Table 2 Cox regression analysis of hospitalizations with pelvic inflammatory disease by previous C. trachomatis infection
Prior infections | No. of women* | Observation years | No. of events | Incidence rate per 100 person-years (95% CI) | Adjusted† hazard ratio (95% CI) |
|---|---|---|---|---|---|
None | 20,534 | 169,192 | 143 | 0.08 (0.07–0.10) | Reference |
One or more | 4,413 | 32,057 | 48 | 0.15 (0.11–0.20) | 1.69 (1.21–2.37) |