Vidya Navaratnam

The rising incidence of idiopathic pulmonary fibrosis in the UK

Background Previous studies have shown that the incidence of idiopathic pulmonary fibrosis (IPF) is rising in the UK and USA. Death registrations and primary care data were used to determine the current trends in IPF incidence in the UK. Because routine clinical data sets were used, the term IPF clinical syndrome (IPF-CS) is used to describe individuals in this study. Methods Age- and stratum-specific death registration rates between 1968 and 2008 were calculated and these were applied to the 2008 population to generate annual standardised expected number of deaths. Annual mortality rate ratios were calculated using Poisson regression. Computerised primary care records were used to determine incidence rates of IPF-CS between 2000 and 2008 stratified by age, sex and geographical region, and survival rates between calendar periods were compared. Results Annual death certificate recording of IPF-CS rose sixfold across the study period from 0.92 per 100 000 in the 1968–1972 calendar periods to 5.10 per 100 000 in the 2006–2008 calendar period, and were higher in men and the older age groups. The incidence of IPF-CS in primary care increased by 35% from 2000 to 2008, with an overall incidence rate of 7.44 per 100 000 person-years (95% CI 7.12 to 7.77). Incidence was higher in men, the older population and in Northwest England. Conclusions The incidence of IPF-CS in primary care and registered deaths from this cause in the UK continues to rise in the 21st century. The current findings suggest that there are >5000 new cases diagnosed each year in the UK.

Increasing Global Mortality from Idiopathic Pulmonary Fibrosis in the Twenty-First Century

RATIONALE Evidence from the United Kingdom suggests that the number of deaths from idiopathic pulmonary fibrosis is increasing, although comparable international data are limited. OBJECTIVES We aimed to collate death certification data from multiple countries to determine global trends in mortality from idiopathic pulmonary fibrosis. METHODS Data were obtained from the national statistics agencies of countries with relevant mortality records. Age-standardized mortality rates were calculated, and Poisson regression modeling was used to calculate rate ratios. Meta-analysis was used to calculate an overall estimate of mortality change over time. MEASUREMENTS AND MAIN RESULTS Ten countries provided mortality data on pulmonary fibrosis over a period from 1999 to 2012. Age-standardized mortality ranged between 4 and 10 per 100,000 population for the most recent years of data, being lowest in Sweden (4.68 per 100,000), Spain (5.38 per 100,000), and New Zealand (5.55 per 100,000), and highest in the United Kingdom (9.84 per 100,000 in England and Wales, 10.71 per 100,000 in Scotland) and Japan (10.26 per 100,000). Positive associations with male sex and increasing age were consistently observed across all countries. There was an overall 2-3% annual increase in mortality depending on codes used for classification: For broad codes the overall rate ratio was 1.03 (95% confidence interval, 1.02-1.04; P < 0.001) and for narrow codes the overall rate ratio was 1.02 (95% confidence interval, 1.01-1.03; P < 0.001). Validation in a local cohort showed that idiopathic pulmonary fibrosis was recorded as the underlying cause of death in two-thirds of known cases and anywhere on the death certificate in 80% of cases. CONCLUSIONS Mortality from idiopathic pulmonary fibrosis is increasing steadily worldwide, despite the fact that death certification will almost certainly underestimate true mortality. We estimate that there will be between 28,000 and 65,000 deaths in Europe and between 13,000 and 17,000 deaths in the United States from idiopathic pulmonary fibrosis clinical syndrome in 2014. Variation between countries remains but is less than previously reported.

Presence of a prothrombotic state in people with idiopathic pulmonary fibrosis: a population-based case–control study

Background Laboratory studies suggest that the clotting cascade is activated in fibrotic lungs. Since humans vary in their tendency to clot due to a variety of inherited or acquired defects, we investigated whether a prothrombotic state increases the chance of developing idiopathic pulmonary fibrosis (IPF) and/or worsens the prognosis of IPF. Methods We recruited 211 incident cases of IPF and 256 age- and sex-matched general population controls and collected data on medical history, medication, smoking habit, blood samples as well as lung function and high-resolution CT scans done as part of routine clinical care. A prothrombotic state was defined as the presence of at least one inherited or acquired clotting defect or marker of fibrinolytic dysfunction. We used logistic regression to quantify the association between a prothrombotic state and IPF adjusted for age, sex, smoking habit and highly sensitive C reactive protein. Cox regression was used to determine the influence of a prothrombotic state on survival. Results Cases were more than four times more likely than controls to have a prothrombotic state (OR 4.78, 95% CI 2.93 to 7.80; p<0.0001). Cases with a prothrombotic state were also likely to have more severe disease (forced vital capacity <70% predicted) at presentation (OR 10.79, 95% CI 2.43 to 47.91) and had a threefold increased risk of death (HR 3.26, 95% CI 1.09 to 9.75). Conclusions People with IPF are more likely to have a prothrombotic state than general population controls and the presence of a prothrombotic state has an adverse impact on survival.

The increasing secondary care burden of idiopathic pulmonary fibrosis: hospital admission trends in England from 1998 to 2010.

BACKGROUND The lack of mandatory clinical registries for idiopathic pulmonary fibrosis (IPF) has meant a reliance on routine clinical data to provide trends in disease incidence. Death certificate and primary care data suggest that the incidence of IPF has increased in the United Kingdom at a rate of approximately 5% per year, but due to possible concerns about the diagnostic validity of these clinical datasets, it is helpful also to analyze data from secondary care. We used national secondary care data to determine trends in hospital admissions for IPF clinical syndrome (IPF-CS) in England between 1998 and 2010. METHODS We obtained the annual number of hospital admissions for all National Health Service (NHS) hospital trusts in England for the International Classification of Diseases and Related Health Problems, 10th Revision codes J84.1 and J84.9 between 1998 and 2010. We calculated annual admission-rate ratios, adjusting for age and sex, using Poisson regression. We also investigated changes in age at admission and length of stay, and we estimated hospitalization costs. RESULTS The number of hospital admissions from IPF-CS increased at an annual rate of approximately 5%, from 5,524 patients in 1998 to 9,525 patients in 2010, and was highest in men and the older population. Mean age at admission increased from 66 to 71 years, while length of stay decreased by 2.1 days during the same period. CONCLUSIONS Hospital admissions for IPF-CS in England follow a similar trend to other data sources in the United Kingdom . This has resulted in escalating costs of inpatient care, which is a significant financial burden on health-care resources.

Does the presence of connective tissue disease modify survival in patients with pulmonary fibrosis

OBJECTIVES Previous studies into the survival differences between individuals with idiopathic pulmonary fibrosis and those with connective tissue disease associated pulmonary fibrosis (CTD-PF) have yielded mixed results. The aim of this study is to compare the survival of individuals with CTD-PF to those with idiopathic pulmonary fibrosis clinical syndrome (IPF-CS) using data derived from The Health Improvement network, a large primary care database in the UK. METHODS Incident cases of CTD-PF and IPF-CS between the years 2000-2009 were identified. Survival analysis was performed using Kaplan-Meier methods, stratified by type of connective tissue disease. Cox regression was then used to compare mortality rates between the groups, adjusting for age, gender and year of diagnosis. RESULTS A total of 324 cases of CTD-PF and 2209 cases of IPF-CS were followed up over a mean period of 2.3 years. During this period, 113 (34.9%) cases of CTD-PF and 1073 (48.6%) cases of IPF-CS died. The mortality rates for cases with CTD-PF and IPF-CS were 123.6 per 1000 person years (95%CI: 102.8-148.9) and 229.8 per 1000 person years (95% CI: 216.4-244.0) respectively. After adjusting for age, sex and year of diagnosis, cases with CTD-PF had a better prognosis compared to those with IPF-CS (HR 0.76,95%CI: 0.62-0.92). CONCLUSION The prognosis of individuals with CTD-PF appears to be significantly better than those with IPF-CS, but remains an important cause of death in patients with connective tissue disease, and requires more effective treatment options.

Bronchiectasis and the risk of cardiovascular disease: a population-based study

Background There are limited data on the burden of cardiovascular comorbidities in people with bronchiectasis. Our cross-sectional study estimates the burden of pre-existing diagnoses of coronary heart disease (CHD) and stroke in people with bronchiectasis compared with the general population. The historical cohort study investigates if individuals with bronchiectasis are at increased risk of incident CHD and stroke events. Methods We used primary care electronic records from the Clinical Practice Research Datalink. The cross-sectional study used logistic regression to quantify the association between bronchiectasis and recorded diagnoses of CHD or stroke. Cox regression was used to investigate if people with bronchiectasis experienced increased incident CHD and strokes compared with the general population, adjusting for age, sex, smoking habit and other risk factors for cardiovascular disease. Results Pre-existing diagnoses of CHD (OR 1.33, 95% CI 1.25 to 1.41) and stroke (OR 1.92, 95% CI 1.85 to 2.01) were higher in people with bronchiectasis compared with those without bronchiectasis, after adjusting for age, sex, smoking and risk factors for cardiovascular disease. The rate of first CHD and stroke were also higher in people with bronchiectasis (HR for CHD 1.44 (95% CI 1.27 to 1.63) and HR for stroke 1.71 (95% CI 1.54 to 1.90)). Conclusion The risk of CHD and stroke are higher among people with bronchiectasis compared with the general population. An increased awareness of these cardiovascular comorbidities in this population is needed to provide a more integrated approach to the care of these patients.

Surgical lung biopsy for the diagnosis of interstitial lung disease in England: 1997–2008

International guidelines and new targeted therapies for idiopathic pulmonary fibrosis have increased the need for accurate diagnosis of interstitial lung disease (ILD), which may lead to more surgical lung biopsies. This study aimed to assess the risk of this procedure in patients from the UK. We used Hospital Episodes Statistics data from 1997 to 2008 to assess the frequency of surgical lung biopsy for ILD in England, UK. We identified cardiothoracic surgical patients using International Classification of Diseases revision 10 codes for ILD and Office of Population Censuses and Surveys Classification of Interventions and Procedures version 4 codes for surgical lung biopsy. We excluded those with lung resections or lung cancer. We estimated in-hospital, 30-day and 90-day mortality following the procedure, and linked to cause of death using data from the UK Office of National Statistics. We identified 2820 patients with ILD undergoing surgical lung biopsy during the 12-year period. The number of biopsies increased over the time period studied. In-hospital, 30-day and 90-day mortality were 1.7%, 2.4% and 3.9%, respectively. Male sex, increasing age, increasing comorbidity and open surgery were risk factors for mortality. Surgical lung biopsy for ILD has a similar mortality to lobectomy for lung cancer, and clinicians and patients should understand the likely risks involved. 30-day mortality after surgical lung biopsy for ILD is 2.4% (similar to lobectomy for lung cancer) http://ow.ly/fQnY302fGvU

Risk Factors for Cardiovascular Disease in People With Idiopathic Pulmonary Fibrosis: A Population-Based Study

OBJECTIVE People with idiopathic pulmonary fibrosis (IPF) have been shown to be at an increased risk for cardiovascular (CV) disease, but reasons for this are unknown. The aim of this study was to compare the prevalence of common CV risk factors in people with IPF and the general population and establish the incidence of ischemic heart disease (IHD) and stroke after the diagnosis of IPF, controlling for these risk factors. METHODS We used data from a large, UK primary care database to identify incident cases of IPF and matched general-population control subjects. We compared the prevalence of risk factors for CV disease and prescription of CV medications in people with IPF (before diagnosis) with control subjects from the general population and assessed the incidence of IHD and stroke in people with IPF (after diagnosis) compared with control subjects. RESULTS We identified 3,211 cases of IPF and 12,307 control subjects. Patients with IPF were more likely to have a record of hypertension (OR, 1.31; 95% CI, 1.19-1.44), and diabetes (OR, 1.20; 95% CI, 1.07-1.34) compared with control subjects; they were also more likely to have been prescribed several CV drugs. The rate of first-time IHD events was more than twice as high in patients than control subjects (rate ratio, 2.32; 95% CI, 1.85-2.93; P < .001), but the incidence of stroke was only marginally higher (P = .09). Rate ratios for IHD and stroke were not altered substantially after adjusting for CV risk factors. CONCLUSIONS Several CV risk factors were more prevalent in people with IPF; however, this did not account for the increased rate of IHD in this group of patients.

Natural history of angiomyolipoma in lymphangioleiomyomatosis: implications for screening and surveillance

BackgroundLAM is a rare disease of women categorised by lung cysts and lymphatic abnormalities. The disease occurs sporadically or associated with Tuberous Sclerosis Complex (TSC-LAM). Angiomyolipoma, a benign tumour, prone to haemorrhage, occurs mostly in the kidneys in many of these patients. Treatment guidelines exist for angiomyolipoma in patients with TSC but the natural history of angiomyolipoma in sporadic LAM has not been studied.AimsTo document the natural history of angiomyolipoma in a national cohort of patients with sporadic LAM to inform tumour screening and surveillance protocols.MethodsDemographic data, clinical features, lung function and tumour size were obtained from clinical records of patients attending the National Centre for LAM in Nottingham, UK.Results122 patients with definite or probable LAM by European Respiratory Society criteria were identified. One hundred and seven had sporadic LAM, of which 53 (50%) had at least one angiomyolipoma. In patients with sporadic LAM presentation of angiomyolipoma preceded or followed onset of lung symptoms by up to 11 and 38 years respectively. Mean tumour size was 28 mm (range 5-140 mm) at presentation and growth was 1.8 mm/yr (95% C.I. 0.42-3.82) thereafter. Eleven patients with sporadic LAM had had a nephrectomy due to angiomyolipoma bleeding. The need for intervention did not differ between those with TSC-LAM and sporadic LAM.ConclusionsPatients with LAM have a high prevalence of symptomatic angiomyolipoma which can present at any time. Angiomyolipoma in sporadic-LAM have a similar risk of bleeding to those with TSC. All patients should be screened for angiomyolipoma at diagnosis of lung disease by MRI scanning and the tumours require continuous monitoring.

Genetic variants associated with susceptibility to idiopathic pulmonary fibrosis in people of European ancestry: a genome-wide association study

Summary Background Idiopathic pulmonary fibrosis (IPF) is a chronic progressive lung disease with high mortality, uncertain cause, and few treatment options. Studies have identified a significant genetic risk associated with the development of IPF; however, mechanisms by which genetic risk factors promote IPF remain unclear. We aimed to identify genetic variants associated with IPF susceptibility and provide mechanistic insight using gene and protein expression analyses. Methods We used a two-stage approach: a genome-wide association study in patients with IPF of European ancestry recruited from nine different centres in the UK and controls selected from UK Biobank (stage 1) matched for age, sex, and smoking status; and a follow-up of associated genetic variants in independent datasets of patients with IPF and controls from two independent US samples from the Chicago consortium and the Colorado consortium (stage 2). We investigated the effect of novel signals on gene expression in large transcriptomic and genomic data resources, and examined expression using lung tissue samples from patients with IPF and controls. Findings 602 patients with IPF and 3366 controls were selected for stage 1. For stage 2, 2158 patients with IPF and 5195 controls were selected. We identified a novel genome-wide significant signal of association with IPF susceptibility near A-kinase anchoring protein 13 (AKAP13; rs62025270, odds ratio [OR] 1·27 [95% CI 1·18–1·37], p=1·32 × 10−9) and confirmed previously reported signals, including in mucin 5B (MUC5B; rs35705950, OR 2·89 [2·56–3·26], p=1·12 × 10−66) and desmoplakin (DSP; rs2076295, OR 1·44 [1·35–1·54], p=7·81 × 10−28). For rs62025270, the allele A associated with increased susceptibility to IPF was also associated with increased expression of AKAP13 mRNA in lung tissue from patients who had lung resection procedures (n=1111). We showed that AKAP13 is expressed in the alveolar epithelium and lymphoid follicles from patients with IPF, and AKAP13 mRNA expression was 1·42-times higher in lung tissue from patients with IPF (n=46) than that in lung tissue from controls (n=51). Interpretation AKAP13 is a Rho guanine nucleotide exchange factor regulating activation of RhoA, which is known to be involved in profibrotic signalling pathways. The identification of AKAP13 as a susceptibility gene for IPF increases the prospect of successfully targeting RhoA pathway inhibitors in patients with IPF. Funding UK Medical Research Council, National Heart, Lung, and Blood Institute of the US National Institutes of Health, Agencia Canaria de Investigación, Innovación y Sociedad de la Información, Spain, UK National Institute for Health Research, and the British Lung Foundation.