Years of life lost due to lower extremity injury in association with dementia, and care need: a 6-year follow-up population-based study using a multi-state approach among German elderly

Abstract

BackgroundDementia and care need are challenging aging populations worldwide. Lower extremity injury (LEI) in the elderly makes matters worse. Using a multi-state approach, we express the effect of LEI on dementia, care need, and mortality in terms of remaining life expectancy at age 75 (rLE) and years of life lost (YLL).MethodsA population-based random sample of beneficiaries aged 75–95 years was drawn from the largest public health insurer in Germany in 2004 and followed until 2010 (N 62,103; Mean Age ± SD 81.5 ± 4.8 years; Female 71.2 %). We defined a five-state model (Healthy, Dementia, Care, Dementia & Care, Dead), and calculated transition-specific hazard ratios of LEI using Cox regression. The transition probabilities as well as the YLL due to LEI were estimated.ResultsLEI significantly increased the risk for each transition, with a maximum risk for the transition from Healthy to Care (HR: 1.70, 95 % CI: 1.63-1.77) and a minimum risk for the transition from Care to Dead (HR: 1.16, 95 % CI: 1.10-1.22). If the elderly had LEI-history, their age-specific mortality was generally higher and their probabilities of transient states peaked at younger ages. At age 75, initially dementia-free and care-independent elderly experiencing LEI lost about 2 years of life, of which more than 90 % were life years free of dementia or care need. Dementia patients lost about one and a half year, more than 60 % were free of long-term care need.ConclusionsLEI not only casts a large health burden on care need, but is also associated with cognitive decline and shortened rLE. LEI plus dementia extend the relative life time in need of care, despite generally shortening rLE. Using the composite measure YLL may help to better convey these results to the elderly, families, and health professionals. This may strengthen preventive measures as well as improve timely and rehabilitative treatment of LEI, not only in cognitive and physically intact elderly.Electronic supplementary materialThe online version of this article (doi:10.1186/s12877-016-0184-7) contains supplementary material, which is available to authorized users.

Age × stage‐classified demographic analysis: a comprehensive approach

“…They classify individuals by age and spatial location, and were one of the earliest applications of matrix population models (Rogers 1968) and have been extensively developed in human demography (e.g., Rogers 1975) and ecology (Lebreton 1996, 2005, Lebreton et al 2000. There is a rich literature in health demography of multistate models (e.g., Willekens 2014) in which individuals are classified by age and health status (see, e.g., Wu et al [2006] for colorectal cancer, Zhou et al (2016) for dementia, or Honeycutt et al (2003) for diabetes). These models focus on longevity and occupancy times in various age-stage combinations, and include only the survival and transition portion of the life cycle.…”

Extremity injuries and dementia disproportionately increase the risk for long-term care at older age in an analysis of German Health Insurance routine data for the years 2006 to 2010

“…As a viable treatment for dementia is not expected to be forthcoming in the foreseeable future and as EI and dementia often occur together, preventing EI or improving their treatment could be a promising strategy to counter LTC need in ageing societies. Because mobility limitations have also been shown to cause or accelerate the onset of dementia [14], better EI prevention and rehabilitation may not only reduce the direct LTC risk, but may also help to prevent dementia. Special attention can be paid to exercises that promote regular activity and which train gait and balance, because they can help prevent falls and subsequent injuries in the first place, but evidence on their effectiveness is mixed and suggests that especially for frail people, exercise alone does not protect from falls, so focusing on the safety of mobility is of high importance.…”

“…Not much is known about the combined effects of EI and dementia on LTC, especially in terms of a finer distinction of severe and non-severe injuries of the lower, upper or both extremities. EI and dementia are discrete LTC risks, but can also be causally related and are often present together [12–14]. …”

“…Lower EI that limit mobility might be even more influential. Thus, the onset of mobility problems, such as unsteady gait, is recognized as a valid predictor of later cognitive decline [14, 18, 19]. An EI can also indirectly increase the risk for dementia due to a subsequent delirium, which is a risk factor for dementia as well [20].…”

“…Conversely, dementia is a pre-existing condition for many fractures, because cognitive deterioration also affects gait and balance, increasing the risk of falling [9, 14, 21, 22]. Dementia thus leads to earlier or more frequent falls and may also increase the severity of fall-related injuries.…”