Trends, Demographic Characteristics and Seasonal Patterns of Rectal Prolapse Surgery in Japan: A Nationwide...

This study investigated nationwide trends, demographic characteristics, and seasonal patterns of rectal prolapse surgery in Japan, using healthcare claims databases.

Surgical data were extracted from the National Database of Health Insurance Claims (NDB) from 2014 to 2023. Procedures were classified by surgical approach as conventional or laparoscopic. Crude and age-adjusted rates per 100 000 person-years were calculated. Temporal trends were assessed using linear and Poisson regression. Seasonal variations (April 2019-March 2024) were evaluated using one-way analysis of variance with post hoc comparisons, and correlations with meteorological variables were examined using Pearson's correlation coefficients.

Over the decade, a total of 62 407 overall surgeries were performed, with an average annual rate of 4.7 per 100 000 person-years and an overall female-to-male ratio of 6.9:1. Overall surgery rates peaked at ages 85-89 in males (5.5 per 100 000 person-years) and females (59.1). While age-adjusted overall and conventional surgeries declined significantly, laparoscopic surgeries significantly increased (all p < 0.01). Age-adjusted overall surgery rates declined significantly in both sexes (RR = 0.960 for males, 0.983 for females, and 0.979 overall; each p < 0.0001), particularly among younger women aged 30-39 years (p < 0.0024). The mean seasonal overall surgeries exhibited distinct seasonal variation: 578.0 (SD 99.2) in spring, 440.0 (SD 85.9) in summer, 432.4 (SD 50.8) in autumn, and 544.4 (SD 71.8) in winter, and showed moderate negative correlations with temperature.

This study provides contemporary epidemiological insights into surgical management of rectal prolapse in Japan.