The epidemiology and treatment of anogenital warts in Singapore: a retrospective evaluation

A retrospective study in the referral centre for sexually transmitted infections (STIs) in Singapore to describe the epidemiology and treatment outcome of patients with anogenital warts.

We reviewed the case records of 301 patients with anogenital warts who were seen over a 1-year period (1999). We also attempted to interview every patient by telephone to find out if they had any clinical recurrences for which treatment was sought elsewhere.

There were 255 males and 46 females with a mean age of 34 years. Two hundred and nineteen (72.8%) presented with symptoms lasting 12 weeks or less. In males, warts occurred most frequently in the preputial cavity (52.5%) and on the penile shaft (40.8%). In females, they occurred most frequently on the external genitalia (91.3%). Two hundred and thirty-five males were treated with cryotherapy and 69% (95% CI, 62.6% to 74.8%) achieved clinical resolution after a mean of 6 treatment cycles. Seven males were treated with podophyllin 0.25% in ethanol and 71% (95% CI, 29.0% to 96.3%) were clinically cured after a mean of 4 treatment cycles. Thirty-nine females were treated with cryotherapy and 67% (95% CI, 49.8% to 80.9%) achieved clinical cure after a mean of 4 treatment cycles. Of the 290 patients treated at the centre, 212 (73%; 95% CI, 67.3% to 77.8%) patients (184 males, 28 females) achieved clinical cure after a mean of 7 weeks (range, 1 to 34 weeks); 90% (95% CI, 86.0% to 93.2%) of them by 15 weeks. Seven-two patients defaulted follow-up and 6 responded partially to treatment. Of the 212 patients who achieved clinical cure, 195 were interviewed by telephone, on an average, 17.7 months after clinical resolution. Thirty-seven (19%; 95% CI, 13.7% to 25.2%), all males, relapsed clinically after a mean of 100 days (range, 5 to 329 days); 90% (95% CI, 84.6% to 93.6%) relapsed by 228 days.

Podophyllin 0.25% in ethanol was the most cost-effective treatment for males. One in 5 patients had a recurrence of their warts and most had their recurrence within 8 months of initial resolution.