Author contacts for retrieval of data for a meta-analysis on exercise and diet restriction.
OBJECTIVE
The mode of contact and response levels of authors who had been asked to provide missing or incomplete data for a systematic review on diet and exercise interventions for weight loss was examined.


METHODS
We contacted authors by electronic mail, letter, or both. Survival analyses were performed with the Kaplan-Meier method to determine differences in the proportion of responders over time among the different modes of contact and to determine whether response rates differed between authors from the United States and those from other countries. Logistic regression was used to determine whether the number of items requested and publication date influenced the likelihood of response.


RESULTS
Two hundred forty-one (39.9 percent) studies had missing or incomplete data (e.g., sample size, age, caloric restriction, exercise amount, and so on). We were unable to locate ninety-five authors (39.4 percent). Of the remaining authors, forty-six authors (31.5 percent) responded to information requests. Time to respond differed by contact method (p < .05): e-mail (3 +/- 3 days), letter (27 +/- 30 days), and both (13 +/-12 days). Response rates from U.S. authors did not differ from those of other countries.


CONCLUSIONS
Our study suggests poor success in the acquisition of essential information. Given considerable time and resources, weight loss studies require improved reporting standards to minimize the relatively unsuccessful attempt to contact authors for important and necessary information.
Department of Internal Medicine, University of Kansas School of Medicine, Kansas City, Missouri 66160, USA. cgibson@kumc.edu
Cheryl A
CA
Gibson
Bruce Wayne
BW
Bailey
Michael J
MJ
Carper
James D
JD
Lecheminant
Erik Paul
EP
Kirk
Guoyuan
G
Huang
Katrina Drowatzky
KD
Dubose
Joseph E
JE
Donnelly
D002986:Clinical Trials as Topic / Q000706:statistics & numerical data; D003625:Data Collection / Q000379:methods* / Q000706:statistics & numerical data*; D004032:Diet; D015444:Exercise; D006801:Humans; D015201:Meta-Analysis as Topic