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Correspondence |

Survival in Pulmonary Hypertension Registries: The Importance of Incident Cases FREE TO VIEW

Robin Condliffe, MD; David G. Kiely, MD; J. Gerry Coghlan, MD; J. Simon R. Gibbs, MD; S. John Wort, MD; Paul A. Corris, MD; Andrew J. Peacock, MD; Joanna Pepke-Zaba, PhD; On behalf of the Adult Pulmonary Hypertension Service of the United Kingdom
Author and Funding Information

From the Pulmonary Vascular Disease Unit (Drs Condliffe and Kiely), Royal Hallamshire Hospital; the Department of Cardiology (Dr Coghlan), Royal Free Hospital; the Pulmonary Vascular Unit (Dr Corris), Freeman Hospital; the Department of Cardiology (Dr Gibbs), Hammersmith Hospital; the Scottish Pulmonary Vascular Unit (Dr Peacock), Golden Jubilee Hospital; the Pulmonary Vascular Disease Unit (Dr Pepke-Zaba), Papworth Hospital; and the Pulmonary Hypertension Unit (Dr Wort), Brompton Hospital.

Correspondence to: Robin Condliffe, MD, Pulmonary Vascular Disease Unit, Royal Hallamshire Hospital, Glossop Rd, Sheffield, S10 2JF, UK; e-mail: robin.condliffe@sth.nhs.uk


Financial/nonfinancial disclosures: The authors have reported to CHEST the following conflicts of interest: Dr Coghlan receives grant money from Pfizer Inc to support a nurse and also performs consultancy work for Pfizer Inc, Actelion Pharmaceuticals Ltd, and GlaxoSmithKline. Dr Peacock has received research support, honoraria, and assistance with travel from Actelion Pharmaceuticals Ltd, Bayer, GlaxoSmithKline, Eli Lilly and Company, Pfizer Inc, and United Therapeutics. Dr Pepke-Zaba has received unrestricted educational grants from Actelion Pharmaceuticals Ltd and Pfizer Inc; has received honoraria for lecturing from Bayer, Actelion Pharmaceuticals Ltd, Pfizer Inc, and GlaxoSmithKline; and is on advisory boards for Pfizer Inc, Actelion Pharmaceuticals Ltd, GlaxoSmithKline, Bayer, United Therapeutics, and Eli Lilly and Company. Drs Condliffe, Corris, Gibbs, Kiely, and Wort have reported that no potential conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.

Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (http://www.chestpubs.org/site/misc/reprints.xhtml).


© 2011 American College of Chest Physicians


Chest. 2011;139(6):1547-1548. doi:10.1378/chest.10-3348
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To the Editor:

We read with interest the characteristics and survival data of patients with connective tissue disease-associated pulmonary arterial hypertension (CTD-APAH) enrolled in REVEAL (the Registry to Evaluate Early and Long-term Pulmonary Arterial Hypertension Disease Management) as described in the article by Chung et al (December 2010).1 We note that the observed survival rates in patients with systemic sclerosis-associated pulmonary arterial hypertension (PAH) were markedly superior to those noted in the UK CTD-APAH registry.2 We would agree that this is likely related to the different composition of the two registry populations and believe this issue merits further discussion.

In the REVEAL cohort, only 15% of the 641 cases of patients with CTD-APAH were incident cases (defined in REVEAL as diagnosed within 3 months of entry). The mean time from diagnosis to enrollment was 27.2 ±29.9 months, with the majority of patients already taking PAH-specific medication at entry into the registry.1 In the United Kingdom, all adult patients with PAH receive their diagnosis, initiation of therapy, and treatment via seven nationally designated centers. Consequently, all 484 patients enrolled into the UK CTD-APAH registry were truly unselected, treatment-naive patients with incident disease.2

The different outcomes of patients with incident and prevalent PAH were highlighted by the French idiopathic PAH (IPAH) registry, in which survival rates were significantly superior for patients with prevalent disease and, indeed, were progressively better the longer the length of time from diagnosis to enrollment.3 Even so, the French registry, composed of 354 patients with IPAH-like disease, included only 56 true incident cases. The 134 patients with prevalent disease enrolled <3 years from diagnosis were used to augment this group to enable formulation of a predictive survival equation. In an attempt to remove the survivor bias caused by the inclusion of patients with prevalent disease and different lengths of time between diagnosis and enrollment, survival estimates were adjusted for delay from diagnosis to study entry. A similar method was employed as a sensitivity analysis in the formation of REVEAL’s PAH survival predictor.4 These statistical techniques may have given the impression of increased survival rates in both the French and REVEAL registries by underestimating the proportion of patients with more severe disease who died soon after diagnosis.

We would, therefore, argue that describing survival on the basis of patients with predominantly prevalent disease produces an inaccurate picture of overall survival. Data derived only from consecutive and unselected true incident cases, such as in the UK CTD-APAH and chronic thromboembolic pulmonary hypertension registries, provide a more reliable estimation of survival.2,5 Future registries should be designed, where possible, to enroll only true incident cases, as in the forthcoming IPAH registry for the United Kingdom and Ireland.

Chung L, Liu J, Parsons L, et al. Characterization of connective tissue disease-associated pulmonary arterial hypertension from REVEAL: identifying systemic sclerosis as a unique phenotype. Chest. 2010;1386:1383-1394. [CrossRef] [PubMed]
 
Condliffe R, Kiely DG, Peacock AJ, et al. Connective tissue disease-associated pulmonary arterial hypertension in the modern treatment era. Am J Respir Crit Care Med. 2009;1792:151-157. [CrossRef] [PubMed]
 
Humbert M, Sitbon O, Yaïci A, et al; French Pulmonary Arterial Hypertension Network French Pulmonary Arterial Hypertension Network Survival in incident and prevalent cohorts of patients with pulmonary arterial hypertension. Eur Respir J. 2010;363:549-555. [CrossRef] [PubMed]
 
Benza RL, Miller DP, Gomberg-Maitland M, et al. Predicting survival in pulmonary arterial hypertension: Insights from the Registry to Evaluate Early and Long-term Pulmonary Arterial Hypertension Disease Management (REVEAL). Circulation. 2010;1222:164-172. [CrossRef] [PubMed]
 
Condliffe R, Kiely DG, Gibbs JSR, et al. Improved outcomes in medically and surgically treated chronic thromboembolic pulmonary hypertension. Am J Respir Crit Care Med. 2008;17710:1122-1127. [CrossRef] [PubMed]
 

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References

Chung L, Liu J, Parsons L, et al. Characterization of connective tissue disease-associated pulmonary arterial hypertension from REVEAL: identifying systemic sclerosis as a unique phenotype. Chest. 2010;1386:1383-1394. [CrossRef] [PubMed]
 
Condliffe R, Kiely DG, Peacock AJ, et al. Connective tissue disease-associated pulmonary arterial hypertension in the modern treatment era. Am J Respir Crit Care Med. 2009;1792:151-157. [CrossRef] [PubMed]
 
Humbert M, Sitbon O, Yaïci A, et al; French Pulmonary Arterial Hypertension Network French Pulmonary Arterial Hypertension Network Survival in incident and prevalent cohorts of patients with pulmonary arterial hypertension. Eur Respir J. 2010;363:549-555. [CrossRef] [PubMed]
 
Benza RL, Miller DP, Gomberg-Maitland M, et al. Predicting survival in pulmonary arterial hypertension: Insights from the Registry to Evaluate Early and Long-term Pulmonary Arterial Hypertension Disease Management (REVEAL). Circulation. 2010;1222:164-172. [CrossRef] [PubMed]
 
Condliffe R, Kiely DG, Gibbs JSR, et al. Improved outcomes in medically and surgically treated chronic thromboembolic pulmonary hypertension. Am J Respir Crit Care Med. 2008;17710:1122-1127. [CrossRef] [PubMed]
 
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