Classical fever of unknown origin in 21 countries with different economic development: an international ID-IRI study
Hakan Erdem, Magdalena Baymakova, Sevil Alkan, A. Létaief, Wissal Ben Yahia, Farouq Dayyab, Entela Kolovani, Svjetlana Grgić, Federica Cosentino, İmran Hasanoğlu, Reham Khedr, Andrea Marıno, Abdullah Umut Pekok, Fatma Eser, Jurica Arapović, Rahmet Güner, Ionela-Larisa Miftode, Kostadin Poposki, Gamze Şanlıdağ, Alper Tahmaz, Oğuz Reşat Sıpahı, Egidia Miftode, Serkan Öncü, Meli̇ha Çağla Sönmezer, Syam Kumar Addepalli, Ilad Alavi Darazam, Hema Prakash Kumari, Meliha Meriç Koç, Meela Ranjith Kumar, Suresh Babu Sayana, Ahmed Ashraf Wegdan, Fatma Amer, Mehmet Reşat Ceylan, Amani El‐Kholy, Taylan ÖNDER, Hamed Azhdari Tehrani, Atousa Hakamifard, Bircan Kayaaslan, Ghaydaa A. Shehata, Hülya Çaşkurlu, Nagwa Mostafa El‐Sayed, Seyed Erfan Mortazavi, Mohammad Pourali, Umran Elbahr, Sholpan Kulzhanova, Tarkan Yetişyiğit, Sahar Saad, Yasemin Çağ, Gülden Eser Karlıdağ, N. Pshenichnaya, M. Belitova, Nasim Akhtar, Fahad Almajid, Müge Ayhan, Mumtaz Ali Khan, Massimiliano Lanzafame, Mateja Janković Makek, Emmanuel Nsutebu, Antonio Cascio, Emine Kübra Dindar‐Demiray, Emine Ünal Evren, Rama Kalas, Ayşe Kaya Kalem, Rusmir Baljić, Aamer Ikram, Selçuk Kaya, Anna Líšková, Bálint Gergely Szabó, Bilal Ahmad Rahimi, Esmeray Mutlu Yılmaz, Alper Şener, Jordi Rello
Abstract
Fever of unknown origin (FUO) is a serious challenge for physicians. The aim of the present study was to consider epidemiology and dynamics of FUO in countries with different economic development. The data of FUO patients hospitalized/followed between 1st July 2016 and 1st July 2021 were collected retrospectively and submitted from referral centers in 21 countries through ID-IRI clinical research platform. The countries were categorized into developing (low-income (LI) and lower middle-income (LMI) economies) and developed countries (upper middle-income (UMI) and high-income (HI) economies). This research included 788 patients. FUO diagnoses were as follows: infections (51.6%; n = 407), neoplasms (11.4%, n = 90), collagen vascular disorders (9.3%, n = 73), undiagnosed (20.1%, n = 158), miscellaneous diseases (7.7%, n = 60). The most common infections were tuberculosis (n = 45, 5.7%), brucellosis (n = 39, 4.9%), rickettsiosis (n = 23, 2.9%), HIV infection (n = 20, 2.5%), and typhoid fever (n = 13, 1.6%). Cardiovascular infections (n = 56, 7.1%) were the most common infectious syndromes. Only collagen vascular disorders were reported significantly more from developed countries (RR = 2.00, 95% CI: 1.19-3.38). FUO had similar characteristics in LI/LMI and UMI/HI countries including the portion of undiagnosed cases (OR, 95% CI; 0.87 (0.65-1.15)), death attributed to FUO (RR = 0.87, 95% CI: 0.65-1.15, p-value = 0.3355), and the mean duration until diagnosis (p = 0.9663). Various aspects of FUO cannot be determined by the economic development solely. Other development indices can be considered in future analyses. Physicians in different countries should be equally prepared for FUO patients.