Introduction: The list of leading geriatric syndromes that determine the overall vitality and quality of life of people includes asthenia and sarcopenia. From a clinical point of view, early-onset age-associated diseases (EADs) (the most common are arterial hypertension, type 2 diabetes mellitus, age-related cataracts) are identical to manifestations of accelerated aging. The study of leading geriatric syndromes in people of different ages with a history of EADs seems especially relevant against the backdrop of a global problem associated with the consequences of the COVID-19 pandemic. The purpose of the study: to study the severity of geriatric syndromes (asthenia and sarcopenia) in middle-aged, elderly and senile people with age-associated diseases. Materials and methods: A prospective single-center observational case-control study was conducted. The study included 412 people. The main group - 335 patients of the hospital of the St. Petersburg State Budgetary Healthcare Institution "City multidisciplinary hospital №2" with EADs: arterial hypertension, type 2 diabetes mellitus, senile cataract. Control group – 77 practically healthy employees of the City multidisciplinary hospital №2. The comparison groups were stratified by age categories: middle age (45-59 years), elderly (60-74 years) and senile (75-89 years). The survey was based on the validated FRAIL and SARC-F scales. Statistical processing was carried out using the Excel 2010 and SPSS Statistics 20.0 application package. Results: It was revealed that in the presence of EADs, signs of asthenia and sarcopenia appear, regardless of the patient’s age. The severity of geriatric syndromes in middle-aged people with a history of EADs corresponded to the level of the elderly control group. The negative impact of COVID-19 on the signs of the considered geriatric syndromes was noted by 88.8% of middle-aged, 94.3% of elderly and 95.7% of senile respondents. Discussion: The data obtained with the considered EADs indicate an increase in the severity of important geriatric syndromes. Registration of signs of preasthenia and sarcopenia at an early stage of life may indicate an acceleration of the rate of aging in a particular population, which was especially noticeable in middle-aged people. The study results also demonstrate the impact of infection with the SARS-CoV-2 coronavirus on the development of geriatric syndromes of asthenia and sarcopenia. Conclusion: Thus, a tendency was found to increase the severity of geriatric syndromes such as asthenia and sarcopenia in middle-aged, elderly and senile patients with age-associated pathology. The vast majority of middle-aged, elderly and senile respondents noted the negative impact of COVID-19 infection on the signs of the geriatric syndromes considered.