Philip J. Peacock

Oxford Handbook of Medical Statistics

1. Research design 2. Collecting data 3. Handling data 4. Presenting research findings 5. Choosing statistical software 6. Summarizing data 7. Probability and distributions 8. Statistical tests 9. Diagnostic studies 10. Other statistical methods 11. Multiple observations 12. Multiple variables 13. Meta-analysis 14. Bayesian statistics 15. Glossary of terms

Changes in the emergency workload of the London ambulance service between 1989 and 1999

Objectives: To examine changes in the emergency workload of the London Ambulance Service (LAS) between 1989 and 1999. Methods: All emergency responses by the LAS during week 16 in each of 1989, 1996, and 1999 were studied. For each week, 999 call responses were analysed by time and day of call, and age/sex of the patient. Call response rates were calculated using age/sex census population estimates for London. Changes in call rates over time were calculated as rate ratios. Results: Emergency responses increased from 6624 to 13 178 in the index weeks of 1989–1999. The ratio of response rates (1999/1989) was 1.91 (95% CI: 1.85 to 1.96). The proportion of out of hours calls increased significantly, from 68.8% in 1989 to 71.3% in 1999 (p = 0.0003). Response rates rose significantly more steeply for male patients than female patients from 1989 to 1999: rate ratio (95% CI); male patients 2.00 (1.91 to 2.08), female patients 1.69 (1.62 to 1.77), p<0.0001. Response rates varied by age in each of the three years investigated. Rates were consistently highest for patients aged 75 and above, and lowest for those aged 5–14. However, there was no evidence that call rates had increased disproportionately in any particular age group (p = 0.79). Conclusions: Demand for emergency ambulance services in London has doubled in a decade. This increase is similar for all age groups, with no evidence of a greater rise in demand among older people. Call rates have increased more steeply in men than in women. Demographic changes do not explain the observed increases in demand.