NEW YORK: The healthcare practice leaders at seven holding company agencies in the US have left their positions in the last 11 months, triggering a shake-up in senior-level staffing.

MS&L, Burson-Marsteller, and Hill & Knowlton have lost at least two of their top healthcare leaders in the last four months. Euro RSCG PR, Cohn & Wolfe, Ketchum, and Porter Novelli have also reported healthcare practice leadership changes since March 2009.

While the reasons for the executive departures vary, ...