Exploring the variation in paediatric tonsillectomy rates between English regions: a 5-year NHS and independent sector data analysis

Objectives: Tonsillectomy rates vary between locations and socio-economic groups and have been noted to do so since the 1930s. We aimed, first, to illustrate the current extent of variation in rates in the NHS across England and, second, to explore whether any observed geographical variation could be accounted for by combining independent sector data with standard NHS datasets. Methods: Analysis of NHS Hospital Episode Statistics data for tonsillectomy in people aged under 15 years, from April 1 2000 to March 31 2005; addition of data from a major independent sector provider of surgery; ranking of local authority areas according to tonsillectomy rates including and excluding independent sector data. Results: The national annual average tonsillectomy rate for the NHS was 304 per 100 000 population aged < 15 (95% CI 320-324). The highest rate was 754 (95% CI 690-822) and the lowest 102 (95% CI 83-125). This seven-fold difference cannot simply be explained by a small number of high or low 'outliers'. When rates in the NHS were ranked and compared with the ranking of rates in the independent sector data, a Kendall tau rank correlation coefficient of 0.003 showed that there was no inverse correlation between the two rankings. That is, low NHS rates were not associated with high independent sector rates or vice versa. Conclusions: There is currently a seven-fold variation in tonsillectomy rates across local authority areas in England. The variation in tonsillectomy rates found in NHS data on surgical workload does not appear to be explained by the exclusion of data from the independent sector.