Evaluation of the epidemiological findings of acute rheumatic fever between 1981 and 2012

Introduction Acute rheumatic fever is a complication of group A βhemolytic streptococcal pharyngitis (1). The disease usually occurs in children between 5-14 years of age (2). It can be prevented with early detection and adequate treatment of streptococcal pharyngitis. Rheumatic valvular lesions will also minimized when secondary prophylaxis applied regularly (3,4). The diagnostic criteria for acute rheumatic fever was first described in 1944 by Jones, and it has been modified several times until 2015 (5-7). In 2015 the last modified criteria were accepted worldwide.


Introduction
Acute rheumatic fever is a complication of group A βhemolytic streptococcal pharyngitis (1).The disease usually occurs in children between 5-14 years of age (2).It can be prevented with early detection and adequate treatment of streptococcal pharyngitis.Rheumatic valvular lesions will also minimized when secondary prophylaxis applied regularly (3,4).The diagnostic criteria for acute rheumatic fever was first described in 1944 by Jones, and it has been modified several times until 2015 (5)(6)(7).In 2015 the last modified criteria were accepted worldwide.
Approximately 300.000 new cases are arised in the world between 5-14 years old children every new year.The majority of cases are seen in developing countries, and the incidence is 200-300/100.000.It is difficult to determine the true incidence in these countries because of the insufficient data collection.The actual incidence of population-based surveillance studies reach up to 500/100.000(9,10).Until now, there is not any nationwide study performed to detect the incidence and prevalence of acute rheumatic fever in Turkey, instead the studies were performed regionally (11,12).The aim of this study is to determine the incidence of acute rheumatic fever throughout Turkey.

Methods and materials
In this report, data were obtained from the population and hospital based studies.All studies about acute rheumatic fever in Turkey were screened in "Ulakbim national database, Higher Education thesis database and PubMed" by entering words like "ARF, acute rheumatic fever, rheumatic fever, RF, rheumatic heart disease and RHD".In this study, we added the unpublished data from pediatric cardiology department of medical schools and also research hospitals in Turkey.We analyzed 12 studies reported from Turkey.Because of the unreliable recordings, data before 1980 were excluded from the study.Data collections were analyzed by dividing the follow up period three decades, as 1981-1990, 1991-2000 and 2001-2012.Only the patients who had major diagnostic criteria of acute rheumatic fever arthritis, carditis, erythema marginatum, subcutaneous nodules and Sydenham's chorea; were included in this study.Other parameters such as minor criteria, supporting evidence, age and sex were excluded because of missing data and discrepancy among the centers.Patients with carditis were also classified according to valve involvement.

Statistical analysis
The statistical analysis was performed by SPSS (Statistical Package for the Social Sciences, Chicago, IL, version 16.0).Numeric variables are expressed as mean ± SD and categorical ones are expressed as percentages (%).

Discussion
According to Turkey Health Statistics Yearbook; in 1965, 1970 and 1975 the incidence of acute rheumatic fever was detected 36/100.000,39/100.000and 44/100.000,respectively.This study showed a dramatic decrease in the incidence of acute rheumatic fever when compared with the data of Health Statistics of Turkey prior to 1980.This dramatic decrease in the incidence is believed to be due to improvement of standards of living, nutrition and individual hygiene; widespread use of antibiotics, the increase in the number of pediatricians and pediatric cardiologists and also the awareness of the disease both among the physicians and the community.20).In our study, a marked decrease in the incidence of acute rheumatic fever was detected when compared with the data of Turkey Statistics of Health before 1980.This decrease can be due to social and cultural development of our country, economic development summit and corresponds to more globalized era.We found the incidence of acute rheumatic fever 2.6/100.000throughout Turkey between 1990-2000.In the same period, Örün et al. (12) reported the incidence of acute rheumatic fever was as 60/100.000 in central Anatolia region.In a local study in Ankara, Karademir et al. (21) detected the incidence of acute rheumatic fever as 107.7/100.000between the years 1990-1992.According to our information, among this period of time both in Turkey and throughout the world prevalence studies were dominated the literature; we could not find studies based on the incidence of acute rheumatic fever except the two studies mentioned above.When compared with the previous decade we observed that the incidence of acute rheumatic fever was doubled.The possible causes of this increase is due to the increase correct diagnosis of acute rheumatic fever rather than the increase in the number of the patients.Between 2001-2012 years the incidence of acute rheumatic fever was detected as 2.3/100.000throughout Turkey.In the same period, Örün et al. (12) found the incidence of acute rheumatic fever as 21/100.000 in Available online at www.jiacm.comCentral Anatolia region.Narin et al. (22) reported the incidence as 7.4/100.000between the years 1998-2011 in Kayseri.
In the same period the incidence of acute rheumatic fever in different parts of the world was reported as in Fiji 15.2/100.000between 2005-2007.Two study were reported from Israel between the years 2000-2005, incidence of acute rheumatic fever was detected as 3.2/100.000between 0-30 years of age, and in the other study including the patients between the years of age 5-14 the incidence was reported to be as 7.5/100.000(23,24).The incidence of acute rheumatic fever was not changed when compared with the previous decade.Acute rheumatic fever incidence can be as high as 50/100.000.The highest incidence has been reported in Australia and New Zealand (19,25).Örün et al. (12) reported the incidence of acute rheumatic fever as 21/100.000 in Central Anatolia region between 2000-2009 in Turkey.The incidence of acute rheumatic fever was quite low as 2.3/100.000during this period in Turkey.At the same time in the north of Australia acute rheumatic fever incidence was reported as 162/100.000 in males and 228/100.000 in females between 5-14 age (26).
In New Zealand, between the years 2000-2009, and among children whose age was between 5 and 14 years, the incidence of acute rheumatic fever was found in Maori, non-Maori/Pacific, Pacific and all children 40.2/100.000,2.1/100.000,81.2/100.000and 17.2/100.000,respectively.In the same study acute rheumatic fever incidence between the years 2000-2009 compared with 1993-2009 years, in 1993-2009 years acute rheumatic fever incidence was found in Maori and Pacific increased 79% and 73%, respectively, but in non-Maori/Pacific decreased 71% (25).Similarly, in New Zealand acute rheumatic fever incidence was found to be 3.1/100.000and 46.1/100.000 in the region of Waikato and in the Maori population between the years 2002-2011, respectively.In the same period in the region of Northland the incidence of acute rheumatic fever in the whole population, in the population of Maori and in non-Maori population were found to be 7.7/100.000,24.8/100.000,0.6/100.000,respectively (26)(27)(28).The incidence of acute rheumatic fever was very low when compared to Maori population of New Zealand where it is almost the same with non-Māori / Pacific population.
We detected that the frequency of the major findings of acute rheumatic fever; arthritis, Sydenham's chorea and erythema marginatum did not change during the last three decades but the frequency of carditis was increased.This increased frequency may be attributed to the increased number of pediatric cardiologists and widespread use of echocardiography all over the country so that silent carditis were also be diagnosed.

Limitations
Most of our data were collected from the Central Anatolia and the Marmara regions of Turkey.Because the number of pediatric cardiology centers is relatively low in Black Sea and East regions of Turkey this study may not reflect the exact incidence in our country.

Conclusion
As a result, the incidence of acute rheumatic fever was more or less had a constant speed until 1980 in Turkey while there has been a rapid decline after the 1980s and this declined speed has remained unchanged at a fixed rate until 2012.We determined that the rate of the incidence of acute rheumatic fever in Turkey was similar to the rates observed in developed countries.The rapid decline in the incidence of acute rheumatic fever in Turkey may be attributed due to the improvement of individual hygiene, nutrition and standards of living, the decrease in the population, widespread use of antibiotics, the increased number of pediatricians and pediatric cardiology departments and the awareness of the disease both among physicians and public.We believe that the incidence of ARF might increase again, since in 2015 the newly defined diagnostic criteria of ARF facilitates the diagnosis of ARF in countries where the incidence of ARF is high.

Figure 1 .
Figure 1.Major components of acute rheumatic fever in Turkey between 1965-2012 years.
Approval: N.A. Informed Consent: N.A. Peer-review: Externally peer-reviewed.Conflict of Interest: No conflict of interest was declared by the author.Financial Disclosure: The author declared that this study has received no financial support.

Table 1 .
The incidence of acute rheumatic fever reported from outside of Turkey.

Table 3 .
Major components of acute rheumatic fever in Turkey between 1981-2012 years.