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Investigating Health Technology Diffusion in New Zealand - How Does it Spread and Who Stands to Gain? - WP 06/05

5.1.5  Stenting has been associated with falling cost weights while cost weights have risen for CABGs…

Table 10 provides the cost weight figures for stents and CABGs for 2000-2004 (the data is not available for the period pre-2000). Cost weights are smaller for stents than CABGs, with a small reduction in the stent cost weights over the period to 2004. Conversely, CABGs are associated with rising cost weights. However, once changes in clinical complexity are noted for both CABGs and stents, it is apparent that the scope of patients receiving coronary operations has broadened as procedures become commonplace.

Table 10– Aggregate Clinical Complexity and Cost Weight Figures
  Cost Weights and Clinical Complications for Stents and CABGs
Stents CABGs
CW CCL CW CCL
2000 3.296 1.664 7.521 2.394
2001 2.877 1.673 7.889 2.447
2002 2.664 1.694 8.362 2.429
2003 2.67 1.7 8.686 2.55
2004 2.764 1.747 8.854 2.618

5.1.6  …but clinical complexity and average age of patients has increased.

Table 11 provides a comparison of clinical complexity and cost weight figures for patients receiving stents in each of the DHBs. Clinical complexity has significantly increased for the South Island DHBs but remained steady for those in the North. This confirms the notion that coverage can be a factor driving health expenditures associated with technology. Comparisons may also be drawn with the well established technology, CABGs. Appendix Table 7 shows the use of CABGs across different DHBs. Notably, neither clinical complexity nor the average age of patients has remained constant over the period.  With the exception of Canterbury, where there are no signs of an increase in clinical complexity of patients receiving CABGs, each has risen over the period. This supports the view that scope has increased not just as a consequence of the introduction of stents, but also in a general advancement in technology e.g. improved anaesthetics. 

Table 11 – Clinical Complexity, Cost Weight Figures and Intervention Rates for Stents in Different District Health Boards

DHB 2000 2001 2002 2003 2004*
  CW CCL IR CW CCL IR CW CCL IR CW CCL IR CW CCL IR
Auckland 3.14 1.78 0.19 2.87 1.8 0.21 2.67 1.84 0.24 2.77 1.77 0.29 2.71 1.78 0.31
Counties Manukau 3.09 1.2 0.00 2.95 1.29 0.00 3.12 2.13 0.00 2.55 1 0.00 2.69 2 0.00
Waikato 3.29 1.73 0.09 3.08 1.62 0.13 2.77 1.7 0.14 2.8 1.56 0.16 2.75 1.65 0.2
Mid Central                   2.24 1 0.00      
Hutt 3.07 1.33 0.00 2.88 1.09 0.00             2.92 1 0.00
Capital and Coast 3 1.5 0.17 2.57 1.36 0.26 2.46 1.35 0.28 2.53 1.4 0.3 2.74 1.54 0.33
Nelson-Marlborough             2.24 3 0.00            
Canterbury 3.64 1.6 0.14 3.13 1.81 0.14 2.82 1.76 0.15 2.77 1.97 0.16 2.88 1.96 0.17
Otago 3.43 1.7 0.19 2.77 1.86 0.18 2.61 1.86 0.19 2.55 1.77 0.21 2.68 1.85 0.22

* denotes half a calendar year of data. The intervention rate has been altered to take account of the smaller sample of data. Intervention rates refer to the number of people in the DHB receiving a stent as a percentage of the total population in the DHB.

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