Lecture 5

1. Morbidity of the population. Sources and methods of its studying Lecture 5

2. Morbidity is one of the major criteria characterizing health of the population. The morbidity is an indicator characterizing prevalence, structure and dynamics of the registered illnesses among the population in whole or in its separate groups (age, sex, territorial, professional, etc.) and serving one of the criteria of work assessment of a doctor, medical institution, public health services unit. As the object of scientific research and practical activities of public health services establishments morbidity represents a complex system of relative concepts:

3. Morbidity represents a complex system of relative concepts: • Incidence (primary disease incidence) – frequency of the new, nowhere recorded before and revealed for the first time in the given calendar year, diseases among the population; • prevalence(morbidity, accumulated disease prevalence) – frequency of all diseases existing among the population, both revealed for the first time in the given calendar year, and registered in previous years because of which the patient has appealed for medical aid in the given year again; • incidence of the diseases revealed at medical inspection(pathological affection, point prevalence) – frequency of pathology among the population, determined at carrying out of single medical inspections (examinations); as a result, all the diseases are considered, as well as premorbide forms and conditions.

4. Disease of the population is studied by three essentially various methods: • by data of population appealability for medical aid, • according to medical inspections, • by data of death causes. By appealability data one can study acute morbidity better as in the structure of appeals for medical aid acute forms of pathology (to 60-70 %) prevail and only the third part of patients appeals to medical institutions because of chronic diseases. Medical inspections are organized for chronic diseases unknown for doctors and medical institutions. The analysis of death causes gives insight about the most severe forms of the death causing diseases.

5. In morbidity statistics it is used to single out: • the general disease incidence (by data of appealability, according to medical inspections, under the analysis of death causes), • infectious morbidity, • morbidity with the main nonepidemic illnesses, • the hospitalized morbidity, • morbidity with temporal disability. The WHO specifies, that whatever morbidity index is calculated, it should correspond to a number of requirements: to be reliable, objective, sensitive, exact.

6. The general morbidity according to appealability data The account of all cases of diseases, with which the population has appealed for medical aid, is conducted in all medical institutions. At studying of the general morbidity by appealability data for a registration unit is accepted the first appealing to the doctor on occasion of the given disease within a calendar year. Diagnoses of acute diseases are registered at their every new occurrence, chronic diseases are considered only once a year, exacerbations of chronic diseases this calendar year are not re-registered as diseases.

7. At the morbidity analysis it is used to count a number of indices: • Primary disease incidence • The general disease incidence by appealability • Morbidity structure

8. . Dynamics of population morbidity in the Russian Federation by appealability data (‰) The morbidity analysis by appealability data shows, that its level is substantially defined by age of patients. Morbidity level at children is the highest, then morbidity by appealability data decreases and reaches the lowest level at adult population.

9. Structure of the general morbidity by appealability data of adult and children population of the Russian Federation Adult population • Respiratory diseases – 19 % • Blood circulation diseases – 15 % • Diseases of musculoskeletal system – 9 % • Diseases of digestive apparatus – 8 % • Other classes of diseases – 49 % Children population • Respiratory diseases – 40 % • Diseases of digestive apparatus – 8 % • Infectious and parasitic diseases – 6 % • Diseases of musculoskeletal system – 5 % • Other diseases – 40 % In morbidity structure, both at children, and at teenagers and adults respiratory diseases prevail, however at children they occur several times more often, than at adults.

10. Structure of morbidity • Respiratory diseases are presented mainly by acute forms of diseases: acute viral respiratory infections and flu, acute tonsillitis –it takes to 90 % of all cases of appeals. Rather insignificant part in the structure falls to a share of chronic diseases of this class: chronic pneumonia – 3 %, bronchial asthma – 1 %, and so on. • The second place in the structure of adult population morbidity is occupied by blood circulation diseases; first of all, it is ischemic disease of the heart – 33,5 %, cerebrovascular diseases – 21,9 %, essential hypertension – 17.8 %. On the third place in the structure of adult population morbidity there are diseases of musculoskeletal system and connective tissue diseases. • In the structure of children morbidity the second place is occupied by diseases of digestive apparatus, and in the third place there are infectious and parasitic diseases.

11. Iceberg of disease The quantity of the diseases revealed in a course of appealability of the population for medical aid is great, but it is considerably below the true number of diseases, which the population suffered within a year. Disease can be compared to an iceberg which surface part are illnesses that make the population appeal to medical institutions, and underwater part is formed by those who remain unknown for medical workers. Therefore, for more complete estimation of public health by appealability data it is necessary to supplement indices with the data received as a result of medical examinations. Whatthe physician sees Symptomatic disease Pre- symptomatic disease What the physician does not sees

12. Depending on tasks in view and used organizational technologies medical inspections subdivide to: • Preliminary medical examinations; • Periodic medical examinations; • Target medical examinations. Preliminary medical examinations are carried out at employment or study for the purpose of definition of conformity of a state of health to trade or training requirements, and also revealing diseases, which can progress in conditions of working with occupational hazards or during the course of study.

13. Another technologies of medical inspections • Target medical examinations are carried out, as a rule, for revealing of early forms of socially-significant diseases (malignant new growths, a tuberculosis, a diabetes, etc.) and cover various groups of the organized and unorganized population. • In the best way of carrying out of mass medical inspection, from the point of view of its quality, is its performance by brigade of experts. However, such examinations are connected with necessity of attraction of considerable personnel, financial, and material resources.

14. Organizational forms of medical examinations • Therefore the aspiration to cover the most possible part of the population by medical examinations with attraction of the limited volume of resources has caused working out and introduction of various organizational forms of inspection with use of various tests. These organizational forms bear the general name of "screening". The concept "screening" originates from an English word "screening" that means sifting, elimination, selection. • Screening is a mass inspection of the population and detection of persons with diseases or with initial signs of diseases. The screening main objective is to carry out primary selection of the persons demanding profound inspection, consultation of specialists, formations of higher risk groups with diseases of certain pathology. As a rule, target (screening) medical examinations are carried out in some stages.

15. Indicator of pathological involvement • As a result of medical examinations, there were revealed additional cases of diseases on occasion of which there were no appeals to the public health services organization within a year. The indicator of pathological involvement is calculated at that: • At well planned and carried out medical examinations 2000-2500 cases of diseases (per 1000 population), which were not the reason of patients’ reference to medical institutions additionally come to light. Besides, to obtain a full and objective picture of population morbidity cases of diseases, which have led to the patient’s death, but were not the reason of his appealing to medical-diagnostic establishments during lifetime should be registered as well. These cases are registered at postmortem study and forensic medical examination.

16. Infectious morbidity • The State Sanitary and Epidemiological Supervision Authority should be necessarily notified of each case of the revealed infectious disease. Infectious diseases are subject to the special account on all territory of Russia irrespective of a place of infection and citizenship of the patient. The list of obligatory infectious diseases for the notice is defined by the Ministry of Health Service of the Russian Federation. All infectious diseases subjected to the notification can be divided into following groups: • quarantine diseases is a conditional name of the infectious diseases group characterized by high contagiousness and high lethality to which the international quarantine restrictions according to the international medical and sanitary rules are applied. The plague, cholera, natural smallpox, yellow fever are considered quarantine diseases. About all cases of these diseases or suspicions to them the extraordinary report goes to public health services higher authorities when due hereunder;

17. Groups of infectious disease which are registered bythe State Sanitary and Epidemiological Supervision Authority • Diseases, each case of which is messaged to local authorities of the State sanitary and epidemiological supervision with detailed information about disease (belly typhus, paratyphus and other salmonelloses, dysentery, enterites, children's infections, meningitis, encephalites, infectious hepatitis, tetanus, poliomyelitis, hydrophobia, ricketsioses, malaria, leptospirosis, sepsis at children of the first month of life, hemorrhagic fevers, ornithosis, etc.); • diseases as the most socially significant illnesses with the simultaneous information of the State Sanitary and Epidemiological Supervision Authority; the information about these diseases is collected by the system of specialized curative and prophylactic establishments (tuberculosis, syphilis, gonorrhea, trachoma, mycoses, lepra, etc.); • diseases, about which the curative and prophylactic establishment gives only the total (digital) information to the State Sanitary and Epidemiological Supervision Authorities and which do not belong by classification to the class of infectious diseases (a flu, acute respiratory viral infection (ARVI).

18. The rules of registration • The medical worker who made the diagnosis or has suspected an infectious disease, is obliged within 12 hours to make "The Emergency notice about an infectious disease, food, acute, professional poisoning, unusual reaction to an inoculation" and to direct it to the territorial centre of the State sanitary and epidemiological supervision. • The state system of the statistical account of infectious diseases is necessary for carrying out against epidemic actions: the observation, revealing of contacts and infection sources, disinfection, vaccination and so on, and also gives the chance to receive the fullest representation about prevalence of infectious diseases in country territory.

19. Level of epidemic morbidity at Stavropol Territoryper 10 thousand population

20. Measles morbidity in dynamics (per 100000 population) • Many infectious diseases have wavy character of the course, therefore specific preventive maintenance (vaccination) it is necessary to carry out, even though the disease is at a low level for a number of years.

21. Non-epidemic diseases Alongside with the obligatory registering of infectious disease the special registration of the major non-epidemic diseases, to which tuberculosis, venereal diseases, mycoses, trachoma, etc belong. Some of them are considered both as infectious diseases, and as the major non-epidemic illnesses. The organization of the special registration of some diseases is connected by the fact, as a rule, that they demand early revealing, total examination of patients, their dispensary registration, constant supervision over them and special treatment, and in some cases –revealing of contacts as well.