Volume 11, Number 8—August 2005
Research
Optimizing Treatment of Antimicrobial-resistant Neisseria gonorrhoeae
, Susan A. Wang*, and Martin I. Meltzer*
Table A1
Average and incremental cost-effectiveness analysis* for a cohort of 1 million women (prevalence of ciprofloxacin resistance = 0.1%)
| Alternative strategies (from least to most effective) | Expected number of cases of PID† | Total cost (intervention + sequelae) (US $1,000s) | Incremental cost | Average cost-effectiveness‡ ratio | Incremental cost-effectiveness ratio§ |
|---|---|---|---|---|---|
| Neisseria gonorrhoeae prevalence = 0.01 | |||||
| ST1: ciprofloxacin + culture | 787 | $26,000 | __ | Baseline | Baseline |
| ST3: ceftriaxone + culture | 787 | $26,210 | $210,000 | (Strongly dominated)¶ | (Strongly dominated)¶ |
| ST2: ciprofloxacin + nonculture | 695 | $32,760 | $6,760,000 | $356,087 | $73,478 |
| ST4: ceftriaxone + nonculture | 694 | $34,070 | $8,070,000 | $366,344 | $8,070,000 |
| N. gonorrhoeae prevalence = 0.10 | |||||
| ST1: ciprofloxacin+ culture | 7,874 | $62,090 | __ | (Strongly dominated)# | (Strongly dominated)# |
| ST3: ceftriaxone + culture | 7,871 | $62,090 | __ | (Strongly dominated)# | (Strongly dominated)# |
| ST2: ciprofloxacin + nonculture | 6,953 | $61,860 | __ | Baseline | Baseline |
| ST4: ceftriaxone + nonculture | 6,941 | $63,420 | $1,560,000 | $7,046,000 | $173,000 |
*Applies baseline values to all variables, other than prevalence of N. gonorrhoeae.
†PID (pelvic inflammatory disease) includes cases of both symptomatic and asymptomatic PID and sequelae. If gonorrhea prevalence is 1%, 1,600 cases of PID would result in the absence of any intervention. If the prevalence of gonorrhea is 10%, the number of PID cases would be 16,000. However, "do nothing" is not a feasible strategy for a clinic as it has already committed to treatment of sexually transmitted diseases.
‡Cost-effectiveness ratios are expressed as cost (in thousands of dollars) per additional case of PID prevented compared to the baseline strategy.
§ Incremental cost-effectiveness ratios are expressed as cost (in thousands of dollars) per additional case of PID prevented compared to the least expensive strategy listed in the preceding row.
¶A strongly dominated strategy is one that is more expensive than an equally or a more effective strategy. For example, ST3 is strongly dominated by ST1 as it is equally effective but more expensive than ST1.
#Both ST1 and ST3 are strongly dominated by ST2 as they are both strategies that are less effective but more expensive than ST2.
1In 2000, only 18% of gonorrhea tests performed by public health laboratories in the United States were culture-based tests.
2Monte Carlo simulation involves specifying a probability distribution of values for model inputs. A computer algorithm then runs the model for several iterations. During each iteration, the computer algorithm selects input values from the probability distributions, and calculates the output (e.g., cost per patient successfully treated). After the final run, the model provides results such as the mean, median, and 5th and 95th percentiles for each specified output.