• Bacterial infection
• pneumonia
• respiratory infection

We read with interest the comments of Dr Singh and colleagues.1 We note that in the data submitted from their local population they found a lower mortality for patients with high severity community acquired pneumonia (CAP) (CURB65 score 3–5) than was found in the National cohort.2 It is not possible to precisely explain this difference from the available information, but there are a number of likely explanations. The first is sampling error, which will be inevitable when small numbers of cases are submitted from a large number although their local data collected over a longer time period than the British Thoracic Society (BTS) audit suggest that their lower mortality score is real. A differential response to treatment is a consideration, but since only selected aspects of patient care were documented in the audit, this …