Oklahoma Leadership

2023-2024 Chapter Leadership

The Oklahoma chapter of HFMA continues to function based on the volunteer efforts of our members. Below are the chapter’s current elected officers, directors and committee chairs. If you would like to volunteer your time and efforts in any capacity, please reach out to any of these chapter leaders.


Tyler Bernier


Tyler is a partner with Eide Bailly in Oklahoma City, Oklahoma. When he’s not working on behalf of his clients, you’ll often find Tyler watching Disney movies, playing with toys and chasing after his two kids. When he’s traveling-either for work or pleasure-he likes to take in new sights, try new restaurants and sample the local craft beers.

Phillip Smith


Phillip is INSURICA’s Healthcare Practice Group Leader. From his years of experience in the Healthcare industry, Phillip protects the assets of healthcare professionals, hospitals, and facilities through risk management and insurance solutions. Phillip is also an adjunct instructor at the University of Central Oklahoma and Mid-America Christian University where he teaches insurance and risk management, healthcare policy, management and leadership, and organizational behavior with a key focus on business ethics.

Darren Walkup

Vice President

Darren Walkup is a Sr. Vice President in the Commercial Bank at Commerce Bank and leads the Commerce Healthcare division for Oklahoma. Darren’s primary responsibilities include relationship management of current relationships as well as expanding Commerce’s Healthcare service offerings to all healthcare institutions across the State of Oklahoma. He received his BA in Finance from the University of Oklahoma in Norman and has an MBA in Accounting from Rockhurst University in Kansas City, MO. Before attending college, he served 5 years active duty in the United States Army. Darren currently serves on the Board of OK HFMA as well as the Board for the Community Food Bank of Eastern Oklahoma and is a past Board member for Tulsa Historical Society and the Arts & Humanities Council of Tulsa (now known as AHHA). 

Lisa Postelwait


Lisa Postelwait is Vice President of Finance at OU Health and has primary responsibility for the financial planning and analytics functions.  Lisa has been a member of HFMA for over 20 years and new to the Oklahoma chapter after relocating from Texas.  In her spare time, Lisa enjoys gardening, home improvement projects and spending time with family and friends.

Cassie Walden


Cassie is with Knowtion Health. Cassie has been in the healthcare industry for sixteen years and values the relationships she has made during that time. Cassie spends her spare time at the ballpark with her girls and enjoying family life.

Louise Kiper

Immediate Past President

Louise is Co-Owner and Vice-President of Sales for American Collection Services, Inc. in Oklahoma City and will celebrate her 40th work anniversary this year. Louise has been an HFMA member for over 24 years and was the Corporate Sponsor Chair for 20 of those years. Also known as Gigi, she adores her 7 grandchildren and enjoys Co-Pastoring a local church with her husband Warren. She loves OU Football, traveling, crafting and party planning.


Rostina Swindall

Director (Year 1)

Oklahoma Heart Hospital

Cori Loomis

Director (Year 1)

Christensen Law Group

George Kruger

Director (Year 1)

Comanche County Memorial Hospital

Mike Lorenz

Director (Year 2)

Mike is a recent transplant to the Oklahoma City area when he joined INTEGRIS Health in 2019 and is the Director of Revenue Cycle for hospital and physician clinic operations.  He has over 20 years’ experience in the accounts receivable arena of which the last nine years have been in acute care hospitals and long term care facilities.  Mike enjoys spending his spare time with his wife and family exploring the area or travelling to favorite destinations.  He also has been producing off-road motorcycle racing events for over 30 years and enjoys participating in races with the two youngest of his three children. 

Priacilla Leatherman

Director (Year 2)

Priacilla is the Vice President of Finance at Northeastern Health System and has over 25 years’ experience in the healthcare industry.  She has been a member of HFMA for over 8 years.  Priacilla enjoys spending time with family and traveling.  In her spare time, you will often find her at the ballfields watching her nephews play or at the lake.

Amanda Martinez-Reyes

Director (Year 2)

Amanda is the Director of Payer Contracting and Revenue Integrity for Norman Regional Health System. Amanda has over 15 years’ experience in healthcare with a focus on managed care. Amanda currently serves as the president of the Oklahoma Hospital Managed Care Association and she is committed to improving the health care delivery system for the citizens of Oklahoma. She finds great joy in making memories and living life to the fullest with her husband and two sons.

Mitzi McCullock

Director ex officio

Mitzi has over 20 years of experience, specializing in managed care insurance contracting, revenue integrity and payer strategies.  Mitzi is responsible for monitoring regulatory issues related to Medicare, Medicaid, managed care, and workers’ compensation, determining their impact on Oklahoma hospitals, and informing Oklahoma hospitals about their implications. She is an active member of the Oklahoma HFMA chapter and the Oklahoma Hospital Managed Care Association.


Josh Tucker
Certification Chair
Preferred Management Corporation

William Rodgers
Communications Chair
HBCS Revenue Cycle

Scott Sanders
Cvent Contact
Friday Health Plans

Cassie Walden
DCMS Contact, Founders Points Contact, Membership Co-Chair
Knowtion Health

Tiffany Alvey
Membership Chair
Eide Bailly

Phillips Smith
Program Chair

Darren Walkup
Program Co-Chair
Commerce Healthcare

Karen Todd
Social Chair
Stillwater Medical Center

Jessica Elsberry
Sponsorship Chair


Erin Thompson
Region 9 Representative

Tamie Young
Region 9 Representative
Stillwater Medical Center


Shannon Cleburn
Region 9 Representative
Knowtion Health

Tamie Young
Region 9 Representative
Stillwater Medical Center


Erin Thompson
Region 9 Treasurer



  • Josh Tucker | Preferred Management Corp | Chair


  • William Rodgers | HBCS Revenue Cycle | Chair
  • Scott Sanders | Friday Health Plans
  • Louise Kiper | American Collection Services, Inc.
  • Tyler Bernier | Eide Bailly


  • Tiffany Alvey | Eide Bailly | Chair
  • Cassie Walden | Knowtion Health | Co-Chair
  • Toni Young | McBride Orthopedic Hospital
  • Tanya Mitchell | St. Mary’s Regional Medical Center  
  • Mike Lorenz | INTEGRIS Health


  • Darren Walkup | Commerce Healthcare | Chair
  • Phillip Smith | INSURICA | Co-Chair
  • Tyler Bernier |Eide Bailly
  • Louise Kiper | American Collection Services
  • Scott Sanders | Friday Health Plans
  • Karen Knight | Face Rock Enterprises
  • Lisa Postelwait
  • Priacilla Leatherman | Northeastern Health System  
  • Tamie Young | Stillwater Medical Center
  • Denise Titsworth | Mercy
  • Jessica Elsberry | FORVIS
  • Bill Rodgers | HBCS Revenue Cycle
  • Rostina Swindall | Oklahoma Heart Hospital
  • Robert Dudley | BOK Financial
  • Mitzi McCullock | Oklahoma Hospital Association
  • Amanda Reyes-Martinez | Norman Regional Health System
  • Darren Walkup | Commerce Healthcare
  • Dollie Sherrill                         
  • Shannon Cleburn | Knowtion Health
  • Mike Lorenz | INTEGRIS Health


  • Karen Todd | Stillwater Medical Center | Chair
  • Shannon Cleburn | Knowtion Health 
  • Rostina Swindall | Oklahoma Heart Hospital


  • Jessica Elsberry | Forvis | Chair
  • Carol Kinzer
  • Mike Lorenz | INTEGRIS Health
  • Louise Kiper | American Collection Services             
  • Tyler Bernier | Eide Bailly
  • Andrew Hejtmanek | FORVIS
  • Scott Sanders | Friday Health Plans
Louise KiperAmerican Collection Services, Inc.2022-23
Scott SandersOklahoma Heart Hospital2021
Scott SandersOklahoma Heart Hospital2020
Andrew HejtmanekBKD2019
Anne AdamsChapman Foundation Management, LLC2018
Julie WardNortheastern Health System2017
William ClarkBKD, LLC2016
Jeff MincherNorman Regional Health System2015
Shannon FullerWorks & Lentz, Inc2014
Sherry CollinsEide Bailly LLPæ2013
Carley WilliamsBKD, LLP2012
Erin HillBKD, LLP2011
Amy MarshINTEGRIS Baptist Regional Health Center2010
Karen ReynoldsINTEGRIS Marshall County Medical Center2009
Tamie OsburnGustafson & Associates, Inc.2008
Karen HendrenStillwater Medical Center2007
Becky SpeightTulsa Regional Medical Center2006
Rick KellySaint Francis Home æ Medical Equip.2005
Lloyd HaggardBKD, LLP2004
Ann L. PaulæAetna Health, Inc.2003
Jerry GardnerIntegris Health2002
Steven MattachioneMercy Health System2001
Kevin GoreBKD, LLP2000
Jack ConklingSouthwestern Memorial Hospital1999
Linda FarrarRenaissance Center1998
Barry SteichenSaint Francis Health System1997
Richard WagnerMadole Wagner PLLC.1996
Duane CutterPrice Waterhouse1995
Dwayne WorthyCaring Touch Home Care (OKC)1994
Dennis PeareBKD, LLP1993
Robert JungerSaint Francis Hospital1992
John MehargæNorman Regional Hospital1991
Patricia AndersenDuncan Regional Hospitalæ1990
Steve DorsettæBroken Arrow Medical Center1989
Errol MitchellIntegris Baptistæ Medical Center1988
Rory WardValley View Regional Hospital1987
Rollo MaxwellSaint Francis Hospital æ1986
Ron CunninghamMercy Health Center1985
George PoseySt. Mary’s Hospital1984
Boyd TudorSt. Anthony Hospital1983
Gary GunderMuskogee General Hospital1982
Herb TohlenJane Phillips Medical Center1981
Darrell WilsonDoctors Medical Center1980
Sam PriceSt. Anthony Hospital1979
Fred MillsMiami Baptist Hospital1978
Max ArmstrongCommunity Hospital (Kingfisher)1977
Bobby ThompsonArbuckle Memorial Hosp.1976
Ben SchnitziusMemorial Hospital (Collinsville)1975
Thomas GiaudroneMcAlester Reg Health Center1974
Ann HeslarGrand Valley Hospital1973
Ann HeslarGrand Valley Hospital1972
Bob ParmeterJane Phillips Medical Center æ1971
Doyal KnowlesHillcrest Medical Center1970
James PowersValley View Regional Hospital1969
Dan NesomMuskogee General Hospital1968
Dan NesomMuskogee General Hospital1967
Clyde McNuttOklahoma General Hospital1966
George PeterSt. Mary’s Hospitalæ1965
Harry HopkinsæNorman Municipal1964
Marion PickettæWesley Hospital1963
Ralph StumppOU Medical Center1962
Opal CampbellACH Hospital1961
John HensonHillcrest Medical Center1960
John HensonHillcrest Medicalæ Center1959
William MauldinCapital Hill Generalæ Hosp. (OKC)1958
William MauldinNorman Municipal1957
Johnnie KimballSouthwestern Hospital1956
Stanley VossValley View Hospital1955

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