Quality assessment of included RCTs in this meta-analysis.

The modified Jadad scoring system for randomized controlled trials (Crowther M et al. Blood. 2010; 116∶3140–3146). Question 1. Was the study described as randomized? If yes, score 1 point. Question 2. If yes to question 1, was an appropriate randomization sequence described and used (eg, table of random numbers, computer generated, etc.)? If yes, score 1 point. Question 3. If yes to question 1, was an inappropriate method to generate the sequence of randomization used (patients were allocated alternately, or according to date of birth, hospital number, etc.)? If yes, subtract 1 point. Question 4. Was the study described as double blinded? If yes, score 1 point. Question 5. If yes to question 4, was an appropriate method of blinding used (eg, identical placebo, active placebo, dummy, etc.)? If yes, score 1 point. Question 6. If yes to question 4, was an inappropriate method for blinding used (eg, comparison of tablet vs. injection with no double dummy)? If yes, subtract 1 point. Question 7. Were the withdrawals and dropouts described? If yes, score 1 point.