Table 2.
Model input parameters: costs and utilities
| Utilities | |||
| Asymptomatic health state | 1.00 | Assume an otherwise healthy population | |
| Symptomatic health state | 0.93 | Sri, 201626 | |
| Waiting for diagnosis (symptomatic) health state | 0.93 | Assume the same as symptomatic | Sri, 201626 |
| Treatment complete, that is, returned to asymptomatic state | 1.00 | Assume they return to asymptomatic | |
| PID diagnosis health state | 0.80 | Smith, 200833 | |
| Costs | |||
| Tariff cost of initial visit plus treatment management | £141.00 | Draft National Tariff Payment System: 2015/2016 | 18 |
| Initial clinic visit of symptomatic patient (microcosting) | £103.71 | Patient pathway adapted from a previous model | Adams, 2014*17 |
| Management of STI (oral medication) on same day as assessment†‡ | £29.19 | Excludes drug cost | Adams, 2014*17 |
| Management of STI (oral medication) at return visit after results†‡ | £31.32 | Excludes drug cost | Adams, 2014* 17 |
| Management of STI (medication via injection) on same day as assessment‡ | £43.79 | Excludes drug cost | Adams, 2014* 17 |
| Management of STI (medication via injection) on return visit after results‡ | £44.32 | Excludes drug cost and GC culture/typing lab processing | Adams, 2014*17 |
| Standard CT/NG NAAT laboratory diagnostic test§ | £13.17 | Adams, 2014*17 | |
| POCT CT-NG§ | £24.00 | Assumption based on cost of products currently available | |
| POCT CT-NG-MG§ | £29.00 | Assumption based on cost of products currently available | |
| POCT CT-NG-MG-TV§ | £34.00 | Assumption based on cost of products currently available | |
| Tariff cost of return visit | £110.00 | Draft National Tariff Payment System: 2015/2016 | 18 |
| Return clinic visit of symptomatic patient (microcosting) | £83.25 | Patient pathway adapted from a previous model | Adams, 201417 |
| NG test of cure using standard NAAT laboratory test | £41.73 | Adams, 2014*17 | |
| NG test of cure using POC A | £55.93 | Adams, 2014*17 | |
| Cost of drug treatment (first line) for CT | £1.20 | Where 95% of patients receive 1 g azithromycin and 5% receive doxycycline 100 mg twice daily for 7 days | BNF, 201634 |
| Cost of drug treatment (first line) for NG | £5.95 | Single-dose ceftriaxone 500 mg deep intramuscular injection with single dose 1 g azithromycin | BNF, 201634 |
| Cost of drug treatment (first line) for MG | £1.87 | Doxycycline 100 mg twice daily for 7 days | BNF, 201634 |
| Cost of drug treatment (first line) for TV | £0.36 | Metronidazole 2 g orally in a single dose | BNF, 201634 |
| Cost associated with treatment of short-term PID | £180.52 | Aghaizu, 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.