IPN 40 Anniversary Seal

Leadership Team

Leadership Team

Hector Lopez, M.D.Hector M. Lopez, M.D.—Board President and Medical Director

Dr. Hector M. Lopez is a board-certified family practice physician with over twenty-eight years of independent practice, and now he also serves as IPN’s Medical Director. He has been a member of IPN for twenty-two years and brings more than seven years of managed care experience to his role as Medical Director. In this role, Dr. Lopez oversees the development and implementation of IPN’s clinical, quality, and utilization management programs. Dr. Lopez completed his pre-med studies and received his medical degree from the University of Puerto Rico, Rio Piedras in 1991. He completed his residency at St. Luke’s Hospital, WI before beginning his solo practice at Milwaukee Family Practice.

Dr. Lopez initially joined IPN for the simple reason that over his entire career as a physician, his goal has been to provide the best care to his patients and his community. For Dr. Lopez, being an independent physician is the best way to achieve this goal. Dr. Lopez suggests that being a member of IPN is a perfect fit for those independent practitioners who want to continue the tradition of delivering exceptional, affordable patient care to benefit the entire community.


Michael J. Repka—Chief Executive Office/Executive Director

Michael Repka brings more than twenty-five years of managed care experience to his role of CEO/Executive Director of IPN. In this role, he maintains responsibility for all aspects of the organization. Prior to joining IPN in 2004, Mr. Repka served in various management roles for Wisconsin Health Organization/Humana (1989-1999) and Doral Dental USA (1999-2004), where he served as Chief Operating Officer. In these previous roles, Mr. Repka oversaw operational aspects, provider contracting, and data analysis. Mr. Repka completed his undergraduate degree at Marquette University and his Master’s Degree in Health Care Administration at University of Wisconsin, Milwaukee.

For Mr. Repka, the IPN difference comes from the fact that it is a physician-led and physician-driven company. By providing the necessary tools, resources, and expertise, individual members benefit from the IPN programs designed to help practitioners develop and maintain quality practices, including programs aimed at lowering administrative costs, improving office efficiencies, streamlining credentialing services, and assisting with provider relations services.

According to Mr. Repka, the most important function of IPN is still the reason why it was initially formed: to bring together independent physicians under a common payer agreement. Together through IPN, independent physicians participate in a variety of highly successful Commercial, Medicaid and Medicare value-based programs. These agreements allow IPN physicians to work together as a group to manage large populations of patients, which results in better patient outcomes, higher quality of care, lower costs to contracted payers and patients, and increased revenues to IPN physicians.


Margaret HoganMargaret Hogan—Director of Administrative Services

Margaret Hogan has been employed by IPN since 1992 and brings more than twenty-five years of managed care experience to her role as Director of Administrative Services. Ms. Hogan began her career with IPN as an Accounting Assistant, was promoted to Accounting Supervisor then Administrative Services Manager before assuming her current position. Her responsibilities encompass many of IPN’s operational aspects, including:  Administrative, Credentialing, Financial, Human Resources, and Provider Relations. Ms. Hogan received her Bachelor’s Degree in Business Administration from the University of Wisconsin, Stevens Point.

According to Ms. Hogan, the difference IPN makes in the growth and development of independent practitioners comes from the services IPN offers to its member physicians. IPN’s many beneficial services include Credentialing, Provider Relations, IPN Member Physician/Office Manager meetings, and Value-Added Programs. Each of these services aims to benefit member physicians by providing educational meetings and office visits, alleviating repetitive credentialing submissions, and discounted vendor services.


Grant Thomas Lutz—Director of Information Systems

Grant Thomas Lutz has been employed by IPN since 2008 and brings more than twenty years of health care information systems experience to his role as Director of Information Systems. Mr. Lutz began his career with IPN as an Network Analyst, was promoted to Information Systems Manager before assuming his current position. Among his duties are overseeing acquisitions, configuration, and maintenance of hardware, software, networks and subsystems, telecommunications, database management, and application development for IPN.

Prior to joining IPN, Mr. Lutz was the Technical Support Manager/System Administrator at Medical Information Management Systems (MIMS), an EMR software company targeting Physical, Occupational and Speech Therapy practices, for 10 years.

For Mr. Lutz, IPN’s best assets are their knowledgeable, dedicated employees, many of whom have been with IPN for more than ten years. This vast working knowledge of all the various aspects of the business allows IPN employees to provide the best service to its member physicians. IPN’s work as liaison between independent physicians and many necessary outside entities allows member physicians to do what they do best: practice medicine.


Christine ZwiefelhoferChristine Thompson, RN, BSN—Director of Quality and Clinical Services

Christine Thompson has been a nurse for twenty-five years. She received her Associate’s Degree in Nursing from Wytheville Community College, her Bachelors of Science degree in Nursing from Virginia Commonwealth University, and is Certified in Lean for Health Care from University of Tennessee. Ms. Thompson has a varied clinical background, including eleven and a half years of clinical quality, nine years in hospital quality, process improvement and risk management, and three and a half years in clinic quality. She joined IPN in 2014 and brings a wealth of experience to her role of Director of Quality and Clinical Services. Her responsibilities include oversight of IPN’s quality, care coordination, and utilization management programs.

Ms. Thompson appreciates how IPN allows member physicians to operate independently yet have the tools to stay informed of current trends in healthcare, specifically quality monitoring and access to portals and data collection systems. With IPN, member physicians have the support and leverage of larger systems without infringing on their rights as individual practitioners.


Sarah ZwiefelhoferSarah Zwiefelhofer—Director of Practice Management

Sarah Zwiefelhofer brings more than twenty-five years of experience to IPN in her role as Director of Practice Management. Ms. Zwiefelhofer is responsible for the oversight, development, and implementation of IPN’s practice management service model, management service organization, and third-party vendors. In addition, Ms. Zwiefelhofer brings over twenty years of independent consulting experience in healthcare operations, compliance, revenue cycle management, software implementations, business development, and marketing in the Southeastern Wisconsin area serving primary care and specialty physicians, hospitals and healthcare organizations.

For Ms. Zwiefelhofer, the best assets of IPN are those that provide the keys to independent physicians’ sustainability in a competitive market. Through their leadership, management, and infrastructure expertise for contracting, quality programs, and industry resources, IPN has the tools that allow independent physicians to successfully grow their practices.


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