Retaining Participants in Community-Based Health Research: A Case Example on Standardized Planning and Reporting

Background Effective strategies for participant retention are critical in health research to ensure validity, generalizability and efficient use of resources. Yet standardized guidelines for planning and reporting on retention efforts have been lacking. As with randomized controlled trial (RCT) and systematic review (SR) protocols, retention protocols are an opportunity to improve transparency and rigor. An RCT being conducted in British Columbia (BC), Canada provides a case example for developing a priori retention frameworks for use in protocol planning and reporting. Methods The BC Healthy Connections Project RCT is examining the effectiveness of a nurse home-visiting program in improving child and maternal outcomes compared with existing services. Participants (N = 739) were girls and young women preparing to parent for the first time and experiencing socioeconomic disadvantage. Quantitative data were collected upon trial entry during pregnancy and during five follow-up interviews until participants’ children reached age 2 years. A framework was developed to guide retention of this study population throughout the RCT. We reviewed relevant literature and mapped essential retention activities across the study planning, recruitment and maintenance phases. Interview completion rates were tracked. Results Results from 3302 follow-up interviews (in-person/telephone) conducted over 4 years indicate high completion rates: 90% (n = 667) at 34 weeks gestation; and 91% (n = 676), 85% (n = 626), 80% (n = 594) and 83% (n = 613) at 2, 10, 18 and 24 months postpartum, respectively. Almost all participants (99%, n = 732) provided ongoing consent to access administrative health data. These results provide preliminary data on the success of the framework. Conclusions Our retention results are encouraging given that participants were experiencing considerable socioeconomic disadvantage. Standardized retention planning and reporting may therefore be feasible for health research in general, using the framework we have developed. Use of standardized retention protocols should be encouraged in research to promote consistency across diverse studies, as now happens with RCT and SR protocols. Beyond this, successful retention approaches may help inform health policy-makers and practitioners who also need to better reach, engage and retain underserved populations

Upregulation of swelling-activated Cl− channel sensitivity to cell volume by activation of EGF receptors in murine mammary cells

Whole-cell recordings showed that, in mouse mammary C127 cells transfected with the full genome of the bovine papilloma virus (BPV), a hypotonic challenge induced the activation of outwardly rectifying Cl− currents with a peak amplitude 2.7 times greater than that in control C127 cells. Cell-attached single-channel recordings showed that BPV-induced augmentation of the peak amplitude of the whole-cell current could not chiefly be explained by a small increase (1.2 times) in unitary conductance. There was no difference between control and BPV-transfected cells in the osmotic cell swelling rate, and hence, osmotic water permeability. However, a plot of the whole-cell current density as a function of cell volume, which was measured simultaneously, showed that the BPV-transfected cells had a strikingly greater volume sensitivity than control cells. Since the E5 protein of BPV has been reported to induce constitutive activation of the epidermal growth factor (EGF) receptor and platelet-derived growth factor (PDGF) receptor in a variety of cell lines including C127 cells, effects of the growth factors on volume-sensitive outwardly rectifying (VSOR) Cl− currents were examined in C127 cells. Application of PDGF peptides failed to affect the Cl− currents in control and BPV-transfected cells, although C127 cells are known to endogenously express PDGF receptors. In contrast, EGF peptides significantly increased the VSOR Cl− current in control cells. However, they failed to induce further augmentation of the current in BPV-transfected cells. VSOR Cl− currents were inhibited by tyrphostin B46, an inhibitor of the EGF receptor tyrosine kinase, in both control and BPV-transfected cells. The IC50 value in BPV-transfected cells (12 μm) was lower than that in control cells (31 μm). However, the VSOR Cl− currents in both cell types were insensitive to tyrphostin AG1296, an inhibitor of the PDGF receptor tyrosine kinase. The rate of regulatory volume decrease (RVD) was markedly diminished by tyrphostin B46 but not significantly affected by tyrphostin AG1296. We thus conclude that the EGF receptor tyrosine kinase upregulates the activity of the VSOR Cl− channel, mainly by enhancing the volume sensitivity