history that the patient had twice had myocardial infarctions during the last ten years, as well as had an acute cerebrovascular event with sinistral hemiplegia more than 15 years ago. apart from that the patient had hypertension, type 2 diabetes with diabetic nephropathy, hysteromyoma, cholelithiasis, osteoporosis and varicose pedi-vein disease. it was also learned that the patient regularly takes a number of antihypertensive drugs, urinatives and oral antihyperglycemic remedies, as well as statins, antiplatelet and nootropics. in the past the patient had undergone cholecystectomy due to cholelithiasis more than 20 years ago, as well as the extraction of a cataract of the right eye 4 years ago. the patient was admitted to cardiac intensive care unit at a general hospital diagnosed for acute transmural myocardial infarction. during the check-up moderate azotemia, mild erythronormoblastic anemia, proteinuria and lowering of left vascular ejection fraction were also identified. methods of evaluation there are currently several generally accepted methods of evaluating (measuring) comorbidity: cumulative illness rating scale (cirs): developed in 1968 by b. s. linn, it became a revolutionary discovery, because it gave the practicing doctors a chance to calculate the number and severity of chronic illnesses in the structure of the comorbid state of their patients. the proper use of cirs means separate cumulative evaluation of each of the biological systems: "0" the selected system corresponds to the absence of disorders, "1": slight (mild) abnormalities or previously had disorders, "2": illness requiring the prescription of medicinal therapy, "3": disease, which caused disability and "4": acute organ insufficiency requiring emergency therapy. the cirs system evaluates comorbidity in cumulative score, which can be from 0 to 56. as per its developers, the maximum score is not compatible with the patient's life. cumulative illness rating scale for geriatrics (cirs-g): this system is similar to cirs, but for aged patients, offered by m. d. miller in 1991. this system takes into account the age of the patient and the peculiarities of the old age disorders. the kaplan–feinstein index: this index was created in 1973 based on the study of the effect of the associated diseases on patients with type 2 diabetes during a period of 5 years. in this system of comorbidity evaluation all the present (in a patient) diseases and their complications, depending on the level of their damaging effect on body organs, are classified as mild, moderate and severe. in this case the conclusion about cumulative comorbidity is drawn on the basis of the most decompensated biological system. this index gives cumulative, but less detailed as compared to cirs, assessment of the condition of each of the biological systems: "0": absence of disease, "1": mild course of the disease, "2": moderate disease, "3": severe disease. the kaplan–feinstein index evaluates comorbidity by cumulative score, which can vary from 0 to 36. apart from that the notable deficiency of this method of evaluating comorbidity is the excessive generalization of diseases (nosologies) and the absence of a large number of illnesses in the scale, which, probably, should be noted in the "miscellaneous" column, which undermines (decreases) this method's objectivity and productivity of this method. however the indisputable advantage of the kaplan–feinstein index as compared to cirs is in the capability of independent analysis of malignant neoplasms and their severities. using this method patient s's, age 73, comorbidity can be evaluated as of moderate severity (16 out of 36 points), however its prognostic value is unclear, because of the absence of the interpretation of the overall score, resulting from the accumulation of the patient's diseases. charlson index: this index is meant for the long-term prognosis of comorbid patients and was developed by m. e. charlson in 1987. this index is based on a point scoring system (from 0 to 40) for the presence of specific associated diseases and is used for prognosis of lethality. for its calculation the points are accumulated, according to associated diseases, as well as the addition of a single point for each 10 years of age for patients of ages above forty years (in 50 years 1 point, 60 years 2 points etc.). the distinguishing feature and undisputed advantage of the charlson index is the capability of evaluating the patient's age and determination of the patient's mortality rate, which in the absence of comorbidity is 12%, at 1–2 points it is 26%; at 3–4 points it is 52% and with the accumulation of more than 5 points it is 85%. regretfully this method has some deficiencies: evaluating comorbidity severity of many diseases is not considered, as well as the absence of many important for prognosis disorders. apart from that it is doubtful that possible prognosis for a patient with bronchial asthma and chronic leukemia is comparable to the prognosis for the patient ailing from myocardial infarction and cerebral infarction. in this case comorbidity of patient s, 73 years of age according to this method, is equivalent to mild state (9 out of 40 points). modified charlson index: r. a. deyo, d. c. cherkin, and marcia ciol added chronic forms of ischemic cardiac disorder and the stages of chronic cardiac insufficiency to this index in 1992. elixhauser index: the elixhauser comorbidity measure include 30 comorbidities, which are not simplified as an index. elixhauser shows a better predictive performance for mortality risk especially beyond 30 days of hospitalization. index of co-existent disease (iced): this index was first developed in 1993 by s. greenfield to evaluate comorbidity in patients with malignant neoplasms, later it also became useful for other categories of patients. this method helps in calculating the duration of a patient's stay at a hospital and the risks of repeated admittance of the same at a hospital after going through surgical procedures. for the evaluation of comorbidity the iced index suggests to evaluate the patient's condition separately as per two different components: physiological functional characteristics. the first component comprises 19 associated disorders, each of which is assessed on a 4-point scale, where "0" indicates the absence of disease and "3" indicates the disease's severe form. the second component evaluates the effect of associated diseases on the physical condition of the patient. it assesses 11 physical functions using a 3-point scale, where "0" means normal functionality and "2" means the impossibility of functionality. geriatric index of comorbidity (gic): developed in 2002 functional comorbidity index (fci): developed in 2005. total illness burden index (tibi): developed in 2007. analyzing the comorbid state of patient s, 73 years of age, using the most used international comorbidity assessment scales, a doctor would come across totally different evaluation. the uncertainty of these results would somewhat complicate the doctors judgment about the factual level of severity of the patient's condition and would complicate the process of prescribing rational medicinal therapy for the identified disorders. such problems are faced by doctors on everyday basis, despite all their knowledge about medical science. the main hurdle in the way of inducting comorbidity evaluation systems in broad based diagnostic-therapeutic process is their inconsistency and narrow focus. despite the variety of methods of evaluation of comorbidity, the absence of a singular generally accepted method, devoid of the deficiencies of the available methods of its evaluation, causes disturbance. the absence of a unified instrument, developed on the basis of colossal international experience, as well as the methodology of its use does not allow comorbidity to become doctor "friendly". at the same time due to the inconsistency in approach to the analysis of comorbid state and absence of components of comorbidity in medical university courses, the practitioner is unclear about its prognostic effect, which makes the generally available systems of associated pathology evaluation unreasoned and therefore un-needed as well. treatment of comorbid patient the effect of comorbid pathologies on clinical implications, diagnosis, prognosis and therapy of many diseases is polyhedral and patient-specific. the interrelation of the disease, age and drug pathomorphism greatly affect the clinical presentation and progress of the primary nosology, character and severity of the complications, worsens the patient's life quality and limit or make difficult the remedial-diagnostic process. comorbidity affects life prognosis and increases the chances of fatality. the presence of comorbid disorders increases bed days, disability, hinders rehabilitation, increases the number of complications after surgical procedures, and increases the chances of decline in aged people. the presence of comorbidity must be taken into account when selecting the algorithm of diagnosis and treatment plans for any given disease. it is important to enquire comorbid patients about the level of functional disorders and anatomic status of all the identified nosological forms (diseases). whenever a new, as well as mildly notable symptom appears, it is necessary to conduct a deep examination to uncover its causes. it is also necessary to be remembered that comorbidity leads to polypragmasy (polypharmacy), i.e. simultaneous prescription of a large number of medicines, which renders impossible the control over the effectiveness of the therapy, increases monetary expenses and therefore reduces compliance. at the same time, polypragmasy, especially in aged patients, renders possible the sudden development of local and systematic, unwanted medicinal side-effects. these side-effects are not always considered by the doctors, because they are considered as the appearance of comorbidity and as a result become the reason for the prescription of even more drugs, sealing-in the vicious circle. simultaneous treatment of multiple disorders requires strict consideration of compatibility of drugs and detailed adherence of rules of rational drug therapy, based on e. m. tareev's principles, which state: "each non-indicated drug is contraindicated" and b. e. votchal said: "if the drug does not have any side-effects, one must think if there is any effect at all". a study of inpatient hospital data in the united states in 2011 showed that the presence of a major complication or comorbidity was associated with a great risk of intensive-care unit utilization, ranging from a negligible change for acute myocardial infarction with major complication or comorbidity to nearly nine times more likely for a major joint replacement with major complication or comorbidity.