The Association Between Baseline Blood Pressure And Short-term Outcome In Patients With Acute Ischemic Stroke

Objectives Early elevation of blood pressure(BP)is common after acute ischemic stroke(AIS)and several studies have been investigated the association between baseline BP and the clinical outcome in patients with AIS.However,evidence on the short-term prognostic of baseline BP among patients with AIS are conflicting.We investigated the association between various BP,including systolic BP(SBP),diastolic BP(DBP),pulse pressure(PP)and mean arterial pressure(MAP)upon hospital admission and short-term outcome in acute ischemic stroke patients.Methods Data of 3450 cases of acute ischemic stroke enrolled from December 1,2013 to May 31,2014 across 22 hospitals in Suzhou city were used for the present studies.Patients baseline information,including patient demographics,vascular risk factors,stroke severity(National Institutes of Health Stroke Scale [NIHSS],modified Rankin Scale score[mRS]),medication use and laboratory variables were collected.The baseline SBP and DBP were collected upon hospital admission and PP as well as MAP were calculated from SBP and DBP.The primary outcome was the combined end point of death or disability(mRS 3-6)at hospital discharge,the secondary outcome were death and major disability(mRS 3-5)separately at hospital discharge.We divided patients into 4 groups according to their level of baseline SBP,DBP,PP,and MAP.Logistic regression models were used to estimate the risk of primary and secondary outcome among different level of baseline SBP,DBP,PP,and MAP.Odds ratios(OR),and 95% confidence interval(CI)were calculated for each group with the Q1 or Q2 as reference.Potential confounders that were adjusted in the multivariable models included age,sex,time from onset to admission,baseline NIHSS score,Oxfordshire Community Stroke Project(OCSP)classification and other confounders.Different subgroup analysis and SBP,DBP,PP,and MAP as continual valuable were used to assess the robustness of the association between different SBP,DBP,PP,and MAP levels and the primary outcome.Results(1)During hospitalization,1318 patients(38.2%)experienced poor functional outcome(mRS 3-6)and 2132 patients(61.8%)experienced good functional outcome(mRS 0-2)among 3450 AIS patients.In comparison to good functional outcome participants,those with poor functional outcome were more likely to be older,female,high level of SBP,PP,high level of blood glucose and MAP and had more severe stroke(higher NIHSS)and other co-morbidities including stroke,coronary heart disease,and atrial fibrillation.(2)3428 cases with baseline BP data were included in our analysis.We divided patients into 4 groups according to their level of admission SBP: Q1(<138mm Hg),Q2(138-150 mm Hg),Q3(150-166 mm Hg)and Q4(?166mm Hg).The ordinal multivariable logistic regression models shown a high level of baseline SBP(from Q1 to Q4)was significant associated with a high mRS scores at hospital discharge(P<0.001).Compare to patients with lowest SBP(Q1),multivariable logistic regression models indicated patients with highest SBP(Q4)was significant with a high risk of death or major disability(OR1.54,95% CI: 1.16-2.03;P-trend=0.001)as well as major disability alone(OR 1.37,95%CI: 1.08-1.74;P-trend=0.008)but not all-cause mortality(P-trend=0.569).(3)We divided cases into 4 groups according to their level of admission DBP: Q1(<78mm Hg),Q2(78-84 mm Hg),Q3(84-92 mm Hg)and Q4(?92mm Hg).The ordinal multivariable logistic regression models shown a high level of baseline DBP(from Q1 to Q4)was associated with a high mRS scores at hospital discharge(P=0.024).Compare to patients with lowest DBP(Q1),multivariable logistic regression models indicated patients with highest DBP(Q4)was significant with a high risk of death or major disability(adjusted OR 1.44,95% CI: 1.09-1.90;P-trend=0.005)as well as major disability alone(adjusted OR 1.37,95% CI: 1.08-1.74;P-trend=0.016);Compare to patients with the second quartile DBP(Q2),multivariable logistic regression models indicated patients with highest DBP(Q4)was not increase the risk of all-cause mortality(P-trend=0.716).(4)We divided cases into 4 groups according to their level of admission PP: Q1(<53mm Hg),Q2(53-65 mm Hg),Q3(65-80 mm Hg)and Q4(?80mm Hg).The ordinal multivariable logistic regression models shown a high level of baseline PP(from Q1 to Q4)was significant associated with a high mRS scores at hospital discharge(P<0.001).Compare to patients with lowest PP(Q1),multivariable logistic regression models indicated patients with highest PP(Q4)with a high risk of death or major disability(OR1.30,95% CI: 0.98-1.72;P-trend=0.047)but not all-cause mortality(P-trend=0.272),major disability alone(P-trend=0.327).(5)We divided cases into 4 groups according to their level of admission MAP: Q1(<98mm Hg),Q2(98-107 mm Hg),Q3(107-117 mm Hg)and Q4(?117mm Hg).The ordinal multivariable logistic regression models shown a high level of baseline MAP(from Q1 to Q4)was significant associated with a high mRS scores at hospital discharge(P=0.005).Compare to patients with lowest MAP(Q1),multivariable logistic regression models indicated patients with highest MAP(Q4)was significant with a high risk of death or major disability(OR 1.72,95% CI: 1.29-2.30;P-trend<0.001)as well as major disability alone(OR 1.50,95% CI: 1.17-1.92;P-trend=0.002);Compare to patients with the second quartile MAP(Q2),multivariable logistic regression models indicated patients with highest MAP(Q4)was not increase the risk of all-cause mortality(P-trend=0.299).(6)In different subgroup including age,sex,baseline NIHSS score,history of hypertension,history of diabetes mellitus,the association between high level of baseline SBP,DBP,PP,and MAP and increased risk of death or major disability were still significant.(7)The association between high level of baseline SBP,DBP,PP,and MAP and a high risk of death or major disability were still significant for SBP,DBP,PP,and MAP as continual valuable(by 10 mm Hg increase).Conclusions Among patients with AIS,there were a significant association between baseline BP level,including SBP,DBP,PP and MAP and short-term outcome.A high level of baseline SBP,DBP,PP and MAP was associated with a high risk of death or major disability,major disability alone,but not all-cause mortality at hospital discharge.