Pelvic Inflammatory Disease and Salpingitis: incidence of primary and repeat episodes in England

Pelvic Inflammatory Disease (PID) and more specifically salpingitis (visually confirmed inflammation) is the primary cause of Tubal Factor Infertility and is an important risk factor for Ectopic Pregnancy. The risk of these outcomes increases following repeated episodes of PID. We develop a homogenous discrete time Markov model for the distribution of PID history in the UK. We use a Bayesian framework to fully propagate parameter uncertainty into the model outputs. We estimate the model parameters from routine data, prospective
studies, and other sources. We estimate that for women aged 35-44, 33.6% and 16.1% have experienced at least one episode of PID and salpingitis respectively (diagnosed or not). 10.7% have experienced 1 salpingitis and no further PID episodes, 3.7% one salpingitis and one further PID episode, and 1.7% one salpingitis and 2 or more further PID episodes. Results are consistent with numerous external data sources, but not all. Studies of the proportion of PID that is diagnosed, and the proportion of PIDs that are salpingitis together
with the severity distribution in different diagnostic settings and of overlap between routine data sources of PID would be of great value