Stroke is the second most common cause of disability worldwide, with more than 70% of the patients having some form of disability [1]; accordingly, the rates of dependency and long-term mortality have increased as well [2]. Recently, mechanical thrombectomy has been established as an effective treatment for preventing disability in patients with ischemic stroke [3]; however, it is not effective in all patients [4]. Therefore, several patients continue to suffer from disabilities caused by stroke [2].

Intensive care is recommended for patients with stroke in the acute phase (including in the stroke-unit care) because they often experience neurological deterioration (ND) [3] ND is one of the causes of disability and is a poor prognostic factor in patients with ischemic stroke [5], [6]; it is often observed during the acute phase [7]. Several factors, such as age, blood pressure, atrial fibrillation, history of stroke, and diabetes mellitus, have been reported to be associated with ND in patients with ischemic stroke [6], [7], [8], [9], [10], [11]; however, the mechanisms underlying ND in these patients remain unclear.

Recently, with an increasing number of older patients with ischemic stroke [12], the number of cases of premorbid disability [13], frailty [14], and sarcopenia [15] have been increasing; this has led to difficulties in treatment and poor outcomes in these patients [13], [14], [15]. Particularly, previous studies have revealed that sarcopenia not only worsens the prognosis, but is also a risk factor for cardiovascular disease [16], [17], [18]. The risk factors for cardiovascular disease, such as diabetes mellitus, are related to the incidence of ischemic stroke; diabetes mellitus is also associated with ND in these patients [6], [7], [9]. Therefore, sarcopenia may be a risk factor for both ischemic stroke and ND. However, the relationship between sarcopenia and ND has not been studied so far.

Thus, this study aimed to investigate the relationship between premorbid sarcopenia and ND in patients with acute ischemic stroke.