QUALITY of INTERVENTIONAL STUDIES

UI Author Year Design * Appropriate Randomization Technique (y/n/nd/NA) Allocation Concealment (y/n/nd/NA) Appropriate Washout Period (y/n/nd/NA) Dropout Rate <20% Blinded Outcome Assessment (y/n/nd) Intention to Treat Analysis (y/n/nd) Appropriate Statistical Analysis ** (y/n) Assessment for Confounding (y/n/nd/NA) Clear Reporting with No Discrepancies (y/n) OVERALL Grade
16481636 Wactawski- Wende 2006 RCT- parallel Y Y NA Y Y Y Y Y Y B
Adverse Event(s): ** Kidney stones
Explanation for Overall Quality Grade (if not Grade A): Original study was designed for assessing the risks and benefits of hormone therapy and dietary modification. At the time the study ended, 352 women assigned to calcium with vitamin D supplements and 332 women assigned to placebo had withdrawn; 144 and 152, respectively, had been lost to follow-up.

This study was downgraded to B because there are very serious problems with WHI as a study reporting no association of Ca+D on endpoints. The most prominent problem with the trial as evidence for no association for Ca+D is the poor compliance with study treatment. Another serious problem is the allowance in the trial of use of supplements. The trial is a B when reporting no association because non-compliance and the “contamination” of the non-intervention group would cause bias to the null.

It was the consensus among the Tufts EPC that overall, the methodological quality of the trial was B, particularly when the trial is being used to guide decisions about DRI, as opposed to decisions about whether to actively recommend supplementation for an individual woman.

NA=not applicable

*

Please do not copy the 4 categories of study designs from above sections. Specify the exact study design: RCT – Parallel, RCT – Cross-over, RCT – Cluster, quasi-RCT, Non-randomized, but controlled trial, before-and-after trial, other interventional design (please explain in detail)

**

Please do not leave blank. Type nd if there was no data on adverse.

From: Appendix C, Evidence Tables: R-Z

Cover of Vitamin D and Calcium
Vitamin D and Calcium: A Systematic Review of Health Outcomes.
Evidence Reports/Technology Assessments, No. 183.
Chung M, Balk EM, Brendel M, et al.

NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.