Letter to the editor: response to 'Epidemiology and seasonal pattern in hospitalizations for microscopic colitis'.

Abstract

We read with great interest the letter to the editor by Al-Taee et al. [1] on the seasonal pattern and epidemiology of hospitalizations for microscopic colitis (MC). Their study reviewed the 2016 National Inpatient Sample (NIS) and discussed all admissions for MC occurred between August and December, suggesting a seasonal pattern of MC. To further study this phenomenon, we analyzed NIS data from 2016 to 2019. Using ICD-10 codes, we identified all hospitalizations with a primary diagnosis code of MC (K52.83). We stratified hospitalizations into months and analyzed seasonal trends. We identified 5190 hospitalizations with a primary diagnosis of MC between January 2016 to December 2019. As described by Al-Taee et al. [1], MC was more commonly seen in southern (31.21%) and midwestern regions (30.25%). Females accounted for more than 80% of hospitalizations. Most patients admitted with a primary diagnosis of MC were White (88.34%) and elderly (70.81%). The prevalence of MC with regard to sex and race was comparable to that of 2016. The mean length of stay in these patients was 4.87 (+/-1.2 days), whereas total hospitalization charges were $37 247 (±1065.61). In 2016, admissions for MC were noted only between August and December, as discussed by Al-Taee et al. [1] However, starting in 2017, we noted admissions every month from January to December. The results are provided in Fig. 1. We excluded patients in 2016 and evaluated the consecutive years for a seasonal effect. We noticed that most admissions occurred in July (n = 500; 9.6%), followed by October (n = 460; 8.86%) and April (n = 450; 8.6%). The lowest number of admissions occurred in November (n = 310; 5.97%). Admissions for MC each month are presented in Fig. 1. There were 1195 admissions (24.81%) in the spring, 1315 in the summer (27.33%), 1195 in the fall (24.81%), and 1110 (23.05%) in the winter. Although Al-Taee et al. [1] reported that most admissions occur from August to December, our study revealed a slight predominance in the summer. Another study by LaSala et al. [2] reported a seasonal pattern of lymphocytic colitis, with higher cases in summer and fall, compared with winter months.Fig. 1.: Monthly admissions for microscopic colitis between 2016 to 2019.The limitations of this study were the same as that of the retrospective cross-sectional study by Al-Taee et al. [1] as the data source is the same for these two studies. Given the variable results in the two studies, it is too early to conclude that there is a definite seasonal pattern for MC. However, larger epidemiological studies may provide further information. Acknowledgements None. Conflicts of interest There are no conflicts of interest.