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Thyroperoxidase Antibody is Not a Useful Screening Test for Thyroid Disease in Patients with Pulmonary Hypertension

Charles Burger


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Conference: 2008 International PHA Conference and Scientific Sessions

Release Date: 06.20.2008

Presentation Type: Abstracts

Burger C.D. 

Mayo Clinic, Jacksonville, FL, USA

BACKGROUND: The prevalence of thyroid disease is increased in pulmonary hypertension (PH) especially in World Health Organization (WHO) diagnostic group 1 pulmonary arterial hypertension (PAH). (Li JH et al. Chest 2007;132:793-79)  A high prevalence of autoimmune thyroid disease has also been shown in PH.  (Chu JW et al. Chest. 2002;122:1668-73)  We postulated that thyroperoxidase (TPO) antibody would be a useful screen for autoimmune thyroid disease in PH.

METHODSConsecutive new patients referred to the PH Clinic at Mayo Clinic in Jacksonville, Florida were reviewed.  Demographics, history of thyroid disease, notation of thyroid medications, thyroid stimulating hormone, and TPO were recorded.  Characteristics of the PH were also evaluated including:  WHO diagnostic group, WHO functional class, six-minute walk distance (6MWD), pulmonary artery systolic pressure (PASP) by echocardiography (ECHO), and hemodynamics by right heart catheterization (RHC).  The latter included:  right atrial pressure (RAP), pulmonary artery pressure (PAP), mean PAP (MPAP), cardiac index (CI) and pulmonary vascular resistance (PVR).  The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of a positive TPO for thyroid disease was calculated.

RESULTS183 patients were 65 ± 13 years old, 69% women, and 89% Caucasian.  WHO functional class was 23% I-II and 77% III-IV.  Mean 6MWD was 279 ± 98 meters.  Average PASP by ECHO was 71 ± 25 mmHg.  RHC (110 patients) revealed: RAP 10 ± 5 mmHg, PASP 72 ± 21, PADP 29 ± 10 mmHg, MPAP 45 ± 13 mmHg, CI 2.4 ± 0.9 L/min/m2, and PVR 669 ± 574 dyne sec cm-5. WHO diagnostic groups were:  Group 1 (PAH) 46%, group 2 was 21%, group 3 was 25%, group 4 was 7% and group 5 was 1%.  Most PAH patients were associated PAH (APAH): 52 of 84 (62%).  Overall (n = 183): sensitivity 30%, specificity 93%, PPV 63%, NPV 78%.  In PAH patients (n = 84): sensitivity 43%, specificity 98%, PPV 91%, NPV 82%.  In one PAH patient, the TPO was positive in the evaluation of a new diagnosis of Grave’s thyroiditis as the cause of the PAH.

COMMENTS AND CONCLUSIONS: In this consecutive series of PH patients, the low sensitivity of TPO demonstrates limited value as a screening test for thyroid disease.  Although quite specific, the sensitivity was only marginally better in PAH.  Indeed, in only one clinical case was the TPO felt to be additive.