assessment rather than directly posing the items to the child or adolescent whose HRQoL is being rated. We concur with their conclusion that the previously established measurement and psychometric prop erties of the HUI3 could be threatened when completed by a proxy who has insufficient opportunity or is constrained by a research design to assess the patient who is the focus of the assessment. But opportunity to develop and validate clinical impressions may not be the most serious challenge to nurse proxies using the HUI3 to rate HRQoL or functional status of p?diatrie oncology patients to determine the impact of treatment. Furlong and Barr [1] correctly point out that the regularity of the nurse proxy interaction with the patient was not reported in the paper by Cox et al [2]. More than 70% of the HUB reports were completed by primary clinic nurses who saw their patients at least weekly during the first two measurement points and in the majority of cases, more often than once weekly. The interactions were clinic-based and thus did not provide opportunities for first-hand observation of behaviors needed to respond to certain items of the HUI3 such as the ability of a child to read a newspaper with or without glasses. But the clinic visits do include a nursing assessment that is focused on the impact of treatment on the child's overall quality of life and ability to achieve age-specific developmental milestones. The assess ment includes questions about the child's experi ence with adverse effects of treatment, ability to interact with others and participate in age-relevant activities, and the child's ability to learn new tasks or behaviors. These questions reflect the consensus by the p?diatrie oncology nurses about what con stitutes important clinical alerts related to the pa tient's quality of life and functional status during treatment and are reflective of items in other HRQoL instruments and assessments developed with input from p?diatrie oncology patients, their parents and health care providers [3-5]. Although Furlong and Barr's questioning of the nurses' understanding of the mathematical scoring system underlying the HUI3 may be quite well-founded, the lack of understanding does not explain or ad dress the nurses' concerns that several items of the HUI3 do not seem to be particularly relevant indicators of p?diatrie quality of life or functional status. The HUI3 and its predecessor instruments were impressively developed using a representative sample (though primarily comprised of adults) but that sample may not reflect what is uniquely important to a subset of individuals, in this case of nurse proxies reporting on the HRQoL for p?di atrie oncology patients. We share the concern of Furlong and Barr [1] about the high rate of missing values in the nurses' reports. Important to note is that the primary