Cognitive transitions based on functional status in older adults with heart failure: a population-based study.

Abstract

Cognitive impairment and functional status are both important determinants of poor outcomes in heart failure (HF). However, little is known about how functional status impacts the changes in cognitive status during the disease course. This study aimed to describe the cognitive transitions in patients with HF and assess the relationship of these transitions to functional status, which was assessed by the dependency of activities of daily living (ADL). This retrospective cohort study included 1764 patients with an International Classification of Diseases-10 code of HF (≥65years, mean age 82.3±7.9years, 39% male) from a long-term care and medical insurance database from Nobeoka city, a rural city of south-western Japan. Cognitive status at baseline and 6, 12, 18, and 24month time points was collected, and participants were stratified based on ADL status at baseline. Generalized estimating equations and multi-state modelling were used to examine associations between ADL dependency and cognitive changes/mortality. Transition probabilities were estimated using multi-state modelling. At baseline, there were 1279 (73%) and 485 (27%) patients with independent and dependent ADL, respectively. In overall patients, 1656 (93.9%) patients had normal/mild cognitive status and 108 (6%) patients had a moderate/severe cognitive status at baseline. The majority [104 (96%) patients] of patients with moderate/severe cognitive status at baseline had dependent ADL. In patients with moderate/severe cognitive status, the number of patients with dependent ADL always outnumbered that of the independent ADL throughout the follow-up. Multi-state modelling estimated that patients with dependent ADL and normal/mild cognitive status at baseline had 47% probability of maintaining the same cognitive status at 24months, while the probability of maintaining the same cognitive status was 86% for those with independent ADL. Patients with normal/mild cognitive status in the dependent ADL group at baseline had a higher risk of experiencing a transition to moderate/severe cognitive status at any time point during 24months compared with those with independent ADL [hazard ratio 5.24 (95% confidence interval 3.47-7.90)]. In older patients with HF, the prevalence of cognitive impairment was always higher for those with reduced functional status. Despite having a normal/mild cognitive status at baseline, patients with dependent ADL are at high risk of experiencing cognitive decline over 24months with substantially less chance of maintaining their cognitive status. ADL dependency was an important risk factor of cognitive decline in patients with HF.