The impact of non-responders on health and lifestyle outcomes in an intervention study

BMC Research Notes

Jørgen Lous⁴  Kirsten S Freund²  Kirsten Fonager³  Elsebeth Hansen¹ 

[1] Department of Social Medicine, Aalborg University Hospital, Havrevangen 1, DK-9000 Aalborg, Denmark;General Practice, DK-9362 Gandrup, Denmark;Department of Health Science and Technology, Faculty of Medicine, Alborg University, DK-9000 Aalborg, Denmark;Research Unit for General Practice, Institute of Public Health, University of Southern Denmark, DK-5000 Odense C, Denmark

关键词: Telephone reminder;    Response bias;    Primary care;    Non-response;    Health interview survey;   

Others  :  1129638
DOI  :  10.1186/1756-0500-7-632

 received in 2014-04-10, accepted in 2014-09-04,  发布年份 2014

【 摘 要 】

Background

A randomized intervention study, “Preventive consultations for 20- to 40-year-old young adults”, investigated whether preventive consultations with a general practitioner could help young adults with multiple psychosocial and lifestyle problems to change health behavior. To optimize the response rate of questionnaires at 1 year post-intervention, the non-responders were reminded by telephone. The aim of this study was to examine potential selection bias induced by non-response by comparing responder and non-responder populations at baseline, and to examine the impact on outcomes by comparing initial respondents to respondents after telephone reminding.

Method

Non-responders were compared with primary responders using logistic regression models that included socio-demographic factors, health-related factors, and variables related to the intervention study. In order to describe the impact of including responders after telephone reminding on the intervention’s effect on different health, resource, and lifestyle outcomes, we compared results in models including and excluding responders after telephone reminding.

Results

Telephone contact raised the response by 10% from 316 (64%) to 364 (74%) among young adults with multiple problems. Being male was the only factor that significantly predicted non-response in the model after adjustment for other variables. The responders after telephone reminding tended to improve health and lifestyle more than the primary responders, but not significantly so. Although the additional responses did not change the estimates of the 1-year effect on health and lifestyle changes, it contributed to increased precision of the results.

Conclusion

Even though the population of primary non-responders had to some degree a different composition than the primary responders, inclusion of responders after telephone reminding did not significantly change the estimates for effect at the 1-year follow-up; however, the additional responses increased the precision of the estimates.

Trial registration

ClinicalTrials.gov: NCT01231256

【 授权许可】

   
2014 Hansen et al.; licensee BioMed Central Ltd.

【 图 表 】

Figure 1.

【 参考文献 】

• [1]Edwards P, Roberts I, Clarke M, DiGuiseppi C, Pratab S, Wentz R, Kwan I, Cooper R: Increasing response rates to postal questionnaires: systematic review. BMJ 2002, 324:1-9.
• [2]White E, Carney PA, Kolar AS: Increasing response to mailed questionnaires by including a pencil/pen. Am J Epidemiol 2005, 162(3):261-266.
• [3]Etter JF, Cucherat M, Perneger TV: Questionnaire color and response rates to mailed surveys. A randomized trial and a meta-analysis. Eval Health Prof 2002, 2:185-199.
• [4]Edwards P, Roberts I, Sandercock P, Frost C: Follow–up by mail in clinical trials: does questionnaire length matter? Control Clin Trials 2004, 25:31-52.
• [5]Wensing M, Schattenberg G: Initial non responders had an increased response rate after repeated questionnaire mailings. J Clin Epidemiol 2005, 58:959-961.
• [6]Nakash R, Hutton J, Jørstad-Stein E, Gates S, Lamb S: Maximizing response to postal questionnaires – A systematic review of randomized trials in health research. BMC Med Res Method 2006, 6:5. BioMed Central Full Text
• [7]Roberts L, Wilson S, Roalfe A, Bridge P: A randomized controlled trial to determine the effect on response of including a lottery incentive in health surveys. BMC Health Serv Res 2004, 4:30. BioMed Central Full Text
• [8]Christensen A, Ekholm O, Kristensen PL, Larsen FB, Vinding AL, Glümer C, Juel K: The effect of multiple reminders on response patterns in a Danish health survey. Eur J Public Health 2014, 22:1. AdvanceAccess published May
• [9]Perneger V, Chamot E, Bovier P: Nonresponse Bias in a Survey of Patient Perceptions of Hospital Care. Med Care 2005, 43:374.
• [10]Mealing N, Banks E, Jorm LR, Steel DG, Clements MS, Rogers KD: Investigation of relative risk estimates from studies of the same population with contrasting response rates and designs. BMC Med Res Methodol 2010, 10:26. BioMed Central Full Text
• [11]Brøgger J, Bakke P, GE E, Gulsvik A: Contribution of follow-up of nonresponders to prevalence and risk estimates: a Norwegian respiratory health survey. Am J Epid 2003, 157:558.
• [12]Freund KS, Lous J: Potentielt marginaliserede 20-44-årige i almen praksis. Hvem er de? Resultater af en spørgeskemascreening [Potentially marginalized 20-44-years-olds in general practice. Who are they? The results from a screening questionnaire]. English summary. Ugeskr Laeger 2002, 164:5367-5372.
• [13]Freund KS, Lous J: The effect of preventive consultations on young adults with psychosocial problems: a randomized trial. Health Educ Res 2012, 27:927-945.
• [14]Ronckers C, Land C, Hayes R, Verduijn P, van Leeuwen F: Factors impacting questionnaire response in a Dutch retrospective cohort study. Ann Epimiol 2004, 14:66-72.
• [15]Tai S, Nazareth I, Haines A, Jowett C: A randomized trial of impact of telephone and recorded delivery reminders on the response rate to research questionnaires. J Public Health Med 1997, 19:219-221.
• [16]Hollnagel H, Sælan H, Garde K, Larsen S: Concept of representativity in epidemiological surveys. Examples from the population study of 40 years olds in Glostrup area, Denmark. Ugeskr Laeger 1981, 143:1781-1788.
• [17]Paganini-Hill A, Hsu G, Chao A, Ross RK: Comparison of early and late respondents to a postal health survey questionnaire. Epidemiology 1993, 4:375-379.
• [18]May A, Adema LE, Romaguera D, Vergnaud AC, Agudo A, Ekelund U, Steffen A, Orfanos P, Slimani N, Rinaldi S, Mouw T, Rohrmann S, Hermann S, Boeing H, Bergmann MM, Jakobsen MU, Overvad K, Wareham NJ, Gonzalez C, Tjonneland A, Halkjaer J, Key TJ, Spencer EA, Hellstrom V, Manjer J, Hedblad B, Lund E, Braaten T, Clavel-Chapelon F, Boutron-Ruault MC, et al.: Determinants of non-response to second assessment of lifestyle factors and body weight in the EPIC-PANACEA study. BMC Med Res Methodol 2012, 12:148. BioMed Central Full Text
• [19]Etter JF, Perneger TV: Analysis of non-response bias in a mailed health survey. J Clin Epidmiol 1997, 50:1123-1128.
• [20]Pirzada A, Yan LL, Garside D, Schiffer L, Dyer AR, Daviglus ML: Response rates to a questionnaire 26 years after baseline examination with minimal interim participant contact and baseline differences between respondents and nonrespondents. Am J Epidemiol 2004, 159:94-101.
• [21]Eaker S, Bergstrøm R, Bergsstrøm A, Adami HO, Nyren O: Response rate to mailed epidemiologic questionnaires: a population-based randomized trial of variations in design and mailing routines. Am J Epid 1998, 147:74-82.
• [22]Jensen L, Pedersen AF, Andersen B, Vedsted P: Identifying specific non-attending groups in breast cancer screening – a population-based study of participation and socio-demography. BMC Cancer 2012, 12:518. BioMed Central Full Text
• [23]Akker B, Buntinx F, Metsemakers JF, Knotterus JA: Morbidity in responders and non-responders in a register-based population survey. Fam Pract 1998, 15:261-263.
• [24]Kjøller M, Thoning H: Characteristics of non-response in the Danish Health Interview Surveys, 1987–1994. Eur J Public Health 2005, 15:528-537.
• [25]Davidsen M, Kjøller M, Helweg-Larsen K: The Danish National Cohort Study (DANCOS). Scand J Public Health 2011, 39:131-135.
• [26]Peat G, Thomas E, Handy J, Wood L, Dziedzic K, Myers H, Wilkie R, Duncan R, Hay E, Hill J, Lacey R, Handy J, Wood L, Dziedzic K, Myers H, Wilkie R, Duncan R, Hay E, Hill J, Lacey R, Croft P: The Knee Clinical assessment Study – CAS(K). A prospective study of knee pain and knee osteoarthritis in the general population: baseline recruitment and retention at 18 month. BMC Musculoskelet Disord 2006, 7:30. BioMed Central Full Text
• [27]Littman A, Boyko E, Jacobsen IG, Horton J, Gackstetter GD, Smith B, Hooper T, Wells TS, Amoroso PJ, Smith TC: Assessing non response bias at follow-up in a large prospective cohort of relatively young and mobile military service members. BMC Med Res Methodol 2010, 10:99. BioMed Central Full Text
• [28]Galea S, Tracy M: Participation rates in epidemiologic studies. Ann Epidemiol 2007, 15:643-653.