The chief executive of Park Nicollet Health Services announced Tuesday that he will retire at the end of the year, nearly two years after helping to engineer a merger with Bloomington-based HealthPartners.

Dr. David Abelson, 63, who served as CEO of the combined company's network of hospitals and clinics, said in an afternoon e-mail to employees that he was leaving "with a mixture of sadness and joy" and wants to spend more time with his family.

HealthPartners will divide the leadership duties among three people in various operational roles, which CEO Mary Brainerd said is common in the health care industry and reflects the evolution of the merged organization.

Abelson was a well-liked leader whose internal blog, Dr. Abelson Connects, offered sometimes deeply personal reflections on medicine, family and life. For a time, he opened the blog up to public view.

Recent posts hinted at Abelson's thoughts of the future and his sense of the fragility of life. In an interview Tuesday, he said health issues in recent years, including a mini-stroke and the loss of vision in one eye, played a significant role. "For the first time in my life, I don't have specific goals other than showing up and seeing how life unfolds for me," he said.

Asked how much the shifting dynamics of working within the merged HealthPartners organization played in his decision, Abelson said: "Zero. … This was completely my choice."

Abelson came to Park Nicollet in 1983 as a practicing internist, and later worked as the health system's chief clinical officer and chief medical officer. He became CEO in 2010.

Brainerd called Abelson a "special leader" who played a vital role in bringing together two organizations with different structures and cultures. HealthPartners, which operates Regions Hospital and primary care clinics around the Twin Cities, earned a little more than half of its revenue from insurance operations at the time of the merger.

"A lot of times the success of mergers is dependent on who the people are, and the relationship they have," she said.

After Abelson retires, Dr. Brian Rank, Dr. Steve Connelly and the medical division's chief operating officer, Nance McClure, will lead the medical groups, Methodist Hospital and TRIA Orthopaedic Center.

Jackie Crosby • 612-673-7335