Ten-year trends in the incidence of microtia: a nationwide population-based study from Taiwan

Purpose: Few studies have explored population-based incidence rates of microtia using nationwide data. The aim of this study was to analyze the 10-year secular trends in the incidence of microtia and/or anotia in Taiwan from 2008 to 2017 using nationwide population-based data.

Methods: Patient data were retrieved from Taiwan's National Health Insurance Dataset, after identifying 1152 children aged ≤ 1 year with a first-time diagnosis of microtia or anotia between January 2008 and December 2017. The annual microtia-anotia incidence rate was the sum of new microtia-anotia cases in a year divided by total infant population in the year. Furthermore, we used the annual percent change (APC) to study the secular trend in microtia-anotia incidence rate.

Results: The annual incidence rate of microtia-anotia averaged across the 10-year period was 57.7 per 100,000 infants (standard deviation = 8.6). The annual incidence rates of microtia and anotia were 53.3 and 4.4 per 100,000 infants, respectively, during this period. Furthermore, female infants had a higher incidence than males (63.3 vs. 52.4 per 100,000). The incidence of microtia-anotia gradually decreased between 2008 and 2017 with an APC of - 5.64% (95% CI - 9.31 ~ - 1.18%, p = 0.004). Since 2011, females had a significantly higher annual incidence rate of microtia-anotia than males.

Conclusions: The incidence of microtia-anotia was 57.7 per 100,000 infants in Taiwan, which declined during the study period 2008-2017. The female-to-male incidence ratio was 1.21:1.