The association between sex and disease impact cannot be confounded by clinical risk factors

Reply to: The association between sex and disease impact cannot be confounded by clinical risk factors

“…We have read with great interest the letter by Heckert et al (1) commenting on our work recently published in this journal regarding the confounding factors in the relationship between sex and disease impact in recentonset psoriatic arthritis (2). Although some epidemiological definitions suggest that the confounding factor must be pre-exposure, in our manuscript we have followed the classic definition of a confounding factor: variable associated with the disease, associated with exposure, and not an intermediate step in the causal chain.…”