Body Mass Index and Clinical Outcomes in Large Vessel Occlusion Acute Ischemic Stroke after Endovascular Therapy

The effect of body mass index on stroke prognosis: A systematic review and meta-analysis of 32 cohort studies with 330,353 patients

BACKGROUND

Many studies have explored the impact of body mass index (BMI) on stroke prognosis, yet findings remain inconsistent.

AIMS

The aims of this study were to conduct a systematic review and meta-analyses to summarize the existing evidence on BMI and stroke outcomes.

METHODS

PubMed, Web of Science, Embase, The Cochrane Library, CNKI, CBM, Wanfang Database, and VIP Database were systematically searched from inception to 1 January 2023. Cohort studies were included if they reported on a population of patients with stroke, evaluated BMI on stroke outcomes (mortality/recurrence/score of modified Rankin scale (mRs)), and reported original data. Data extraction and quality assessment were independently undertaken by two reviewers. Stata 16.0 software was used for meta-analysis.

RESULTS

Thirty-two studies involving 330,353 patients (5 Chinese language articles) were included in the analysis. The proportion of underweight, overweight, and obese patients was 1.85%, 18.2%, and 15.6%, respectively. Compared with normal weight, being underweight was associated with an increased risk of mortality (relative risk (RR) = 1.78, 95% confidence interval (CI) = 1.60-1.96), poor functional outcomes defined as modified Rankin scale ⩾ 3 (RR = 1.33, 95% CI = 1.22-1.45), and stroke recurrence (RR = 1.19, 95% CI = 1.04-1.37). Being overweight but not obese was associated with reduced mortality (RR = 0.81, 95% CI = 0.74-0.89) and better functional outcomes (RR = 0.92, 95% CI = 0.89-0.96), but did not alter the risk of stroke recurrence (RR = 1.03, 95% CI = 0.90-1.17). Obesity was associated with lower risk of mortality (RR = 0.76, 95% CI = 0.72-0.81) and better functional outcomes (RR = 0.89, 95% CI = 0.84-0.94).

CONCLUSIONS

Our findings indicate that in patients with stroke, being underweight is associated with an increased risk of mortality, poor functional outcomes, and stroke recurrence. In contrast, being overweight but not obese, or being obese, was associated with a decreased risk of mortality and better functional outcomes. This is consistent with the obesity paradox in stroke, whereby obesity increases stroke risk in the general population but is associated with improved outcome in patients suffering stroke.

Low body mass index patients have worse outcomes after mechanical thrombectomy

BACKGROUND

There is evidence that frailty is an independent predictor of worse outcomes after stroke. Similarly, although obesity is associated with a higher risk for stroke, there are multiple reports describing improved mortality and functional outcomes in higher body mass index (BMI) patients in a phenomenon known as the obesity paradox. We investigated the effect of low BMI on outcomes after mechanical thrombectomy (MT).

METHODS

We conducted a retrospective analysis of 231 stroke patients who underwent MT at an academic medical center between 2020-2022. The patients' BMI data were collected from admission records and coded based on the Centers for Disease Control and Prevention (CDC) obesity guidelines. Recursive partitioning analysis (RPA) in R software was employed to automatically detect a BMI threshold associated with a significant survival benefit. Frailty was quantified using the Modified Frailty Index 5 and 11.

RESULTS

In our dataset, by CDC classification, 2.6% of patients were underweight, 27.3% were normal BMI, 30.7% were overweight, 19.9% were class I obese, 9.5% were class II obese, and 10% were class III obese. There were no significant differences between these groups. RPA identified a clinically significant BMI threshold of 23.62 kg/m2. Independent of frailty, patients with a BMI ≤23.62 kg/m2 had significantly worse overall survival (P<0.001) and 90-day modified Rankin Scale (P=0.027) than patients above the threshold.

CONCLUSIONS

Underweight patients had worse survival and functional outcomes after MT. Further research should focus on the pathophysiology underlying poor prognosis in underweight MT patients, and whether optimizing nutritional status confers any neuroprotective benefit.

Weight status influences the effect of hyperglycemia at admission on clinical outcomes after endovascular thrombectomy

BACKGROUND

Insulin resistance is more prevalent in the overweight population, which can affect their glucose metabolism. This study explores whether weight status influences the relationship between admission hyperglycemia and outcomes after thrombectomy.

METHODS

Four hundred and fifty-two patients with acute anterior circulation ischemic stroke undergoing thrombectomy were retrospectively analyzed. Hyperglycemia at admission was described as venous blood glucose ≥7.8 mmol/L and overweight as body mass index ≥24 kg/m2. The outcomes included the rates of functional independence (90-day modified Rankin Scale 0-2), symptomatic intracranial hemorrhage within 24 h after thrombectomy, and mortality at 90 days.

RESULTS

Overall, hyperglycemia at admission decreased the likelihood of functional independence (adjusted odds ratio [OR] 0.50, 95% confidence interval [CI] 0.30-0.83, P = 0.008). Weight status modified the efficacy of admission hyperglycemia on functional independence (P = 0.022 for interaction). Hyperglycemia at admission was negatively associated with functional independence among overweight patients (adjusted OR 0.30, 95% CI 0.15-0.60, P = 0.001) but not among normal-weight patients (adjusted OR 1.13, 95% CI 0.48-2.70, P = 0.776). Weight status did not influence the efficacy of hyperglycemia at admission on mortality (P = 0.201 for interaction) or symptomatic intracerebral hemorrhage (P = 0.105 for interaction).

CONCLUSIONS

Weight status influenced the effect of hyperglycemia at admission on functional independence after thrombectomy. Hyperglycemia at admission was related to functional independence among overweight patients but not among normal-weight patients. Our findings suggest tight control of glucose may be needed for overweight patients in the thrombectomy setting.

The Influence of Body Mass Index on Outcomes in Patients Undergoing Mechanical Thrombectomy for Anterior Circulation Large Vessel Occlusion: Institutional Experience and Meta-analysis

BACKGROUND

An obesity paradox, whereby patients with higher body mass index (BMI) experience improved outcomes, has been described for ischemic stroke. It is unclear whether this applies to patients undergoing mechanical thrombectomy (MT) for large vessel occlusion (LVO).

METHODS

Mechanical thrombectomies for anterior circulation LVO between 2015 and 2021 at a single institution were reviewed. Multivariable logistic regressions were used to determine the association between BMI and favorable functional outcome (90-day modified Rankin Scale 0-2), intracranial hemorrhage, and malignant middle cerebral infarction. A systematic review was performed to identify studies reporting the effect of BMI on outcomes among patients receiving MT for LVO. The data from the systematic review were combined with the institutional data by using a random effects model.

RESULTS

The institutional cohort comprised 390 patients with a median BMI of 27 kg/m2. Most patients were obese [36.7% (BMI ≥ 30 kg/m2)], followed by overweight [30.5% (BMI ≥ 25 and < 30 kg/m2)], normal [27.9% (BMI ≥ 18.5 and < 25 kg/m2)], and underweight [4.9% (BMI < 18.5 kg/m2)]. As a continuous variable, BMI was not associated with any of the outcomes. When analyzing BMI ordinally, obesity was associated with lower odds of favorable 90-day modified Rankin Scale (odds ratio 0.42, 95% confidence interval 0.20-0.86). The systematic review identified three eligible studies comprising 1,348 patients for a total of 1,738 patients. In the random effects model, there was no association between obesity and favorable outcome (odds ratio 0.89, 95% confidence interval 0.63-1.24).

CONCLUSIONS

Obesity is not associated with favorable outcomes in patients undergoing MT for LVO.

Association of Chinese visceral adiposity index with clinical outcome in patients after endovascular thrombectomy

BACKGROUND AND PURPOSE

The Chinese Visceral Adiposity Index (CVAI) is a reliable indicator of visceral adiposity dysfunction in the Chinese population. We aimed to evaluate the association between CVAI and clinical outcome in Chinese ischemic stroke patients who received endovascular thrombectomy (EVT).

METHODS

This study retrospectively included patients with large vessel occlusive stroke receiving EVT treatment in 2 China stroke centers. Baseline CVAI was calculated after admission. Patients with a modified Rankin scale score ≥ 3 at 3 months after ischemic stroke were defined as poor outcome. Binary multivariate logistic regression models were utilized to explore the association between CVAI and the risk of 90-day unfavorable outcome.

RESULTS

A total of 453 patients (mean age, 70.4  ± 12.1 years; 280 male) were included. During the 90-day follow-up, 236 (52.1 %) patients experienced poor outcome. After multivariable adjustment for potential confounders, increasing CVAI was associated with an increased risk of 90-day poor outcome (odds ratios, per-standard deviation increase: 1.521; 95 % confidence interval, 1.127-2.052; P = 0.006). Similar significant results were observed when the CVAI was analyzed as a categorical variable. Furthermore, the multiple-adjusted spline regression model showed an inverted J-shape association between CVAI and risk of unfavorable outcome (P = 0.048 for non-linearity).

CONCLUSIONS

This study demonstrated that CVAI is positively correlated with 90-day poor outcome in Chinese ischemic stroke patients after EVT.

Non-linear association between body weight and functional outcome after acute ischemic stroke

This study aimed to determine whether body weight is associated with functional outcome after acute ischemic stroke. We measured the body mass index (BMI) and assessed clinical outcomes in patients with acute ischemic stroke. The BMI was categorized into underweight (< 18.5 kg/m²), normal weight (18.5-22.9 kg/m²), overweight (23.0-24.9 kg/m²), and obesity (≥ 25.0 kg/m²). The association between BMI and a poor functional outcome (modified Rankin Scale [mRS] score: 3-6) was evaluated. We included 11,749 patients with acute ischemic stroke (70.3 ± 12.2 years, 36.1% women). The risk of a 3-month poor functional outcome was higher for underweight, lower for overweight, and did not change for obesity in reference to a normal weight even after adjusting for covariates by logistic regression analysis. Restricted cubic splines and SHapley Additive exPlanation values in eXtreme Gradient Boosting model also showed non-linear relationships. Associations between BMI and a poor functional outcome were maintained even after excluding death (mRS score: 3-5) or including mild disability (mRS score: 2-6) as the outcome. The associations were strong in older patients, non-diabetic patients, and patients with mild stroke. Body weight has a non-linear relationship with the risk of a poor functional outcome after acute ischemic stroke.

No Racial Disparity in Outcome Measures After Endovascular Treatment for Stroke in the Elderly

BACKGROUND AND PURPOSE

Despite the lower rates of good outcomes and higher mortality in elderly patients, age does not modify the treatment effect of mechanical thrombectomy for large vessel occlusion strokes. We aimed to study whether racial background influences the outcome after mechanical thrombectomy in the elderly population.

METHODS

We reviewed a prospectively maintained database of patients with acute ischemic stroke treated with mechanical thrombectomy from October 2010 through June 2020 to identify all consecutive patients with age ≥80 years and anterior circulation large vessel occlusion strokes. The patients were categorized according to their race as Black and White. Univariable and multivariable analyses were performed to define the predictors of 90-day modified Rankin Scale and mortality in the overall population and in each race separately.

RESULTS

Among 2241 mechanical thrombectomy, a total of 344 patients (median [interquartile range]; age 85 [82-88] years, baseline National Institutes of Health Stroke Scale score of 19 [15-23], Alberta Stroke Program Early CT Score 9 [7-9], 69.5% females) were eligible for the analysis. White patients (n=251; 73%) had significantly lower median body mass index (25.37 versus 26.89, P=0.04) and less frequent hypertension (78.9% versus 90.3%, P=0.01) but more atrial fibrillation (64.5% versus 44.1%, P=0.001) compared with African Americans (n=93; 27%). Other clinical, imaging, and procedural characteristics were comparable between groups. The rates of symptomatic intracerebral hemorrhage, 90-day modified Rankin Scale score of 0 to 2, and mortality were comparable among both groups. On multivariable analysis, race was neither a predictor of 90-day modified Rankin Scale score of 0 to 2 (White race: odds ratio, 0.899 [95% CI, 0.409-1.974], P=0.79) nor 90-day mortality (White race: odds ratio, 1.368; [95% CI, 0.715-2.618], P=0.34).

CONCLUSIONS

In elderly patients undergoing mechanical thrombectomy for acute ischemic stroke, there was no racial difference in terms of outcome.

Association between abnormal body weight and stroke outcome: A meta-analysis and systematic review

BACKGROUND AND PURPOSE

To test the hypothesis that "obesity paradox" exists in stroke patients, we conducted a meta-analysis and systematic review on the association between abnormal body weight (obesity, overweight, or underweight) and the outcome of different types of stroke.

METHODS

This meta-analysis and systematic review was performed in conformity to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines in Appendix S2. Studies investigating the association between abnormal body weight and the outcome of different types of stroke were searched for in the PubMed and Embase databases from their inception to 20 March 2021.

RESULTS

Thirty-three articles including 84,660 patients were included in this study. Obesity and overweight were associated with longer survival in mixed-stroke patients (acute ischemic stroke [AIS] combined with one or more other stroke subtypes) than was normal weight, whereas underweight was related to shorter survival; the pooled hazard ratios (HRs) of mortality were 0.77 (95% confidence interval [CI] = 0.71-0.83) for obesity, 0.76 (95% CI = 0.72-0.80) for overweight, and 1.71 (95% CI = 1.56-1.87) for underweight. However, only obesity was associated with longer survival in AIS patients compared with normal weight, and underweight was related to shorter survival; the pooled HR of mortality was 0.75 (95% CI = 0.64-0.88) for obesity and 1.53 (95% CI = 1.27-1.85) for underweight. After merging mixed-stroke and AIS patients, we obtained similar results as in mixed-stroke patients.

CONCLUSIONS

Our results suggested that in patients with mixed stroke or AIS, obesity was associated with a longer survival time than normal weight, whereas underweight was associated with a shorter survival time.

Higher BMI Confers a Long-Term Functional Status Advantage in Elderly New Zealand European Stroke Patients

OBJECTIVE

Obesity is a risk factor for ischaemic stroke but provides a survival advantage. The relationship between body mass index (BMI) and long-term function is less clear. The presence of an obesity paradox can inform clinical care and identify vulnerable patients who need additional support post-stroke.

MATERIALS AND METHODS

This study used linked health administrative data of a population based cohort of adult patients who experienced an ischaemic stroke between 2012 and 2017 in New Zealand. Patient demographics were obtained from the National Minimum Dataset (NMDS). BMI and Activities of Daily Living scores (ADLs) for the same patients were obtained from the International Resident Assessment Instrument (InterRAI™).

RESULTS

Linked data was obtained for 3731 patients. Ninety-five percent of the cohort were aged 65 or older and the average age of stroke was 84.5 years. The majority of patients (55%) identified as New Zealand European. Beta regression indicated BMI and European ethnicity were negatively associated with ADL score. Univariate analysis confirmed patients with underweight stroke had significantly higher ADL scores than other BMI categories (p<0.001), however functional status for patients with overweight and obesity were comparable. Further, Asian and Pacific Peoples had higher ADL scores than Europeans (p<0.05). A higher BMI was advantageous to all ADL subscores.

CONCLUSION

An abridged obesity paradox was evident in our cohort of stroke patients where a BMI in the overweight, but not obese range conferred a long-term functional status advantage. Collectively these results suggest underweight and non-European patients may require additional supportive clinical care post-stroke.

Obesity and Stroke: Does the Paradox Apply for Stroke?

Historically, obesity has been identified as one of the most important risk factors for developing cardiovascular diseases including stroke; however, a theory called "The Obesity Paradox" has been recently considered. The paradoxical theory is that obese or overweight patients (according to body mass index score) can have better outcomes compared to leaner or malnourished patients. The paradox was initially discovered in patients with heart failure. The purpose of this manuscript was to investigate whether this paradox also applies to stroke patients, according to information available in the current literature.

The impact of Body Mass Index on functional rehabilitation outcomes of working-age inpatients with stroke

BACKGROUND

Stroke is the most relevant cause of acquired persistent disability in adulthood. The relationship between patient's weight during rehabilitation and stroke functional outcome is controversial, previous research reported positive, negative and no effects, with scarce studies specifically addressing working-age patients.

AIM

To evaluate the association between Body Mass Index (BMI) and the functional progress of adult (<65 years) patients with stroke admitted to a rehabilitation hospital.

DESIGN

Retrospective observational cohort study.

SETTING

Inpatient rehabilitation center.

POPULATION

178 stroke patients (ischemic or hemorrhagic).

METHODS

Point-biserial and Spearman's correlations, multivariate linear regressions and analysis of covariance were used to describe differences in functional outcomes after adjusting for age, sex, severity, dysphagia, depression and BMI category. Functional Independence Measure (FIM), FIM gain, efficiency and effectiveness were assessed.

RESULTS

Participants were separated in 3 BMI categories: normal weight (47%), overweight (33%) and obese (20%). There were no significant differences between BMI categories in any functional outcome (total FIM [T-FIM], cognitive [C-FIM]), motor [M-FIM]) at discharge, admission, gain, efficiency or effectiveness. In regression models BMI (as continuous variable) was not significant predictor of T-FIM at discharge after adjusting for age, sex, severity, dysphagia, depression and ataxia (R²=0.4813), significant predictors were T-FIM at admission (β=0.528) and NIHSS (β=-0.208). M-FIM efficiency did not significantly differ by BMI subgroups, neither did C-FIM efficiency. Length of stay (LOS) and T-FIM effectiveness were associated for normal (r=0.33) and overweight (r=0.43), but not for obese. LOS and T-FIM efficiency were strongly negatively associated only for obese (r=-0.50).

CONCLUSIONS

FIM outcomes were not associated to BMI, nevertheless each BMI category when individually considered (normal weight, overweight or obese) was characterized by different associations involving FIM outcomes and clinical factors.

CLINICAL REHABILITATION IMPACT

In subacute post-stroke working-age patients undergoing rehabilitation, BMI was not associated to FIM outcomes (no obesity paradox was reported in this sample). Distinctive significant associations emerged within each BMI category, (supporting their characterization) such as length of stay and T-FIM effectiveness were associated for normal weight and overweight, but not for obese. Length of stay and T-FIM efficiency were strongly negatively associated only for obese.

Metabolic Syndrome Predicts Poor Outcome in Acute Ischemic Stroke Patients After Endovascular Thrombectomy

BACKGROUND AND AIMS

The metabolic syndrome (MetS) is believed to contribute to a higher probability of developing cardiovascular diseases. This study aimed to investigate whether MetS could predict the prognosis in ischemic stroke patients after endovascular thrombectomy (EVT).

METHODS

Between January 2016 and September 2019, patients treated with EVT due to large vessel occlusions in anterior circulation were prospectively recruited. MetS was defined using the International Diabetes Federation criteria after admission. The primary outcome was a 3-month poor outcome (modified Rankin scale score of 3-6). Secondary outcomes included symptomatic intracranial hemorrhage (sICH) and mortality at 3 months. Multivariable logistic regression models were used to assess the relationship between MetS and clinical outcomes.

RESULTS

A total of 248 patients were enrolled (mean age, 66.7 years; 37.5% female) and 114 (46.0%) met with the MetS criteria. The median National Institutes of Health Stroke Scale score was 15.0. There were 131 (52.8%) patients achieving the poor outcome at 3 months, among which 26 (10.5%) patients developed sICH. The mortality at 3 months was 19.0% (47/248). In multivariable analysis, MetS was significantly correlated to poor outcome (odds ratio [OR], 2.48; 95% confidence interval [CI], 1.29-4.78, P = 0.014). The risk for poor outcome was positively associated with the increased number of MetS components (OR 1.78; 95% CI 1.39-2.35, P = 0.001). No significant findings were found in the association of MetS with sICH and mortality.

CONCLUSION

Our data demonstrated that MetS was associated with poor prognosis in acute ischemic patients treated with EVT.