*3. MORTALITY AFTER HEART TRANSPLANT: STATISTICAL ANALYSIS*

*3.1 The NSC Team commissioned a specific review of mortality after heart transplants carried out at Harefield between 1 January 2006 and 31 August 2008. This was compiled by members of the Audit Project Group of the Cardiothoracic Transplant Audit (UKCTA). The findings of the UKCTA report are summarised below. (see Appendix A for its executive summary and the limitations of statistical analysis – this is available in the full report)* 

### *Mortality within 30 days*

*3.2 30-day mortality at Harefield for the whole period (1 January 2006 to 31 August 2008) was similar to other UK centres: 10.3% (95% CI 3.9%-21.2%) compared to 12.3% (95% CI 8.3%- 17.3%) elsewhere. Although the 30-day mortality of 26.7% (95% CI 7.8%-55.1%) at Harefield in 2008 was more than double the expected rate, the number of transplants was low and the difference from other centres was not statistically significant.* 

#### *Mortality within 90 days*

*3.3 90-day mortality was not significantly different from other centres for the period 1 January 2006 to 30 June 2008: 9.6% (95% CI 3.2%-21%) at Harefield compared to 13.1% (8.9%-18.4%) elsewhere. Similarly, the difference in 90-day mortality for the nine transplants done between 1 January 2008 and 30 June 2008 was not statistically significant: 22.2% (95% CI 2.8%-60%) compared to 5.4% (95% CI 0.6%- 18.2%) elsewhere. But further analysis, when 90 days have elapsed after all the transplants undertaken up to 31 August 2008, will include the patients transplanted after 30 June and this will affect the estimate of statistical significance.* 

#### *Mortality rates by donor organ retrieval centre*

*3.4 There was no evidence that donor hearts retrieved by Harefield were associated with higher mortality than those retrieved by other UK centres (p=0.11). However, nationally in the last three years, the 30-day mortality was significantly higher for donor hearts retrieved by any one centre and then transplanted in a different centre (p=0.006). The UKCTA report gives evidence that this was not the case before 2006.* 
