Chronic obstructive pulmonary disease (COPD): primary care data

The Scottish Primary Care Information Resource (SPIRE) provided data estimating the prevalence of COPD based on primary care consultations between 2018 and 2023, when the data collection was decommissioned. National prevalence of COPD in 2023 for all ages was estimated by SPIRE to be 2.2 registered cases per 100 patients (2.2%) for males and 2.4 registered cases per 100 patients (2.4%) for females. This represents no change compared to the previous year for males and a reduction from 2.5 registered cases per 100 patients for females.

Although sex-based differences in COPD prevalence across all groups have almost reached parity in recent years, in 2023 prevalence in over 85s was 26.4% higher in males than females, with 9.1 registered cases per 100 recorded in males and 7.2 per 100 in females. These gender differences may be a result of the cohort effect produced by a historical lag of female smoking rates behind that of their male contemporaries. Whilst Scotland-specific data are not available to confirm such a trend, models describing the smoking epidemic, such as that presented by Lopez et al. (1994) frequently refer to this female lag in the uptake of smoking. Such a lag may explain the lower prevalence of COPD in older women relative to men as a reflection of their lower rates of smoking in previous years. The earlier peak and subsequent decline of smoking rates in men might predict a decrease in COPD prevalence in men ahead of a similar decrease in women and thus may also contribute to the observed sex-based difference.

Research on the diagnosis rate of COPD has yielded conflicting findings. An observational study by Josephs et al. (2019) revealed that in the UK, an estimated 13.1% of patients had been diagnosed with COPD following a primary care consultation with either unrecorded spirometry test results or those not showing consistent obstruction to airflow, both of which the National Institute for Health and Care Excellence (NICE) requires for diagnosis. Being female, never smoking, and having higher BMI were all associated with a diagnosis of COPD in the absence of or with irregularity of spirometry results. Conversely, NICE estimates that approximately two thirds of COPD cases in the UK are undiagnosed. As there is evidence that COPD is both under- and mis-diagnosed at the UK level, the SPIRE estimates of prevalence of the disease in Scotland should be treated with caution.

More detailed statistics on COPD consultations including breakdowns of prevalence by age group and area are available in the SPIRE General Practice Disease Prevalence dashboard. Historically, SPIRE was an aggregate collection representing only 69% of General Practices in Scotland; therefore, these figures may not be representative of the entire population. Public Health Scotland (PHS) is working in partnership with National Services Scotland and the Scottish Government to deliver a new primary care data extraction tool. Information on prescriptions in the community for COPD therapies are reported on by the PHS Prescribing Team.