Wang 2017.

Study characteristics
Methods	Design: randomised, controlled, parallel‐group trial Duration: 26 weeks Location: Zhengzhou Hospital, China
Participants	Population: 86 adults with moderate to severe COPD were randomly assigned to azithromycin (n = 43) or placebo (n = 43) Baseline characteristics: age (mean years): 71.4 (SD 8.2), % male (mean): 59, FEV₁ (mean): 0.67 L (SD 0.095); exacerbation history: not reported Inclusion criteria: 45 years of age with history of severe COPD diagnosed with pulmonary function test and tracheostomy Exclusion criteria: allergy to macrolides, life expectancy < 1 year
Interventions	Azithromycin 250 mg once daily plus simvastatin 20 mg once daily Placebo: simvastatin 20 mg once daily Allowed co‐medications: cough relief medication, aminophylline, beta2 receptor agonist
Outcomes	Blood gas analysis, FEV₁, FVC, 6MWT, pulmonary arterial pressure
Notes	Funding: "Grant Support & Financial Disclosures: None" Identifier: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"randomly divided into an observation group and a control group using random number table, 43 in each group"
Allocation concealment (selection bias)	Unclear risk	No further information was provided
Blinding of participants and personnel (performance bias) All outcomes	High risk	No blinding of participants or personnel was described. Study was assumed to be open‐label
Blinding of outcome assessment (detection bias) All outcomes	High risk	No blinding of outcome assessors was described. Study was assumed to be open‐label
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	No further information was provided
Selective reporting (reporting bias)	High risk	No prospective trial registration or protocol was identified. Dyspnoea grade was reported as measured in the abstract but was not described in the methods. It is not clear if FEV₁ and FVC variance are SDs or SEs
Other bias	Low risk	No other bias was identified

Abbreviations

6MWT: six‐minute walk test; AE: adverse event; AECOPD: acute exacerbation of chronic obstructive pulmonary disease; bpm: beats per minute; BTS: British Thoracic Society; CAT: COPD assessment test; COPD: chronic obstructive pulmonary disease; ED: emergency department; FEV₁: forced expiratory volume in one second; FVC: forced vital capacity; GOLD: Global Initiative for Chronic Obstructive Lung Disease; HRQoL: health‐related quality of life; ICS: inhaled corticosteroid; ITT: intention‐to‐treat; LABA: long‐acting beta‐agonist; LAMA: long‐acting muscarinic antagonist; LCQ: Leicester Cough Questionnaire; NR: not reported; OCS: oral corticosteroids; QT: uncorrected QT interval (measurement of electrical properties of the heart); QTc: corrected QT interval; SABA: short‐acting beta‐agonist; SAE: serious adverse event; SAMA: short‐acting muscarinic antagonist; SD: standard deviation; SE: standard error; SF36: short form 36; SGRQ: St George's Respiratory Questionnaire; ULN: upper limit of normal.