Background and aim Cognitive impairment and sleep disorder are both common poststroke conditions and are closely related to the prognosis of patients who had a stroke. The Impairment of CognitiON and Sleep after acute ischemic stroke or transient ischemic attack in Chinese patients (ICONS) study is a nationwide multicentre prospective registry to investigate the occurrence and associated factors of cognitive impairment and sleep disorder after acute ischaemic stroke (AIS) or transient ischaemic attack (TIA).

Methods Consecutive AIS or TIA in-hospital patients within 7 days after onset were enrolled from 40 participating sites in China. Comprehensive baseline clinical and imaging data were collected prospectively. Blood and urine samples were also collected on admission and follow-up visits. Patients were interviewed face to face for cognition and sleep related outcomes at 2 weeks, 3, 6 and 12 months after AIS/TIA and followed up for clinical outcomes by telephone annually over 5 years.

Results Between August 2015 and January 2018, a total of 2625 patients were enrolled. 92.65% patients had AIS and 7.35% patients had TIA. Overall, the average age was 61.04 years, and 72.38% patients were male. Median National Institutes of Health Stroke Scale score was 3 in AIS patients.

Conclusions The ICONS study is a large-scale nationwide prospective registry to investigate occurrence and the longitudinal changes of cognitive impairment and sleep disorder after AIS or TIA. Data from this registry may also provide opportunity to evaluate associated factors of cognitive impairment or sleep disorder after AIS or TIA and their impact on clinical outcome.