Bias in Assessment of Health-Related Quality of Life in a Hemodialysis Population: A Comparison of Self-Administered and Interviewer-Administered Surveys in the HEMO Study MARK UNRUH,* GUOFEN YAN, † MILENA RADEVA, † RON D. HAYS, ‡ ROBERT BENZ, § NICOLAOS V. ATHIENITES,  JOHN KUSEK, ¶ ANDREW S. LEVEY,  KLEMENS B. MEYER,  and THE HEMO STUDY GROUP *University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania; † Cleveland Clinic Data Coordinating Center, Cleveland, Ohio; ‡ Department of Health Services, University of California Los Angeles, Los Angeles, California; § Lankenau Hospital, Wynnewood, Pennsylvania;  New England Medical Center, Boston, Massacusetts; ¶ Division of Kidney, Urologic, and Hematologic Disease, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland Abstract. Examined is the relationship of patient-reported health-related quality of life (HRQOL) to the mode of survey administration in the Hemodialysis Study. In addition to self- administered surveys to assess HRQOL, interviewer-adminis- tered surveys were made available to include patients with poor vision, decreased manual dexterity, or strong preference. For examining the predictors of participation by self-administration of the survey, multiple logistic regression was performed. For examining the relationship of HRQOL results to mode of survey administration, adjusted differences between the self- administered and interviewer-administered groups were ob- tained from multiple linear regression models accounting for sociodemographic and case-mix factors. A total of 978 of the first 1000 subjects in the Hemodialysis Study completed the survey by interview (n = 427) or by self-administration (n = 551). The interviewer-administered group was older, was more likely black, had longer duration of ESRD, had a higher prev- alence of diabetes, and had more severe comorbidity (all P  0.01). After adjustment for these differences, patients in the interviewer-administered group had higher scores on scales that measured Role-Physical, Role-Emotional, and Effects of Kidney Disease (all P  0.001). Dialysis studies that restrict HRQOL measurement to patients who are able to complete surveys without assistance will not accurately represent the health of the overall hemodialysis population. Clinical studies and clinical practices using HRQOL as an outcome should include interviewer administration or risk a selection bias against subjects with older age, minority status, and higher level of comorbidity. Future investigation should include re- search of survey modalities with a low response burden such as telephone interview, computer-assisted interview, and proxy administration. Patient reports of health-related quality of life (HRQOL) are recognized as providing important information about the impact of ESRD and its treatment on daily life (1– 6). HRQOL question- naires are used increasingly in studies of ESRD patients (7) and by dialysis providers (8,9). HRQOL surveys may be used in clinical care to screen for potential problems, to prioritize problems, to facilitate communication between health care workers and pa- tients, and to monitor response to treatment (10,11). However, there is little guidance about how best to gather HRQOL infor- mation from patients with kidney failure. HRQOL surveys may be self-administered, but other alter- natives, such as interviewer administration of surveys, may be particularly important in the ESRD population, because many of these patients are advanced in age and have comorbid conditions that preclude traditional questionnaire self-admin- istration. It is precisely these older and sicker patients for whom HRQOL measures may be most needed (12). Although HRQOL assessment has become a commonly reported out- come in ESRD, we are unaware of previous studies examining the influence of mode of survey administration on survey results among this aged and chronically ill population. There- fore, we examined HRQOL results from both interviewer- administered and self-administered questionnaires in the Na- tional Institute of Diabetes and Digestive and Kidney Diseases Hemodialysis (HEMO) Study, a randomized clinical trial of the effects of hemodialysis dose and membrane flux. The HEMO Study offered interviewer-administered surveys as an alternative to self-administration for patients who were physi- cally impaired or who expressed a strong preference for inter- viewer administration. First, we assessed the demographic and clinical predictors of participating by self-administered ques- tionnaire. Second, we examined the extent to which scale scores were related to the mode of survey administration. Received September 10, 2002. Accepted April 22, 2003. Correspondence to Dr. Mark Unruh, University of Pittsburgh Medical Center, A909 Scaife Hall, Pittsburgh, PA 15231. Phone: 412-647-2561; Fax: 412-647- 6891; E-mail: unruhm@msx.dept-med.pitt.edu 1046-6673/1408-2132 Journal of the American Society of Nephrology Copyright © 2003 by the American Society of Nephrology DOI: 10.1097/01.ASN.0000076076.88336.B1 J Am Soc Nephrol 14: 2132–2141, 2003