Obesity paradox in stroke – Myth or reality? A systematic review

<div><p>Background and purpose</p><p>Both stroke and obesity show an increasing incidence worldwide. While obesity is an established risk factor for stroke, its influence on outcome in ischemic stroke is less clear. Many studies suggest a better prognosis in obese patients after stroke (“obesity paradox”). This review aims at assessing the clinical outcomes of obese patients after stroke by performing a systematic literature search.</p><p>Methods</p><p>The reviewers searched MEDLINE from inception to December 2015. Studies were eligible if they included outcome comparisons in stroke patients with allocation to body weight.</p><p>Results</p><p>Twenty-five studies (299’750 patients) were included and none was randomised. Ten of 12 studies (162’921 patients) reported significantly less mortality rates in stroke patients with higher BMI values. Seven of 9 studies (92’718 patients) ascertained a favorable effect of excess body weight on non-fatal outcomes (good clinical outcome, recurrence of vascular events). Six studies (85’042 patients) indicated contradictory results after intravenous thrombolysis (IVT), however. Several methodological limitations were observed in major part of studies (observational study design, inaccuracy of BMI in reflecting obesity, lacking body weight measurement, selection bias, survival bias).</p><p>Conclusion</p><p>Most observational data indicate a survival benefit of obese patients after stroke, but a number of methodological concerns exist. No obesity paradox was observed in patients after IVT. There is a need for well-designed randomized controlled trials assessing the effects of weight reduction on stroke risk in obese patients.</p></div

Copeptin levels and characteristics of study patients.

<p>IQR: interquartile range; WFNS: World Federation of Neurological Surgeons; ICH: intracerebral hemorrhage; IVH: intraventricular hemorrhage.</p>a<p>WFNS grade: Good-grade WFNS 1–3; Poor-grade: WFNS 4–5.</p>b<p>modified Rankin Scale (mRS) score 0–3: Good outcome; mRS 4–6: Poor outcome.</p

Copeptin Level by WFNS Grade.

<p>The figure represents a boxplot of copeptin values per WFNS grade. Displayed are lowest, highest and median copeptin values (pmol/L), with upper (75%) and lower (25%) quartiles.</p

Baseline characteristics of participating general practitioners (GPs) and hospital physicians (HPs).

<p>^a26 physicians filling out the paper version of the questionnaire did not state whether they are GPs or HPs.</p><p>^bThese Characteristics where applicable to GPs only, HPs only respectively.</p><p>^cParticipants where asked: "I see patients with transient ischemic attacks (TIAs)…"</p><p>Baseline characteristics of participating general practitioners (GPs) and hospital physicians (HPs).</p

Stroke risk estimations after TIA and causes for recurrence by general practitioners and hospital physicians^*.

<p>*for exact questions and answer possibilities see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0135885#pone.0135885.s001" target="_blank">S1 Appendix</a>.</p><p>**26 physicians did not state to be GP or HP.</p><p>Stroke risk estimations after TIA and causes for recurrence by general practitioners and hospital physicians^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0135885#t002fn001" target="_blank">*</a>}.</p

Investigational procedures chosen by general practitioners and hospital physicians.

<p>*26 physicians did not state to be GP or HP.</p><p>Investigational procedures chosen by general practitioners and hospital physicians.</p

Pooled relative risks of primary and secondary outcomes comparing antiplatelets with anticoagulants.

<p>^* Primary endpoint. ICH = intracranial haemorrhage; TIA = transient ischaemic attack.</p

Number of included patients and events reported in included studies.

*<p>Primary endpoint.</p><p>IS = Ischaemic Stroke; ICH = intracranial haemorrhage; TIA = transient ischaemic attack.</p><p>Ref = references.</p

Study flow diagram.

<p>Study flow diagram.</p

Influence of in- or exclusion of studies on estimated effects.

<p>Outcomes included if reported in at least two out of the three available meta-analyses.</p><p>ICH = intracranial haemorrhage; TIA = transient ischaemic attack.</p