Recruitment in randomized clinical trials: The MeMeMe experience

Introduction

Recruitment is essential for the success of clinical trials. We are conducting a randomized clinical trial to test the effect of a Mediterranean dietary intervention with or without 1700 mg/day of metformin for the prevention of age-related chronic diseases, the MeMeMe trial (Trial registration number: EudraCT number: 2012-005427-32 ClinicalTrials.gov ID: NCT02960711). MeMeMe recruiting experience, highlighting strengths, limitations encountered and results is reported.

Patients and methods

Statistical analysis focused on the reasons for withdrawal according to the recruitment method (“active” versus “passive” criterion) and the time of withdrawal. Logistic regression models were used to explore the associations between the risk of withdrawal and sex, recruitment method, randomization arm, and with markers of compliance to the intervention, such as one-year change in body weight.

Results

Out of 2035 volunteers, 660 (32.4%) were recruited “actively” and 1375 (67.6%) “passively”. Among people who dropped out of the trial after randomization, there were 19.5% for the “active” and 22.0% for the “passive” method (p = 0.28). The risk of withdrawal was significantly higher in women (OR:1.91; 95% CI:1.17–3.12; p = 0.01), in volunteers older at recruitment (OR:1.25; 95% CI:1.07–1.45; p = 0.004), and in those with a higher BMI at baseline (OR:1.23; 95% CI:1.07–1.43; p = 0.004). Volunteers who lost at least 2 kg (the median weight change) in the first year of intervention were significantly less (53%) likely to withdraw from the trial (OR:0.48; 95% CI:0.30–0.75; p = 0.001).

Conclusion

Our findings suggest that the “passive” recruitment method was more effective than the “active” one to advance recruitment. The benefits of “passive” recruitment hardly outweighed the drawbacks.

Trial registration

Trial registration number: EudraCT number: 2012-005427-32. ClinicalTrials.gov ID: NCT02960711.

Plasma Testosterone and Prognosis of Postmenopausal Breast Cancer Patients

Purpose

High endogenous testosterone is associated with increased breast cancer (BC) risk. We designed this study specifically to assess the long-term prognostic role of testosterone in a cohort of postmenopausal BC patients.

Patients and Methods

We considered 194 postmenopausal women, operated on for early BC (T1-2N0M0), who never received chemotherapy or hormonal therapy, and who participated in a fenretinide BC prevention trial as untreated controls. Blood samples were collected 3 months (median) after surgery; plasma samples, stored at −80°C, were radioimmunoassayed for testosterone. Median follow-up was 14 years. The main end point was any cancer event. Event-free survival was estimated by the Kaplan-Meier method. Hazard ratios (HRs) of events by testosterone level were estimated by the Cox model, adjusting for age, tumor size, and histology.

Results

Patients with high testosterone (≥ 0.40 ng/mL, median of distribution) had significantly lower event-free survival than those with low testosterone (log-rank P = .004). The adjusted HR of patients with high versus low testosterone was 2.05 (95% CI, 1.28 to 3.27). High testosterone was also associated with a significantly higher risk of BC events (relapse and second primary) with an adjusted HR of 1.77 (95% CI, 1.06 to 2.96). Eleven second primaries (non-BC) occurred in the high-testosterone group, four in the low-testosterone group.

Conclusion

High plasma testosterone strongly predicts poorer prognosis in postmenopausal BC patients not administered adjuvant therapy. Testosterone levels should be determined as part of the prognostic work-up.