Characteristics and outcomes of severe acute respiratory infection syndrome as indicator of severe forms of influenza

UVOD: Influenca je sezonska bolest koja zahvaća respiratorni sustav i značajan je uzrok pobola i smrtnosti pučanstva. Virusi influence neprestano se mijenjaju i odgovorni su za epidemije koje se pojavljuju svake godine u zimskim mjesecima, te uzrokuju teške oblike bolesti osobito u osoba s čimbenicima rizika. Pojava pandemijskog virusa influence A(H1N1)pdm09 naglasila je važnost uspostave sustava nadzora i praćenja influence, a jedna od mogućnosti je praćenje sindroma teške akutne respiratorne infekcije (SARI, od engl. Severe Acute Respiratory Infection) kao pokazatelj učinka influence na zdravlje pučanstva, osobito pobol i smrtnost, neovisno o dokazanim slučajevima influence. Cilj ovog rada bio je istražiti čimbenike rizika, klinička obilježja i ishode u bolesnika hospitaliziranih sa sindromom SARI. ----- METODE I BOLESNICI: Provedeno je prospektivno istraživanje u odraslih bolesnika hospitaliziranih u Klinici za infektivne bolesti „Dr. Fran Mihaljević“ u Zagrebu sa slikom SARI. Istraživanje je provedeno tijekom epidemije influence 2017./2018. godine. Za definiciju SARI korištena je definicija slučaja Svjetske zdravstvene organizacije. Podatci o obilježjima i ishodima uzeti su iz prijemnog i otpusnog lista svakog ispitanika. RT-PCR je bila metoda kojom je laboratorijski potvrđena influenca. ----- REZULTATI: Tijekom istraživanog razdoblja hospitalizirano je 497 odraslih bolesnika sa sindromom SARI. Tjedni broj slučajeva SARI odgovarao je broju slučajeva influence, i etiološki dokazanih i nedokazanih. Najčešći simptomi i znakovi bolesti bili su: kašalj (100%), vrućica u anamnezi (96.4%), tahipneja i/ili dispneja i/ili bol u rsima (70.8%) te vrućica pri prijemu (52.5%). Konačne otpusne dijagnoze u bolesnika bile su: akutna respiratorna infekcija u 429 (86.3%), sepsa u 34 (6.8%), uroinfekcija u 10 (2.0%), ostale infektivne bolesti u 19 (3.6%) te nejasno febrilno stanje u 6 (1.2%) bolesnika. Klinička dijagnoza influence potvrđena je u 264 (53.1%), a etiološki potvrđena u 204 (41%) bolesnika. Etiološka dijagnostika influence (RT-PCR) nije napravljena u 191 (38.4%) bolesnika. Indikaciju za cijepljenje protiv influence imalo je 439 (88.3%) bolesnika, a cijepljeno ih je bilo svega 71 (14.3%). Smrtnost među bolesnicima sa sindromom SARI iznosila je 8%, a u onih sa influencom 6.1% (u onih sa dokazanom influencom 6.4%, a sa nedokazanom influencom 5%). ----- ZAKLJUČAK: Praćenje sindroma SARI pokazalo se kao dobar pokazatelj aktivnosti virusa influence u populaciji i teških kliničkih oblika influence. Unapređenje nadzora i praćenja SARI pružilo bi javnozdravstvenim ustanovama korisne informacije te omogućilo bolje planiranje odgovarajućih intervencija u prevenciji i zbrinjavanju influence.INTRODUCTION: Influenza, a seasonal disease of the respiratory system, is a significant cause of morbidity and mortality. Rapidly mutating influenza viruses are responsible for annual winter epidemics causing severe illness, particularly in people with risk factors. The emergence of the pandemic influenza virus A(H1N1)pdm09 has exacerbated the need for the surveillance of severe acute respiratory infection (SARI) syndrome in order to determine the public impact of influenza, especially on morbidity and mortality, besides confirmed cases of influenza. The objective of this study was to investigate the risk factors, clinical features and outcomes in patients hospitalized with SARI. ----- METHODS AND PATIENTS: A prospective study was conducted on adult patients hospitalized for SARI, as defined according to the World Health Organization (WHO) surveillance case definitions, at the Dr Fran Mihaljević University Hospital for Infectious Diseases in Zagreb during the 2017/2018 influenza epidemic. Data on the symptoms and outcomes were taken from each patient’s hospital admission and discharge summaries. Reverse Transcription-Polymerase Chain Reaction (RT-PCR) was used for the laboratory confirmation of influenza. ----- RESULTS: During the study, 497 adult patients were hospitalized with SARI. The number of SARI cases per week corresponded to the number of etiologically confirmed and unconfirmed influenza cases. The most common symptoms were cough (100%), fever in the medical history (96.4%), tachypnea and/or dyspnea and/or chest pain (70.3%) and fever on admission (52.5%). The final discharge diagnoses were acute respiratory infection in 429 (86.3%) of the patients, sepsis in 34 (6.8%), urinary tract infection in 10 (2.0%), other infectious diseases in 19 (3.6%) and febrile state of unknown origin in 6 (1.2%). The diagnosis of influenza was clinically confirmed in 264 (53.1%) of the patients and etiologically confirmed in 204 (41%). Etiological diagnosis of influenza (RT-PCR) was not performed in 191 (38.4%) of the cases. There were 439 patients (88.3%) with indications for influenza vaccination but only 71 (14.3%) had been vaccinated. Mortality among the patients with SARI was 8%, and 6.1% among the patients with influenza (6.4% among confirmed influenza cases and 5% among unconfirmed cases). ----- CONCLUSION: Surveillance of SARI has been shown to be a good indicator of influenza virus activity and severe clinical forms of influenza among the population. Improvement in the surveillance of SARI would provide public health services with useful information for the planning of appropriate interventions for the prevention and management of influenza