Prognostic significance of age in patients with acute ischaemic stroke treated with intravenous thrombolysis

Aim of the study. To assess the influence of age on long-term functional outcome in patients with acute ischaemic stroke (AIS) treated with intravenous thrombolysis (IVT). Material and methods. We performed retrospective analysis of 362 AIS patients treated with IVT or IVT and subsequent mechanical thrombectomy in the University Hospital in Krakow, Poland. Patients were categorised into four subgroups by age: (I) below the age of 60, (II) 60 to 69, (III) 70 to 79, and (IV) 80 or more. The outcomes were assessed with modified Rankin scale ( mRS) 90 days after stroke onset, and defined as favourable (mRS 0-2), poor (mRS 3-5), or death (mRS = 6). Results. Patients aged 80 or more compared to those below 60 were more often women (72.64% vs. 26.76%, < 0.001), more often suffered from hypertension (94.34% vs. 60.56%, p < 0.001), ischaemic heart disease (27.36% vs. 8.45%, p = 0.002), atrial fibrillation (49.06% vs. 5.63%, p < 0.001), and premorbid disability (pre-stroke mRS >= 1: 17.92% vs. 1.41%, p < 0.001), less often were active smokers (0% vs. 27.14%, p < 0.001), more often had cardioembolic aetiology (50.00% vs. 16.90%, p < 0.001), and less often other stroke aetiology (1.89% vs. 15.49%, < 0.008), had shorter time from stroke onset to IVT (125 [93-180] vs. 140 [110-186] min, p < 0.008), less often underwent mechanical thrombectomy (18.87% vs. 46.48%, p <0.001), had higher CRP levels (10.3 [3.2-39.8] vs. 4.3 [2.1-9.6] mg/L, p =0.003), higher maximal systolic blood pressure within 24 hours after IVT (153 [140-170] vs. 138 [120-145] mmHg, p < 0.001), and higher creatinine concentration (88 [68-108] vs. 77 [67-87] mu mol/l, p = 0.004), less often had a favourable outcome (48.04% vs. 85.51%, odds ratio [OR] 0.16, 95%CI: 0.07-0.34, p < 0.001), and had a greater risk of death (26.47% vs. 5.80%, OR 5.85, 95%CI: 1.95-17.59, p < 0.001) within three months of stroke onset. Multivariable logistic regression analysis showed that the independent predictors of worse outcome in patients aged 80 or more were NIHSS score after IVT (OR 0.64, 95%CI: 0.53-0.78, p < 0.001), pre-stroke mRS score >= 1 (OR 0.10, 95%CI: 0.02-0.61, p = 0.012), and CRP levels (OR 0.96, 95%CI: 0.93-0.99, p = 0.007). Conclusions. AIS patients treated with reperfusion therapy and aged 80 or more have around a six times higher risk of an unfavourable outcome or death within three months of stroke onset compared to those aged below 60. Higher NIHSS score after IVT, any signs of disability before stroke as measured with mRS, and higher CRP levels are independent risk factors for worse prognosis in the elderly.