Background
Methods
Definitions of structure formats
-
Unstructured format: abstracts presented in one paragraph, with no distinct, labelled sections;
-
IMRaD format: structured abstracts with four distinct main sections labelled with Introduction/Background/Objective(s), (Materials/Patients and) Methods, Results, and Discussion/Conclusion(s) respectively, with or without other separate sections for trial registration and/or source of funding;
-
HS format: structured abstracts with more than four distinct, labelled main sections and at least one of the five headings (Design, Setting, Patients/Participants, Interventions, Main outcome measures) that Haynes et al. [9] proposed for methodology reporting, with or without other separate sections for trial registration and/or source of funding.
Journal selection
Part 1: Structure format usage and journal policies
RCT identification
Data extraction
-
Not mentioned: the reporting guideline (RG) was not mentioned in the instruction;
-
Recommended: the instruction suggested that the RG ought to be considered or used (e.g., ‘should…’, ‘please…’, ‘we suggest/encourage authors to…’);
-
Required: the instruction stated that adherence to the RG is a condition for publication, or the corresponding RG checklist was required to be submitted (e.g., ‘authors must…’, ‘authors are required to…’).
Part 2: Structure format and methodology reporting quality
Pilot study
Items/Supplementary itemsa | Criteria/Contentb |
---|---|
1. Design | Explicit description of the trial design (e.g. parallel, cluster, crossover) |
2. Participants | Eligibility criteria for participants |
3. Setting | Settings where the data were collected |
4. Interventions | Interventions intended for each group |
5. Outcome | Clearly defined primary/main outcome(s) for the trial |
5a. Time point
| When was the primary/main outcome(s) assessed |
5b. No. of outcomes
c
| The number of described primary/main outcome(s) |
6. Random assignment | Clear statement that participants were allocated to groups in a randomised manner |
6a. Unit of randomisation
| Description of the unit of randomisation (e.g. patients, schools, communities) |
7. Sequence generation | Method used for random sequence generation |
8. Allocation concealment | Method used for allocation concealment |
9. Blinding (Masking) | Whether or not participants, caregivers, and those assessing the outcomes were blinded to group assignment |
9a. Generic blinding
| Generic description only (e.g. single-blind, double-blind) |
Full study
Statistical analyses
Ancillary analyses
-
8-heading group: abstracts that incorporated all the eight headings proposed by Haynes et al. [9];
-
Other HS group: abstracts that did not incorporate all eight headings but still fulfilled our definition for HS abstracts.
Results
Part 1: Structure format usage and journal policies
Characteristics of included journals and abstracts
No. | Journal | N of RCTs identified (%) | Structure format used (%) | Structure format required | Specific instructions for each heading | Word limit | CONSORT for Abstracts endorsement | ||
---|---|---|---|---|---|---|---|---|---|
Unstructured (n = 46) | IMRaD (n = 215) | HS (n = 109) | |||||||
1 | New England Journal of Medicine | 73 (19.7) | 0 (0.0) | 73 (100.0) | 0 (0.0) | IMRaD | No | 250 | Not mentioned |
2 | The Lancet | 53 (14.3) | 0 (0.0) | 53 (100.0) | 0 (0.0) | IMRaD | Yes | 300 | Required |
3 | JAMA - Journal of American Medical Association | 38 (10.3) | 0 (0.0) | 0 (0.0) | 38 (100.0) | HS | Yes | 350 | Not mentioned |
4 | Annals of Internal Medicine | 7 (1.9) | 0 (0.0) | 0 (0.0) | 7 (100.0) | HS | No | 275 | Not mentioned |
5 | BMJ - British Medical Journal | 8 (2.2) | 0 (0.0) | 4 (50.0) | 4 (50.0) | HS | Yes | 400 | Required |
6 | PLOS Medicine | 4 (1.1) | 0 (0.0) | 4 (100.0) | 0 (0.0) | IMRaD | Yes | No limit | Not mentioned |
7 | JAMA Internal Medicine | 7 (1.9) | 0 (0.0) | 0 (0.0) | 7 (100.0) | HS | Yes | 350 | Not mentioned |
8 | BMC Medicine | 6 (1.6) | 0 (0.0) | 6 (100.0) | 0 (0.0) | IMRaD | Yes | 350 | Recommended |
9 | Journal of Cachexia Sarcopenia and Muscle | 0 (0) | – | – | – | IMRaD | No | 400 | Not mentioned |
10 | Mayo Clinic Proceedings | 2 (0.5) | 0 (0.0) | 2 (100.0) | 0 (0.0) | IMRaD | No | 250 | Not mentioned |
11 | Journal of Internal Medicine | 1 (0.3) | 0 (0.0) | 0 (0.0) | 1 (100.0) | IMRaD | No | 250 | Not mentioned |
12 | Canadian Medical Association Journal | 1 (0.3) | 0 (0.0) | 1 (100.0) | 0 (0.0) | IMRaD | Yes | 250 | Not mentioned |
13 | Medicine (Baltimore) | 42 (11.4) | 42 (100.0) | 0 (0.0) | 0 (0.0) | Not specified | – | 350 | Not mentioned |
14 | Annals of Family Medicine | 4 (1.1) | 0 (0.0) | 4 (100.0) | 0 (0.0) | IMRaD | No | 250 | Not mentioned |
15 | Translational Research | 2 (0.5) | 2 (100.0) | 0 (0.0) | 0 (0.0) | Unstructured | – | 250 | Not mentioned |
16 | American Journal of Medicine | 6 (1.6) | 0 (0.0) | 6 (100.0) | 0 (0.0) | IMRaD | No | 250 | Not mentioned |
17 | American Journal of Preventive Medicine | 11 (3.0) | 0 (0.0) | 4 (36.4) | 7 (63.6) | HS | No | 300 | Not mentioned |
18 | Medical Journal of Australia | 2 (0.5) | 0 (0.0) | 0 (0.0) | 2 (100.0) | HS | Yes | 250 | Not mentioned |
19 | Annals of Medicine | 0 (0) | – | – | – | IMRaD | No | 200 | Not mentioned |
20 | Deutsches Arzteblatt International | 5 (1.4) | 0 (0.0) | 5 (100.0) | 0 (0.0) | IMRaD | No | 200 | Not mentioned |
21 | Journal of General Internal Medicine | 12 (3.2) | 0 (0.0) | 4 (33.3) | 8 (66.7) | HS | No | 300 | Not mentioned |
22 | Preventive Medicine | 8 (2.2) | 0 (0.0) | 7 (87.5) | 1 (12.5) | Unstructured | – | 250 | Not mentioned |
23 | European Journal of Internal Medicine | 1 (0.3) | 0 (0.0) | 1 (100.0) | 0 (0.0) | Not specified | – | 250 | Not mentioned |
24 | Palliative Medicine | 0 (0) | – | – | – | HS | Yes | Not specified | Not mentioned |
25 | Journal of Pain and Symptom Management | 4 (1.1) | 0 (0.0) | 4 (100.0) | 0 (0.0) | IMRaD | No | 250 | Not mentioned |
26 | American Journal of Chinese Medicine | 0 (0) | – | – | – | Unstructured | – | 250 | Not mentioned |
27 | European Journal of Clinical Investigation | 1 (0.3) | 0 (0.0) | 1 (100.0) | 0 (0.0) | IMRaD | No | 250 | Not mentioned |
28 | Current Medical Research and Opinion | 10 (2.7) | 0 (0.0) | 8 (80.0) | 2 (20.0) | HS | Yes | 300 | Not mentioned |
29 | Internal and Emergency Medicine | 1 (0.3) | 1 (100.0) | 0 (0.0) | 0 (0.0) | Not specified | – | 250 | Not mentioned |
30 | International Journal of Clinical Practice | 5 (1.4) | 1 (20.0) | 4 (80.0) | 0 (0.0) | Not specified | – | Not specified | Not mentioned |
31 | QJM - An International Journal of Medicine | 0 (0) | – | – | – | HS | No | 250 | Not mentioned |
32 | Pain Medicine | 10 (2.7) | 0 (0.0) | 5 (50.0) | 5 (50.0) | HS | No | 250 | Not mentioned |
33 | Journal of Hospital Medicine | 0 (0) | – | – | – | HS | No | 250 | Not mentioned |
34 | British Journal of General Practice | 3 (0.8) | 0 (0.0) | 0 (0.0) | 3 (100.0) | HS | No | 250 | Not mentioned |
35 | BMJ Open | 21 (5.7) | 0 (0.0) | 2 (9.5) | 19 (90.5) | HS | Yes | 300 | Recommended |
36 | American Journal of Managed Care | 5 (1.4) | 0 (0.0) | 0 (0.0) | 5 (100.0) | HS | Yes | 250 | Not mentioned |
37 | Polish Archives of Internal Medicine | 0 (0) | – | – | – | IMRaD | No | 250 | Not mentioned |
38 | Journal of the Royal Society of Medicine | 0 (0) | – | – | – | HS | No | 300 | Not mentioned |
39 | Swiss Medical Weekly | 0 (0) | – | – | – | IMRaD | No | 600 | Not mentioned |
40 | Journal of Women’s Health | 2 (0.5) | 0 (0.0) | 2 (100.0) | 0 (0.0) | IMRaD | No | 250 | Not mentioned |
41 | Archives of Medical Science | 3 (0.8) | 0 (0.0) | 3 (100.0) | 0 (0.0) | IMRaD | No | 250 | Not mentioned |
42 | AMYLOID - Journal of Protein Folding Disorders | 0 (0) | – | – | – | Not specified | – | 200 | Not mentioned |
43 | International Journal of Medical Sciences | 4 (1.1) | 0 (0.0) | 4 (100.0) | 0 (0.0) | Not specified | – | Not specified | Not mentioned |
44 | Journal of the American Board of Family Medicine | 3 (0.8) | 0 (0.0) | 3 (100.0) | 0 (0.0) | IMRaD | No | Not specified | Not mentioned |
45 | Upsala Journal of Medical Sciences | 0 (0) | – | – | – | IMRaD | No | 250 | Not mentioned |
46 | Netherlands Journal of Medicine | 0 (0) | – | – | – | IMRaD | Yes | 250 | Not mentioned |
47 | Journal of the Formosan Medical Association | 2 (0.5) | 0 (0.0) | 2 (100.0) | 0 (0.0) | IMRaD | Yes | 250 | Not mentioned |
48 | Journal of Urban Health | 0 (0) | – | – | – | Unstructured | – | Not specified | Not mentioned |
49 | Family Practice | 0 (0) | – | – | – | IMRaD | No | Not specified | Not mentioned |
50 | Postgraduate Medicine | 3 (0.8) | 0 (0.0) | 3 (100.0) | 0 (0.0) | IMRaD | No | 300 | Not mentioned |
Actual usage of structure formats
Relevant editorial polices
Part 2: Structure format and methodology reporting quality
Sample creation
Characteristics of included abstracts
Structure format and overall reporting quality
Univariable | Multivariableb | |||||||
---|---|---|---|---|---|---|---|---|
Explanatory variables | Category/unit |
B
| 95% CI | P value | QICCa |
B
| 95% CI | P value |
Structure format
| IMRaD | Reference | Reference | |||||
HS | 0.66 | (0.15, 1.16) | 0.011 | 620.2 | 0.54 | (0.06, 1.03) | 0.028 | |
Journal type
| General | Reference | ||||||
Specialty | −0.30 | (−0.86, 0.25) | 0.285 | 650.3 | ||||
Continent
| 0.838 | 651.0 | ||||||
Europe | Reference | |||||||
North America | −0.16 | (−0.55, 0.22) | 0.408 | |||||
Asia | −0.28 | (−0.86, 0.31) | 0.353 | |||||
Oceania | 0.20 | (−0.63, 1.03) | 0.638 | |||||
Others | −0.23 | (−1.29, 0.84) | 0.677 | |||||
Publication year
| 1 year | 0.09 | (−0.06, 0.25) | 0.224 | 652.7 | |||
No. of centres
| Single centre | Reference | Reference | |||||
Multi-centre | 0.42 | (0.16, 0.68) | 0.002 | 623.9 | 0.36 | (0.08, 0.64) | 0.013 | |
Funded
| No | Reference | Reference | |||||
Yes | 0.69 | (0.39, 0.99) | <0.001 | 625.5 | 0.57 | (0.24, 0.90) | 0.001 |
Structure format and reporting of each item
Items/Supplementary items | N (%) | Crude OR (95% CI) | Adjusted OR (95% CI); P valuea | ||
---|---|---|---|---|---|
Overall (n = 341) | IMRaD (n = 176) | HS (n = 165) | |||
1. Design | 120 (35.2) | 54 (30.7) | 66 (40.0) | 1.51 (0.96, 2.36) | 1.51 (0.77, 2.93); 0.228 |
2. Participant | 327 (95.9) | 166 (94.3) | 161 (97.6) | 2.43 (0.75, 7.89) | 2.43 (0.80, 7.33); 0.116 |
3. Setting | 182 (53.4) | 65 (36.9) | 117 (70.9) | 4.16 (2.64, 6.56) | 4.16 (1.74, 9.97); 0.001 |
4. Interventions | 268 (78.6) | 138 (78.4) | 130 (78.8) | 1.02 (0.61, 1.72) | 1.02 (0.64, 1.62); 0.924 |
5. Outcome | 177 (51.9) | 72 (40.9) | 105 (63.6) | 2.53 (1.63, 3.91) | 2.53 (1.30, 4.92); 0.006 |
5a. Time point
| 138 (40.5) | 49 (27.8) | 89 (53.9) | 3.04 (1.94, 4.76) | 3.04 (1.49, 6.19); 0.002 |
5b. No. of outcomes
b
| 123 (36.1)c | 93 (52.8)c | 30 (18.2)c | 1.87 (0.88, 3.97)f | 1.83 (0.69, 4.87); 0.224 |
177 (51.9)d | 72 (40.9)d | 105 (63.6)d | |||
41 (12.0)e | 11 (6.3)e | 30 (18.2)e | |||
6. Random assignment | 336 (98.5) | 172 (97.7) | 164 (99.4) | 3.81 (0.42, 34.48) | 3.81 (0.47, 30.76); 0.209 |
6a. Unit of randomisation
| 246 (72.1) | 141 (80.1) | 105 (63.6) | 0.43 (0.27, 0.71) | 0.43 (0.25, 0.77); 0.004 |
7. Sequence generation | 16 (4.7) | 11 (6.3) | 5 (3.0) | 0.47 (0.16, 1.38) | 0.47 (0.10, 2.25); 0.343 |
8. Allocation concealment | 7 (2.1) | 5 (2.8) | 2 (1.2) | 0.42 (0.08, 2.19) | 0.42 (0.06, 2.76); 0.366 |
9. Blinding (Masking) | 72 (21.1) | 38 (21.6) | 34 (20.6) | 0.94 (0.56, 1.59) | 0.94 (0.42, 2.14); 0.887 |
9a. Generic blinding
| 57 (16.7) | 28 (15.9) | 29 (17.6) | 1.13 (0.64, 1.99) | 1.13 (0.51, 2.47); 0.765 |
Sensitivity analysis
Discussion
Principal findings
Conclusions
Comparison with other studies
Structure format usage and journal policies
Structure format and methodology reporting quality
Strengths and limitations
Implications and recommendations
Heading | Content instruction |
---|---|
1. Objective | State the specific objective or question addressed in the trial. If more than one objective is addressed, indicate the primary objective (based on the predetermined primary outcome) and key secondary objectives. |
2. Designa | Use the term ‘randomised’ to indicate that this is an RCT; describe explicitly the design of the trial (e.g. parallel group, cluster randomised, crossover, factorial, superiority, equivalence or noninferiority, or a combination of these designs); report the duration of follow-up. |
3. Settinga | Provide information about the trial setting, including the level of care (e.g. primary, secondary, tertiary care) and number of participating centres; describe the geographical location if important (e.g. population research in communities). |
4. Participants and interventionsb | Provide eligibility criteria for participants (e.g. demographics, clinical diagnosis, comorbid conditions) and details about the interventions for each group (e.g. dose, route and duration of administration, surgical procedure/technique, name of drug, manufacturer of inserted device, main content of education/lifestyle intervention activity); state the number of participants randomised to each group and the unit of randomisation; |
5. Main outcome measure(s)c | Clearly state what the primary outcome was (i.e. the predetermined outcome considered of greatest importance and usually the one used in sample size calculation) and when it was assessed; describe key secondary outcome if important, make sure that primary outcome and secondary outcomes are distinguished; if the trial abstract focuses on a secondary outcome, identify both this outcome and the primary outcome. |
6. Sequence generationa | Describe the methods used for random sequence generation (e.g. random number table, computer random number generator, coin tossing, minimisation). |
7. Allocation concealmenta | Describe the methods used for allocation concealment (e.g. central allocation, sequentially numbered identical containers, sequentially numbered opaque, sealed envelopes); state ‘None’ when no measures were taken to conceal allocation. |
8. Blinding (masking) | State the blinded parties among participants, caregivers/personnel, data assessors and data analysts (automatically indicating that those unmentioned parties were not blinded); avoid generic descriptions (e.g. single-blind, double-blind); state ‘None’ if blinding was not used or not possible/appropriate in the trial. |
9. Results | Describe the number of participants in each group that were included in the analysis; for the primary outcome, state a result for each group, the estimated effect size and its precision; report any important adverse events (if no adverse events occurred state this explicitly). |
10. Conclusions | Give a general interpretation that is consistent with the trial results, with benefits and harms balanced. |
11. Trial registrationa | Provide the registration number and name of trial register. |
12. Fundinga | Report the source of funding. |