Diagnostic accuracy of major stroke types in Chinese adults: A clinical adjudication study involving 40,000 stroke cases

BACKGROUND: Widespread use of brain imaging in suspected stroke cases in Chinese adults has prompted the need for clinical adjudication studies of stroke types. We conducted a clinical adjudication study to assess the reporting and diagnostic accuracy of major stroke types. METHODS: The prospective China Kadoorie Biobank recruited >512,000 adults (mean age 52 years, 59% women) from 10 urban and rural areas in China during 2004–2008, and recorded 45,859 first-ever incident stroke cases during an 11-year follow-up. Medical records were retrieved in ∼85%, and clinical details were recorded using a handheld computer for specialist physician adjudicators who applied conventional WHO clinical criteria for diagnosis of stroke. The positive predictive value (PPV) for reported and adjudicated stroke cases was examined for major stroke types (ischaemic stroke [IS], intracerebral haemorrhage [ICH], subarachnoid haemorrhage [SAH]), calendar year, area, and hospital type. FINDINGS: Of 38,823 cases with retrieved medical records, the PPV for reported strokes was 91%. Among 29,952 adjudicated cases, the PPV for adjudicated cases was 81%, with higher PPV for ICH (n = 3391; 98%) and SAH (364; 98%) than for IS (20,473; 79%). Of 5504 cases with a verified IS diagnosis that was refuted on adjudication, 3763 (68%) had silent lacunar infarcts (LACI). The proportion of cases with silent LACI increased from 7.1% in 2004–2008 to 18.2% in 2016–2017. If cases with silent LACI were classified as IS, as advocated by new International Classification of Diseases (ICD-11) diagnostic criteria for stroke involving imaging and clinical rather than clinical criteria alone, the PPV increased to 93%. INTERPRETATION: While the overall reporting and diagnostic accuracy of stroke types in Chinese adults is high, the recent implementation of new diagnostic criteria for IS has important implications for contemporary clinical practice and research on stroke in Chinese populations. FUNDING: Kadoorie Charitable Foundation, Hong Kong, China, UK Wellcome Trust (212946/Z/18/Z, 202922/Z/16/Z, 104085/Z/14/Z, 088158/Z/09/Z), Chinese National Natural Science Foundation (91843302), and the National Key Research and Development Program of China (2016YFC0900500, 2016YFC0900501, 2016YFC0900504, 2016YFC1303904). British Heart Foundation, and UK Medical Research Council, and Cancer Research UK.