Abstract
We must be mindful of the caveats of the methods used to estimate the incidence and prevalence of IPF http://ow.ly/MAa0306XRLp
From the authors:
Idiopathic pulmonary fibrosis (IPF) is a very complex disease and despite the diagnostic criteria published in evidence-based guidelines in 2011, there are significant pitfalls in making an accurate diagnosis of IPF [1]. This has surfaced as a reason for the high rate of screen failures in recent prospective clinical trials for IPF [2–5]. Since epidemiological studies are simply based on data entered in medical records and health claim databases, and are not subject to validation by review of actual raw data by experienced experts and multidisciplinary discussions among experts in the field of interstitial lung disease, the reports of the incidence and prevalence of IPF can only be estimates of diagnosis made on assumptions and, thus, must be interpreted with caution. Indeed, tracking the true occurrence of IPF is challenging [6].
The case definition used to identify patients with IPF in our study was not validated. Besides, false positives may well have been a problem and without correction for false positives, the algorithms used to estimate the incidence and prevalence of IPF may be an overestimate by as much as 50% [7, 8].
In this regard, the correspondence from S. Harari and colleagues is very much appreciated as it surfaces other concerns with epidemiological studies and methodological issues associated with estimating incidence and prevalence of disease in the USA, Canada and beyond. We agree that such methodological issues must be considered in appreciating and understanding the differences in reports from different studies. Indeed, we had acknowledged the limitations in our study as well.
Footnotes
Conflict of interest: None declared.
- Received December 5, 2016.
- Accepted December 5, 2016.
- Copyright ©ERS 2017