Table 3 Inclusion of the data source as a variable in the analysis of heterogeneity of the included meta-analyses

Weiss J [20]

Harms outcomes

.

.

.

No

.

.

.

No

Bally M [21]

Timing of exposure to NSAIDs, dosage and duration of treatment, concomitant drug treatment

Comorbidities

Alternative statistical model, reason for exclusion

No

.

.

.

No

Sordo L [22]

Time interval in and out of opioid substitution treatment

.

Alternative statistical model

No

Treatment provider, prevalence of opioid injection, average methadone dose

.

Mean age, percentage of men, location, percentage of inpatient induction, percentage loss to follow-up, midpoint follow-up period

No

Tariq R [23]

Type of gastric acid suppressant (PPI and H2B reported together, PPI alone, or H2B alone)

Case definition (time interval of recurrence: within 60 days vs within 90 days), type of diagnostic assay used for Clostridium difficile infection

Study design, study setting (inpatients vs outpatients), data adjustment

No

.

.

.

No

Maruthur NM [24]

Mode of therapy

.

.

No

.

.

.

No

Paul S [25]

Primary outcome

.

Chronic or resolved hepatitis B virus infection

Tumor and chemotherapy subtype, alternative statistical model, quality of design

No

.

.

.

No

Paul S [25]

Secondary outcomes

.

.

Alternative statistical model, quality of design

No

.

.

.

No

Li L [26]

Type of control, mode of therapy, individual drugs

.

Length of follow up, type of design

No

.

.

.

No

Molnar AO [27]

.

.

Type of design

No

.

.

.

No

Ziff OJ [28]

Primary outcome

.

.

Data adjustment, population type

No

Difference between digoxin and control arms at baseline: Diabetes, hypertension, diuretics, anti-arrhythmic drugs

.

Summary bias score, baseline study level variable: Year of publication, age, sex, previous myocardial infarction

No

Ziff OJ [28]

Secondary outcomes

.

.

.

No

.

.

.

No

CGESOC [29]

Duration of use in current and past users of hormone therapy, types of hormone therapy

Tumour histology and malignant potential of the tumour

Study design, geographical region, age at first use of hormone therapy, age at menarche, parity, oral contraceptive use, height, bosy mass index, alcohol use, tobacco use, mother or sister with ovarian/breast cancer, histerectomy

No

.

.

.

No

Bellemain-Appaix A [30]

Clopidogrel dose

Types of percutaneous coronary intervention

Type of design

No

.

.

.

No

Grigoriadis S [31]

Timing of exposure to SSRIs

.

Study design, congenital malformations, control, meconium aspiration

No

.

.

.

No

Li L [32]

Type of incretin agents, type of control, mode of therapy, individual incretin agents

.

Length of follow-up, alternative effect measure, alternative statistical model

No

.

.

.

No

Kalil AC [33]

Different MIC cutoffs, assay type

Hospital or 30-d mortality

Publication year, quality of design

No

Vancomycin MIC cut-off, vancomycin exposure in the previous 6 months, vancomycin trough levels, proportion of patients who received vancomycin treatment

Control mortality, APACHE II score, Charlson score, duration of bacteremia, proportion of patients with endocarditis, proportion of patients located in the intensive care unit

Age

No

Stegeman BH [34]

Generation of progestogen used in combined oral contraceptives, combined oral contraceptive pill

Method of diagnosis confirmation

Funding source, study design

Yes (outcome)

.

.

.

No

Maneiro JR [35]

Type of biologic agent, concomitant treatment (monotherapy vs combined therapy), prior use of TNF inhibitors

Type of disease

Length of follow-up, data quality, study design, level of evidence of studies

No

Type of biologic agent, prior use of TNF inhibitors,

method of measurement of antibodies, type of the anti-TNF monoclonal antibody

Type of disease, time of disease duration, time to assess response

Age and sex of patients, number of participants, length of follow-up, data quality, study design, level of evidence of studies

No

Hartling L [36]

Primary outcomes

Type of drug-comparison

Type of scale for the assessment of symptoms and quality of life

.

No

.

.

.

No

Hartling L [36]

Secondary outcomes

.

.

.

No

.

.

.

No

Hsu J [37]

Individual drugs, dosage of antiviral, timing of treatment

.

Data adjustment, confirmed influenza, type of influenza A vs B, pandemic versus seasonal influenza, severity of influenza, age, pregnancy, baseline risk (e.g. immune-compromised), setting, funding conflict

No

.

.

.

No

Caldeira D [38]

Incidence of pneumonia

.

.

Study design, previous stroke, heart failure, chronic kidney disease, non-Asian patients

No

.

.

.

No

Caldeira D [38]

Pneumonia related mortality

.

.

Study design

No

.

.

.

No

MacArthur GJ [39]

Duration of exposure to opiate substitution treatment

.

Data adjustment, geographical region, site of recruitment, monetary incentives, percentage of female participants, percentage of individuals from ethnic minorities

No

Exposure to methadone maintenance treatment at baseline only

.

Inclusion only of studies at lower risk of bias, inclusion only of studies that measured an incidence rate ratio, exclusion of studies that did not adjust for confounders

No

Mantha S [40]

Route of administration

.

Data adjustment

No

.

.

.

No

Silvain J [41]

Route of administration

.

Types of percutaneous coronary intervention, study publication, study size, quality of design

No

.

.

.

No

McKnight RF [42]

.

.

.

No

.

.

.

No