Comparative epidemiology of Clostridium difficile infection: England and the USA.

Objective: To examine whether there is an epidemiological difference between Clostridium difficile infection (CDI) inpatient populations in England and the United States.

Design: A cross-sectional study.

Setting: National administrative inpatient discharge data from England (Hospital Episode Statistics) and the USA (National Inpatient Sample) in 2012.

Participants: De-identifiable non-obstetric inpatient discharges from the national datasets were used to estimate national CDI incidence in the United States and England using ICD9-CM(008.45) and ICD10(A04.7) respectively.

Main outcome measures: The rate of CDI was calculated per 100 000 population using national population estimates. Rate per 100 000 inpatient discharges was also calculated separated by primary and secondary diagnosis of CDI. Age, sex and Elixhauser comorbidities profiles were examined.

Results: The USA had a higher rate of CDI compared to England: 115.1/100 000 vs. 19.3/100 000 population (P < 0.001). CDI age profiles differed between the countries (P < 0.001): in England, patients ≥75 years constitute a larger proportion of CDI cases, whilst those aged 25-70 constitute more cases in the US (P < 0.001). Overall adjusted odds of CDI in females compared to males was elevated in both England (odds ratios (OR) 1.26 95% CI [1.21,1.31] P < 0.001) and the USA (OR 1.20 95% CI [1.18,1.22] P < 0.001). The proportion of CDI patients with comorbidities was greater in the USA compared to England apart from dementia, which was greater in England (9.63% vs. 1.25%, P < 0.0001).

Conclusions: The 2012 inpatient CDI rate within the USA was much higher than in England. Age and comorbidity profiles also differed between CDI patients in both countries. The reasons for this are likely multi-factorial but may reflect national infection control policy.