The effect of home visits as an additional recruitment step on the composition of the final sample: a cross-sectional analysis in two study centers of the German National Cohort (NAKO)

Background Participation in epidemiologic studies has been declining over the last decades. In addition to postal invitations and phone calls, home visits can be conducted to increase participation. The aim of this study was therefore to evaluate the effects of home visits in terms of response increase and composition of the additionally recruited and final sample. Methods In the framework of the German National Cohort (NAKO) recruitment process, two of 18 study centers, Halle (Saale) and Berlin-Center, performed home visits as additional recruitment step after postal invitation and reminders. Response increase was calculated and differences between participants recruited via home visits and standard recruitment were examined. Proportions are presented as percentages with 95%-confidence intervals. Results In the general population in Halle, 21.3-22.8% participated after postal invitation and two reminders in the five assessed recruitment waves. The increase of the overall response was 2.8 percentage points (95%confidence interval: 1.9-4.0) for home visits compared to 2.4 percentage points (95%CI: 1.7-3.3) for alternatively sent third postal reminder. Participants recruited via home visits had similar characteristics to those recruited via standard recruitment. Among persons of Turkish descent in Berlin-Center site of the NAKO, home visits conducted by native speakers increased the participation of women, persons living together with their partner, were born in Turkey, had lower German language skills, lower-income, lower education, were more often smokers and reported more often diabetes and depression to a degree which changed overall estimates for this subsample. Conclusions As an additional recruitment measure in the general population, home visits increased response only marginally, and the through home visits recruited participants did not differ from those already recruited. Among persons with migration background, home visits by a native speaker increased participation of persons not reached by the standard recruitment, but the effects of using a native speaker approach could not be separated from the effect of home visits.

The Cost-Effectiveness Analysis of Cervical Cancer Screening Using a Systematic Invitation System in Lithuania

In Lithuania, cytological screening of cervical cancer (CC) is largely opportunistic. Absence of standardized systematic invitation practice might be the reason for low participation rates. The study aimed to assess the cost-effectiveness of systematic invitation approach in CC screening programme from the perspective of a healthcare provider. A decision tree was used to compare an opportunistic invitation by a family doctor, a personal postal invitation letter with appointment time and place, and a personal postal invitation letter with appointment time and place with one reminder letter. Cost-effectiveness was defined as an incremental cost-effectiveness ratio (ICER) per one additionally screened woman and per one additional abnormal Pap smear test detected. The ICER of one personal postal invitation letter was €9.67 per one additionally screened woman and €55.21 per one additional abnormal Pap smear test detected in comparison with the current screening practice. The ICER of a personal invitation letter with an additional reminder letter compared to one invitation letter was €13.47 and €86.88 respectively. Conclusions: A personal invitation letter approach is more effective in increasing the participation rate in CC screening and the number of detected abnormal Pap smears; however, it incurs additional expenses compared with current invitation practice.

Feasibility of Using Different Approaches for Recruiting Younger Twins to Establish a Population Based Twin Register in Sri Lanka

Identifying twins for a population-based register can be achieved through birth records or community surveys. We studied the feasibility and effectiveness of different methods of identifying and recruiting twins to establish a population based register. To trace twins a population survey was carried out using an interviewer administered questionnaire. We also inspected the birth registration certificates at a divisional secretariat reported from a specified hospital between the years of 1985–1997 and compared it to the birth register of this same hospital. To recruit twins a random sample of 75 twin pairs (150 twins) identified at the Divisional Secretariat were contacted through the post and 25 twin pairs (50 twins) were personally visited. The prevalence of twins was 6.5 twins per 1000 people in the area surveyed. The twinning rate at the hospital was 18.92 twins per 1000 births. A discrepancy of 38 multiples births between the hospital labour room records and those registered at the DS was noted. The response from the postal invitation for recruitment was 59% and the response from the personal invitation was 68%. (Difference 9.4% 95% CI; 7.06–11.73). Community survey and systematic inspection of birth records either at the hospital or the birth registration office was an effective method to trace twins. Once traced, personal contact was more effective than the postal invitation for recruitment of younger twins. A cost-effective approach would be to use a postal coverage followed by personal contact for non-responders. The alternative method, community coverage, would have financial implications.