Gout single map Consumer summary (50KB, PDF)

This Atlas presents information on gout by district health board (DHB), including gout prevalence, prevalence by ethnicity, and treatment. The goal is to identify any areas of wide variation between DHBs and opportunities for quality improvement.

Update 2018

This Atlas has been updated with data from 2012–16.

Key messages

  • Gout is estimated to affect around 5 percent of the total population aged 20 and over. People aged 65 and over, men, Māori and Pacific peoples are most affected.
  • About two in five people with gout regularly received urate-lowering therapy to prevent gout flares. The data do not allow us to infer whether or not treatment is clinically indicated.
  • The use of urate-lowering therapy increased with age.
  • Although Māori and Pacific peoples were more affected, they were less likely to regularly receive urate-lowering therapy. This inequity needs to be addressed.
  • About one in three of those with gout were dispensed non-steroidal anti-inflammatory drugs (NSAIDs) in 2016. Rates were much higher in younger people. This use of NSAIDs by people with gout may indicate the need for more preventive treatment. Māori and Pacific peoples with gout aged between 20 and 44 were dispensed more NSAIDs than other ethnic groups. There is concern about the relationship between the use of NSAIDs and kidney damage. Kidney disease is more common in Māori and Pacific peoples, so more research and debate into the use of these drugs is needed.
  • Only one-third of those dispensed urate-lowering therapy had a serum urate test within six months of the therapy being dispensed. Achieving a serum urate target of less than 0.36 mmol/L is essential for effective long-term treatment of gout; serum urate needs to be monitored in those receiving urate-lowering therapy to ensure effective treatment that will protect their joints in the long term.
  • Māori and Pacific peoples had four to nine times as many admissions due to gout than those of non-Māori non-Pacific ethnicities.

Key findings 2018 update

The number and prevalence of people identified as having gout is increasing. Men, Māori and Pacific peoples and people aged 65 and over are most affected.

  • In 2016, on average, 5.3 percent of the population aged 20 and over were identified as having gout (182,000 people). This has increased from 4.5 percent in 2012 (124,400 people).
  • Gout prevalence varied 2.4-fold between DHBs, ranging from 3.5 percent in Canterbury DHB to 8.5 percent in Hauora Tairāwhiti, likely reflecting different ethnicity and age structures between DHBs.
  • Gout prevalence increased significantly with age.
  • Men had over three times the gout prevalence of women.
  • Māori and Pacific peoples had two to three times the gout prevalence of non-Māori non-Pacific populations. In men aged 65 and over, gout is estimated to affect 17 percent of those of non-Māori non-Pacific ethnicities, 37 percent of Māori and 47 percent of Pacific peoples.

Table 1: Population identified as having gout, by age, ethnicity and gender, 2016

  20–44 years 45–64 years 65+ years All age groups
  Female Male Female Male Female Male Female Male
Māori 0.9 5.4 5.3 19.5 19.1 37.1 4.3 13.3
Pacific peoples 1.7 12.0 9.1 33.2 24.5 46.6 6.5 21.9
Non-Māori, non-Pacific 0.3 1.5 1.3 7.1 6.0 16.8 2.0 6.8
All ethnic groups 0.5 2.8 2.1 9.7 7.3 18.8 2.5 8.4

Māori and Pacific peoples were less likely to receive urate-lowering therapy regularly.

  • On average, 42 percent of people identified with gout regularly received urate-lowering therapy.
  • Rates of receiving urate-lowering therapy increased significantly with age.
  • There was variation between ethnic groups. Pacific peoples received less urate-lowering therapy (35 percent), followed by Māori (40 percent). Forty-four percent of people identifying as non-Māori, non-Pacific ethnicity received urate-lowering therapy regularly.
  • This inequity needs to be addressed.

NSAIDs were dispensed to 37 percent of those identified as having gout. Māori and Pacific peoples were dispensed more NSAIDs.

  • In 2016, 37 percent of people identified as having gout were dispensed an NSAID compared with 23 percent for the resident population aged 20 years and over.
  • There was limited regional variation.
  • People with gout identifying as non-Māori, non-Pacific ethnicity used statistically fewer NSAIDs – 34 percent, compared with 47 percent of Pacific peoples and 41 percent of Māori.
  • Younger people, particularly Māori and Pacific people, were dispensed significantly more NSAIDs.

An NSAID without any urate-lowering therapy was dispensed in 15 percent of people identified as having gout.

  • On average, 15 percent of people with gout received an NSAID in a year without any urate-lowering therapy being dispensed.
  • Rates did not vary widely by ethnicity, but did decrease with age.

The percent of people receiving colchicine without any urate-lowering therapy has reduced from 8 percent to 6 percent in 2016.

  • On average, 6 percent of people with gout received colchicine and no urate-lowering therapy over the course of a year.
  • This varied 2.1-fold between DHBs, with some DHBs having consistently high rates.
  • Younger people received more colchicine without urate-lowering therapy.

Serum urate was tested in 31 percent of people identified as having gout in the six months following dispensing of urate-lowering therapy.

  • On average, 3 in 10 people identified with gout received a serum urate test within 6 months of receiving urate-lowering therapy.
  • Achieving a serum urate target of less than 0.36 mmol/L is essential for the effective long-term treatment of gout.
  • This varied 1.9-fold between DHBs.
  • Rates of serum urate testing did not vary widely by ethnicity but increased with age.

Note: This indicator is not the same as the indicator denoting people with gout whose serum urate was tested in the six months following allopurinol dispensing reported in the Equity Explorer (www.hqsc.govt.nz/atlas/equity-explorer).

Māori and Pacific peoples combined had four times as many hospital admissions for gout.

  • Pacific peoples had more than nine times as many hospital admissions due to gout as people of non-Māori, non-Pacific ethnicity while Māori had more than four times as many hospital admissions as people of non-Māori, non-Pacific ethnicity.
  • Admissions due to gout increased with age. The variation was widest by DHB and by ethnicity in the 65 and over age group.

Background

Gout is the most common form of inflammatory arthritis. It is caused by an inflammatory response to monosodium urate (MSU) crystals, which form in the presence of high urate concentrations. Patients typically present initially with recurrent flares of severe joint inflammation. Over time, in the presence of elevated serum urate concentrations (hyperuricaemia), tophi, chronic arthritis and joint damage can occur.

Gout is estimated to affect approximately 5 percent of adult New Zealanders. Rates of gout are particularly high in Māori and Pacific men, affecting up to one-third aged over 65 years.[1] Gout flares are extremely painful, and disrupt work and home life. Tophaceous gout causes bone and joint damage and musculoskeletal disability.[2–4]

Long-term urate-lowering therapy is recommended for patients with recurrent gout flares (more than one per year), chronic gouty arthritis and joint damage. Allopurinol is the first-line urate-lowering therapy drug in New Zealand, but probenecid, benzbromarone and febuxostat are also effective. A target serum urate of less than 0.36mmol/L is required to achieve dissolution of MSU crystals, suppression of gout flares and regression of tophi. Gout flares can be treated with NSAIDs, colchicine or corticosteroids.

Other indicators of the quality of gout management include the frequency of serum urate monitoring,[5] the use of NSAIDs and the rate of hospital admissions with gout as the primary diagnosis.

For each of the indicators, it was not possible to assess whether medicine was clinically indicated, whether the dose was optimal or whether the dose was taken. The methodology used is available here.

The rates for the Asian population were similar to the European/other group, and in some DHBs the Asian population was small, so it was decided to combine these groups into a non-Māori, non-Pacific group.

Recent research has found that genetics were significantly more likely than unhealthy foods to lead to higher urate levels[6].

Find My Patients query and clinical audit template

Find My Patients allows you to run a query using your patient management system (PMS) to identify patients who have not had a recent serum uric acid test. You can also use the query as part of a clinical audit. GPs who complete the audit are entitled to Maintenance of Professional Standards credits from the Royal New Zealand College of General Practitioners.

Download the Find My Patients query and clinical audit template.

Links

BPAC: Managing gout in primary care, part 1: https://bpac.org.nz/2018/gout-part1.aspx
BPAC: Managing gout in primary care, part 2: https://bpac.org.nz/2018/gout-part2.aspx
BPAC guidance: The medical management of gout revisited: https://bpac.org.nz/BPJ/2013/March/managing-gout.aspx
South Auckland providers responding to gout: www.hqsc.govt.nz/our-programmes/primary-care/news-and-events/news/3166



References

  1. Winnard D, Wright C, Taylor W, et al. 2012. National prevalence of gout derived from administrative health data in Aotearoa New Zealand. Rheumatology 51(5): 901–9.
  2. Lindsay K, Gow P, Vanderpyl J, et al. 2011. The experience and impact of living with gout: a study of men with chronic gout using a qualitative grounded theory approach. J Clin Rheumatol 17(1): 1–6.
  3. Martini N, Bryant L, Te Karu L, et al. 2012. Living with gout in New Zealand: an exploratory study into people's knowledge about the disease and its treatment. J Clin Rheumatol 18(3): 125–9.
  4. Dalbeth N, House ME, Horne A, et al. 2013. The experience and impact of gout in Maori and Pacific people: a prospective observational study. Clin Rheumatol 32(2): 247–51.
  5. Dalbeth N, Winnard D, Gow PJ, et al. 2015. Urate testing in gout: why, when and how. NZMJ 128(1420): 65–8.
  6. Major TJ, Topless RK, Dalbeth N, Merriman TR. 2018. Evaluation of the diet wide contribution to serum urate levels: Meta-analysis of population based cohorts. BMJ 2018; 363:k3951. URL: https://www.bmj.com/content/363/bmj.k3951 (accessed 6 November 2018).

Last updated 08/11/2018