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Survey Nonresponse Is Associated with Increased Mortality in Patients with Rheumatoid Arthritis and in a Community Population
MARKKU KAUPPI, TUULIKKI SOKKA, and PEKKA HANNONEN
ABSTRACT.
Methods. A 5-page health questionnaire was administered in 2000. Two years later the vital status of the subjects was ascertained from the Population Registry. Results. A total of 1095 (73%) patients with RA and 1530 (77%) community control subjects returned a completed questionnaire. Over the 2-year period, the number of deaths was 57 (5.2%) in RA responders and 37 (9.3%) in RA nonresponders (p = 0.004). The corresponding figures in community controls were 34 (2.2%) and 23 (4.9%) (p = 0.002). In a Cox regression model adjusted for age and sex, RA patient and community control nonresponders were respectively 1.65 (95% CI 1.07 to 2.55) and 2.89 (95% CI 1.69 to 4.94) times more likely to die over the 2 years compared to the responders. Conclusion. Nonresponders to a mailed health survey were more likely to die over 2 years compared to responders. The possible nonresponse bias should be kept in mind in the interpretation of the results of studies that are based on mail questionnaires only. (J Rheumatol 2005;32:807-10) Key Indexing Terms:
SURVEY RESEARCH
From the Jyväskylä Central Hospital, Jyväskylä, and the Rheumatism Foundation Hospital, Heinola, Finland; and Vanderbilt University Medical School, Nashville, Tennessee, USA. M. Kauppi, MD, PhD, Rheumatism Foundation Hospital; T. Sokka, MD, PhD, Jyväskylä Centrae Hospital and Vanderbilt University School of Medicine; P. Hannonen, MD, PhD, Jyväskylä Central Hospital. Address reprint requests to Dr. T. Sokka, Vanderbilt University School of Medicine, Division of Rheumatology, 203 Oxford House, Nashville, TN 37232-4500, USA. E-mail: tuulikki.sokka@vanderbilt.edu Accepted for publication December 20, 2004. |