Significance. Population ageing is associated with an increasing need for long-term follow-up and a growing burden on primary health care. In this context, hospital-substituting technologies, including outpatient day hospitals, become especially important as they help redistribute volumes of care and ensure continuity of treatment for older adults. Purpose. To assess the contribution of people over working age to the workload of the primary health care system in the city of Sevastopol in 2015-2024. Materials and methods. A retrospective descriptive and analytical study of primary health care performance indicators in Sevastopol for 2015-2024 was conducted. Data sources included federal statistical reporting forms on the activities of medical organizations and outpatient day hospitals for 2015-2024. Statistical processing was performed using Microsoft Excel 2019. Results. The average number of physician visits per resident (outpatient and home visits) increased from 6.01 to 7.04. The visit structure shifted toward prevention: the share of preventive visits rose from 32.12% to 45.79%, while the share of visits for medical conditions declined from 70.53% to 56.15%. The proportion of home visits decreased from 9.64% to 1.90%, while older adults continued to account for a high share of these visits (70.36% in 2015 and 63.23% in 2024). The contribution of older adults to outpatient workload increased: their share in total visits among adults aged 18+ rose from 36.50% to 44.03%, and in visits for medical conditions it exceeded 50% (from 48.99% to 51.15%). In day hospitals, the hospitalization rate increased from approximately 4.5 to approximately 16.8 cases per 1,000 population. Bed turnover reached 34.5 patients per bed per year, while the average length of stay decreased to 8.5–8.6 days (approximately 9.4 days among older adults). Discussion. The study reveals the structural adaptation of primary health care to population aging, characterized by a shift from reactive care to long-term management of chronic pathologies. The key adaptation mechanisms are day hospitals and home-based care; however, a reduction in the latter indicates a risk of unmet needs among patients with limited mobility. To improve system efficiency, patient stratification by degree of vulnerability and the development of multidisciplinary models of integrated care are required. Conclusions. In 2015-2024, outpatient utilization increased, and the contribution of people over working age to the primary health care workload, including disease-related visits, grew. The structure of care shifted towards preventive activities, while the share of home-based care declined in the post-pandemic period. Outpatient day hospitals demonstrated intensified resource use while maintaining the leading role of people over working age.