Background: Idiopathic pulmonary fibrosis (IPF) and sarcoidosis are common diagnoses in patients attending chest clinics, but little is known about the epidemiology of these diseases. We used data from a general practice database to provide information on the current incidence of IPF and sarcoidosis in the UK. Methods: Data were extracted for all patients with a diagnosis of IPF or sarcoidosis between 1991 and 2003. The whole population of the database was used to calculate disease incidence stratified by age, sex, region, and time period. Poisson regression was used to compare the incidence between populations and Cox regression was used to compare survival between populations. Results: 920 cases of IPF (mean age 71 years, 62% male) and 1019 cases of sarcoidosis (mean age 47 years, 47% male) were identified. The overall incidence rate per 100 000 person-years was 4.6 for IPF and 5.0 for sarcoidosis. The incidence of IPF increased progressively between 1991 and 2003 (p,0.00001), and was highest in Northern England and Scotland (p,0.0001). The survival of patients with IPF was stable over time. In contrast, the incidence of sarcoidosis was highest in London, West Midlands and Northern Ireland and remained stable over time.Conclusions: The incidence of IPF has more than doubled between 1990 and 2003; this is not due to the ageing of the UK population or an increased ascertainment of milder cases. The incidence of sarcoidosis has not changed during this time period. Our findings suggest that more than 4000 new cases of IPF and 3000 new cases of sarcoidosis are currently diagnosed each year in the UK.

This study provides further evidence of a marked increase in the incidence of lung cancer in people with IPF, but we found no increase in the risk of other cancers. People with sarcoidosis did have an increase risk of skin cancers, but not cancers at other sites.

People with IPF have an increased risk of vascular disease in comparison with the general population. This effect is most marked for acute coronary syndrome and deep-vein thrombosis after the diagnosis of IPF has been made.

The study provides further evidence of an association between idiopathic pulmonary fibrosis and both diabetes mellitus and gastro-oesophageal reflux.

the study provides evidence that current prescribing of thiazides is associated with an increased risk of falling and that this is strongest in the 3 weeks following the first prescription.

The study provides evidence that at least some of our earlier estimates were subject to confounding. Nevertheless, thiazide prescription remains associated with an increased risk of first fall, and this effect is strongest in the first 3 weeks of prescription. Our study demonstrates that the case series method provides an effective way to assess the extent of residual confounding in case-control studies.

Following the introduction of the NICE guideline for COPD and the new QOF, there has been an increase in the prevalence of COPD in general practice and a large increase in spirometry data and prescriptions for combination inhalers. This represents significant progress for people with COPD.

These data suggest that more than 475,000 fall events in older people are recorded in general practice each year in the UK, and are associated with increased mortality and relative deprivation. The underlying incidence rate has remained stable in recent years.