Table 2

Model input parameters: costs and utilities

Utilities
 Asymptomatic health state1.00Assume an otherwise healthy population
 Symptomatic health state0.93Sri, 201626
 Waiting for diagnosis (symptomatic) health state0.93Assume the same as symptomaticSri, 201626
 Treatment complete, that is, returned to asymptomatic state1.00Assume they return to asymptomatic
 PID diagnosis health state0.80Smith, 200833
Costs
 Tariff cost of initial visit plus treatment management£141.00Draft National Tariff Payment System: 2015/2016 18
 Initial clinic visit of symptomatic patient (microcosting)£103.71Patient pathway adapted from a previous modelAdams, 2014*17
 Management of STI (oral medication) on same day as assessment†‡£29.19Excludes drug costAdams, 2014*17
 Management of STI (oral medication) at return visit after results†‡£31.32Excludes drug costAdams, 2014* 17
 Management of STI (medication via injection) on same day as assessment‡£43.79Excludes drug costAdams, 2014* 17
 Management of STI (medication via injection) on return visit after results‡£44.32Excludes drug cost and GC culture/typing lab processingAdams, 2014*17
 Standard CT/NG NAAT laboratory diagnostic test§£13.17Adams, 2014*17
 POCT CT-NG§£24.00Assumption based on cost of products currently available
 POCT CT-NG-MG§£29.00Assumption based on cost of products currently available
 POCT CT-NG-MG-TV§£34.00Assumption based on cost of products currently available
 Tariff cost of return visit£110.00Draft National Tariff Payment System: 2015/2016 18
 Return clinic visit of symptomatic patient (microcosting)£83.25Patient pathway adapted from a previous modelAdams, 201417
 NG test of cure using standard NAAT laboratory test£41.73Adams, 2014*17
 NG test of cure using POC A£55.93Adams, 2014*17
 Cost of drug treatment (first line) for CT£1.20Where 95% of patients receive 1 g azithromycin and 5% receive doxycycline 100 mg twice daily for 7 daysBNF, 201634
 Cost of drug treatment (first line) for NG£5.95Single-dose ceftriaxone 500 mg deep intramuscular injection with single dose 1 g azithromycinBNF, 201634
 Cost of drug treatment (first line) for MG£1.87Doxycycline 100 mg twice daily for 7 daysBNF, 201634
 Cost of drug treatment (first line) for TV£0.36Metronidazole 2 g orally in a single doseBNF, 201634
 Cost associated with treatment of short-term PID£180.52Aghaizu, 201116
  • *Costs were inflated to 2015/2016 costs using the Hospital and Community Health Services Inflation Indices 2015 produced by the Personal Social Services Research Unit.15 No data were available for inflation from 2014/2015 to 2015/2016 so it was assumed to be the same as between 2013/2014 and 2014/2015. The UK consumer price index for health services shows similar annual growth in this sector from 2014, which validates this assumption.

  • †The cost of management of MG/TV infection is assumed to be the same as the costs associated with management of CT infection.

  • ‡These costs vary due to the difference in administrative staff time for patient registration if the patient is treated on the same day or on a subsequent visit.

  • §MSM have samples from three sites (urethral, rectal, pharyngeal) tested at the initial visit, whereas women and MSW typically have one sample taken.

  • BNF, British National Formulary; CT, Chlamydia trachomatis; MG, Mycoplasma genitalium; NAAT, nucleic acid amplification test; NG, Neisseria gonorrhoeae; PID, pelvic inflammatory disease; POC, point-of-care; TV, Trichomonas vaginalis.