Asthma: primary care data

Practice Team Information

The Practice Team Information (PTI, formerly CMR) programme routinely reports statistics on consultations for asthma in primary care in Scotland, using a sample of around 60 Scottish practices. PTI data can be used to estimate the national prevalence of asthma (defined as those who have consulted at least once during the year because of the condition). In 2010/11 this figure was 4.6% for all ages (4.0% for men and 5.2% for women).

The peak prevalence of consultation is in the 5-14 year age group in males and in 55-74 year olds in females. Because these figures are based on the number of people consulting they are likely to be an underestimate of the true prevalence of asthma.

An overview of PTI data is available in the Practice Team Information section of the ScotPHO site. More detailed information is available on ISD's Practice Team Information web page.

Quality and Outcomes Framework data

The General Medical Services contract for general practice, introduced in 2004, includes a set of quality indicators within the voluntary Quality and Outcomes Framework (QOF). The QOF measures achievement against a range of evidence-based indicators and includes quality indicators for asthma.

Four indicators in the 2010/11 reporting guidelines cover the maintenance of an asthma register (ASTHMA 1 - limited to patients who have been prescribed asthma drugs during the previous 12 months); the percentage of patients aged 8 and over who have recorded measures of variability or reversibility (ASTHMA 8), the percentage of patients with asthma between the ages of 14 and 19 in whom there is a record of smoking (ASTHMA 3) and the percentage of patients who have had a recent asthma review (ASTHMA 6). Before 2006 patients could not be included in both asthma and COPD registers, but from 1st April 2006 it was recognised that the two conditions could co-exist, so that COPD patients with substantial reversibility (>400ml in forced expiratory volume - FEV1) are now included on both COPD and asthma registers. As revised rules now allow patients to be included on both COPD and asthma registers, comparisons in QOF-based prevalence before and after this time should be made with caution.

In the four years since the introduction of the QOF in 2004/05, the crude prevalence of asthma in Scotland (as measured in QOF registers on 14th February each year for practices with nGMS contracts) has increased slightly from 5.4% in 04/05 and 05/06 to 5.5% in 06/07 and 07/08, 5.7% in 2008/09 and 5.9% in 2009/10 and 2010/11.

Note that QOF data are aggregate and do not provide information on age or sex so that comparisons of asthma prevalence between areas using QOF cannot take account of differences in population age structure.

Prescribing data

ISD's Prescribing Programme provides information on the quantity of bronchodilator and other drugs prescribed. As these drugs may also be prescribed for other conditions such as COPD, it is not possible to link prescriptions directly to asthma diagnoses. Work is underway to produce data that will use community health index (CHI) numbers to allow person-based analyses.

PCCIU/SPICE data

The Primary Care Clinical Informatics Unit (PCCIU) at the University of Aberdeen manages the data collection and formation of the national comparative database for the Scottish Programme for Improvement in Clinical Effectiveness in Primary Care (SPICE PC). The unit currently collects data from around 200 Scottish practices and uses this for quality improvement and benchmarking purposes. The data have also been used for research and to produce consultation and prevalence figures for asthma, although these analyses are not routinely available.

Survey data

Scottish Health Survey

The Scottish Health Survey was carried out in 1995, 1998 and 2003 and has now moved to a continuous design. The survey includes questions on doctor diagnosed asthma and self-reported wheeze in adults over 16 years, based on the MRC respiratory symptom questionnaire. Mean forced expiratory volume (FEV1), forced vital capacity (FVC) and peak expiratory flow rate (PEFR) was recorded in a subset of respondents. A subsample of children received a nurse visit, at which lung function was measured in children over 7 years and children over 11 years tested for total and house dust specific IgE antibodies. An overview of the Scottish Health Survey is available in the ScotPHO resources section. Detailed results are available from the Scottish Health Survey publications web page.

ISAAC

The International Study of Asthma and Allergies in Childhood (ISAAC) is an international survey that has collected internationally comparable data from children since 1991. The most recent wave of surveys examined 798 685 children aged 13 - 14 years from 233 centres in 97 countries, and 388 811 children aged 6 - 7 years from 144 centres in 61 countries and was conducted between 2000 and 2003. The results were reported by Lai et al (2009).