Table 3

Summary of results of meta-analyses

ComparatorOutcomeStudies (n)Pooled effect estimate including all studiesStudies (n)Pooled estimates excluding studies with ingredients other than honey*
PlaceboCombined symptom score2 (372)SMD −0.63, 95% CI −1.44 to 0.18, I2=91%1 (270)SMD −1.03, 95% CI −1.32 to −0.75
Usual careCombined symptom score3 (333)MD −3.96, 95% CI −5.42 to −2.51, I2=0%2 (192)MD −4.47, 95% CI −6.47 to −2.48, I2=0%
Cough frequency8 (832)SMD −0.36, 95% CI −0.50 to −0.21, I2=0%6 (586)SMD −0.40, 95% CI −0.58 to −0.21, I2=0%
Cough severity5 (598)SMD −0.44, 95% CI -0.64, to -0.25, I2=20%4 (457)SMD −0.44, 95% CI −0.70 to −0.17, I2=40%
Improvement2 (334)OR 1.01, 95% CI 0.45 to 2.27, I2=56%1 (200)OR 0.73, 95% CI 0.42 to 1.27
Throat pain recovery by day 51 (200)OR 0.75, 95% CI 0.43 to 1.32No change
Fever recovery by day 51 (200)OR 2.58, 95% CI 1.22 to 5.46No change
Dextromethorphan†Combined symptom score1 (68)MD −2.32, 95% CI −5.88 to 1.24NA
Cough frequency2 (137)MD −0.52, 95% CI −1.51 to 0.46, I2=0%NA
Cough severity2 (137)MD −0.56, 95% CI −1.65 to 0.53, I2=0%NA
Diphenhydramine†Combined symptom score1 (87)MD −5.31, 95% CI −7.96 to −2.67NA
Cough frequency4 (385)SMD −0.29, 95% CI −0.58 to −0.01, I2=46%3 (280)SMD −0.41, 95% CI −0.69 to −0.14, I2=17%
Cough severity3 (280)SMD −0.50, 95% CI −0.88 to −0.13, I2=53%NA
  • Pooled results compare honey to comparator, meta-analysed with Mantel–Haenszel random effects models. Studies=number of included studies reporting outcome.

  • *Results excluding Cohen 2017,21 Gupta 2016,22 Miceli Sopo 201518 and Canciani 201419.

  • †Subgroup of usual care.

  • MD, mean difference; n, total number of participants; NA, not applicable, as these studies were not in the primary analysis so results are unchanged; SMD, standard mean difference.