cochrane评分表

则有发生相应

偏倚的中等度可能性；如其中一条为

“

不充分

”

或

“

未采用

”,

则有发生相应偏倚的高 度可能性。

可参见：

RCT

的质量评价标准选择总结

/bbs/topic/18137535?tpg=1&a ge=-1

Quality assessment

The quality of the trials was assessed and graded independently by two authors according to the

criteria described in The Cochrane Handbook 4.2.6 (

Higgins 2006

). Gradings were compared and

any

inconsistencies

between

the

authors

in

the

interpretation

of

inclusion

criteria

and

their

significance to the selected study were discussed and resolved.

The selected study was assessed for the following characteristics:

1. The adequacy of the randomisation process (possible selection bias). Adequate randomisation

includes

any

one

of

the

following

methods:

computer

generated

or

table

of

random

numbers,

drawing

of

lots,

coin- toss,

shuffling

cards

or

throw

of

a

dice.

Inadequate

methods

of

randomisation include the following: case record number, date of birth or alternate numbers.

2.

The

adequacy

of

the

allocation

concealment

(possible

selection

bias).

Adequate

methods

of

allocation concealment include either central randomisation (i.e. separate to other aspects of trial

administration)

or

sequentially

numbered

sealed

opaque

envelopes.

Inadequate

concealment

means an open allocation sequence in which either participants or trialists were able to foresee the

upcoming assignment.

3. The blinding of outcome assessors (i.e. whether the persons assessing the outcome of care were

aware of which treatment the participant had received - possible performance bias).

4. The extent and handling of losses to follow up (possible attrition bias). Adequate handling of

losses

to

follow

up

involves

a

clear

description

and

explanation

being

given

of

any

significant

difference

between

the

losses

of

the

intervention

groups.

An

unacceptable

loss

in

any

one

intervention group was considered to be loss greater than 20%.

Study gradings A, B or C were employed for overall quality as follows.

A: Minimisation of bias in

all four categories above: i.e. adequate randomisation, few losses to

follow

up

and

intention-to-treat

analysis,

blinding

of

outcome

assessors,

high

quality

outcome

assessment;

B: Each of the criteria in A partially met;

C: One or more of the criteria in A not met.

Risk of bias in included studies

We classified this study as grade C because of the uncertainty about

blinding. The possibility of an uneven distribution of complete and

incomplete

palsies

between

the

two

groups

is

another

potential

source

of

bias and we conclude overall that this is a low quality study.

Table 8.5.a: The Cochrane Collaboration’s tool for assessi

ng

risk of bias

Domain

Sequence

generation.

Description

Review authors’

judgement

Describe the method used to

Was the allocation

generate the allocation sequence

sequence adequately

in sufficient detail to allow an

generated?

assessment of whether it should

produce comparable groups.

Describe the method used to

Was allocation

conceal the allocation sequence

adequately concealed?

in sufficient detail to determine

whether intervention allocations

could have been foreseen in

advance of, or during, enrolment.

Describe all measures used, if

Was knowledge of the

any, to blind study participants

allocated intervention

and personnel from knowledge of

adequately prevented

which intervention a participant

Allocation

concealment.

Blinding of

participants,

personnel and

outcome

received. Provide any information

during the study?

assessors

Assessments

relating to whether the intended

should be made for

blinding was effective.

each main outcome

(or class of

outcomes).

Describe the completeness of

Were incomplete

Incomplete

outcome data for each main

outcome data

outcome data

Assessments

outcome, including attrition and

adequately addressed?

should be made for

exclusions from the analysis.

each main outcome

State whether attrition and

(or class of

exclusions were reported, the

numbers in each intervention

outcomes).

group (compared with total

randomized participants),

reasons for attrition/exclusions

where reported, and any

re- inclusions in analyses

performed by the review authors.

Selective outcome

State how the possibility of

selective outcome reporting was

reporting.

examined by the review authors,

and what was found.

Are reports of the study

free of suggestion of

selective outcome

reporting?

Was the study

Other sources of

State any important concerns

about bias not addressed in the

apparently free of other

bias.

other domains in the tool.

problems that could put

it at a high risk of bias?

If particular questions/entries

were pre-

specified in the review’s

protocol, responses should be

provided for each question/entry.

Table 8.5.c: Criteria for judging risk of bias in the ‘Risk of bias’

assessment tool

SEQUENCE GENERATION

Was the allocation sequence adequately generated? [Short form:

Adequate sequence generation

?]

Criteria for a

The investigators describe a random component in the

judgement of ‘YES’

sequence generation process such as:

(i.e. low risk of bias).

?

Referring to a random number table;

?

?

?

?

?

?

Using a computer random number generator;

Coin tossing;

Shuffling cards or envelopes;

Throwing dice;

Drawing of lots;

Minimization*.

*Minimization may be implemented without a random

element, and this is considered to be equivalent to being

random.

Criteria for the

judgement of ‘NO’

(i.e. high risk of

bias).

The investigators describe a non-random component in

the sequence generation process. Usually, the

description would involve some systematic, non-random

approach, for example:

?

?

Sequence generated by odd or even date of birth;

Sequence generated by some rule based on date

(or day) of admission;

Sequence generated by some rule based on

hospital or clinic record number.

?

Other non-random approaches happen much less

frequently than the systematic approaches mentioned

above and tend to be obvious.

They usually involve

judgement or some method of non-random categorization

of participants, for example:

?

?

?

Allocation by judgement of the clinician;

Allocation by preference of the participant;

Allocation based on the results of a laboratory test

or a series of tests;

Allocation by availability of the intervention.

?

Criteria for the

judgement of

‘UNCLEAR’

(uncertain risk of

bias).

Insufficient information about the sequence generation

process to permit judgement of ‘Yes’ or ‘No’.

ALLOCATION CONCEALMENT

Was allocation adequately concealed? [Short form:

Allocation

concealment

?]

Criteria for a

Participants and investigators enrolling participants could

judgement of ‘YES’

not foresee assignment because one of the following, or

(i.e. low risk of bias).

an equivalent method, was used to conceal allocation:

?

Central allocation (including telephone,

web-based, and pharmacy- controlled,

randomization);

Sequentially numbered drug containers of identical

appearance;

Sequentially numbered, opaque, sealed

envelopes.

?

?

Criteria for the

Participants or investigators enrolling participants could

judgement of ‘NO’

possibly foresee assignments and thus introduce

(i.e. high risk of

selection bias, such as allocation based on:

bias).

?

Using an open random allocation schedule (e.g. a

list of random numbers);

?

Assignment envelopes were used without

appropriate safeguards (e.g. if envelopes were

unsealed or nonopaque or not sequentially

numbered);

Alternation or rotation;

Date of birth;

Case record number;

Any other explicitly unconcealed procedure.

?

?

?

?

Criteria for the

judgement of

‘UNCLEAR’

(uncertain risk of

bias).

Insufficient information to permit judgement of ‘Yes’ or

‘No’. This is usually the case if the method of

concealment is not described or not described in

sufficient detail to allow a definite judgement

–

for

example if the use of assignment envelopes is described,

but it remains unclear whether envelopes were