Professionally designed information materials and telephone reminders improved consent response rates: evidence from an RCT nested within a cohort study.
Bottom Line: The primary outcome was return of the consent form ("response"), with consent decision being the secondary outcome.Response rates were 2.7% higher (95% confidence interval: -0.06, 5.5%; P = 0.06) among those receiving designed packs than among those receiving standard packs and 6.4% higher (2.3, 10.6%; P = 0.002) among those receiving phone reminders (compared with postal reminders).The prior-notification postcard did not influence response rates [difference = 0% (-2.8, 2.8%; P = 1.0)], and we found no evidence that the communication method influenced consent decision.
Affiliation: ALSPAC, School of Social and Community Medicine, University of Bristol, Oakfield House, Oakfield Grove, Bristol BS8 2BN, UK. Electronic address: firstname.lastname@example.org.Show MeSH
Mentions: We found no evidence to suggest that the effect of the prior-notification intervention or the information pack intervention differed according to any of the demographic and social factors shown previously to be associated with participation in ALSPAC (see Supplementary Table 3 at www.jclinepi.com). However, there was evidence that the phone reminder had more of an impact on response rates among individuals with lower educational attainment (Fig. 4). We observed an increase in long-term response from those with fewer than 5 A*–C grades of 11.7%, compared with a 3.5% increase in long-term response from those with five or more A*–C grades for phone vs. postcard reminder (P-value for interaction = 0.004). A similar pattern was observed when comparing the impact of the phone reminder among participants living in the most deprived neighborhoods to that among participants living in the least deprived neighborhoods (10.7% difference vs. 6.4% difference, respectively, P-value for interaction = 0.09). However, when we controlled for educational attainment, the interaction effect did not remain (P = 0.2), suggesting these neighborhood differences are explained by educational attainment. There was no evidence that the effect of the reminder intervention varied according to any of the other factors (see Supplementary Table 3 at www.jclinepi.com).
Affiliation: ALSPAC, School of Social and Community Medicine, University of Bristol, Oakfield House, Oakfield Grove, Bristol BS8 2BN, UK. Electronic address: email@example.com.