Figure. Incidence of Outcomes by Communication Type.

For each outcome, the control group (no letter) was compared with all of the intervention groups combined, with tailored and standard letters groups, and with mailed and electronic delivery methods. Comparisons by χ² analysis were performed first. When P was <.05 by χ² analysis, pairwise comparisons were performed.

^aP < .05 for pairwise comparison with the no letter group, adjusted via the Holm method.

^bP < .05 for pairwise comparison within the letter group, adjusted via the Holm method.