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Table 2 Tool for assessment of quality and bias

From: The burden of pertussis in low- and middle-income countries since the inception of the Expanded Programme on Immunization (EPI) in 1974: a systematic review protocol

Item

Score

1. Study design (selection score)

 

  a. Prospective clinical studies (any type)

 

   ♦ Consecutive enrolment

2

   ♦ Unspecified/random enrolment

1

  b. Autopsy studies

 

   ♦ Consecutive enrolment

2

   ♦ Unspecified/random enrolment

1

  c. Retrospective reviews (including subgroup analysis)

1

  d. Review/editorial

0

  e. Case report

0

2. Study objectives (selection score)

 

  a. Clear inclusion criteria

 

   ♦ Aim related to pertussis prevalence or outcomes

3

   ♦ Related to OIs/general morbidity/respiratory disease but not specific to pertussis

2

   ♦ Unrelated to clinical pertussis prevalence

1

  b. Unclear inclusion criteria

1

3. Diagnosis* (quality of outcome ascertainment)

 

  a. Laboratory-confirmed (any specified method/specimen)

2

  b. Clinical case definition (consistent with WHO or CDC guidelines)

1

  c. Not specified

0

4. Denominator

 

  a. Raw data denominator

2

  b. Calculated denominator

1

  c. No/unclear denominator/investigated < % of cohort for pertussis/exclusion group

0

5. Numerator (Pertussis numbers)

 

  a. Raw data numerator

2

  b. Calculated numerator

1

  c. No/unclear numerator (clinical pertussis not mentioned/tested)

0

6. Assessment of bias (low, high or unclear risk)

 

  a. Attrition bias

 

   ♦ Amount, nature or handling of incomplete outcome data

 

  b. Selection bias

 

   ♦ Representativeness of the cases/cohort (clear reasons for and rates of non-inclusion)

 
  1. *Do not include data from clinical episodes of pertussis if no case definition provided (even if study otherwise qualifies). CDC, Centers for Disease Control; OI, opportunistic infection; WHO, World Health Organisation.