Therapy,

(Therapy) systemic review,

()????(intention-to-treat analysis)?(blind)??

Data collectionEnd pointsData MonitoringStatistical analysis

Entry, Randomization, and Follow-up of Patients in the Hypertension in the Very Elderly TrialBeckett NS et al. N Engl J Med 2008;358:1887-1898

Baseline Characteristics of the PatientsBeckett NS et al. N Engl J Med 2008;358:1887-1898

()

() (9595% CI)

5.3 (relative risk reduction, RRR) (relative benefit increase, RBI) (relative risk increase, RRI)

RRR

ARR

(NNT)

CRE

EER

CEREER/CER

CEREER

1/ARR

MRC

5.7%

4.3%

5.7%-4.3%/5.7%25%

5.7%-4.3%1.4%

1/1.4%72

0.000057%

0.000043%

0.000057%-0.000043%/0.000057%25%

0.000057%-0.000043%0.000014%

1/0.000014%7142857

RRR(ARR)ARRRRRRRR NNT (Number Needed to Treat), NNH

NNT (number need to treat)NNTNNT=1/ARR=1/CER-EERNNTNNH (number need to harm) =1/ARI ()

Treatment EffectsOccurrence of diabetic retinopathy at 5 years among insulin-dependent diabetic in the DCCT trialUsual insulin regimen (CER: control event rate): 38%Intensive insulin regimen (EER: experimental event rate): 13%Risk Reduction (calculation): NNT Absolute risk reduction (ARR) = CER-EER= 38%-13% = 25%Relative risk reduction (RRR) = CER-EER/CER = 25%/38% =66%Number needed to treat (NNT) = 1/ARR = 1/25% = 4 patients NNT: The number of patients that need to be treated to prevent one bad outcome or get one good outcome.

HarmThe proportion of patients with at least one episode of symptomatic hypoglycemiaUsual insulin regimen (CER: control event rate): 23%Intensive insulin regimen (EER: experimental event rate): 57%Risk Increase(calculation): NNH Absolute risk increase (ARI) =EER - CER = 57%-23% = 34% Relative risk increase (RRI) =EER-CER/CER = 57%-23%/ 23% = 148%Number needed to harm (NNH) = 1/ARI = 1/0.34 = 3 patients () NNH: The number of patients that need to be treated to cause one bad outcome (being harmed).

NNT

Event rate

NNT

CER

EER

110-129 mmHg

Death, stroke, MI

13 %

1.4 %

1.5 years

8

90-109 mmHg

Death, stroke, MI

5.5 %

4.7 %

5.5 years

128

()

Death or major stroke

18 %

8 %

2 years

10

Donepezil (vs. placebo)

No functional decline

44 %

59 %

1 year

7

7()

Death or MI

16 %

12 %

24 months

24

Oral acetylcysteine (vs. placebo)

Contrast media-induced reduction in renal function

12 %

4 %

8 months

12

Figure 1. Entry, Randomization, and Follow-up of Patients in the Hypertension in the Very Elderly Trial. Of the 461 patients who did not meet the protocol criteria, 229 did not meet the criteria on the basis of blood pressure, 18 on the basis of age, 61 on the basis of serum potassium level, 20 on the basis of serum creatinine level, 26 because they were receiving other antihypertensive treatment, and 107 for other reasons. The other administrative reasons for the censoring of data were death or retirement of a local investigator and change in national legislation as to where patients in clinical trials could be seen.Table 1. Baseline Characteristics of the Patients.