Low density lipoprotein cholesterol values and outcome of stroke patients: influence of previous aspirin therapy

ABSTRACT

Background: The link between low-density lipoprotein cholesterol (LDL-C) and stroke risk remains controversial and few studies have evaluated the effect of LDL-C after stroke survival.

Aims: We assessed the hypothesis proposing the effect of LDL-C on the outcome of stroke patients under the influence of previous Aspirin Therapy.

Methods: Associations between LDL-C and outcomes. The effect of LDL cholesterol on stoke outcome was evaluated using Kaplan-Meier methodology, log-rank test, Cox proportional hazard models and Bootstrap Analysis.

Results: In a cohort of 342 cases, we observed that among stroke patients with no record of previous aspirin therapy LDL-C levels within recommended range (nLDL-C) are associated to a poor overall survival on (p < 0.001, log-rank test) leading to a 4-fold increased mortality risk in both timeframes of 12 (HR 4.45, 95% CI 1.55–12.71; p = 0.004) or 24 months (HR 4.13, 95%CI 1.62–10.50;p = 0.003) after the first event of stroke. Moreover, modelling the risk of a second event after the first stroke in the timeframe of 24 months demonstrated a predictive capacity for nLDL-C plasmatic levels (HR 3.94, 95%CI 1.55–10.05; p = 0.004) confirmed by Bootstrap analysis (p = 0.003; 1000 replications). In a further step, the inclusion of LDL-C in simulating models equations to predict the risk of a second event in the timeframe of 12 months increased nearly 20% the predictive ability (c-index from 0.763 to 0.956).

Conclusion: A worse outcome was seen in stroke patients with normal levels of LDLC, but this finding was restricted to patients not under previous aspirin therapy.

KEYWORDS:

• Stroke
• aspirin
• low density lipoprotein cholesterol

Acknowledgments

The authors acknowledge the funding support of this work by the Minister of Health of Portugal (CFICS-80/2007), and Faculty of Medicine of Porto and Centro Hospitalar de S Joao.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Notes on contributors

Margarida Freitas-Silva

Margarida Freitas-Silva, medical doctor (MD) at the Department of Medicine of Centro Hospitalar de S Joao (Porto) with a speciality in internal medicine, assistant professor at the Faculty of Medicine of Porto.

Rui Medeiros

Rui Medeiros, PhD, Professor of Pharmacogenomics and Molecular Epidemiology. Head of Molecular Oncology and Viral Pathology Research Departmente at IPO Porto.

José Pedro L. Nunes

José Pedro L. Nunes, medical doctor (MD) at the Department of Medicine of Centro Hospitalar de S Joao (Porto) with a speciality in cardiology, Professor at the Faculty of Medicine of Porto.