+385 1 5620 921


Hruševečka 1

10 000 Zagreb


Ivan Kruljac, M.D., Ph.D
Consultant endocrinologist – diabetologist
Croatian medical chamber licence number: 34671

I graduated at University of Zagreb School of medicine in 2010, obtained my Ph.D. degree in 2016 by performing an epidemiological study in the field of diabetes mellitus and completed training program in endocrinology and diabetology in 2018. I have gained extensive clinical experience at the Department of Endocrinology in University hospital center Sestre milosrdnice, while working with patients with the most complex diseases referred from all county and university hospitals across Croatia and Bosnia and Herzegovina. I was the coordinator and eventually the leader of a multidisciplinary team for endocrine oncology, which dealt with patients with pituitary tumors, tumors of the thyroid and parathyroid glands, adrenal tumors and neuroendocrine tumors.

I would like to emphasize the importance of my scientific work, which has been fruitful over the last ten years. To date, I have published 50 papers in international journals including some most prestigious journals, such as The New England Journal of Medicine and American Journal of Medicine, which rank me as one of the best scientists in Croatian endocrinology. Numerous publications have given me an international visibility, which led to intensive collaboration with some of the most prominent endocrinologists and scientists in Italy, Germany, Czech Republic, Slovakia, Hungary and Slovenia. My research papers have reported several new clinical entities and diseases, described new diagnostic tests and offered new treatment modalities. Moreover, the most important aspect of my dedicated scientific work is the ability to solve the most complex clinical cases by facilitating the entire published scientific literature. This is due to the fact that the knowledge of scientific methodology enables me to read scientific articles critically and to implement findings of other colleagues into my everyday clinical practice.

I was the co-founder of an international journal entitled “Endocrine Oncology and Metabolism”. My dedicated work as an executive editor of the Journal in the period between 2015 and 2018, had lead to inclusion of a Journal in leading bibliographic databases (SCOPUS, EMBASE), which helped in gaining its international recognition. My dedicated work as a clinician and scientist has been recognized by my Croatian colleagues as well. Hence, I was appointed secretary of the Croatian Society of Endocrinology and Croatian representative in European Society of Endocrinology. Currently, I also serve as a scientific associate at University of Zagreb School of medicine, participating in undergraduate program of education.

I have been the co-founder and medical advisor at Solmed Clinic Ltd. since 2018, which is currently recognized as a center of excellence for clinical trials. I serve as a principal investigator or sub-investigator in ten clinical trials and provide innovative treatment options for patients in Croatia.

Excellence in clinical and scientific work, contacts in world’s leading endocrine centers and access to innovative therapies are the guarantee of success in the process of establishing the right diagnosis and initiation of the proper treatment for your disease.

Detailed biography

Academic degrees
  • 20th June 2010. Medical degree at University of Zagreb School of medicine
  • 27th December 2016. Ph.D degree with the doctoral thesis entitled: „Hyperglycemic crises in patients with diabetes mellitus in Republic of Croatia“; University of Zagreb School of medicine
  • 19th February 2018. Specialist in endocrinology and diabetology
Education abroad
  • Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Oxford, UK; Mentors Prof. Ashley Grossman and Dr. Niki Karavitaki, education in the field of endocrinology, endocrine oncology and clinical trials in diabetes
  • Uppsala University Hospital, Uppsala, Sweden; Mentor Prof. Kjell Oberg, education in the field of endocrine oncology and neuroendocrine tumors
  • Profil Institute, Neuss, Germany; Mentor Prof. Tim Heissea, education in the field of diabetes and methodology of clinical trials in diabetes
Academic projects
  • 2015-2016. Research associate in a project “Systemic inflammation and body composition – how it influences survival” (cro. Sistemska upala i sastav tijela-utjecaj na preživljenje bolesnika). Funded by Croatian ministry of science, leader of the project: Professor Neven Ljubičić, MD, PhD
  • 2018 – present. Research associate in a project “Synergic effect of sex hormones and GLP-1 on body mass decline in patients with type 2 diabetes mellitus” (cro. “Procjena sinergiskog učinka spolnih hormona i glukagonu-I sličnog peptida na tjelesnu masu u tipu 2 šećerne bolesti”), Funded by Croatian ministry of science, leader of the project: Professor Ivana Pavlić Renar, MD, PhD
  • 2018 – present. Research associate in a project“Crosstalk between bone and vascular redox state in diabetes”. Funded by European Foundation for the Study of Diabetes, leader of the project: Kristina Blaslov, MD, PhD
Organization of congresses, meetings and medical training courses
  • 2012 – 2019; member of the organizing committee of the Croatian first on-line course in endocrinology and diabetology (E-kongres), which is the official teaching material for residents of endocrinology and diabetology recommended by Croatian Society of Endocrinology.
  • 2015 and 2017; member of the organizing committee of Croatian congress of endocrinology with international participation, supported by Croatian Society of endocrinology
  • 2017 – 2019; member of the organizing committee of a course entitled “Zagreb school of endocrine oncology”, supported by the Croatian Society for endocrine oncology.
Rewards and recognitions:
  • Dean’s Award for Excellence, 2010, University of Zagreb Medical School, Zagreb, Croatia
  • Award for best poster presentation and young scientist, 2011, 5th Croatian Congress of endocrinology with international participation, Pula, 2011
  • City of Zagreb scholarship for postgraduate education at University of Zagreb School of medicine
  • Travel grant winner by European Neuroendocrine tumor Society in 2018
Editorial work in scientific journals
  • November 2015 – August 2018; executive editor and co-founder of scientific journal , Endocrine Oncology and Metabolism, which was included in international bibliographic databases DOAJ, SCOPUS and EMBASE.
Reviews for international journals

Reviewed a total of 34 papers in the following journals: New England Journal of Medicine, Scientific Reports, Obesity Surgery, Archivum Immunologiae et Therapiae Experimentalis, BMJ Case Reports, International Journal of Endocrine Oncology, Endocrinology, Diabetes and Metabolism Case Reports, Journal of International Medical Research, World Journal of Surgical Oncology.

Membership in societies
  • European Society of Endocrinology
  • European Neuroendocrine Tumor Society
  • Croatian Society of Endocrinology (secretary)
  • Croatian Society for Diabetes and Metabolic Disorders
Lectures at congresses:
  • Chromogranin A in diagnostics of NETs: old biomarker with new perspectives; 27th Hungarian Endocrinology Congress, May 2018, Hajduszoboszlo, Hungary
  • Clinical impact of diabetic ketosis in patients with type 2 diabetes mellitus; 82. Diabetologist’s days, May 2018, Mali Lošinj, Croatia
  • MEN-1 syndrome; International Novartis Expert Forum, Online course 2018.
  • Differential diagnosis of hypoglycemia in patients without diabetes. 8th Croatian Endocrinology Congress, October 2017, Opatija, Croatia
  • Bringing a NET registry to a developing country: Croatian experience; Meeting of the German NET-registry, November 2016, Mainz, Germany
  • Chromogranin A in diagnostics of NENs: advantages and pitfalls; October 2016, Crikvenica, Croatia.
  • Hypothalamic Langerhans cell histiocytosis – challenges in treatment and follow-up; 18th ESE Postgraduate Training Course on Endocrinology, Diabetes and Metabolism, February 2016, Opatija, Croatia
  • Treatment of NENs in Croatia; 7th Croatian Endocrinology Congress, October 2015, Lovran, Croatia
  • Incidence of diabetic ketosis and ketoacidosis in type 2 diabetes mellitus in Croatia; 78. Diabetologist’s days, May 2016, Dubrovnik, Croatia
List of publications

Papers in international peer-reviewed journals

  1. Prpic M, Kruljac I, Kust D, Suton P, Purgar N, Bilos LK, Gregov M, Mrcela I, Franceschi M, Djakovic N, Frobe A. Dose-volume derived nomogram as a reliable predictor of radiotherapy-induced hypothyroidism in head and neck cancer patients. Radiol Oncol. 2019 Nov 20;53(4):488-496.
  2. Košec A, Kruljac I, Ajduk J. Remission of Recurrent Cochlear Hydrops Associated With Bromocriptine Treatment For Macroprolactinoma. Am J Audiol; 2019 Sep 13;28(3):548-552.
  3. Kruljac I, Dabelić N, Marjan D, Blaslov K, Perić B, Mirošević G, Vagić D, Vrkljan M. Cushing’s disease in a patient with MEN 2B syndrome. Am J Med. 2019 Aug 14. pii: S0002-9343(19)30687-4. doi: 10.1016/j.amjmed.2019.07.043.
  4. Režić T, Blaslov K, Kruljac I, Rahelić D, Vrkljan M, Renar IP. The possible synergistic action of sex hormones and glucagon-like peptide-1 (GLP-1) agonists on body mass decline in patients with type 2 diabetes mellitus. Med Hypotheses 2019 ;DOI : 10.1016/j.mehy.2019.109308
  5. Zeljković I, Đula K, Babacanli A, Kruljac I, Mustapić V, Brkljačić DD, Bulj N, Radeljić V, Manola Š, Pavlović N. High prevalence of hyperlipidaemia in patients with AV re-entry tachycardia and AV nodal re-entry tachycardia. Sci Rep. 2019 Aug 8; 9(1):11502. doi: 10.1038/s41598-019-47940-9.
  6. Ćaćić M, Marinković J, Kruljac I, Perić B, Čerina V, Stipić D, Pažanin L, Pećina HI, Vrkljan M. ISCHEMIC Pituitary Apoplexy, Hypopituitarism And Diabetes Insipidus: A Triad Unique To Necrotizing Hypophysitis. Acta Clin Croat. 2018 Dec; 57(4):768-771. doi: 10.20471/acc.2018.57.04.20.
  7. Kirigin Biloš LS, Kruljac I, Radošević JM, Ćaćic M, Škoro I, Ćerina V, Pećina IH, Vrkljan M. Empty sella in the making. World Neurosurg. 2019 May 22. Pii: S1878-8750(19)31396-8. Doi: 10.1016/j.wneu.2019.05.119. [Epub ahead of print]
  8. Blaslov K, Naranđa FS, Kruljac I, Renar IP. Treatment approach to type 2 diabetes: Past, present and future. World J Diabetes. 2018 Dec 15; 9(12):209-219. doi: 10.4239/wjd.v9.i12.209. Review.
  9. Krušlin B, Vučić M, Mašić S, Kruljac I, Lež C, Ružić B, Spajić B, Ulamec M. Expression of LMO2 in Prostate Carcinoma and Adjacent Prostatic Parenchyma. Acta Clin Croat. 2018 Oct; 57(Suppl 1):56-60. doi: 10.20471/acc.2018.57.s1.08.
  10. Kruljac I, Vičić I, Blaslov K, et al. The role of acute octreotide suppression test in detecting patients with neuroendocrine neoplasms. Neuroendocrinology. August 2018. doi:10.1159/000492934
  11. Blaslov K, Kruljac I, Mirošević G, Gaćina P, Kolonić SO, Vrkljan M. The prognostic value of red blood cell characteristics on diabetic retinopathy development and progression in type 2 diabetes mellitus. Clin Hemorheol Microcirc. July 2018:1-7. doi:10.3233/CH-180422
  12. Kruljac I, Vurnek I, Maasberg S, et al. A score derived from routine biochemical parameters increases the diagnostic accuracy of chromogranin A in detecting patients with neuroendocrine neoplasms. Endocrine. 2018; 60(3):395-406. doi:10.1007/s12020-018-1592-6
  13. Blaslov K, Kruljac I, Mirošević G, Kirigin Biloš LS, Vrkljan M. The possible role of stress induced hormonal disbalance in the patophysiology of insulin resistane in lean individuals. Med Hypotheses. 2018; 114:8-10. doi:10.1016/j.mehy.2018.02.032
  14. Nicolae A, Murgic J, and Kruljac I, et al. Dosimetric impact of inter-observer catheter reconstruction variability in ultrasound-based high-dose-rate prostate brachytherapy. Brachytherapy. 2018;17(2):306-312. doi:10.1016/j.brachy.2017.10.015
  15. Kruljac I, Ćaćić M, Ćaćić P, et al. The Impact of Hyperosmolarity on Long-Term Outcome in Patients Presenting with Severe Hyperglycemic Crisis: A Population Based Study. Exp Clin Endocrinol Diabetes. November 2017. doi:10.1055/s-0043-117416
  16. Marso SP, McGuire DK, Zinman B, et al. Efficacy and Safety of Degludec versus Glargine in Type 2 Diabetes. N Engl J Med. 2017; 377(8):723-732. doi:10.1056/NEJMoa1615692
  17. Gulin T, Kruljac I, Kirigin Biloš LS, Gulin M, Grgurević M, Borojević M. The role of adipokines as prognostic factors of one-year mortality in hip fracture patients. Osteoporos Int. 2017; 28(8):2475-2483. doi:10.1007/s00198-017-4068-2
  18. Kruljac I, Ćaćić M, Ćaćić P, et al. Diabetic ketosis during hyperglycemic crisis is associated with decreased all-cause mortality in patients with type 2 diabetes mellitus. Endocrine. 2017; 55(1):139-143. doi:10.1007/s12020-016-1082-7
  19. Kruljac I, Mirošević G, Bešlin MB. Should We Inspect Small Intestine During Laparoscopic Bariatric Surgery? Obes Surg. 2017;27(5):1343-1344. doi:10.1007/s11695-017-2648-z
  20. Prpic M, Kust D, Kruljac I, et al. Prediction of radioactive iodine remnant ablation failure in patients with differentiated thyroid cancer: A cohort study of 740 patients. Head Neck. 2017; 39(1):109-115. doi:10.1002/hed.24550
  21. Kust D, Lucijanic M, Urch K, et al. Clinical and prognostic significance of anisocytosis measured as a red cell distribution width in patients with colorectal cancer. QJM. 2017; 110(6):361-367. doi:10.1093/qjmed/hcw223
  22. Pecina HI, Pecina TC, Vyroubal V, Kruljac I, Slaus M. Age and sex related differences in normal pituitary gland and fossa volumes. Front Biosci (Elite Ed). 2017; 9:204-213.
  23. Zeljkovic I, Pintaric H, Vrsalovic M, Kruljac I. Effectiveness of cardiogoniometry compared with exercise-ECG test in diagnosing stable coronary artery disease in women. QJM. 2017;110(2):89-95. doi:10.1093/qjmed/hcw162
  24. Rahelić D, Altabas V, Bakula M, et al. [CROATIAN GUIDELINES FOR THE PHARMACOTHERAPY OF TYPE 2 DIABETES]. Lijec Vjesn. 2017; 138(1-2):1-21.
  25. Prpic M, Kruljac I, Kust D, et al. Re-ablation I-131 activity does not predict treatment success in low- and intermediate-risk patients with differentiated thyroid carcinoma. Endocrine. 2016; 52(3):602-608. doi:10.1007/s12020-015-0846-9
  26. Cerina V, Kruljac I, Radosevic JM, et al. Diagnostic Accuracy of Perioperative Measurement of Basal Anterior Pituitary and Target Gland Hormones in Predicting Adrenal Insufficiency After Pituitary Surgery. Medicine (Baltimore). 2016; 95(9):e2898. doi:10.1097/MD.0000000000002898
  27. Kruljac I, Mirošević G, Kirigin LS, et al. Changes in metabolic hormones after bariatric surgery and their predictive impact on weight loss. Clin Endocrinol (Oxf). 2016; 85(6):852-860. doi:10.1111/cen.13160
  28. Perić B, Kruljac I, Šundalić S, et al. Obesity and hypercholesterolemia in patients with prolactinomas: Could DHEA-S and growth hormone be the missing link? Endocr Res. 2016; 41(3):200-206. doi:10.3109/07435800.2015.1135444
  29. Kruljac I, Rinčić G, Pećina HI. Hyperosmolar coma in a patient with hypothalamic Langerhans cell histiocytosis. Endocrine. 2016; 52(1):176-177. doi:10.1007/s12020-015-0675-x
  30. Gulin T, Kruljac I, Kirigin L, et al. Advanced Age, High β-CTX Levels, and Impaired Renal Function are Independent Risk Factors for All-Cause One-Year Mortality in Hip Fracture Patients. Calcif Tissue Int. 2016; 98(1):67-75. doi:10.1007/s00223-015-0070-x
  31. Kust D, Kruljac I, Peternac AŠ, et al. Pleural and pericardial effusions combined with ascites in a patient with severe sunitinib-induced hypothyroidism. Acta Clin Belg. 2016; 71(3):175-177. doi:10.1179/2295333715Y.0000000065
  33. Liberati-Čizmek A-M, Kruljac I, Bakula M. A 65-year-old female with poorly controlled type 2 diabetes mellitus. Neth J Med. 2015; 73(10):489-490.
  35. Vrkljan AM, Pašalić A, Strinović M, Perić B, Kruljac I, Miroševć G. COEXISTENCE OF ADDISON’S DISEASE And Pernicious Anemia: Is the New Classification of Autoimmune Polyglandular Syndrome Appropriate? Acta Clin Croat. 2015; 54(2):232-235.
  36. Kruljac I, Balenović A, Gaćina P, Imashuku S, Vrkljan M. Complete response of adult-onset CNS Langerhans cell histiocytosis documented on 18F-FDG PET/CT. Clin Nucl Med. 2015;40(12):981-982. doi:10.1097/RLU.0000000000000994
  37. Kruljac I, Kirigin LS, Strinović M, et al. Treatment of prolactinomas in low-income countries. Int J Endocrinol. 2015; 2015:697065. doi:10.1155/2015/697065
  38. Kruljac I, Šikić A. Aortic aneurysm and the split eggshell sign. QJM. 2015; 108(12):979. doi:10.1093/qjmed/hcv125
  39. Nikolić M, Kruljac I, Kirigin L, et al. Initial Weight Loss after Restrictive Bariatric Procedures May Predict Mid-Term Weight Maintenance: Results from a 12-Month Pilot Trial. Bariatr Surg Pract patient care. 2015; 10(2):68-73. doi:10.1089/bari.2014.0049
  40. Kruljac I, Solter D, Vrkljan AM, Solter M. Remission of Graves’ disease is not related to early restoration of euthyroidism with high-dose methimazole therapy. Endocr Res. 2015; 40(1):25-28. doi:10.3109/07435800.2014.914038
  41. Kruljac I, Butorac D, Vrkljan M. Letrozole or clomiphene for infertility in the polycystic ovary syndrome. N Engl J Med. 2014; 371(15):1462-1463. doi:10.1056/NEJMc1409550
  42. Nikolić M, Sabol M, Kruljac I, et al. A first case of endoscopical removal of an eroded adjustable gastric band in Croatia. Coll Antropol. 2014; 38(1):345-348.
  43. Mirošević G, Nikolić M, Kruljac I, et al. Decrease in insulin resistance has a key role in improvement of metabolic profile during intragastric balloon treatment. Endocrine. 2014; 45(2):331-334. doi:10.1007/s12020-013-0069-x
  44. Kruljac I, Cerina V, Pećina HI, et al. Pituitary metastasis presenting as ischemic pituitary apoplexy following heparin-induced thrombocytopenia. Endocr Pathol. 2012; 23(4):264-267. doi:10.1007/s12022-012-9224-9
  45. Marić A, Kruljac I, Čerina V, Pećina HI, Šulentić P, Vrkljan M. Endocrinological outcomes of pure endoscopic transsphenoidal surgery: a Croatian Referral Pituitary Centre experience. Croat Med J. 2012; 53(3):224-233.
  46. Kruljac I, Pavic I, Matesa N, et al. Intrathyroid parathyroid carcinoma with intrathyroidal metastasis to the contralateral lobe: source of diagnostic and treatment pitfalls. Jpn J Clin Oncol. 2011; 41(9):1142-1146. doi:10.1093/jjco/hyr094
  47. Kruljac I, Sulentić P, Cigrovski-Berković M, et al. Hypopituitarism caused by pituitary metastasis of supraglottic laryngeal carcinoma: case report. Acta Clin Croat. 2010; 49(3):347-351.


List of abstracts at international congresses

  1. Blaslov K, Males VK, Kokic S, Kruljac I. The Platelet-Derived Growth Factor a—An Additional Pathophysiological Factor in Hepatic Steatosis and Fibrosis Development Both in Patients with Hepatitis C and Patients with Prediabetes. Diabetes. 2019; 68(Supplement 1).
  2. Kruljac I, Tometić G, Petranović Ovčariček P, Gladić Nenadić V, Vazdar Lj, Marić Brozić J, Demirović A, Bišćanin A, Pavić T, Marjan D, Penavić I, Vrkljan M. The Role of Subcutaneous Octreotide Suppression Test in Detecting Patients with Neuroendocrine Neoplasms: A Pilot Study. Neuroendocrinology 2018; 106: Supplement 1.
  3. Kruljac I, Petranović Ovčariček P, Gladić Nenadić V, Marić Brozić J, Dabelić N, Demirović A, Ulamec M, Marjan D, Vazdar L, Filipović Čugura J, Ljubičić N, Vrkljan M. A nomogram consisted of routine biochemical tests may increase the diagnostic accuracy of chromogranin an in detecting patients with neuroendocrine tumors. Neuroendocrinology 2017; 105: Supplement 1.
  4. Nikolić M, Kruljac I, Mirošević G, Ljubičić N, Supanc V, Nikolić BP, Duvnjak M, Budimir I, Bišćanin A, Vrkljan M, Bekavac Bešlin M, Milošević M. Weight loss after first month of treatment with bariatric surgery and intragastric baloon: can it predict long-term weight maintainence? J Gastroenterol Hepatol 2013; 28: Suppleent 3.
  5. Nikolić M, Kruljac I, Mirošević G, Supanc V, Ljubičić N, Nikolić BP, Duvnjak M, Budimir I, Sabol M, Vrkljan M, Bekavac Bešlin M, Milošević M. Metabolic parameters, liver function and hepatic steatosis improvement after intagastric balloon treatment. Gut 2012; 61: Supplement 3.
  6. Kruljac I, Vrkljan M. Gastric neuroendocrine tumor type 1 associated vith autoimmune polyglandular syndrome type 3B. Neuroendocrinology 2012; 96: Supplement 1.
  7. Kruljac I, Vrkljan M. Extreme Obesity due to Insulinoma within Multiple Endocrine Neoplasia (MEN) 1 Syndrome. Neuroendocrinology 2011; 94: Supplement 1.
  8. Ćaćić P, Kruljac I, Ćaćić M, Perić B, Filipović-Grčić M, Mirošević G, Vrkljan M. Incidence of diabetic ketosis and ketoacidosis in Caucasian adults with type 2 diabetes mellitus: a population-based study. Endocrine Abstracts 2017; 49:EP463.
  9. Vurnek I, Kruljac I, Ćaćić M, Perić B, Filipović-Grčić M, Mirošević G, Kust D, Vrkljan M. A nomogram consisted of routine biochemical tests may increase the diagnostic accuracy of chromogranin A in detecting patients with neuroendocrine tumors. Endocrine Abstracts 2017; 49:EP172.
  10. Vicic I, Kruljac I, Cacic M, Peric B, Filipovic-Grcic M, Mirosevic M, Cerina V, Pazanin L, Vrkljan M. A case of recurrent Cushing’s disease after total bilateral adrenalectomy. Endocrine Abstracts 2017; 49: EP43. DOI:10.1530/endoabs.49.EP43
  11. Mirošević G, Butorac D, Kruljac I, Vrkljan M. Erythrocytosis and thrombocytosis secondary to hypertestosteronemia caused by ovarian leydig cell tumor. Endocrine Abstracts 2012; 29:P977.
  12. Nikolić M, Mirošević G, Kruljac I, Vrkljan M, Supanc V, Ljubičić N, Duvnjak M, Budimir I, Pezo-Nikolić B, Sabol M, Nikolac I, Bekavac Bešlin M. Different metabolic response to intagastric balloon treatment between non-morbid and morbid type of obesity. Endocrine Abstracts 2012; 29:P1204.
  13. Kruljac I, Sulentic P, Berkovic Cigrovski M, Herman Mahecic D, Mirosevic G, Ivkic M, Vrkljan M. A unique case of multifocal intrathyroid parathyroid carcinoma. Endocrine Abstracts 2011; 26:P595.
  14. Kruljac I, Maric A, Sulentic P, Berkovic Cigrovski M, Herman Mahecic D, Mirosevic G, Kastelan D, Vrkljan M. Multimodal treatment and minimally invasive surgery for 117 pituitary adenomas: a Croatian Pituitary Centre experience. Endocrine Abstracts 2011; 26:P214.