A new study has employed contemporary diagnostic algorithms for cystic fibrosis (CF) in North America and found that incidence rates may be lower than previously reported.

The study, published in the Journal of Cystic Fibrosis, also found that the incidence rates varied widely within North America, which could impact future resource planning and usage.

“The landscape of CF has dramatically evolved over the past three decades, which could influence incidence rates,” the authors wrote. “The objectives of this study were (1) to estimate the overall incidence rate of CF in North America, by country, by region, and by sex; and (2) to evaluate the longitudinal trends in incidence rates between 1995 and 2019. We hypothesized that (1) overall incidence rates will be similar in the two countries but vary across geographical regions within countries and (2) incidence rates will decrease over time.”

The research team conducted a population-based cohort study on data from the Canadian CF Registry, Statistics Canada, US CF Foundation Patient Registry data, and US Center for Disease Control National Vital Statistics System between 1995 and 2019. Incidence rates were calculated using Poisson regression and the number of live CF births per year, by sex, and by geographic region.

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The authors note that incidence rates are typically underestimated because some people born with CF in a particular year may not have been diagnosed by the end of the study period. They accounted for these delayed diagnoses by calculating the proportion of expected diagnoses based on historical trends and regional rates of newborn screening.

The results revealed substantial variation in incidence between regions of Canada and the US, as well as decreasing incidence rates in both regions since 1995. The authors expect this data to be useful for resource planning as well as for assessing the impact of CF programs on incidence rate.

Reference

Stephenson A, Swaleh S, Sykes J, et al. Contemporary cystic fibrosis incidence rates in Canada and the United States. J Cyst Fibros. Published online November 10, 2022. doi:10.1016/j.jcf.2022.10.008