Quality of life parameter helps ID PAH patients at higher risk of death

Findings reinforce 'critical role' of QOL measures in routine evaluations

Patricia Inácio, PhD avatar

by Patricia Inácio, PhD |

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The physical activity component of the PAH-SYMPACT — a patient-reported measure of quality of life tailored for people with pulmonary arterial hypertension (PAH) — is an independent predictor of the risk of death among PAH patients, according to a new study from Australia.

One unit increase in this parameter was linked to a more than 40% higher likelihood of a patient being at an intermediate to high mortality risk.

“We therefore found further support for additional prognostic value being conferred by measurement of [quality of life] as part of routine PAH evaluation, reinforcing its critical role,” the researchers wrote.

The study, “Assessing quality of life in pulmonary arterial hypertension: An independent prognostic marker,” was published in the journal Pulmonary Circulation.

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Investigating patient-reported outcomes and quality of life measures

PAH is a progressive disease characterized by the narrowing of the pulmonary arteries, which are the blood vessels that transport blood to the lungs. Such narrowing restricts blood flow and causes high blood pressure, or hypertension.

Patient‐reported outcomes (PROs) and quality of life (QOL) measures are common parameters used to assess disease outcomes and the effectiveness of therapies. But such assessments also may offer further prognostic information, helping stratify patients into different groups according to their risk of death — and in turn, guiding the best choice of treatment.

Now, a team led by researchers in New South Wales investigated whether QOL measures could serve as a noninvasive indicator that would help further refine patient stratification and therapeutic choices.

To that end, the researchers analyzed clinical data from a total of 33 adults with PAH. All had been followed at the Hunter multidisciplinary PAH clinic between July 2020 and June 2021, or had enrolled in a PAH database.

Assessed parameters included the class of the World Health Organization functional classification (WHO FC) and the six-minute walking distance (6MWD) test, a measure of exercise capacity and endurance. Each parameter was graded from 1-3, where one corresponded to a low risk of mortality, with two linked to an intermediate risk, and three to a high risk.

QOL was assessed with the Pulmonary Arterial Hypertension-Symptoms and Impact questionnaire, known as PAH-SYMPACT, which is specifically tailored for PAH, and the EuroQol 5-Dimension 5-level (EQ-5D-5L) questionnaire, a validated tool to assess overall health-related QOL.

PAH-SYMPACT assesses PAH-associated impairments to the cardiovascular and cardiopulmonary system, as well as physical and cognitive domains. Scores range from one to five, with higher scores being indicative of more severe impairments. The EQ-5D-5L results were converted into Australia-specific health utility scores (HUS), in which values close to zero meant close to death and one indicated no impairments in health perception.

The patients had a mean age of 69.5 years (range 39-84) and most (85%) were women.

The majority of patients were categorized either as WHO FC class I — 42% — or WHO FC class II, comprising 49% of participants. A small number, 9% in all, were in the WHO FC class III, and none were in the most severe PAH category, known as WHO FC class IV.

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41% increase in likelihood of higher risk of death with each unit jump

The PAH-SYMPACT score for cardiopulmonary symptom burden correlated with a higher impairment in the EQ‐5D‐5L domain assessing patients’ ability to take part in usual activities, according to the data.

The researchers then assessed QOL parameters and functional parameters relative to a patient’s one-year mortality risk, which was defined as low (below 5%), intermediate (5% to 20%), or high (greater than 20%).

As expected, patients in the lowest risk group walked a significantly longer distance in the 6MWD test when compared with those in the higher risk group (mean of 435.83 vs. 206 m; those in the intermediate risk group walked 317.3 m).

The impact of PAH on physical activity also was greater in the high-risk group, as shown by a higher PAH-SYMPACT physical impact score when compared with the low-risk group (mean of 18.5 vs. 8.83; the score for the intermediate group was 9.6).

The use of PROs [patient‐reported outcomes] can refine existing risk-assessment tools by enhancing their predictive value and allowing risk stratification to occur even more accurately.

A statistical analysis taking into account the 6MWD and the two QQL scores — PAH‐SYMPACT and EQ‐5D‐5L — showed that the PAH‐SYMPACT physical impact score was a significant predictor of mortality risk. Each unit increase in the PAH‐SYMPACT physical activity score was associated with a 41% increase in the likelihood of a patient being at an intermediate to high risk of death.

A decrease of 40 meters in the 6MWD also was associated with a significantly increased risk of mortality.

“The use of PROs can refine existing risk-assessment tools by enhancing their predictive value and allowing risk stratification to occur even more accurately,” the researchers wrote. “Despite the challenges involved in using and interpreting these instruments, there should be more widespread and uniform use of PROs as part of standard PAH assessment and management.”

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