Background:
Living systematic reviews play an important role in the synthesis of evidence, especially in the context of the COVID-19 pandemic, and the need for timely updates of clinical evidence is more urgent. However, the frequency of living systematic reviews’ updates is not well known.

Objectives:
To investigate the reporting rate and time of living systematic reviews’ updated frequency.

Methods:
Our study searched PubMed and Google for living systematic reviews from January 1, 2020, to January 1, 2023, using the keywords “living systematic reviews” and “living reviews.” We extracted and analyzed publication country, year, disease, and update frequency reports of the included reviews.

Results:
We included 164 living systematic reviews; 26.22% of the reviews were published in 2020, 46.95% were published in 2021, and 26.83% were published in 2022. The country with the highest number of included reviews was the United Kingdom, with 21.34%. The most common disease was COVID-19, with 81.10%. The number of reviews that reported updates was 120, accounting for 73.17%, but only 49 reviews reported the specific update frequency, accounting for 29.88%, of which the shortest time of update frequency was 1 week, the longest was 18-24 months, and the median was 3 months.

Conclusions:
Living systematic reviews have a low reporting rate for their update time and a large variation in update frequency. It suggests that researchers need to further focus on living systematic review methods in the future.

Patient, public and/or healthcare consumer involvement:
None.