Tew 2017.
| Study characteristics | ||
| Methods | Study design: multi‐centre, parallel‐group, two‐arm randomised controlled feasibility trial Number of participants: 53 people were randomised Exclusions post‐randomisation: 3 people in the intervention group did not receive the intervention (declined surgery, n = 2; expedited surgery, n = 1) Losses to follow‐up: 3 people in the intervention group lost to follow‐up, 2 people in the control group lost to follow‐up Intention‐to‐treat analysis: intention‐to‐treat analysis not used, people excluded from analysis in every outcome. Duration/dates study conducted: September 2013 to January 2016 |
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| Participants | Country: UK Setting: three teaching hospitals in England Age, years (SD): exercise group: 74.6 (5.5), control group: 74.9 (6.4) Sex: 50 men, 3 women Inclusion criteria: people aged at least 18 years who had been listed, following routine clinical assessment and vascular multidisciplinary team consideration, for an open or endovascular repair of an infrarenal AAA with a diameter of 5.5 cm to 7.0 cm. Exclusion criteria: refusal or inability to provide informed consent, AAA managed non‐operatively, not an infrarenal aneurysm (juxtarenal, suprarenal or thoracic), infrarenal AAA diameter exceeding 7.0 cm, emergency AAA repair, contraindication to exercise testing or training, specialist referral required (for example to cardiology) and BMI below 20 or above 40 kg/m2 |
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| Interventions | Intervention group (and sample size): exercise, n = 27 Three hospital‐based exercise sessions per week, for the 4 consecutive weeks (weeks 1 to 4; main phase) immediately preceding their intended operation date (in week 5). Participants whose operation was delayed beyond week 5 (e.g. owing to lack of availability of a hospital bed) also received a maintenance phase of training (1 exercise session per week). All exercise was undertaken on a cycle ergometer. Each of the first 3 sessions comprised a 10‐min warm‐up of unloaded cycling, eight 2‐min intervals of high‐intensity cycling interspersed with 2‐min rest periods of unloaded cycling, and then a 5‐min cool‐down of unloaded cycling. In all subsequent sessions, participants had the choice of performing eight 2‐min or four 4‐min ‘work’ intervals for the main body of the workout. Control group (and sample size): usual care, n = 26 Evidence‐based medical optimisation |
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| Outcomes | Organ specific morbidity (POMS) (postoperative complications); mortality; duration of critical care; length of hospital stay; HQoL (SF‐36 and EQ‐5D); adverse events. Exercise group only: adherence. |
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| Notes | This study was funded by National Institute for Health Research under its Research for Patient Benefit (RfPB) Programme (Grant Reference Number PB‐PG‐1111‐26068). No competing interests. | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | "After baseline assessment, patients will be randomly allocated 1:1 to exercise or usual care control (no supervised exercise), using minimisation to ensure balance across trial arms for important prognostic factors." Protocol, page 5 paragraph 2 |
| Allocation concealment (selection bias) | Low risk | "After baseline assessment, patients will be randomly allocated 1:1 to exercise or usual care control (no supervised exercise), using minimisation to ensure balance across trial arms for important prognostic factors. We do not list these factors here, to avoid any risk of the staff recruiting patients being able to decipher the allocation sequence." Protocol, page 5 paragraph 2 |
| Blinding of participants and personnel (performance bias) All outcomes | Low risk | "All peri‐operative care will be at the discretion of the vascular teams (as per usual practice) who will be blinded to group allocation." Protocol, page 5 paragraph 2 Due to the nature of the intervention, participants cannot be blinded. |
| Blinding of outcome assessment (detection bias) All outcomes | Low risk | Investigators were blinded to allocation. Study report page 104, paragraph 3‐4 |
| Incomplete outcome data (attrition bias) All outcomes | High risk | Missing data/participants excluded in every outcome Although relevant missing outcomes were fairly distributed across groups and many outcomes had > 20% attrition, the small sample meant that even a small amount of attrition might cause significant attrition bias. ITT analysis was not implemented to reduce the attrition bias. Study report page 104, figure 1 |
| Selective reporting (reporting bias) | High risk | Protocol stated that the participants’ destination would be recorded, i.e. ward or critical care, but this was not given in the study report. Duration of critical care stay was also not presented in the study report. Protocol, page 7 paragraph 4 |
| Other bias | High risk | Small sample size. Study not powered to detect effect size or clinically important difference. |
AAA: aortic abdominal aneurysm APACHE II: Acute Physiology and Chronic Health Evaluation II BMI: body mass index COPD: chronic obstructive pulmonary disease EQ‐5D: EuroQol quality of life questionnaire FET: forced expiration techniques HQoL: health‐related quality of life ITT: intention‐to‐treat MIP: maximal inspiratory pressure NR: not reported POMS: Post‐Operative Morbidity Survey RCT: randomised controlled trial SD: standard deviation SF‐36: short form 36 quality of life questionnaire VO2: oxygen consumption