• Hypertension, pulmonary
• clinical trials
• economics, medical
• cost savings
• pulmonary arterial hypertension (PAH)
• delivery of care, public health

In a world of spiralling healthcare costs, no healthcare system can afford the standard of healthcare it would like to achieve. The current need to reduce public spending means that, although the NHS has been considered to be good value by international standards, it will need to save £15–20 billion in efficiency gains in the next 3 years without compromising on quality. A key part of this would be to stop providing treatments that lack evidence or bring little or no benefit to patients. While the biggest savings will be on common diseases, rare diseases with expensive treatments must also be considered.

Pulmonary hypertension has numerous causes and the diagnosis is incomplete without determining the cause and severity. The causes are described in a clinical classification which can be used to guide treatment.1 Five main categories describe the type of pulmonary hypertension: pulmonary arterial hypertension (PAH); pulmonary hypertension due to left heart disease; pulmonary hypertension due to lung diseases and/or hypoxia; chronic thromboembolic pulmonary hypertension; and causes with unclear mechanisms.

The causes of PAH span internal medicine. The randomised clinical trials have been conducted in several aetiologies of PAH and have focused principally on idiopathic, heritable and associated with anorexogens and toxins, connective tissue diseases, congenital heart disease and HIV. Other associated causes of PAH include portal hypertension, congenital haemolytic anaemia and schistosomiasis. A small number of trials have enrolled patients with a single aetiology of PAH (eg, connective tissue disease, Eisenmenger's syndrome and HIV), while most trials have included a selection of these aetiologies to enable more productive recruitment. The benefit of treatment demonstrated for one aetiology cannot necessarily be extrapolated to another within the PAH group with the same level of safety and efficacy.

PAH is a rare disease which causes severe disability and is lethal. It affects …