### Systematic Review Scenario

You are referred a 75 year old man with a stroke who had been admitted one day previously to general medicine. He has left-sided weakness and has difficulty with ambulating, bathing, feeding and dressing himself. He has hypertension which is well-controlled with a diuretic. He is otherwise well and you decide to transfer him to a stroke unit. His family is concerned because they live close to the hospital where he is currently as an inpatient and want to know why he needs to be transferred to a stroke unit of a different hospital and why he can’t stay on the general medicine ward. You (with them) formulate the question: “In a patient with a stroke, does admission to a stroke unit decrease the risk of death and dependency?”

You search Best Evidence using the terms “stroke unit” and “death” and find a promising systematic review. The abstract and commentary look helpful and you decide to retrieve the complete article. BMJ 1997;314:1151-9.

Read the article and decide:

• Is the evidence from this systematic review valid?
• Is this valid evidence from this systematic review important?
• Can you apply this valid and important evidence from this systematic review in caring for your patient?

### Completed Systematic Reviews Worksheet for Evidence-Based Geriatric Medicine

#### Citation

Stroke unit trialists’ collaboration. Collaborative systematic review of the randomised trials of organised inpatient (stroke unit) care after stroke.
BMJ 1997;314:1151-9.

#### Are the results of this systematic review (systematic review) of therapy valid?

Is it a systematic review of randomised trials of the treatment you’re interested in?
Yes
Does it include a methods section that describes finding and including all the relevant trials?
Yes
Does it include a methods section that describes assessing their individual validity?
No, but does include characteristics of individual trials
Were the results consistent from study to study?
Consistent results when death is the outcome. When death or dependency is the outcome, some heterogeneity but this was explored and seems to reflect the nature of the control group i.e. less heterogeneity when the stroke unit group was compared to a general medical unit. There was significant heterogeneity in length of stay.

#### Are the valid results of this systematic review important?

Translating odds ratios to NNTs. The numbers in the body of the table are the NNTs for the corresponding odds ratios at that particular patient’s expected event rate (PEER).
Odds Ratios
0.9 0.85 0.8 0.75 0.7 0.65 0.6 0.55 0.5
Patient’s Expected Event Rate (PEER) 0.05 209 139 104 83 69 59 52 46 41
0.10 110 73 54 43 36 31 27 24 21
0.20 61 40 30 24 20 17 14 13 11
0.30 46 30 22 18 14 12 10 9 8
0.40 40 26 19 15 12 10 9 8 7
0.50 38 25 18 14 11 9 8 7 6
0.70 44 28 20 16 13 10 9 7 6
0.90 101 64 46 34 27 22 18 15 12

#### Can you apply this valid, important evidence from a systematic review in caring for your patient?

##### Do these results apply to your patient?
Is your patient so different from those in the systematic review that its results can’t help you?
No
How great would the potential benefit of therapy actually be for your individual patient?
Method I: In the table on page 1, find the intersection of the closest odds ratio from the overview and the CER that is closest to your patient’s expected event rate if they received the control treatment (PEER):
EER and CER provided in Best Evidence. For death and dependency the NNT is 15 (12 to 41)
Method II: To calculate the NNT for any OR and PEER:

$$NNT = frac{1-[mathit{PEER}times(1-mathit{OR})]}{(1-mathit{PEER}) times mathit{PEER}times(1-mathit{OR})}$$

##### Are your patient’s values and preferences satisfied by the regimen and its consequences?
Do your patient and you have a clear assessment of their values and preferences?
Needs to be assessed in each patient
Are they met by this regimen and its consequences?
Needs to be assessed in each patient
##### Should you believe apparent qualitative differences in the efficacy of therapy in some subgroups of patients?

Only if you can say “yes” to all of the following:

• Do they really make biologic and clinical sense?
• Is the qualitative difference both clinically (beneficial for some but useless or harmful for others) and statistically significant?
• Was this difference hypothesised before the study began (rather than the product of dredging the data), and has it been confirmed in other, independent studies?
• Was this one of just a few subgroup analyses carried out in this study?

### Stroke – Stroke units decrease death, dependency and institutionalisation

#### Clinical Bottom Line

Stroke units decrease death and dependency, and death and institutionalisation.

#### Citation

Stroke unit trialists’ collaboration. Collaborative systematic review of the randomised trials of organised inpatient (stroke unit) care after stroke.
BMJ 1997;314:1151-9.

#### Clinical Question

In a patient with a stroke, does admission to a stroke unit decrease the risk of death and dependency?

#### Search Terms

“stroke unit” and “death” in Best Evidence

#### The Study

Systematic review of RCTs that studied dedicated stroke units, mixed assessment and rehab units or general medical wards with outcomes of death, dependency or institutionalisation.

#### The Evidence

Outcomes* CER (weighted) EER (weighted) RRR (95% CI) ARR (weighted) NNT (95% CI)
death and dependency 0.679 0.611 9% (16 to 39) 0.068 15 (12 to 41)
death and institutionalisation 0.475 0.377 18% (6 to 28) 0.098 11 (7 to 32)
*dependency defined as the need for physical assistance with transfers, mobility, feeding, dressing or toileting. Institutionalisation included nursing home placement, residential care placement or hospitalisation at the end of the rehab period.

#### Comments

• mortality rate 21% in the stroke unit and 25% in the general medicine group
• heterogeneity in death or dependency amongst the trials but seems to reflect the nature of the control group
• advantages as great in older patients as in younger patients and in those who have had severe stroke as in those who have had milder strokes
• little difference in staff numbers or mix or in intensity of rehab provided in organised vs conventional care settings but tendency for assessment and treatment to begin earlier in organised settings
• most significant difference were the degree of specialised medical and nursing interest in stroke, staff training and involvement of family and caregivers in the rehab process.

Straus