Research

Diagnostic delay still a barrier to effective PAH treatment: respiratory physician


The diagnostic delay which prevents early intervention in patients with PAH is not improving over time, according to data from the Pulmonary Hypertension Society of Australia and New Zealand registry between 2004 and 2017

The evidence from a cohort of more than 2,000 patients was that the mean diagnostic interval was 2.5 years.

More than a third of patients (35%) were diagnosed after more than two years from symptom onset. 

“When stratified by the year of diagnosis, there was no improvement in diagnostic interval across the study period. Subpopulations of SSc-PAH and HPAH also demonstrated no improvement in diagnostic interval over time,” the study said.

The study also found a longer diagnostic interval was associated with decreased survival.

The 5-year survival was 70% if diagnosed within 1 year of symptom onset, 66% if diagnosed at 1-2 years, and 61% if diagnosed after two years.  

“After adjustment for age, gender and PAH subtype, a diagnostic delay of 2 years increased mortality rates by 11% (95% CI: 5–17%), while a delay of 5 years increased mortality by 29% (95% CI: 12–47%).”

Diagnostic delay was also associated with poorer 6MWD and measures of pulmonary function (DLCO, FEV1 and FVC).

It found older age, CHD-PAH subtype, the presence of peripheral vascular disease and obstructive sleep apnoea were independent predictors of longer diagnostic interval. 

The authors, including respiratory physician Associate Professor Edmund Lau from the University of Sydney and Royal Prince Alfred Hospital, said the lack of improvement in diagnostic interval was disappointing given the availability of targeted therapy. 

“This was a surprising result considering there has been greater general awareness of PAH in the community, and greater emphasis on screening in SSc-PAH and HPAH.”

They suggested CHD-PAH patients would be identified earlier if there was less loss to follow-up following transition from paediatric to adult care.

The insidious onset of non-specific symptoms, such as breathlessness and fatigue, may also be misattributed to age-related functional decline in older patients, they said. 

“Presentation to health professionals may therefore occur later in the course of the disease. Furthermore, dyspnoea may be initially misdiagnosed more commonly in older patients due to higher burden of cardiovascular and respiratory disease.”

“Conversely, the smaller number of differential diagnoses and more rapid progression of PAH in young patients may lead to earlier referral and disease recognition.”

“Further efforts are needed to actively screen patients at risk for developing PAH (such as systemic sclerosis and CHD patients) and to raise awareness in primary and secondary care physicians to investigate for alternative causes of dyspnoea when symptoms are progressive or fail to respond to initial treatment.”

Associate Professor Lau told the limbic the findings were consistent with data from other registries but still concerning.  

“I think the most important take home message is that there are certain populations that we know that are at high risk of having PAH – so people who have scleroderma or people that may have a family history of PH.”

“So those two groups are where we shouldn’t be diagnosing people after one or two years of symptoms. We should be diagnosing them as part of routine screening rather than when they get symptoms.”

“Outside of those selected populations, I think it is a difficult area as to how we can improve diagnostic delay.”

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