Our Providers

Karen Rendt-Zagar, MD

Karen E. Zagar, MD is a native of Pennsylvania, where she attended college (majoring in mathematics and chemistry at Clarion State College) and attended medical school (University of Pennsylvania in Philadelphia). She remained at the Hospital of the University of Pennsylvania for her internship and residency in Internal Medicine. She did her fellowship in Rheumatology at Duke University in Durham, North Carolina.

Dr Zagar joined our staff in 2005.  Prior to that, she spent six years on the staff of the Department of Rheumatic and Immunologic Diseases at the Cleveland Clinic Foundation in Cleveland, Ohio. There she served as the Fellowship Education Program Director to train physicians specializing in Rheumatology. She was also a member of the Center for Vasculitis Care and Research, headed by Dr. Gary Hoffman, and has participated in numerous clinical trials related to osteoarthritis, rheumatoid arthritis, and vasculitis.

Dr. Zagar is board certified in both Internal Medicine and Rheumatology, and she is a fellow in the American College of Rheumatology. Dr Zagar is currently Principal Investigator for all research trials and studies performed at Arthritis Center.

Dr. Zagar and her family enjoy numerous outdoor activities, particularly sailing, biking, and gardening. She also plays flute and classical piano.

Tatiana Nagibina, MD

Dr. Nagibina received her medical degree from Minsk State Medical Institute (former USSR). She completed her internship and residence in Internal medicine at The Chicago Medical School as well as fellowship in Rheumatology at the University of Illinois at Chicago.

Before joining our staff in 2011, Dr. Nagibina spent 10 years serving patients in Pinellas County providing Rheumatological care.

Dr. Nagibina is board certified in Internal medicine and Rheumatology and she is a fellow of the American College of Rheumatology.

Dr. Nagibina enjoys travel, theater, and museums.

Tatyana Korableva, PA-C

Tatyana is a nationally certified Physician Assistant with 10 years of experience in Rheumatology who obtained her Master of Clinical Medical Science degree in Physician Assistant Studies from Barry University in St. Petersburg, Florida, in 2011. She is licensed by the state of Florida and is a member of the Florida Society of Rheumatology, Florida Academy of Physician Assistants and the International Society for Clinical Densitometry.

Before attending Barry University, Tatyana attended the University of South Florida, where she obtained her Bachelor of Biomedical Science degree. She worked as an Ophthalmic Assistant in St. Petersburg, Florida for two years, Bay Area Arthritis & Osteoporosis for the following 10 years until most recently joining the Arthritis Center in October of 2021.

As a Physician Assistant Tatyana provides care in all aspects of Rheumatology with special interest in Osteoporosis treatment and prevention.

Tatyana resides in Lutz with her husband and two children and enjoys spending her free time with family and friends.

Dr Bianshly Rivera

Dr. Rivera will be joining our staff  October 17, 2022. She completed her undergraduate studies in cellular and molecular biology and obtained her medical degree from the University of Puerto Rico. During this time, she was participating in research studies on metabolic syndrome in women, which is one of her big interests. Dr. Rivera moved to Florida to complete an Internal Medicine residency at the University of South Florida (USF). She finished her Endocrinology, Diabetes, and Metabolism fellowship at USF-affiliated hospitals Tampa General Hospital, James A. Hailey Veterans Hospital, and Moffitt Cancer Center. During her training, she participated in projects related to diabetes mellitus, quality improvement, and patient safety, and presented her work at national endocrinology conferences.

Dr. Rivera is board certified in Internal Medicine and board eligible in Endocrinology, Diabetes, and Metabolism. She is particularly interested in metabolic health, obesity, diabetes mellitus, and autoimmune thyroid disease.

During her free time, she enjoys exercising, cooking healthy recipes, going to the beach, spending time with her two dogs, and shopping for new plants.