Recruiting a representative sample in adherence research-The MALT multisite prospective cohort study experience.

Medication adherence is an important determinant of transplant outcomes. Attempts to investigate adherence are frequently undermined by selection bias: It is very hard to recruit and retain non-adherent patients in research efforts. This manuscript presents recruitment strategies and results from the MALT (Medication Adherence in children who had a Liver Transplant) multisite prospective cohort study. MALT sites recruited 400 pediatric liver transplant patients who agreed to be followed for 2 years. The primary purpose was to determine whether a marker of adherence, the Medication Level Variability Index (MLVI), predicts rejection outcomes. The present manuscript describes methods used in MALT to ensure that a representative sample was recruited, and presents detailed recruitment results. MALT sites were able to recruit a nationally representative sample, as determined by a comparison between the MALT cohort and a national sample of transplant recipients. Strategies that helped ensure that the sample was representative included monitoring of the outcome measure in comparison with a national sample, drastically limiting patient burden, and specific recruitment methods. We discuss the importance of a representative sample in adherence research and recommend that future efforts to study adherence pay special attention to sample characteristics.

Oral risedronate sodium improves bone mineral density in non-ambulatory patients: a randomized, double-blind, placebo controlled trial.

AIMS: Investigate the efficacy of risedronate sodium (Procter and Gamble, Cincinnati, USA) for treating reduced lumbar spine (LS) bone mineral density (BMD) in non-ambulatory patients. METHODS: Nine (10-39 years, mean age 23.0 years, 7 males) in the risedronate arm and 10 (10-35 years, mean age 21.4 years, 8 males) in the placebo arm completed 24 months of therapy at baseline, 6, 12, 18, and 24 months. The primary outcome was change in LS BMD assessed by dual energy x-ray absorptiometry (DXA). Secondary outcomes included changes in serum bone markers, bone specific alkaline phosphatase, osteocalcin, and N-telopeptides. Mixed models examined group, time, and the group by time interaction for the 4 post-baseline time points. RESULTS: The change in LS BMD score from baseline to 24 months was 0.069 (95% CI 0.014 to 0.124) in risedronate participants compared to -0.015 (95% CI -0.073 to 0.042) (t Value = -2.40, P > t=0.03) in the controls. When controlling for baseline scores, the difference was consistent across four post-baseline time points tested (F=5.67, Pr > F=0.03). No differences in serum bone markers were observed. CONCLUSIONS: Risedronate increases LS BMD in non-ambulatory patients with minimal side effects.