Characteristic | Derosa 2004 | Derosa 2006a | Derosa 2006b |
Intervention 1 (I1) / intervention 2 (I2) / control 1 (C1) | I1: rosiglitazone + glimepiride C1: pioglitazone + glimepiride | I1: rosiglitazone + metformin C1: pioglitazone + metformin | I1: rosiglitazone + metformin C1: glimepiride + metformin |
Randomised controlled clinical trial (RCT) | Y | Y | Y |
Non‐inferiority / equivalence trial | N | N | N |
Controlled clinical trial | N | N | N |
Design: parallel study | Y | Y | Y |
Design: crossover study | N | N | N |
Design: factorial study | N | N | N |
Crossover study: wash‐out phase | NA | NA | NA |
Crossover study: carryover effect tested | NA | NA | NA |
Crossover study: period effect tested | NA | NA | NA |
Method of randomisation | randomisation codes prepared by statistician | ? | drawing of envelopes; randomisation codes prepared by a statistician |
Unit of randomisation (individuals, cluster ‐ specify) | individuals | ? | individuals |
Randomisation stratified for centres | ? | ? | ? |
Randomisation ratio | 1:1 | 1:1 | 1:1 |
Concealment of allocation | envelopes; a copy of the randomisation code was provided only to the statistician | envelopes containing randomisation code; a copy of the randomisation code was provoided only for the statistician | ?; drawing of envelopes |
Stated blinding (open; single, double, triple blind) | double‐blind | double‐blind | double‐blind |
Actual blinding: participant | Y | Y | Y |
Actual blinding: caregiver / treatment administrator | ? | ? | ? |
Actual blinding: outcome assessor | ? | ? | ? |
Actual blinding: others | ? | ? | ? |
Blinding checked: participant | N | N | N |
Blinding checked: caregiver / treatment administrator | N | N | N |
Primary endpoint defined (power calculation) | N | N | Y |
[n] of primary endpoint(s) | 6 | 5 | 5 |
[n] of secondary endpoints | ? | ? | 6 |
Total [n] of endpoints | ? | ? | 11 |
Prior publication of study design | N | ? | N |
Outcomes of prior/current publication identical | NA | N | N |
Power calculation | N | N | ?; see notes for details |
[n] participants per group calculated | NA | NA | ?; stated but no details provided |
Non‐inferiority trial: interval for equivalence specified | NA | NA | NA |
Intention‐to‐treat analysis (ITT) | Y | Y | Y |
Per‐protocol‐analysis | N | N | N |
ITT defined | Y | Y | Y |
Missing data: last observation carried forward (LOCF) | ? | ? | N |
Missing data: Other methods | Y Bonferroni | Y Bonferroni | N |
LOCF defined | NA | NA | N |
Analysis stratified for centres | N | ? | N |
[n] of screened patients (I1 / I2/ C1/ total) | ? | ? | ? |
[n] of randomised participants (I1/ I2 / C1 / total) ‐ primary endpoint | I1: 42 (baseline) C1: 45 (baseline) total: 91 | I1: 48 (baseline) C1: 48 (baseline) total: 103 | I1: 48 (baseline) C1: 47 (baseline) total: 99 |
[n] of participants finishing the study (I1/ I2 / C1 / total) | I1: 42 C1: 45 total: 87 | I1: 48 C1:48 total: 96 | I1: 48 (baseline) C1: 47 (baseline) total: 95 |
[n] of participants analysed (I1/ I2 / C1 / total) ‐ primary endpoint | I1: 42 C1: 45 total: 87 | I1: 48 C1:48 total: 96 | ? |
Description of discontinuing participants | N | N | N |
Drop‐outs (reasons explained) | Y | N | N |
Withdrawals (reasons explained) | Y | N | Y |
Losses‐to‐follow‐up (reasons explained) | N | N | N |
[n] of participants who discontinued (I1/ I2 / C1 / total) | I1: 2 C1: 2 total: 4 | I1: ? C1: ? total: 7 | I1: 2 C1: 2 total: 4 |
[%] discontinuation rate (I1/ I2 / C1 / total) | I1: 5 C1: 4 total: 4 | I1: ? C1: ? total: 6 | I1: ? C1: ? total: 4 |
Discontinuation rate similar between groups | Y | ? | Y |
[%] crossover between groups | ? | ? | ? |
Differences [n] calculated to analysed patients | NA | ? | ? |
Adjustment for multiple outcomes / repeated measurements | Y | see comments | N |
Baseline characteristics: Clinically relevant differences | N | N | N |
Treatment identical (apart from intervention) | N some patients received behaviour modification, sessions for weight‐loss | Y | Y |
Compliance measured | Y pill count | Y pill count | Y pill count |
Other important covariates measured (specify) | N | N | N |
Co‐morbidities measured | N | N | N |
Co‐medications measured | Y | N | Y |
Specific doubts about study quality | Y see notes | Y see notes | ? |
Funding: commercial | ? | N | ? |
Funding: non‐commercial | ? | N | ? |
Publication status: peer review journal | Y | Y | Y |
Publication status: journal supplement | N | N | N |
Publication status: abstract | N | N | N |
Publication status: other | N | N | N |
Notes | patients were requested to follow a controlled‐energy diet (ADA); some patients received behaviour modifications for weight‐loss; exercise recommendations were given; co‐medications not specified for intervention vs control | patients were requested to follow a controlled‐energy diet (ADA); patients received behaviour modifications for weight‐loss; exercise recommendations were given; adjustment stated as Bonferroni but P‐values provided show no indication of application of the method; drop‐outs per group not specified | patients were requested to follow a controlled‐energy diet (ADA); all patients received behaviour modifications for weight‐loss; exercise recommendations were given; co‐medication not specified for intervention vs control; publication in Pharmacotherapy 2005 states that a power calculation was performed whereas the publication in Clinical Therapeutics 2005 states that no power calculation was performed |
Footnotes Y = yes; N = no; ? = unclear I = intervention; C = control; (baseline) = if numbers for certain features could ne be derived from the text, numbers from baseline characteristics were used |