Although there has been considerable recent work on the prevention, management and causes of Chronic Obstructive Pulmonary Disease (COPD), the contribution of housing has not been well researched. This is despite the socio-economic patterning of COPD (Maori women have the highest rate of COPD that has been recorded for any group of women), and the relationship between socio-economic deprivation and housing conditions.

It is likely that improved heating would reduce exacerbations of COPD as:

  • COPD patients with the most advanced disease tend to be older people who often live on a fixed income and may be unable to afford adequate heating
  • There is a high excess of winter hospitalisations in COPD patients indicating COPD exacerbations may be triggered by cold conditions.
  • About one third of exacerbations of COPD are triggered by respiratory infections.
  • The Housing, Insulation and Health Study demonstrated a reduction in self-reported respiratory disease after houses were insulated. Therefore improving the heating in households with a COPD patient may reduce respiratory infections and this in turn would reduce the number and severity of exacerbations.

The percentage of people over 65 in New Zealand will increase from 12% to 22% over the next 25 years. Therefore it will become increasingly important to find cost-effective ways of reducing the morbidity of the older age group.  As COPD is a significant cause of morbidity amongst older people, this study investigates a potentially cost effective intervention to reduce both the likelihood of expensive hospital stays and improve the quality of life for older people.


To evaluate whether fuel subsidies reduce exacerbations of COPD among people aged over 55, and therefore whether providing such subsidies is a cost-beneficial policy initiative.


The design is a randomised controlled trial.  Participants will have their house insulated if necessary and feasible.  The participants are randomised to “early” and “late” groups.  The people randomised to the “early” intervention group receive a fuel voucher/subsidy for the first winter they are enrolled in the study, and the people randomised to the “late” intervention group will receive a fuel voucher/subsidy for the second winter.

The participants will be 600 people over the age of 55 diagnosed with COPD who report an exacerbation in the last 3 years, or who have “moderate” or “worse COPD.  Each participant must be living in the community and the household they live in must be responsible for paying their own power bill.

Main Outcome Measures

  • Moderate exacerbations of COPD that are treated with systemic corticosteroids and/or antibiotics.
  • Severe exacerbations of COPD for which hospitalisation is required
  • All-cause hospitalisation
  • Temperature in the living and bedrooms
  • Electricity usage.

Potential Benefits

The potential benefits of the study include reducing the burden of disease.  The patients and their caregivers may experience improved quality of life.  Hospitals may experience fewer patients requiring treatment during the winter.  A cost-benefit analysis will quantify the benefits.

Pilot Study

A pilot study was run in the winter of 2007, to test the questionnaires and methods used in the study. The pilot found the study acceptable to participants, and only minor modifications were needed to the questionnaires. In addition a qualitative component to the Warm Homes pilot study examined the heating experiences of the study participants.

WHEZ Supporters

The study is supported by the Health Research Council, the University of Otago,  and the Lotteries Commission. The pilot study was supported by the Hutt Mana Charitable Trust.