Risk

Question 1

What is risk

Answer 1

• Probability that a hazard will give rise to harm

Question 2

Risk versus benefits: Finasteride

Answer 2

• • = Prevents further hair loss
• Decrease in urgency
• Decrease in frequency
• Decrease in episodes of urinary incontinence
  
  • • = Impotence
  • Loss of libido
  • Decrease semen
  • Pain in testicles
  • Breast tenderness
  • Breast cancer
• Decrease in episodes of urinary incompetence

Question 3

Risk reduction

Answer 3

• Relative risk reduction (RRR)
  
  • The reduction of risk in the intervention group relative to the risk in the control group
• Absolute risk reduction (ARR)
  
  • The difference in risk between intervention and control

Question 4

Number needed to treat (NNT)

Answer 4

• The number needed to treat (NNT)
  
  • The number of patients who need to be treated to prevent one additional adverse outcome
  • The lower the NNT the more effective the treatment
  • Ideal NNT = 1
    
    • Everyone improves with treatment, nobody improves with control

Question 5

NNT

Answer 5

• NNTs for treatment should be small
  
  • Expect to see large effects in a small number of people
  • Between 2 and 4
• NNTs for prophylaxis
  
  • Expect to see small effect in large numbers of people
  • Around 50 not common
• BUT
  
  • Depends entirely on clinical context and needs to be weighed against potential harm

Question 6

RRR, ARR and NNT- an example

Answer 6

Question 7

Presentation of risk reduction

Answer 7

• Anglo-Scandinavian cardiac outcomes trial- lipid lowering arm
  
  • Lasted 3.3 years
  • RRR (heart attack)
  • ARR
  • NNT

Question 8

The effect of event frequency on risk reduction

Answer 8

Question 9

NNT

Answer 9

• Converse of NNT
• The average number of patients who need to be treated with the intervention for one extra patient to experience harm (e.g. ADR)
  
  • The lower the NNH, the more likely the treat os to cause harm
  • NNH of 1= everybody who is treated suffers the harm in question

Question 10

NNH- An example

Answer 10

Question 11

NNT v NNH in acute bipolar disorder

Answer 11

Question 12

Understanding of RRR, ARR and NNT

Answer 12

• RRR makes reductions in risk appear larger than they are (overstates benefits of treatments)
• Cochrane review
  
  • RRR and ARR are equally well-understood by both patients and clinicians and both are better understood than NNT
  • When the same information is expressed as ARR and NNT, ARR is perceived to indicate a larger effect

Question 13

Framing of risk

Answer 13

Question 14

Mean rating of the effectiveness of ChE lowering drugs

Answer 14

Question 15

Contraceptive pill scare

Answer 15

• Oct 1995: UK committee on safety of medicines dispatches 190,000 letters to doctors and pharmacists
• Warns VTE risk 100% more in 3rd gen to 2nd gen OCP

Question 16

Shared decision making

Answer 16

• A process in which patients, when they reach a decision crossroads in their health care, can review all the treatment options available to them and participate actively with their healthcare professional in making that decisions

Question 17

Adherence

Answer 17

• The extent to which the patient’s behaviour matches agreed recommendations from the prescriber

Question 18

Decision aids

Answer 18

• Help patients to participate in healthcare decisions by providing clear, evidence-based information on the available choices
• Use of decision aids
  
  • Improves patient knowledge and risk perception
  • Increases patients’ participation in decision making
• However, they have not been shown to improve patient outcomes

Question 19

Decision aids- statins

Answer 19

Question 20

Decision aids- diabetes management

Answer 20