CO(2) combining power and outcomes in patients with acute ischaemic stroke or transient ischaemic attack

BACKGROUND AND PURPOSE: The clinical significance of carbon dioxide combining power (CO(2)CP) in ischaemic cerebrovascular disease is not well established, and the role of CO(2)CP in the prognosis of acute ischaemic stroke (AIS) or transient ischaemic attack (TIA) has not been reported. The objective of the study was to investigate the associations between CO(2)CP and clinical outcomes in patients with AIS or TIA. METHODS: Data were derived from the China National Stroke Registry III. Patients were classified into five groups by quintiles of CO(2)CP levels and three groups according to the normal range of CO(2)CP (23–29 mmol/L). Multivariable Cox and logistic regressions were adopted to explore the associations of CO(2)CP levels with all-cause death and poor functional outcomes (modified Rankin Scale (mRS) 3–6/2–6) at 3 months and 1 year. RESULTS: Among 9531 patients included in the study, the median (IQR) CO(2)CP was 24.9 (23.0–27.0) mmol/L. After adjustment for potential confounders, patients in the first CO(2)CP quintile (21.1–23.3 mmol/L) had higher risk of all-cause death and poor functional outcomes (mRS score of 3–6/2–6) (HR or OR with 95% CI 2.37 (1.32 to 4.25), 1.49 (1.20 to 1.83) and 1.21 (1.03 to 1.42), respectively) compared with those in the fourth quintile. Similar results were found for outcomes at 1 year. Furthermore, all associations were also significant when CO(2)CP was <23 mmol/L compared with CO(2)CP of 23–29 mmol/L. CONCLUSIONS: Decreased CO(2)CP was associated with high risk of all-cause death and poor functional outcomes in patients with AIS or TIA.