Agreement found between self-reported and health insurance data on physician visits comparing different recall lengths.
OBJECTIVE
To analyze the impact of different recall lengths on agreement between self-reported physician visits and those documented in health insurance data applying an experimental design.


METHODS
We randomly assigned 432 patients with diabetes to one of two versions of a written survey, each asking about the number of physician visits over a 3- or 6-month recall period. Health insurance data were linked individually.


RESULTS
In both groups, the mean number of self-reported physician visits per month was lower than in the insurance data, with a larger difference in the 6-month group (-0.9; 95% CI -1.0, -0.7) than in the 3-month group (-0.5; -0.7; -0.2), difference between the two groups: 0.4 (0.1-0.7; P = 0.009). The percentage of participants with correct reporting was small and did not differ largely between the two groups (6.5% and 9.3%). However, there was more overreporting in the 3-month group (25.6% vs. 11.1%).


CONCLUSIONS
Shorter recall periods may produce more accurate results when estimating the mean number of physician visits. However, this may be driven not by a more accurate reporting, but by a higher proportion of respondents that overreported and a lower proportion of respondents that underreported, when compared to the longer reporting period.
Institute of Health Services Research and Health Economics, Centre for Health and Society, Faculty of Medicine, Heinrich-Heine University Düsseldorf, Moorenstraβe 5, 40225 Düsseldorf, Germany; Paul Langerhans Group of Health Services Research and Health Economics, German Diabetes Center, Auf'm Hennekamp 65, 40225 Düsseldorf, Germany; German Diabetes Center, Leibniz Institute for Diabetes Research at Heinrich-Heine-University Düsseldorf, Institute of Biometrics and Epidemiology, Auf'm Hennekamp 65, 40225 Düsseldorf, Germany; German Center for Diabetes Research (DZD), Ingolstädter Landstraβe 1, 85764 Neuherberg, Germany. Electronic address: andrea.icks@uni-duesseldorf.de.
Andrea
A
Icks
Institute of Health Services Research and Health Economics, Centre for Health and Society, Faculty of Medicine, Heinrich-Heine University Düsseldorf, Moorenstraβe 5, 40225 Düsseldorf, Germany.
Alexandra
A
Dittrich
Paul Langerhans Group of Health Services Research and Health Economics, German Diabetes Center, Auf'm Hennekamp 65, 40225 Düsseldorf, Germany; German Diabetes Center, Leibniz Institute for Diabetes Research at Heinrich-Heine-University Düsseldorf, Institute of Biometrics and Epidemiology, Auf'm Hennekamp 65, 40225 Düsseldorf, Germany.
Manuela
M
Brüne
German Diabetes Center, Leibniz Institute for Diabetes Research at Heinrich-Heine-University Düsseldorf, Institute of Biometrics and Epidemiology, Auf'm Hennekamp 65, 40225 Düsseldorf, Germany; German Center for Diabetes Research (DZD), Ingolstädter Landstraβe 1, 85764 Neuherberg, Germany; Centre for Health and Society, Faculty of Medicine, Heinrich-Heine-University, Moorenstraβe 5, 40225 Düsseldorf, Germany.
Oliver
O
Kuss
German Diabetes Center, Leibniz Institute for Diabetes Research at Heinrich-Heine-University Düsseldorf, Institute of Biometrics and Epidemiology, Auf'm Hennekamp 65, 40225 Düsseldorf, Germany.
Annika
A
Hoyer
Institute of Health Services Research and Health Economics, Centre for Health and Society, Faculty of Medicine, Heinrich-Heine University Düsseldorf, Moorenstraβe 5, 40225 Düsseldorf, Germany; mediStatistica, Lambertusweg 1, 58809 Neuenrade, Germany.
Burkhard
B
Haastert
Paul Langerhans Group of Health Services Research and Health Economics, German Diabetes Center, Auf'm Hennekamp 65, 40225 Düsseldorf, Germany; German Diabetes Center, Leibniz Institute for Diabetes Research at Heinrich-Heine-University Düsseldorf, Institute of Biometrics and Epidemiology, Auf'm Hennekamp 65, 40225 Düsseldorf, Germany.
Alexander
A
Begun
Institute of Health Services Research and Health Economics, Centre for Health and Society, Faculty of Medicine, Heinrich-Heine University Düsseldorf, Moorenstraβe 5, 40225 Düsseldorf, Germany; Paul Langerhans Group of Health Services Research and Health Economics, German Diabetes Center, Auf'm Hennekamp 65, 40225 Düsseldorf, Germany; German Diabetes Center, Leibniz Institute for Diabetes Research at Heinrich-Heine-University Düsseldorf, Institute of Biometrics and Epidemiology, Auf'm Hennekamp 65, 40225 Düsseldorf, Germany.
Silke
S
Andrich
Paul Langerhans Group of Health Services Research and Health Economics, German Diabetes Center, Auf'm Hennekamp 65, 40225 Düsseldorf, Germany; German Diabetes Center, Leibniz Institute for Diabetes Research at Heinrich-Heine-University Düsseldorf, Institute of Biometrics and Epidemiology, Auf'm Hennekamp 65, 40225 Düsseldorf, Germany.
Jonas
J
Hoffmann
Specialised Diabetes Practice Leverkusen, Kalkstraβe 117, 51377 Leverkusen, Germany.
Matthias
M
Kaltheuner
Institute of Health Services Research and Health Economics, Centre for Health and Society, Faculty of Medicine, Heinrich-Heine University Düsseldorf, Moorenstraβe 5, 40225 Düsseldorf, Germany.
Nadja
N
Chernyak
D003920:Diabetes Mellitus / Q000628:therapy*; D005260:Female; D006801:Humans; D007348:Insurance, Health / Q000706:statistics & numerical data*; D008297:Male; D011939:Mental Recall; D008875:Middle Aged; D009819:Office Visits / Q000706:statistics & numerical data*; D057566:Self Report
Agreement between data sources; Diabetes; Experimental design; Health care use; Physician visits; Recall length