Table 1

Results of meta-analyses of studies reporting the prevalence of NG infection in infertile populations stratified by relevant indicators

Studies/strataSampleNG prevalence (%)Heterogeneity measures
Total NTested*NG positiveMedian†Range‡Pooled mean95% CIQ‡ (P value)I2§ (%, 95% CI)Prediction interval¶ (95% CI)
WHO region
AFRO
 Current infection161825893.30–46.25.01.9 to 9.3133.0 (p<0.0001)88.7 (83.3 to 92.4)0.0 to 28.3
 Ever infection (IgG)532413250.025.0–92.046.628.4 to 65.338.3 (p<0.0001)89.6 (78.4 to 94.9)0.0 to 99.3
 IgA and unclear313210.00–2.00.10.0 to 2.41.4 (p=0.5046)0.0 (0.0 to 84.8)0.0 to 37.2
AMRO
 Current infection247204790.00–53.01.00.0 to 3.4312.7 (p<0.0001)92.6 (90.3 to 94.4)0.0 to 20.7
 Ever infection (IgG)3260175.61.3–10.45.41.2 to 12.06.9 (p=0.0324)70.9 (0.8 to 91.4)0.0 to 100.0
 IgA and unclear6496223.70–9.83.10.4 to 7.521.8 (p=0.0006)77.0 (48.8 to 89.7)0.0 to 23.4
EMRO
 Current infection131471361.00–50.02.70.6 to 5.877.0 (p<0.0001)84.4 (74.8 to 90.3)0.0 to 19.0
 Ever infection (IgG)17923.0–**
 IgA and unclear
EURO
 Current infection5463983610.00–52.22.40.8 to 4.5917.9 (p<0.0001)94.2 (93.1 to 95.1)0.0 to 27.7
 Ever infection (IgG)73594811.70–60.612.22.8 to 26.365.0 (p<0.0001)90.8 (83.6 to 94.8)0.0 to 69.9
 IgA and unclear1222302235.20–31.06.31.9 to 12.6245.3 (p<0.0001)95.5 (93.7 to 96.8)0.0 to 38.9
SEARO
 Current infection884310.00–0.40.00.0 to 0.062.0 (p=0.9578)0.0 (0.0 to 0.0)0.0 to 0.1
 Ever infection (IgG)5307488.64.9–36.414.74.6 to 28.836.6 (p<0.0001)89.1 (77.2 to 94.8)0.0 to 75.0
 IgA and unclear25700.00–0--**--------
WPRO
 Current infection174760780.00–47.02.50.4 to 5.7269.2 (p<0.0001)94.1 (91.9 to 95.7)0.0 to 21.1
 Ever infection (IgG)--------------------
 IgA and unclear2145103.80–7.5--**--------
Multicentre
 Current infection223321.50–3.0--**--------
 Ever infection (IgG)51416439.531.8–62.244.230.6 to 58.37.7 (p=0.0521)61.2 (0.0 to 87.0)1.7 to 93.3
 IgA and unclear--------------------
Global
 Current infection13422 7346460.00–53.02.21.3 to 3.22002.6 (p<0.0001)93.4 (92.6 to 94.1)0.0 to 20.1
 Ever infection25147031125.00–92.021.013.2 to 30.0363.4 (p<0.0001)93.4 (91.4 to 94.9)0.0 to 71.6
 IgA and unclear2530602562.00–31.03.81.3 to 7.0302.1 (p<0.0001)92.1 (89.5 to 94.0)0.0 to 26.9
Assay type
 NAAT (current infection)3312 5941180.00–32.90.70.08 to 1.6395.1 (p<0.0001)91.9 (89.7 to 93.7)0.0 to 9.0
 Culture (current infection)9496824820.00–53.02.71.4 to 4.31212.9 (p<0.0001)92.3 (91.2 to 93.3)0.0 to 25.7
 Other†† (current infection)3221150.00–23.83.80.0 to 24.438.7 (p<0.0001)94.8 (88.2 to 97.7)0.0 to 100.0
 Gram stain (current infection)42373113.00–29.68.70.0 to 31.358.9 (p<0.0001)94.9 (90.0 to 97.4)0.0 to 100.0
 IgG (ever infection)25147031125.00–92.021.013.2 to 30.0363.4 (p<0.0001)93.4 (91.4 to 94.9)0.0 to 71.6
 IgA3260217.86.7–9.88.04.9 to 11.70.5 (p=0.7937)0.0 (0.0 to 55.0)0.0 to 40.3
 Unclear2228002350.30–31.03.20.8 to 6.8300.2 (p<0.0001)93.0 (90.7 to 94.8)0.0 to 27.8
Sex
Women
 Current infection10080384070.00–53.02.51.2 to 4.11151.4 (p<0.0001)91.4 (90.1 to 92.5)0.0 to 27.0
 Ever infection (IgG)22128328525.00–92.022.413.8 to 32.3321.3 (p<0.0001)93.5 (91.3 to 95.1)0.0 to 74.2
 IgA and unclear1913831270.00–31.02.70.3 to 6.7166.0 (p<0.0001)89.2 (84.6 to 92.4)0.0 to 28.5
Men
 Current infection3414 6962390.20–29.61.50.5 to 3.0712.6 (p<0.0001)95.4 (94.3 to 96.2)0.0 to 14.1
 Ever infection (IgG)3187268.61.3–36.412.20.03 to 37.233.4 (p<0.0001)94.0 (85.9 to 97.5)0.0 to 100.0
 IgA and unclear616771297.10–28.56.91.7 to 15.0134.9 (p<0.0001)96.3 (94.0 to 97.7)0.0 to 46.1
Infertility type
Primary/majority primary
 Current infection3578581620.00–39.00.50.0 to 1.7442.7 (p<0.0001)92.3 (90.3 to 93.9)0.0 to 12.1
 Ever infection (IgG)1251910527.10–92.022.08.9 to 38.6177.1 (p<0.0001)93.8 (90.9 to 95.8)0.0 to 87.3
 IgA and unclear5953796.30–14.85.11.4 to 10.626.1 (p<0.0001)84.7 (65.8 to 93.1)0.0 to 30.8
Secondary/majority secondary
 Current infection161212590.00–47.02.50.2 to 6.5145.6 (p<0.0001)89.7 (84.9 to 93.0)0.0 to 28.1
 Ever infection (IgG)642015138.414.5–60.636.422.1 to 52.048.6 (p<0.0001)89.7 (80.3 to 94.6)0.3 to 87.5
 IgA and unclear212485.64.2–7.0--**--------
Not specified/not applicable
 Current infection8313 6644250.00–53.03.11.7 to 4.81390.9 (p<0.0001)94.1 (93.2 to 94.9)0.0 to 26.1
 Ever infection (IgG)7531558.61.3–36.49.64.0 to 17.037.9 (p<0.0001)84.2 (69.0 to 91.9)0.0 to 40.6
 IgA and unclear1819831690.30–31.03.20.4 to 7.8272.4 (p<0.0001)93.8 (91.5 to 95.4)0.0 to 33.6
Infertility diagnosis
Tubal factor infertility
 Current infection2921451290.00–53.03.60.9 to 7.7372.2 (p<0.0001)92.5 (90.3 to 94.2)0.0 to 36.5
 Ever infection (IgG)1267819434.62.0–92.031.116.6 to 47.8207.4 (p<0.0001)94.7 (92.4 to 96.3)0.0 to 1.6
 IgA and unclear9415160.00–9.81.70.1 to 4.817.4 (p=0.0266)53.9 (2.2 to 78.3)0.0 to 13.2
Ovarian and non-tubal infertility
 Current infection171709150.00–17.10.060.0 to 0.842.1 (p=0.0004)62.0 (35.7 to 77.5)0.0 to 4.4
 Ever infection (IgG)6392477.80–31.89.62.6 to 19.736.3 (p<0.0001)86.2 (72.2 to 93.2)0.0 to 52.5
 IgA and unclear315490.00–7.82.50.0 to 9.73.8 (p=0.1472)47.8 (0.0 to 84.7)0.0 to 100.0
Male factor infertility
 Current infection1972081620.70–29.61.40.2 to 3.3361.7 (p<0.0001)95.0 (93.4 to 96.2)0.0 to 14.6
 Ever infection (IgG)17411.3----**--------
 IgA and unclear4981557.10–7.54.30.4 to 11.444.3 (p<0.0001)93.2 (85.9 to 96.8)0.0 to 56.2
Mixed and unexplained infertility
 Current infection14536500.00–47.03.60.0 to 11.6141.5 (p<0.0001)90.8 (86.4 to 93.8)0.0 to 51.6
 Ever infection (IgG)31532825.03.0–38.918.90.3 to 52.133.9 (p<0.0001)94.1 (86.2 to 97.5)0.0 to 100.0
 IgA and unclear3378396.30–14.86.00.5 to 16.016.7 (p=0.0002)88.0 (66.5 to 95.7)0.0 to 100.0
General infertility and partners
 Current infection5511 3632900.00–50.02.61.1 to 4.5991.6 (p<0.0001)94.6 (93.6 to 95.4)0.0 to 24.7
 Ever infection (IgG)31734126.78.6–36.422.78.4 to 41.214.0 (p=0.0009)85.7 (58.2 to 95.1)0.0 to 100.0
 IgA and unclear611321372.10–31.06.70.2 to 19.7190.7 (p<0.0001)97.4 (96.0 to 98.3)0.0 to 69.5
Median year of data collection
<2005
 Current infection8583524820.00–53.03.01.5 to 4.81185.9 (p<0.0001)92.9 (91.8 to 93.9)0.0 to 28.7
 Ever infection (IgG)25147031125.00–92.021.013.2 to 30.0363.4 (p<0.0001)93.4 (91.4 to 94.9)0.0 to 71.6
 IgA and unclear2224192291.30–31.03.81.1 to 7.6289.1 (p<0.0001)92.7 (90.3 to 94.6)0.0 to 30.6
≥2005
 Current infection4914 3821640.00–50.01.10.4 to 2.0542.7 (p<0.0001)91.2 (89.1 to 92.8)0.0 to 10.6
 Ever infection (IgG)--------------------
 IgA and unclear3641273.40–7.53.50.9 to 7.34.0 (p=0.1341)50.2 (0.0 to 85.6)0.0 to 70.8
Sample size
<100 participants
 Current infection6531752730.00–53.04.11.8 to 6.9662.0 (p<0.0001)90.3 (88.4 to 91.9)0.0 to 38.2
 Ever infection (IgG)83878025.93.0–92.029.412.1 to 50.3114.7 (p<0.0001)93.9 (90.2 to 96.2)0.0 to 95.6
 IgA and unclear824120.00–4.20.10.0 to 1.63.2 (p=0.8710)0.0 (0.0 to 27.9)0.0 to 2.2
≥100 participants
 Current infection6919 5593730.00–50.01.00.3 to 1.91111.1 (p<0.0001)93.9 (92.9 to 94.8)0.0 to 12.9
 Ever infection (IgG)17108323114.50–62.217.79.3 to 27.9248.6 (p<0.0001)93.6 (91.1 to 95.3)0.0 to 68.3
 IgA and unclear1728192546.70–31.05.72.4 to 10.1278.5 (p<0.0001)94.3 (92.2 to 95.8)0.0 to 32.0
Urogenital symptoms
Asymptomatic
 Current infection5315 5672330.00–33.31.00.3 to 2.0694.0 (p<0.0001)92.5 (91.0 to 93.8)0.0 to 11.5
 Ever infection (IgG)73228431.80–62.225.010.1 to 43.469.1 (p<0.0001)91.3 (84.7 to 95.1)0.0 to 88.0
 IgA and unclear4595170.00–3.421.20.02 to 3.43.8 (p=0.2898)20.0 (0.0 to 87.7)0.0 to 10.6
Symptomatic‡‡
 Current infection1986318318.20–53.016.27.1 to 27.7282.9 (p<0.0001)93.6 (91.4 to 95.3)0.0 to 75.7
 Ever infection (IgG)1601626.7----**--------
 IgA and unclear4485322.10–14.82.80.0 to 17.460.2 (p<0.0001)95.0 (90.2 to 97.5)0.0 to 95.0
Not specified
 Current infection6263042300.00–50.01.20.3 to 2.5610.0 (p<0.0001)90.0 (87.9 to 91.7)0.0 to 18.1
 Ever infection (IgG)17108821110.41.3–92.019.210.0 to 30.4282.5 (p<0.0001)94.3 (92.3 to 95.8)0.0 to 73.6
 IgA and unclear1719802076.30–31.05.01.7 to 9.4199.7 (p<0.0001)92.0 (88.7 to 94.3)0.0–31.3
  • *The same population may have contributed different measures for current NG infection and ever infection with NG.

  • †Median and range of stratified gonorrhoea prevalence measures included in meta-analyses.

  • ‡Q: the Cochran’s Q statistic is a measure assessing the existence of heterogeneity in effect size (here, NG prevalence) across studies.

  • §I2: a measure assessing the magnitude of between-study variation that is due to differences in effect size (here, NG prevalence) across studies rather than chance.

  • ¶Prediction interval: a measure estimating the 95% interval of the distribution of true effect sizes (here, NG prevalence measures).

  • **A minimum of three studies was necessary to conduct a meta-analysis.

  • ††Other assays assessing current infection such as gonozyme and fluorescent antibody tests.

  • ‡‡Across studies, commonly reported diagnosis and clinical manifestations in infertile women included abnormal/mucopurulent cervical and vaginal discharge, pelvic inflammatory disease, cervicitis, salpingitis, and genital tuberculosis; and in infertile men, dysuria, urethritis, orchitis, epididymitis, prostatitis, vesiculitis, isolated funiculitis, varicocele and testicular trauma.

  • AFRO, African Region; AMRO, Region of the Americas; EMRO, Eastern Mediterranean Region; EURO, European region; NAAT, nucleic acid amplification test; NG, Neisseria gonorrhoeae; SEARO, South-East Asia Region; WPRO, Western Pacific Region.