SSM Health Waupun Memorial Hospital
August 22, 2025
SSM Health Waupun Memorial Hospital celebrates dialysis leader career, retirement
WAUPUN — After more than 33 years of dedicated service with SSM Health, Diane Posthuma—who most recently served as SSM Health Regional Director of Dialysis for Wisconsin—retired capping a career defined by compassion, leadership, and a deep love for patient care.
Posthuma’s journey began in July 1992 at SSM Health Waupun Memorial Hospital during a maternity leave with her second son. At the time, the hospital’s dialysis unit was expanding to meet growing patient needs, and Posthuma stepped in to help launch the new PM shift. It was a perfect fit for her young family—and the beginning of a lifelong passion for dialysis care.
Before joining Waupun Memorial Hospital, Posthuma had already built a strong foundation in nursing, working five years at SSM Health St. Agnes Hospital on a med/surg floor and later in neuro/physical rehab.
But it was at Waupun where her career truly blossomed. Starting as a staff RN in dialysis, Posthuma quickly became a cornerstone of the department. Her leadership journey evolved from coordinator to supervisor, then director of dialysis units. In 2006, her responsibilities expanded to include Waupun Memorial Hospital surgery, and by 2015, she was also overseeing the ER, cardiopulmonary, and cardiac rehab.
Her final role as Regional Director of Dialysis for Wisconsin brought her full circle—back to her first love. Posthuma led the development of inpatient dialysis programs across the state, drawing on her deep experience in launching new services and building strong, mission-driven teams.
“It has been my absolute pleasure and honor to work for SSM Health and Waupun Memorial Hospital since I became a nurse in 1987,” Posthuma shares. “Each role and leadership position I had were amazing opportunities and something that challenged and grew me. It was such a privilege to grow teams and programs and to serve both our patients and our staff. I also felt so very privileged to work for so many great leaders and mentors. And most of all, I enjoyed working in a ministry that lived out our mission values and maintained a culture where that truly was our foundation.”
Posthuma says she’ll miss the challenges and the people most—especially the team members—she had the privilege of hiring and mentoring. Retirement holds exciting new adventures: time with her grandchildren, travel, reconnecting with friends, and staying active.
