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Missing data is common in electronic health records (EHR)-based obesity research. To avoid bias, it is critical to understand mechanisms that underpin missingness. We conducted a survey among bariatric surgery patients in three integrated health systems to (i) investigate predictors of disenrollment and (ii) examine differences in weight between disenrollees and enrollees at 5 years.We identified 2883 patients who had bariatric surgery between 11/2013 and 08/2014. Patients who disenrolled before their 5-year anniversary were invited to participate in a survey to ascertain reasons for disenrollment and current weight. Logistic regression was used to investigate predictors of disenrollment. Five-year percent weight change distributions were estimated using inverse-probability weighting to adjust for (un)availability of EHR weight data at 5 years among enrollees and survey (non-)response among disenrollees.Among 536 disenrolled patients, 104 (19%) completed the survey. Among 2347 patients who maintained enrollment, 384 (16%) had no weight measurement in the EHR near 5 years. Insurance, age, Hispanic ethnicity, and site predicted disenrollment. Disenrollees had slightly greater weight loss than enrollees.We found little evidence of weight loss differences by enrollment status. Collecting information through surveys can be an effective tool to investigate and adjust for missingness in EHR-based studies.

OBJECTIVE: In 2009, the National Children’s Study (NCS) Vanguard Study tested the feasibility of household-based recruitment and participant enrollment by using a birth rate probability sample. In 2010, the NCS Program Office launched 3 alternative recruitment methods. We tested whether direct outreach (DO) recruitment could be a more efficient strategy to recruit women of child-bearing age. METHODS: The NCS DO recruitment approach recruited women, 18 to 49 years, who were pregnant or trying to conceive using passive recruitment methods emphasizing broad community outreach and engagement to create study awareness. Study mailings to listed households included a pregnancy screening questionnaire to identify potentially eligible women from selected neighborhoods to contact the study center. Unique features of this recruitment approach included the following: (1) expansion of selected neighborhoods to maximize potential participant recruitment and enrollment while minimizing in-person participant contact and (2) offering 2 levels of study participation distinguished by data collection intensity. RESULTS: Ten study centers listed 255 475 geographically eligible households for contact representing, on average, 3.3% of households per Primary Sampling Unit. A total of 19 354 women were identified for screening, and 17 421 completed a pregnancy screener representing 6.8% of eligible households. Study-eligible pregnant women were older, more educated, and less likely to be Hispanic than the general population. Only 16% (2786) of 17 421 screened women were study-eligible, and 81.1% of these 2786 women consented to participate. CONCLUSIONS: Although feasible, the DO approach recruited a sample of study-eligible pregnant women significantly different from the population. This recruitment approach was labor intensive for the yield of enrolled women.

OBJECTIVE: Few studies have reported the outcome of direct outreach methods for recruitment of research participants in population-based samples. We describe the relationship of outreach strategies that are tailored to specific community factors to recruitment and consent outcomes in 10 National Children’s Study direct outreach study locations (all were single counties). METHODS: Each study center collected data from a target population of women who resided in selected county segments that were sampled based on a geographic area probability sampling design. Based on county characteristics of the 10 study locations, each study center used site-specific marketing approaches (direct mail, mass media, provider referrals, social networking) to recruit study participants. Recruitment success was measured by the number of recruited women as well as by a qualitative assessment of the effectiveness of various recruitment methods. RESULTS: The number of women who consented varied from 67 to 792. The majority of women were pregnant at the time of consent. Community awareness varied from CONCLUSIONS: In a small sample of 10 US counties, recruitment success was not associated with community characteristics. It was, however, associated with certain types of outreach strategies that may be more effective in close-knit communities.