Institute for Health Research, Kaiser Permanente Colorado, Denver, CO

Supported by grant number R01 HS019859 from the Agency for Healthcare Research and Quality. The content is solely the responsibility of the author and does not necessarily represent the official views of the Agency for Healthcare Research and Quality.

The author declares no conflict of interest.

Reprints: John F. Steiner, MD, MPH, Institute for Health Research, Kaiser Permanente Colorado, 10065 E. Harvard Ave, Suite 300, P.O. Box 378066, Denver, CO 80237-8066. E-mail: john.f.steiner@kp.org.