Skip to main content

Table 1 Study characteristics for studies reporting on benefit outcomes for screening versus no screening (key question 1)

From: Screening for chlamydia and/or gonorrhea in primary health care: systematic reviews on effectiveness and patient preferences

Author, year

Country

Design, intensity, sample size, risk of bias

Screening rates in intervention group (IG), rates of testing outside of study (IG; control group [CG])

Sex and age

Baseline CT positivity of tested, all sexually active (Y/N)

Recruitment

Screening approach; CT vs CT and NG; location, test, and person testing; re-testing; co-interventions

Outcome assessment

Incidence of PID in CG

Follow-up durations

Randomized controlled trials

 Andersen et al. 2011 [59]

Denmark

RCT

1 screen offered

15,459

ROB: unclear (detection bias)

29%

IG 9.0% vs CG 9.4% during 3 mos study period

F

21–24 yrs

7.1%; N

Population-based via mailed kits

Universal; CT; home-collected vaginal pipette, with NAAT; 70% re-tested; none

PID: hospital discharge ICD codes or doxycycline prescriptions (only used for PID in Denmark; 33% by GPs). Incidence in CG 0.65%. Follow-up duration, 1 yr

EP and infertility: hospital discharge ICD codes. Follow-up duration, 9 yrs

 Garcia et al. 2012 [60]

Brazil

RCT cluster

Screening offered every 8 wks over 3 yrs

20 cities with >50,000 inhabitants; follow-up survey using sampling at random sites at baseline (3732) and after 4 yrs (4156)

ROB: unclear (performance bias)

NR (interviewed FSWs 48,207 times during 20 8-wk cycles)

NR

F

>14 yrs

Mean 24.5 yrs

15.5% CT, 2.4% NG; Y

Outreach via mobile teams

Universal; CT and NG (and other STIs); mobile site self-collected vaginal swabs with NAAT; re-testing NR but frequent visits; multi-faceted syndromic management in general population and clients of FSWs; condom promotion with motivational interviewing and free condoms; peer education

Estimated population prevalence in FSWs using surveys (>99% of eligible enrolled) at random FSW sites. Follow-up duration, 3.5 yrs

 Hocking et al. 2018 [8]

Rural Australia

RCT cluster

3 annual screens offered

52 clusters (130 clinics of >500 16–29 yr olds)

ROB: unclear (performance and attrition biases)

24% ≥1 times over 3 yrs (8.2% pre-trial yr to 20% at 25–36 mos)

IG NR; CG rates increased from 8.2% pre-trial to 12.9% (stable over trial)

F and M

16–29 yrs

10% in those testing; 4.8% (4.5% females and 5.5% males) in prevalence surveys; Y

Primary care (clinic attenders)

Opportunistic; CT; in-clinic patient-collected vaginal or urine with NAAT; approx. 25% re-testing each year; multi-faceted with provider reminders, incentives, education, payments and feedback, and patient recall systems

Clinic PID: cumulative incidence in clinics for women 16–33 with at least one clinic visit during intervention period. Criteria provided to all providers but not blinded. Incidence in CG 0.4%.

Hospital PID: ICD codes for all 15–34 yr olds living in each cluster. Incidence in CG 0.4%. Not used for main analysis because of low ascertainment and difference in trial and hospitalized populations

Estimated population prevalence (in clinic attenders): Using surveys of consecutive clinic attenders (70% response) before randomization and at end of trial (difference in change from baseline)

Follow-up duration for all outcomes: 3 yrs

 Hodgins et al. 2002 [12]

Nunavik region in Northern Quebec

RCT cluster

1 screen offered

12 communities in Nunavut (2320, 15–39 years)

ROB: high (incomplete outcome data with reported rates based on low uptake; multiple unclear domains)

31%

NR

F and M

All; focus on 15–39 yrs

7%; Y

Outreach via community

Universal CT; home urine sampling with PCR; re-testing NR; intensive community health education program

Estimated population prevalence via reported rates over past yr in communities.

Follow-up duration, 1 yr

 Klovstad et al. 2013 [98]

Norway

RCT

1 screen offered

41,519 (10,000 IG)

ROB: low

IG 14% (85% of 16.5% testing via study or healthcare system)

IG 2.5%, CG 3.4%

F and M

18–25 yrs

IG 6.3% vs 11.6%; N

Population-based register via mailed invitations with screening kits (no reminders)

Universal; CT; home urine sampling via mailed kit via NAAT; N; N

Treatment for CT: national prescription database (filled at least one prescription for (azithromycin, doxycycline, erythromycin, lymecyklin, amoxicillin) within 30 days following a positive test result. Follow-up duration, 3 mos

 Oakeshott et al. 2010 [28]

London, UK

RCT

1 screen

2529

ROB: low

100%

22% both groups (43% of those CT+ in CG)

F

16–27 (mean 21) yrs

5.4%; Y

Outreach at common rooms, lecture theaters, and student bars at universities and further education colleges in London

Universal; CT; outreach site self-collected vaginal swabs with NAAT; re-testing NR; informed of risks of CT infection

PID: Any report by participants or their providers about signs and symptoms or dx, looked to medical records in general practitioners, hospitals, family planning clinics, and genitourinary medicine clinics. Used criteria for all cases, but medical records sometimes incomplete. Incidence in CG 1.8%.

Follow-up duration, 1 yr

 Ostergaard et al. 2000 [105]

Denmark

RCT cluster

1 screen

17 schools (IG 928 vs CG 833)

ROB: high (attrition [>50%] and lack of cluster analysis), unclear for other domains except allocation concealment

IG 93% vs CG 7.5%

IG 29% and CG 36% (p=0.04)

F

≥15 yrs in high school (9% ≥19 yrs)

IG 5% vs CG 7.9%; Y

Outreach in schools with provision of home kits or invitation/reminder to go to general practitioner or STI clinics

Universal; CT; home sampling using vaginal pipette and NAAT vs. in-clinic swab with EIA; re-testing NR; information about consequences

PID: Self-reported at follow-up questionnaire, with confirmation in registration for prescriptions. Incidence in CG 4.1%. Follow-up duration, 1 yr

 Scholes et al. 1996 [108]

Washington, USA

RCT

1 screen offered to selected females

2607

ROB: unclear (selection, performance and detection biases)

64%

NR

F

18–34 yrs; 81% ≤24 yrs

7%; Y

Primary care using telephone recruitment with questionnaire for high-risk considering race, douching, and ≥2 sexual partners in the preceding 12 months; married women excluded

Universal; CT; in-clinic; clinician-collected cervical swabs (EIA or culture); re-testing NR; none

PID: Self-report signs, symptoms, dx; medical records, hospital discharge, and pharmacy records. Dx had to be recorded and considered “clinical” (37 of 142 reported PID confirmed) but no specific criteria provided. Incidence in CG 2%. Follow-up duration, 1 yr

 Senok et al. 2005 [109]

UK

RCT postal and opportunistic vs usual care over 4-month period

476

ROB: high for attrition bias; unclear for selection and detection

Opportunistic 21%; postal 48%; UC 0%; NR

F

16–30 yrs; mean 24 yrs

Opportunistic 14%

Postal 5%

Usual care NR; N

Letters from general practice lists

Universal opportunistic and postal; CT; NR; no; incentives to providers at practices

Treatment for CT: clinic records. Follow-up duration, 4 mos

 van den Broek et al. 2012 [9]

Netherlands

RCT stepped-wedged cluster

3 annual offered

190 clusters with 317,304 people in three regions

ROB: unclear for performance and detection biases and incomplete outcome data (prevalence); high for incomplete outcome data (positivity)

16% (1st round), 10% (3rd round) (vs 13% in controls)

NR

F and M

16–29 yrs

4.3% (7.1% in <20 yr olds); NR

Population-based with postal invite to request sampling kit via internet

Universal; CT; home with urine for males and vaginal swab or urine for females; kits for re-testing sent 6 mos after CT+ (uptake NR); none

Estimated population prevalence using data from positivity with extrapolation to sexually active population of same ages in communities.

Follow-up duration, 2 yrs

Controlled clinical trials

 Clark et al. 2001 [88]

USA (Army recruits to South Carolina)

CCT

1 screen

28,074

ROB: high (selection and detection bias)

100%

NR

F

17-39 yrs;

88% ≤25yrs

9.1%; N (93% of IG but higher and unknown for CG)

Community outreach via non-health Army training examination center

Universal; CT; on-site self-collected urine with NAAT; re-testing NR; education on STDs

PID, EP, infertility: Hospital discharge records. Incidence in CG 5.1/1000 PY (0.8%), 1.9/1000 PY and <0.01/1000 PY. Follow-up duration: mean 1.5 yrs

 Cohen et al. 1999 [89]

Louisiana, USA

CCT

Bi-annual screening offered over 2.5 years (CG invited in 3rd year with 1 test period)

5907 from 3 IG and 5 CG schools

ROB: high for selection, performance (11–53% testing outside of trial), attrition and other (no cluster adjustment) biases

83% at least once; annually, 52 to 65%

IG and CG 11% grade 9 and 53% grade 12, males ~20%

F and M

Grades 9–12

CT 11.5% females (8.7% in grade 9s vs 14% in grade 12s), 6.2% males

NG 2.5% females, 1.2% males (similar across ages)

N

Community health in high school health centers

Universal; CT and NG; on-site urine with NAAT; re-testing NR but bi-annual testing; information about risks and consequences

CT positivity in screening eligible students, who participated in screening, in IG after year 2 (5 tests offered) and CG (offered screening after year 2 in IG); Follow-up duration, 2.5 yrs

NG positivity in screening eligible students, who participated in screening, in IG after year 1 (3 tests offered) and CG (offered screening after 1 year of NG testing added in 2nd year of study). Follow-up duration, 1.5 yrs

Observational studies

 Sufrin et al. 2012 [111]

California, USA

Retrospective cohort

1 screen

57,728

ROB: moderate (selection bias with some adjustment)

100%

NA

F

14–49 yrs; mean 32 yrs (non-screened 7 yrs older)

NR; Y

Primary care

Unknown but assume some form of risk assessment for screening same day or up to 1 year before IUD insertion; CT; in-clinic but unknown test and methods; re-testing NR; none

PID after IUD insertion: Health Maintenance Organization database ICD plus antibiotic pharmacy dispensed, with record review in 10% random sample if discordant; closed system. No specific criteria. Incidence in CG 0.36%. Follow-up duration, 3–15 mos (3 mos after IUD insertion but up to 15 mos from screen)

 Low et al. 2006 [101]

Sweden

Retrospective cohort

48% screened once, 22% twice, 30% ≥3 tests over 10 yr

43,715

ROB: moderate (selection bias with some adjustment)

100%

NA

F

15–24 yrs

NR (11.5% at some time during follow-up); N

Population-based

Opportunistic used in county; CT; in-clinic sampling NR with culture; none

PID, EP, infertility: hospital discharge in-(all yrs) and out-(last 6 yrs) patient. No criteria. Incidence in CG 2.9%, 1.9%, 3.1% over 10 yrs. Follow-up duration, 10 yrs

  1. Abbreviations: CCT controlled clinical trial, CG control group, CT Chlamydia trachomatis, Dx diagnosis, F females, FSW female sex workers, ICD International Classification of Diseases, IG intervention group, IUD intrauterine device, M males, mos months, NAAT nucleic acid amplification test, NG Neisseria gonorrhoeae, NR not reported, PID pelvic inflammatory disease, RCT randomized controlled trial, ROB risk of bias, wks weeks, yrs years