Vascular access for haemodialysis in Scotland

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Vascular access for haemodialysis in Scotland

• Alison Severn, Jan Kerssens and Keith Simpson
• on behalf of the Scottish Renal Registry

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Background

• The best form of vascular access is a native
  arteriovenous fistula (AV)
• Central venous catheters (CVCs) are associated
  with a higher risk of bacteraemia
• And also with a higher mortality
• The use of CVCs is increasing

Pastan et al.,2002 Kidney Int 62620-626. Xue et
al. 2003 Am J Kidney Dis 421013-1019. Lacson
et al. 2009 Am J Kidney Dis 5379-90.
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Audit questions

• What types of vascular access are used in
  Scotland?
• What are the determinants of access type?
• Sex Age Diagnosis Time since start of
  treatment
• Are there differences in access type between the
  Scottish renal units, and if so, how large are
  these differences?

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Patients on haemodialysis (HD)

• The number of prevalent patients on home or
  hospital HD on 2 April 2007 was 1708
• Details of vascular access were available for
  1609 patients (94)
• Median age was 64 years
• 59 were male
• In April 2006, 76 of patients on haemodialysis
  in Scotland were having AV access

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AV access and CVC use among HD patients (April
2007)
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Determinants of AV access - 1

• Males are more likely to have AV access
• No relation with age

Note only 11 patients younger than 20
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Determinants of AV access - 2

• Only patients with Diabetes are different from
  the rest

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Determinants of AV access - 3

• AV access is low at the start of RRT
• It takes over a year before AV access is above 70

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Differences in AV access between Scottish renal
units April 2007
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Differences in AV access in a funnelplot

• A graph with a performance indicator on the
  vertical-axis and the number of observations on
  the horizontal-axis
• A data point is added for each unit
• The overall mean of AV access is added as a
  horizontal line
• Control limits are added, assuming that the units
  differ by chance only
• Because the limits are tighter as the number of
  observations is larger, the shape of a funnel
  appears
• Units outside the outer control limits are
  considered to be different from the rest.

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Differences in AV access between adult Scottish
renal units April 2007
AV access High in RAIG and ARI Low in XH and MONK
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Results summary

• Arteriovenous access (predominantly fistulas) is
  used by 73 of patients
• Slight decrease in AV access since April 2006
• It takes longer than a year before AV access is
  above 70
• Males more likely to have AV access
• Patients with Diabetes less likely to have AV
  access
• Large differences in AV access between the
  Scottish renal units

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Reasons for differences between units

• Data quality?
• Data completeness?
• Patient mix?
• Service provision?
• Clinical practice?
• Or what.?