Diseases of the circulatory system in the Kyrgyz Republic in the period of 2002–2017

To analyze a tendency in circulatory system diseases (CSD) in Republic (KR). Material Medical statistics on morbidity, prevalence, mortality, and primary disability related with CSD in the adult population was obtained from the National Health Information Center (NHIC) of the Ministry of Health of the KR and the National Statistical Committee of the KR. For the purpose of comparative analysis, relative values were calculated per 100,000 and 10,000 population. A retrospective epidemiological study of prevalence, morbidity, mortality, and primary disability related with CSD for 2002–2017 was performed with calculation of the increase / decrease rate using the least square method for aligning the dynamic row. Also, the epidemiological situation of CSD was analyzed by sex and in 9 administrative divisions of the KR with calculation of the mean long-term incidence (MLTI) of CSD from 2007 through 2017. Statistical analysis was performed with specialized Statistica 10.0 and SPSS 11.5 software. Results Mean long-term indexes of CSD significantly differ in different regions and cities of the KR. The highest primary morbidity and prevalence of CSD is observed in Bishkek (1546.90 / 0000 and 12415.40 / 0000). Relatively low levels of these values are found in the Talas Region (720.70 / 0000 and 3675.10 / 0000, respectively). Conclusion CSD remains the major cause of death and primary disability in the population of the KR. Prevalence of CSD shows a pronounced increasing trend whereas the increase in incidence rate is moderate. The major structure of CSD is determined by essential hypertension, ischemic heart disease, and cerebrovascular diseases. Incidence of CSD is statistically significantly higher for women than for men. Mean long-term indexes of CSD significantly differ in different regions and cities of the KR. Therefore, it is essential to enhance preventive measures in the KR; to identify individuals with hypertension at the level of primary care; and to motivate healthcare professionals to improve the quality of healthcare (CSD prevention, detection, and treatment).

C ardiovascular diseases (CVDs) are the leading cause of death worldwide. According to the World Health Organization (WHO), 17.9 million people died of CVDs in 2016, for 31 % of all deaths worldwide. Heart attacks and strokes were causes of death in 85 % of these cases. The problem of CVDs has remained an issue in the Kyrgyz Republic (KR) for more than a decade. Circulatory diseases (CDs), which have increased in incidence, are the leading cause of mortality among the Kyrgyz population. According to official statistics, CDs rank first in the structure of total mortality due to CVDs and cause almost one-half (51.6 % in 2017) of deaths. More than 18 thousand people die, on average, of CDs in KR annually, or about 50 people every day. The objective of this study was to analyze the trends of CD morbidity in KR.

Material and methods
Medical statistics on CD incidence, prevalence, mortality, and first-time disablement in adults were obtained from the Republican Medical Information Center (RMIC) of the Ministry of Healthcare of KR and the Natio nal Statistical Committee of KR. The relative values for 100,000 thousand and 10,000 people were calculated for comparative analysis. A retrospective epidemiological study of the CD prevalence, incidence, mortality, and firsttime disablement was carried out in 2002-2017, and the rate of increase (decrease) was calculated using the leastsquare regression to align the statistical series. The rate of increase or decrease determines the trend: • from 0 to ±1 % -the incidence is stable; • from ±1.1 % to ±5.0 % -the trend is moderate; ORIGINAL ARTICLES § • more than ±5 -the trend is pronounced.
Sex-adjusted epidemiological analysis of CDs was performed, including the calculation of the mean annual incidence from 2007 to 2017 in nine administrative territories of KR.
Statistical processing of findings was carried out using the Statistica 10.0 and SPSS 11.5 software suites.

Results
The annual mean of the KR resident population for 2017 was 6,198,500 people.
Analysis of available statistics showed that the epidemiological situation in KR is acute due to the spread of CVDs, which has been the leading cause of death for many years, ranking first in the structure of all-cause mortality ( Table 1). In 2007-2017, the proportion of CDs in the all-cause mortality structure increased 1.07-fold.
Within the analyzed period, CD mortality rates ranged from 278.6 to 349.70 per 10,000 people and had a slight downward trend (0.3 % vs. 2007) ( Figure 1).
It was found that the general prevalence of CDs in the adult KR population varied from 4,805.9 to 7,879.50 per 10,000 people within several years with a clear upward trend (the rate of increase was 6.8 % vs. 2002) ( Figure 2). Primary morbidity rates ranged from 1,050.8 to 1,344.30 per 10,000 people with a moderate upward trend (the rate of increase was 3.5 %).
These CVDs result in premature disability and loss of the capacity to work as well as being the leading cause of mortality in KR. According to the RMIC data for 2007-2017, the proportion of CDs among the causes of firsttime disability was 19.68 %, significantly exceeding that of other diseases and ranking first during this period (Figu re 4).
Analysis of sex distribution of CVDs for 2007-2017 ( Figure 5) showed that the incidence of CDs in female patients was higher than that in male patients (59.0 % and 41.0 %, p < 0.001).  KR is formed by nine administrative territories, inclu ding seven provinces and two cities of national significance. According to the mean annual data (2007-2017), the highest incidence and prevalence rates of CDs among the nine administrative territories of KR were registered in Bishkek ( Figure 6). Chuy and Batken provinces are in a grave situation, followed by Naryn and Issyk-Kul provinces. In Jalal-Abad and Osh provinces, as well as Osh, the mean annual prevalence and incidence rates were almost the same. They are relatively low in Talas province.  [2].

Discussion
In KR, various campaigns have been developed to reduce CD morbidity and mortality under the national health policy, including «Healthy Heart to Every Kyrgyz Resident by 2010,» «Manas Taalimi for 2006-2010,» «Den Sooluk,» and «CVD Control Package Program for 2009-2013.» However, despite all these healthcare efforts, the prevalence of CDs remains relatively high, and they remain the leading cause of death in the Kyrgyz population. In addition, CDs lead to loss of ability to work and are therefore an enormous economic burden to the state [3,4].
Analysis of mortality cause statistics showed that CDs define the total mortality of the Kyrgyz population. In 2007-2017, there was also an increase in cardiovascular pathology mortality rates in the structure of total mortality. The authors of previous studies also noted an increase in cardiovascular mortality, such as a 25 % increase in 1991-1996 [3,4]. Over the past 20 years, the mean death rate from CVDs has increased by 40.5 % in people aged 30-39 years and 18.1 % in people aged 40-59 years. More than 18,000 people die of heart disease every year in KR, and about 50 people die every day [5]. Foreign authors report similar data. For example, CDs remain the main causes of death (52 %) in the Republic of Bashkortostan, Russian Federation [6,7]. In 2016, the CVD mortality rate was 49 % in the Moscow region [8]. CDs still predominate among causes of death in the Russian population (44 % and 49.6 % of total mortality in male and female patients, respectively) [9].
The economic burden of the population's disability is highly significant because most people who recognized to have disabilities for the first time are of working age and are excluded from the sphere of public production due to their diseases. The state bears enormous expenditures   in social security, medical care, and rehabilitation of people with disabilities [10]. According to 2007 data, the economic damage from the first-time disability retirement was 9.7 million soms a year in KR. Together with the economic damage caused by the premature death among the working-age Kyrgyz population caused by CVDs, the annual economic losses exceeded 53 million soms. These amounts have increased many times due to inflation. Not to mention indirect losses and family costs caused by the death of a family member, often the main breadwinner [4]. CDs were the leading causes of first-time disability in KR from 2002 to 2017, which is consistent with the data reported by the foreign authors. For example, CDs have ranked first among the reasons for first-time disability of the adult population in the various Russian regions for many years [11,12]. CVDs are also the main causes of disability in Tajikistan [13,14].
Sex-related analysis of CDs shows that CVDs are more common in female than in male patients. The prevalence of CDs (except for myocardial infarction) is also higher in the female population of Uzbekistan [15]. Globally, CVDs are the major causes of morbidity, disability, and mortality in men and women. A decrease in CAD morbidity and mortality has been reported in men, but not in women [16]. Women have a worse prognosis for CVDs than men. More women die of the first myocardial infarction and within the following 12 months [17].
Hypertension is a CVD itself and a leading risk factor that largely determines the development of many diseases globally, such as CAD, heart failure, cerebrovascular disease, peripheral artery disease, chronic kidney disease, and atrial fibrillation. The general prevalence of hypertension in the population aged ≥ 18 years old is 30 % -45 % and increases sharply with age [1].
In Kyrgyzstan, hypertension (51.2 %) predominates among CDs, followed by CAD (28.0 %), cerebrovascular disease (10.0 %), and other CVDs (10.8 %). According to the Russian Federal Service of State Statistics, in 2018 the proportion of CDs caused by hypertension was 44.2 %, that caused by CAD was 21.4 %, and that caused by cerebrovascular disease was 19.7 % [12]. The  Bishkek Osh Batken province Jalal-Abad province Issyk-kul province Naryn province Osh province Chuy province Talas province Figure 6. Mean annual (2007-2017) incidence and prevalence of circulatory diseases among administrative territories of Kyrgyz Republic (per 100,000 people) 19,68

Injuries and poisonings Congenital abnormalities (birth defects)
Diseases of the genitourinary system Diseases of the musculoskeletal system and connective tissue Diseases of the skin and subcutaneous tissue Diseases of the digestive system Diseases of the respiratory system Diseases of the ear and mastoid process Diseases of the eye and adnexa Diseases of the nervous system Mental and behavioral disorders Endocrine, nutritional and metabolic diseases Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism Neoplasms Certain infectious and parasitic diseases Circulatory diseases (CDs)    [19]. The mean 2007-2017 annual prevalence in the nine Kyrgyz administrative territories ranged from 12,415.40 per 10,000 in Bishkek to 3,675.10 per 10,000 people in Talas province; incidence ranged from 1,633.90 per 10,000 people in the Batken province to 720.70 per 10,000 people in Talas province. The inter-territory differences in the incidence and prevalence rates appear to be due to the different professional levels of medical personnel and the availability of treatment and diagnosis services in the major cities and rural territories of the country. However, further research is required to identify regional specificities in the incidence and prevalence of CDs, such as causes and factors of their development in different segments of the population.

Conclusion
• Circulatory diseases remain the leading causes of mortality and first-time disability among the Kyrgyz population. • The prevalence of circulatory diseases has a clear upward trend, and the incidence is growing moderately. • The structure of circulatory diseases is mainly defined by hypertension, CAD, and cerebrovascular diseases. • Circulatory diseases are statistically more common in women than in men. • The mean annual rates of CDs vary significantly in different Kyrgyz regions and cities. • Given these findings, it is necessary to strengthen preventive care and identify people with hypertension in a timely manner at the primary health care level, and motivate healthcare professionals to improve the quality of medical care for the population (prevention, detection, treatment of CVDs) in the Kyrgyz Republic.

No conflict of interest is reported.
The article was received on 17/10/19