Smyth 2010.
| Study characteristics | ||
| Methods | Pilot double‐blinded, placebo‐controlled RCT. Parallel design. Location: Nottingham, UK. Duration: 8 weeks. |
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| Participants | 34 participants over 8 years of age with CF (definition given) and chronic pulmonary infection with P aeruginosa and at the time of randomisation. Age, median (range): 18 years (11– 54 years). Adult/child split: garlic group 8 adults (62%) and 5 children (38%); placebo group 9 adults (69%) and 4 children (31%). Gender split: 14/26 (54%) were male. Baseline FEV1 (L), mean (SD): garlic group 1.84 L (0.79); placebo group 1.91 L (1.05) Baseline FEV1 % predicted, mean (SD): garlic group 62.0% (18.4); placebo group 57.4% (26.1). Weight (kg), mean (SD): garlic group 46.7 kg (14.6); placebo group 54.2 kg (14.1). Baseline clinical score, median (range): garlic group 2 (0 to 6) 3 (0 to 6); placebo group: 4 (0 to 6). |
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| Interventions |
Intervention: garlic capsule once daily (656 mg of garlic oil macerate and 10 mg cardamom oil). Control: placebo capsule once daily (656 mg of olive oil and 10 mg cardamom oil). |
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| Outcomes |
Primary outcome: FEV1. Secondary outcomes: weight, clinical score, quorum sensing signal molecule level, number of courses of IV antibiotics over the 8‐week trial period. Measured at baseline and 8 weeks. |
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| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Web‐based randomisation sequence. |
| Allocation concealment (selection bias) | Low risk | Procedure for dispensing preparation unclear ‐ unpublished details demonstrate the supplements were dispensed in coded sealed opaque containers. |
| Blinding (performance bias and detection bias) PUFA first | Low risk | Double‐blind, identical placebo. The cardamom oil was present as an odour control agent. |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | 8 participants withdrew ‐ four in each group: Garlic ‐ 1 received lung transplant, 1 forgot to take capsules, 1 side effect of indigestion, 1 could not attend second visit; Placebo ‐ 2 forgot to take capsules, 1 side effect of halitosis, 1 could not attend visit 2. Analysis was per protocol. |
| Selective reporting (reporting bias) | Low risk | No selective reporting identified. |
| Other bias | Low risk | No other bias identified. |
BMI: body mass index CF: cystic fibrosis CFQ‐R: cystic fibrosis questionnaire revised CFU: colony forming units FEF25-75: mid peak expiratory volume FEV1: forced expiratory volume at 1 second FVC: forced vital capacity ITT: intention‐to‐treat IV: intravenous
Ln: natural logarithm NO: nitric oxide P aeruginosa: Pseudomonas aeruginosa QoL: quality of life SD: standard deviation