Statistics in Practice: Post-Stroke Research

Overview of Aims

• Aim to understand the practical use of statistics in collaborative research, particularly in real-world settings.
• Focus on the use of statistics rather than advanced statistical methods or examination.

Stroke Overview

• Stroke is a severe medical condition caused by interrupted blood supply to the brain.
• Annually, over 15 million people experience a stroke globally, resulting in:
  • One-third die.
  • One-third left with disabilities or cognitive impairment.
  • One-third recover without serious effects.

Post-Stroke Cognitive Impairment

• Defined as vascular cognitive impairment (VCI), caused by brain tissue damage due to reduced oxygen supply.
• VCI correlates with increased disability and mortality rates.
• Prevalence rates include:
  • 10% of patients had dementia prior to the first stroke.
  • 10% develop dementia post-first stroke.
  • Over one-third experience cognitive impairment following recurrent strokes.

Collaborative Research

• Research studies from the South London Stroke Register focused on cognitive impairment post-stroke:
  • Significant finding: Approximately 25% of patients develop cognitive impairment after their first-ever stroke.

Statistical Methods Used

• Calculation of adjusted rates and 95% confidence intervals.
• Regression analyses to evaluate relative risk ratios and hazard ratios.

Knowledge Gaps

• Existing treatment strategies primarily reduce cardiovascular event risks, lacking approaches for preventing cognitive decline and dementia progression after a stroke.

Study Objectives and Design

• Objective: Analyze if vascular secondary prevention drugs safeguard cognitive function post-stroke.
• Design: Utilized the South London Stroke Register database (1995-2011) with 4,413 patients.
• Global cognitive function measured using the Abbreviated Mental Test or Mini-Mental State Exam.
• Statistical methods included generalized estimating equation Poisson models.

South London Stroke Register

• A population-based registry tracking first-ever strokes in North Lambeth and North Southwark since 1995.
• Source population demographics:
  • 56% White,
  • 25% Black (7% Caribbean, 14% African, 4% Other),
  • 4% Mixed,
  • 15% Other ethnic groups.

Results: Drug Efficacy by Stroke Type

• Antihypertensives showed varying protective effects against cognitive decline based on stroke type, particularly effective in ischaemic strokes without atrial fibrillation.
• Optimal therapy leads to a significant reduction in cognitive impairment risk.

Clinical Perspective

• Secondary prevention strategies decrease not just the chance of recurrent ischaemic events but also global cognitive decline.
• Treating with certain antihypertensive medications and combinations of antithrombotics substantially protects cognitive ability.
• Effectiveness appears limited in patients with hemorrhagic strokes or associated atrial fibrillation.

Conclusion

• Customized combinations of antithrombotic, antihypertensive, and lipid-lowering agents can potentially protect against cognitive impairment.
• Managing vascular risk factors is crucial for cognitive function preservation post-stroke.
• Statin use associated with lower risks of cognitive impairment and improved patient survival rates.

Future Research Directions

• STROKOG consortium aims to study cognitive disorders following strokes and transient ischaemic attacks (TIAs).
• Plans for better management and monitoring by linking primary care and mental health services, focusing on depression and social isolation.
• Incorporating big data for risk prediction in small vessel disease and enhancing cardiovascular management and stroke prevention strategies.

Explore the role of statistics in real-world research, particularly in the context of post-stroke cognitive impairment. This quiz emphasizes collaboration among statisticians and how statistical methods apply to practice rather than traditional exam settings. Enhance your understanding of the practical applications of statistics in healthcare.