Aim The effect of health depreciation in older people on medical care demand is not well understood. We tried to assess the medical care demand with length of hospitalization and their impact on profits as a result of health depreciation. Methods All participants who underwent comprehensive geriatric assessment were from a prospective cohort study at a tertiary hospital. A total of 1191 cases between September 2008 to October 2012 were investigated. Three sets of qualitative response models were constructed to estimate the impact of older adults' health depreciation on multidisciplinary geriatric care services. Furthermore, we analyzed the factors affecting the composite end‐point of rehospitalization within 14 days, re‐admission to the emergency department within 3 days and patient death. Results Greater health depreciation in elderly patients was positively correlated with greater medical care demand. Three major components were defined as health depreciation: elderly adaptation function, geriatric syndromes and multiple chronic diseases. On admission, the better the basic living functions, the shorter the length of hospitalization (coefficient = −0.35, P < 0.001 in Poisson regression; coefficient = −0.33, P < 0.001 in order choice profit model; coefficient = −0.29, P < 0.001 in binary choice profit model). The major determinants for poor outcome were male sex, middle old age and length of hospitalization. However, factors that correlated with relatively good outcome were functional improvement after medical care services and level of disease education. Conclusions An optimal allocation system for selection of cases into multidisciplinary geriatric care is required because of limited resources. Outcomes will improve with health promotion and preventive care services. Geriatr Gerontol Int 2017; 17: 645–652.