Table 14Significant univariate risk factors for serious events at 1–2 weeks – low quality evidence is indicated, otherwise moderate quality

Sign / symptom is a risk factor for serious adverse outcomesProtective factor
  • Age over 40 years (2 studies) – 7 days; lowest RR 4.0 (1.3–12.5)
  • Age over 60 years (2 studies) - 7 days;
    • Lowest RR 1.8 (1.1–3.0)* low
  • Age over 65 years (1 study) – 10 days
    • RR 3.8 (1.9 – 7.9) - Costantino54
  • Age continuous (1 study) – 7 days; MD 6.0 years (1.7–10.3)
  • Male gender (3 agreed, 1 disagreed for 7 & 30 days)
    • median RR 2.3 (1.4 – 3.8) – 7 days
  • Coronary artery disease (2 studies, 7 & 30 days)
    • RR 1.5 (0.96–2.5)* – 7 days borderline significant low
  • Congestive heart failure (5 studies; at 7, 10 and 30 days)
    • median RR 2.2 (1.2–4.2)* low
  • Structural heart disease (Costantino54; 10 days) RR 2.9 (1.6 – 5.3)
  • Hypertension (borderline effect - 2 studies, 7 and 10 days);
    • RR 1.5 (0.98 – 2.3)* - 7 days low
  • Abnormal ECG (4 studies at 7 days) not sig at 30 days
    • median RR 4.1(1.8 – 9.5)
  • Arrhythmia (7 days) RR 2.5 (1.5 – 4.1)
  • Abnormal rhythm (non sinus) (1 study, 7 days)
    • RR 2.8 (1.8 – 4.1)
  • Diabetes (1 study; 7 days) RR 1.9 (1.1 – 3.3)* low
  • COPD (1 study; 10 days; Costantino54) RR 2.4 (1.1 – 5.1)* low
  • Diuretics (1 study; 7 days) RR 1.8 (1.1 – 3.0)* low
  • Antiarrhythmic medication (1 study; 7 days) RR 2.5 (1.4–4.6)
  • Dyspnoea (4 studies, 7 and 30 days) low
    • Median 7d studies: borderline RR 1.8 (0.99–3.3)*
  • Chest pain (1 study, 7 days), not sig 30d RR 1.9 (1.1–3.4)* low
  • Absence of symptoms pre-TLoC (10 days, Costantino54)
    • RR 2.2 (1.2 – 3.9)* low
  • Systolic blood pressure < 90 mm Hg (3 studies (7 days; 1 study 30 days); some heterogeneity; Median RR 3.2 (1.9 – 5.4) low
  • Oxygen saturation < 95% (1 study, 7 days) RR 1.8 (1.1 – 3.0)* low
  • Respiratory rate > 24 / min (1 study, 7 days) RR 3.7 (2.1–6.4)
  • Pulse rate < 50bpm or >110 (1 study, 7 days, not sig at 30 days)
    • RR 3.9 (2.5 – 5.9)
  • Rales (1 study, 7 days) RR 2.7 (1.7 – 4.4)
  • Abnormal heart sounds (1 study, 7 days) RR 3.4 (2.2 – 5.4)
  • Heart murmur (systolic or diastolic; 1 study, 7 days),
    • not significant at 30 days RR 3.8 (1.6 – 9.2) diastolic
  • Carotid bruits (1 study, 7 days) RR 3.8 (1.6 – 9.2)
  • Profound dehydration (1 study, 30 days)
    • RR 2.9 (1.3 – 6.7) – indirect time low
  • Haematocrit < 30% (3 studies at 7 days)
    • RR median 3.7 (2.4 – 5.7) not sig at 30 days
  • GI bleed (1 study at 30 days) borderline significant
    • RR 2.2 (0.96 – 5.1)* very low
  • Trauma (1 study Costantino54 at 10 days) not sig at 7 days for face and head trauma; RR 2.2 (1.2 – 4.1)* low
Vagal symptoms (borderline, 1 study at 7 days)
RR 0.52 (0.28 – 0.99)* low

From: 3, Initial assessment and diagnosis of people who had TLoC

Cover of Transient Loss of Consciousness (‘Blackouts’) Management in Adults and Young People
Transient Loss of Consciousness (‘Blackouts’) Management in Adults and Young People [Internet].
NICE Clinical Guidelines, No. 109.
National Clinical Guideline Centre for Acute and Chronic Conditions (UK).
Copyright © National Clinical Guideline Centre for Acute and Chronic Conditions, 2010.

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