Larger pulmonary hypertension (PH) registries are needed to advance knowledge about this disease and improve patient care, a new study emphasizes. The report outlines data from a Latvian PH registry and compares it with registries across Europe — and recommends combining registries.
With internet access now common and worldwide, patient registries are seen as an increasingly important means of gathering information on, and learning more about, a patient population. These registries are particularly helpful in the research of rare diseases such as PH.
The study, “Characteristics and Survival Data from Latvian Pulmonary Hypertension Registry: Comparison of Prospective Pulmonary Hypertension Registries in Europe” was published in the journal Pulmonary Circulation.
Between Sept. 1, 2007, and Dec. 31, 2016, 174 patients with either pulmonary arterial hypertension (PAH) or chronic thromboembolic pulmonary hypertension (CTEPH) were enrolled in the Latvian registry. Most — 75 percent —had PAH.
To assess the health of people in the Latvian PH registry, a team of researchers in that country and in Austria analyzed their data, and then compared it to information from 12 national and multinational PH registries, namely from member European Union states and from Canada.
Latvian patients showed similar gender distribution, age and body mass index (BMI) across both PAH and CTEPH groups. Over 60% of patients in the registry were female, with a median age at the time of diagnosis of 65 years for PAH, and 67 for CTEPH.
Clinically, both PAH and CTEPH patient groups had elevated levels of B-type natriuretic peptide (BNP), a marker of heart failure, although the levels were significantly higher in the CTEPH group. High levels of the protein indicate a more advanced disease at the time of diagnosis. This correlated with a patient’s poorer functional status.
In both disease groups, most people were classified as New York Heart Association (NYHA) class III/IV — 72% of PAH patients and 84% of those with CTEPH . The heart failure classification system categorizes patients based on their ability to perform specific physical activities; class III refers to a person with significant limitation, where less than ordinary activity causes fatigue, palpitation, or dyspnea (shortness of breath). This given a class IV are unable to do any such activity without discomfort.
Similar clinical data was seen in the European registries, with most patients also classified as NYHA class III/IV (69% to 94%).
Survival rates in the Latvian population were relatively similar between PAH and CTEPH groups. In the PAH group, 88%, 73.3% and 58.1% survived at 1, 3, and 5 years, respectively. For CTEPH patients, survival rates at 1, 3, and 5 years were 83.8%, 59.0% and 44.2%, respectively.
But compared to European adult PH registries, Latvian PAH patients had the second lowest — and CTEPH patients the lowest — one-year survival rates.
The prevalence of PAH and CTEPH in Latvia in 2016 was also among the highest in Europe. The estimated prevalence rate was 45.7 and 15.7 cases per million inhabitants for PAH and CTEPH, respectively. The researchers suggested this could be attributed to better public awareness and subsequent higher rates of diagnosis.
The team highlighted that most PH registries in Europe, including the Latvian study, are small. To generate better and more reliable results, combining registries is recommended. According to the researchers, because most registries have similar inclusion criteria based on international guidelines, this globalization of registries should not be too difficult.
“More efforts should be made towards a wider collaboration between countries/regions as new global clinical data on rare diseases, would permit to gain new insights on a broader range of PH types,” the researchers wrote, “and would also allow to design more representative and purposeful clinical trials, therefore advancing the knowledge on PH and ultimately improving the quality of care.”