Table 3.
Male Circumcision Status and Risk of Herpes Simplex Virus 2 Incidence
| Variables | Conventional Cox Model Unadjusted, HR (95% CI) | Cox Regression with Weights From Marginal Structural Modelinga, | Conventional Cox Model Adjusted for Time-Varying Factors, |
|---|---|---|---|
| HR (95% CI) | HR (95% CI) | ||
| Circumcised | 0.89 (.73–1.09) | 0.88 (.77–1.10) | 1.00 (.82–1.22) |
| Self-reportedb or clinically detected GUD | 4.75 (3.02–7.48) | ||
| HIV positive | 3.75 (2.55–5.52) | ||
| Skin of penis ever gets scratches during or after sexb | 1.47 (1.18–1.83) | ||
| Number of sex partners in the past 30 d | |||
| 0 | Ref | ||
| 1 | 1.27 (.99–1.62) | ||
| ≥2 | 1.54 (1.14–2.08) | ||
| Married or cohabiting | 1.66 (1.34–2.07) | ||
| Lives in Kisumu district | 1.24 (1.02–1.50) | ||
All covariates are time-varying.
Abbreviations: CI, confidence interval; GUD, genital ulcer disease; HIV, human immunodeficiency virus; HR, hazard ratio; HSV-2, herpes simplex virus 2.
a Weighted marginal structural model is adjusted for month of visit (5-knot cubic spline with knots at the 5th, 27.5th, 50th, 72.5th, and 95th percentiles).
b Recall period is past 6 months.