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Charles D Burger,1 Mohamedanwar Ghandour,1 Divya Padmanabhan Menon,2 Haytham Helmi,3 Raymond L Benza4 1Division of Pulmonary, Allergy and Sleep Medicine, Mayo Clinic, 2Department of Internal Medicine, Mayo Clinic, 3Division of Transplant Medicine and Research Administration, Mayo Clinic, Jacksonville, FL, USA; 4Advanced Heart Failure, Transplant, Mechanical Circulatory Support and Pulmonary Hypertension, Allegheny Health Network, Pittsburg, PA, USA Abstract: Pulmonary arterial hypertension (PAH) has a high morbidity rate and is fatal if left untreated. Increasing evidence supports early intervention, possibly with initial combination therapy. PAH-specific pharmaceuticals, however, are expensive and may have serious adverse effects, particularly when used in combination. The currently dynamic health care economy reinforces the need for a review of early intervention from both outcomes and economic perspectives. We aimed to review the clinical and economic impact of PAH therapy, particularly examining drug cost, hospitalization burden, and health care economics impact, and the effect of early intervention on clinical outcomes. We searched PubMed, Scopus, Ovid, and MEDLINE databases from 2005 to 2017 for studies comparing drug cost, clinical outcomes, and hospitalization burden associated with therapy for PAH. Emerging data indicate that early therapy is effective, but drug therapy is expensive, particularly with combination therapy. Efficacy studies also generally show benefit of combination therapy for patients in World Health Organization functional class II, with a consistent decrease in hospitalization. Pharmacoeconomic studies are limited but indicate that increased pharmacy costs are at least partially offset by decreased health care utilization, particularly inpatient care. Modeling also shows a cost benefit with combination therapy at 2 years. Nonetheless, more rigorously collected health care economic data should be incorporated into future drug efficacy trials to provide a clearer understanding of the impact and the associated cost benefit of early PAH therapy. Increasing evidence in support of early intervention and combination therapy for PAH is associated with rising medication costs that are largely offset by reduced hospitalization, on the basis of the currently available literature. Nonetheless, the studies performed to date have methodologic limitations that highlight the need for prospective studies using more robust economic modeling. Keywords: combination therapy, health care costs, hospitalization, pulmonary arterial hypertension

Background Raregenetic variantscause pulmonary arterial hypertension, but the contribution of commongenetic variationto disease risk and natural history is poorly characterised. We tested for genome-wide association for pulmonary arterial hypertension in large international cohorts and assessed the contribution of associated regions to outcomes. Methods We did two separate genome-wide association studies (GWAS) and a meta-analysis of pulmonary arterial hypertension. These GWAS used data from four international case-control studies across 11 744 individuals with European ancestry (including 2085 patients). One GWAS usedgenotypesfrom 5895 whole-genome sequences and the other GWAS used genotyping array data from an additional 5849 individuals.Cross-validationof loci reaching genome-wide significance was sought by meta-analysis. Conditional analysis corrected for the most significant variants at each locus was used to resolve signals for multiple associations. We functionally annotated associated variants and tested associations with duration ofsurvival.All-cause mortalitywas the primary endpoint in survival analyses. Findings A locus nearSOX17(rs10103692, odds ratio 1·80 [95% CI 1·55–2·08], p=5·13 × 10–15) and a second locus inHLA-DPA1andHLA-DPB1(collectively referred to asHLA-DPA1/DPB1here; rs2856830, 1·56 [1·42–1·71], p=7·65 × 10–20) within the class II MHC region were associated with pulmonary arterial hypertension. TheSOX17locus had two independent signals associated with pulmonary arterial hypertension (rs13266183, 1·36 [1·25–1·48], p=1·69 × 10–12; and rs10103692). Functional andepigenomicdata indicate that the risk variants nearSOX17altergene regulationvia anenhanceractive inendothelial cells. Pulmonary arterial hypertension risk variants determined haplotype-specific enhancer activity, and CRISPR-mediated inhibition of the enhancer reducedSOX17expression. TheHLA-DPA1/DPB1rs2856830 genotype was strongly associated with survival. Median survival fromdiagnosisin patients with pulmonary arterial hypertension with the C/C homozygous genotype was double (13·50 years [95% CI 12·07 to >13·50]) that of those with the T/T genotype (6·97 years [6·02–8·05]), despite similar baselinedisease severity. Interpretation This is the first study to report that common genetic variation at loci in an enhancer nearSOX17and inHLA-DPA1/DPB1is associated with pulmonary arterial hypertension. Impairment of SOX17 function might be more common in pulmonary arterial hypertension than suggested by raremutationsinSOX17. Further studies are needed to confirm the association betweenHLA typingor rs2856830 genotyping and survival, and to determine whether HLA typing or rs2856830 genotyping improvesrisk stratificationin clinical practice or trials.

Background Rare genetic variants cause pulmonary arterial hypertension, but the contribution of common genetic variation to disease risk and natural history is poorly characterised. We tested for genome-wide association for pulmonary arterial hypertension in large international cohorts and assessed the contribution of associated regions to outcomes. Methods We did two separate genome-wide association studies (GWAS) and a meta-analysis of pulmonary arterial hypertension. These GWAS used data from four international case-control studies across 11 744 individuals with European ancestry (including 2085 patients). One GWAS used genotypes from 5895 whole-genome sequences and the other GWAS used genotyping array data from an additional 5849 individuals. Cross-validation of loci reaching genome-wide significance was sought by meta-analysis. Conditional analysis corrected for the most significant variants at each locus was used to resolve signals for multiple associations. We functionally annotated associated variants and tested associations with duration of survival. All-cause mortality was the primary endpoint in survival analyses. Findings A locus near SOX17 (rs10103692, odds ratio 1·80 [95% CI 1·55–2·08], p=5·13 × 10–15) and a second locus in HLA-DPA1 and HLA-DPB1 (collectively referred to as HLA-DPA1/DPB1 here; rs2856830, 1·56 [1·42–1·71], p=7·65 × 10–20) within the class II MHC region were associated with pulmonary arterial hypertension. The SOX17 locus had two independent signals associated with pulmonary arterial hypertension (rs13266183, 1·36 [1·25–1·48], p=1·69 × 10–12; and rs10103692). Functional and epigenomic data indicate that the risk variants near SOX17 alter gene regulation via an enhancer active in endothelial cells. Pulmonary arterial hypertension risk variants determined haplotype-specific enhancer activity, and CRISPR-mediated inhibition of the enhancer reduced SOX17 expression. The HLA-DPA1/DPB1 rs2856830 genotype was strongly associated with survival. Median survival from diagnosis in patients with pulmonary arterial hypertension with the C/C homozygous genotype was double (13·50 years [95% CI 12·07 to >13·50]) that of those with the T/T genotype (6·97 years [6·02–8·05]), despite similar baseline disease severity. Interpretation This is the first study to report that common genetic variation at loci in an enhancer near SOX17 and in HLA-DPA1/DPB1 is associated with pulmonary arterial hypertension. Impairment of SOX17 function might be more common in pulmonary arterial hypertension than suggested by rare mutations in SOX17. Further studies are needed to confirm the association between HLA typing or rs2856830 genotyping and survival, and to determine whether HLA typing or rs2856830 genotyping improves risk stratification in clinical practice or trials.