Table 2

Description of the effects of setting, age, time and socio-economic status on Chlamydia trachomatis test positivity†

 Test positivity
category
GP
Test positivity 11.8%
STI clinic
Test positivity 12.3%
Gynaecology
Test positivity 4.3%
Chlamydia screening
Test positivity 4.4%
N%nAdj. OR (95% CI)nAdj. OR (95% CI)nAdj. OR (95% CI)nAdj. OR (95% CI)
Men
 Provider5659.82511 (ref)**2350.61 (0.50 to 0.74)n.a.n.a.790.19 (0.15 to 0.26)
 Age (years)
  16–21967.7381 (ref)301 (ref)n.a.n.a.281 (ref)
  22–2416710.7621.16 (0.74 to 1.80)811.49 (0.95 to 2.34)n.a.n.a.241.03 (0.58 to 1.84)
  25–2930210.31511.20 (0.81 to 1.77)1241.21 (0.79 to 1.87)n.a.n.a.270.77 (0.44 to 1.34)
 Test year (cont.)‡ 0.84 (0.76 to 0.93)1.16 (1.03 to 1.30)n.a.n.a.0.74 (0.55 to 1.00)
 SES§n.a.n.a.
  Low20610.6990.93 (0.66 to 1.31)811.20 (0.85 to 1.70)n.a.n.a.261.46 (0.80 to 2.67)
  Medium19510.1830.98 (0.69 to 1.39)821.03 (0.73 to 1.46)n.a.n.a.301.75 (0.97 to 3.16)
  High1538.9691 (ref)651 (ref)n.a.n.a.191 (ref)
Women0.54 (0.45–0.63)¶1.22 (1.02 to 1.47)¶n.a.n.a.1.30 (0.99 to 1.71)¶
 Provider12437.64991 (ref)**3411.37 (1.18 to 1.59)1970.42 (0.35 to 0.49)2060.44 (0.37 to 0.52)
 Age (years)
  16–213919.21591 (ref)**971 (ref)*421 (ref)**931 (ref)**
  22–243729.31320.91 (0.71 to 1.17)1201.10 (0.82 to 1.48)570.91 (0.60 to 1.39)630.96 (0.69 to 1.34)
  25–294805.92080.68 (0.55 to 0.85)1240.73 (0.54 to 0.98)980.51 (0.35 to 0.74)500.56 (0.39 to 0.79)
 Test year (cont.)‡0.93 (0.87–1.00)*1.06 (0.97 to 1.16)1.04 (0.93 to 1.16)0.87 (0.73 to 1.05)
 SES§
  Low5358.72281.32 (1.04 to 1.66)1281.24 (0.92 to 1.65)1071.84 (1.24 to 2.73)721.31 (0.92 to 1.85)
  Medium3757.31451.08 (0.84 to 1.39)1111.05 (0.78 to 1.42)521.40 (0.90 to 2.17)671.04 (0.73 to 1.48)
  High3086.51211 (ref)*901 (ref)341 (ref)**631 (ref)
  • Overall p values for categorical variables were specified by *p<0.05; **p<0.01.

  • †Calculated by means of multivariable logistic regression analysis, including provider, age, test year and SES, where appropriate. Test positivity means the proportion of Chlamydia tests that were positive. The rows stating ‘Provider’ should be read horizontally and include the analyses of differences in test positivity between providers. Analyses evaluating test positivity by age, test year and SES were stratified per provider and should be read vertically.

  • ‡Range of test years: 2006–2010, except for chlamydia screening: 2008–2010, because chlamydia screening started in 2008.

  • §The numbers given for the SES categories do not add up to the total number of tests performed because of missing SES data for a proportion of patients.

  • ¶Comparison of test positivity among Chlamydia trachomatis tests between men and women; men are reference category.

  • Adj. OR, adjusted OR; GP, general practitioner; SES, socio-economic status; STI, sexually transmitted infection.