Original Research

Recruiting for a randomized controlled trial from an ethnically diverse population: Lessons from the Maternal Infection and Preterm Labor Study

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OBJECTIVES: To compare recruitment rates for Caucasians and minorities in a randomized, controlled trial based in a family practice residency clinic.

STUDY DESIGN: A retrospective chart review of all patients eligible for the Maternal Infection and Preterm Labor (MIPTL) study.

POPULATION: All prenatal patients at 1 clinic site presenting for care at earlier than 34 weeks’ gestation.

OUTCOMES MEASURED: Patients choosing to enroll in the MIPTL study (n = 70) were compared with those who did not (n = 210) on a variety of demographic variables, including self-reported ethnicity, ability to speak English, and socioeconomic factors.

RESULTS: African American patients were recruited at the same rate as Caucasians (28% of each eligible population). Immigrants and patients requiring a translator were less likely to enroll (P = .014 and .008, respectively).

CONCLUSIONS: Clinic-based research studies in a family practice residency program can successfully recruit African American patients. Immigration status and the ability to speak English were important factors that affected participation. More research is needed to understand the role of clinic-based research in the recruitment of minorities for clinical trials.

The national research agenda encourages recruitment of minority populations, yet they are underrepresented in most clinical trials.1,2 Minority populations need to be included in research for several reasons. Minority populations may have a disproportionate disease burden, such as certain cancer rates among black persons.3 Minority populations may have different responses to medications, such as with antihypertensive medications in the African American population. Lastly, clinical trials can offer state-of-the-art care, which should be freely available to minorities. The National Institutes of Health Revitalization Act of 1993 requires all investigators receiving National Institutes of Health funding to include minority subjects.4

Most literature on minority recruitment focuses on African American subjects’ participation in clinical research.1,5-9 Information about other ethnic groups’ participation in clinical trials,9-11 particularly those involving non-English-speaking participants,12 is more limited. No data have been systematically compiled to evaluate the effectiveness of minority recruitment in a clinic-based research study.

This study used the data set from a primary care, clinic-based, randomized controlled trial, the Maternal Infection and Preterm Labor Study (MIPTLS).13 We examined rates of recruitment for different ethnicities, for immigrants, and for non-English-speaking patients in a trial that had no specific plan for minority recruitment.


We conducted a retrospective chart review of all pregnant women presenting for prenatal care at Smiley’s Clinic from September 1996 through December 1997 during the time of the MIPTLS. This study was a multisite investigation of the effect of vaginal pH testing on early detection and treatment of bacterial vaginosis in pregnant women and subsequent maternal and infant outcomes.13 Smiley’s Clinic is a community-based family practice residency clinic in Minneapolis, which serves a diverse, low-to middle-income population. Sixty percent of prenatal patients seek care in the main clinic and see the same provider throughout their pregnancy. Smiley’s Clinic also operates a medically indigent prenatal clinic called “Birthpartners” that is staffed by a full-time registered nurse and rotating faculty and residents. Forty percent of prenatal patients seek care at Birthpartners; they do not see the same provider throughout their pregnancy.

All women presenting for prenatal care at less than 34 weeks’ gestation were eligible for the MIPTL study. All women presenting for care were asked to participate in the study by the certified medical assistant, registered nurse, and/or their physician. The patient’s own physician, registered nurse, or certified medical assistant obtained informed consent for all patients to be studied, and a physician collected the data from the patient at each subsequent prenatal visit. For this chart review, we divided this population of women into those who enrolled in the trial and those who did not enroll.

Data abstracted from the medical record included age, ethnicity, parity, history of previous pregnancy complications, and history of sexually transmitted disease. Ethnicity data were based on self-report and abstracted from 1 of 2 standard locations in the chart-a patient demographics form and prenatal database. “African” patients denoted either their native country or Africa on their database; “African American” patients’ self-reported their ethnicity as well. For the purpose of this study, Native American and biracial women were categorized as “Other.” Women who did not have ethnicity data in either location were not assigned an ethnicity.

We analyzed the data using SPSS software (SPSS Inc, Chicago, IL); t tests were used for continuous data and chi-square tests for categorical data, with a 2-sided P < .05 as significant. The Institutional Review Board of the University of Minnesota approved this study.


During the study period, 310 women presented for prenatal care to Smiley’s Clinic before 34 weeks’ gestation and were thus eligible for the MIPTL trial and our chart review. Seventy-one subjects chose to enroll in the trial, leaving 239 who refused. We could not locate 1 chart; the data set thus included 70 patients enrolled in the MIPTL study and 239 patients not enrolled (309 total charts reviewed). Complete data were available for most subjects; 297 charts had complete ethnicity data, 273 charts had complete data on education level, and 291 charts reported need for a translator (96%, 88%, and 94% complete, respectively). In all other areas, data collection was complete.

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