Expert Conversations: Trends in Pulmonary Arterial Hypertension From 2007 to 2017


In this podcast, Bisharah Rizvi, MD, and Vijay Balasubramanian, MD, MRCP (UK), talk about their research paper that they presented at CHEST 2021, which examined hospital data to determine the burden of pulmonary arterial hypertension from 2007 to 2017.

Additional Resource:

  • Rizvi D, Desai R, Elwing J, Balasubramanian V. Hospitalizations of idiopathic pulmonary arterial hypertension in the United States: a national perspective a decade apart (2007 vs 2017). CHEST. 2021;160(4 Suppl):A2281-A2282. 


Bishara Rizvi, MD
Bisharah Rizvi, MD, is an academic hospitalist at Saint Agnes Medical Center in Fresno, California.

Vijay Bala, MD
Vijay Balasubramanian, MD, MRCP (UK), is a professor of medicine and director of the pulmonary hypertension program at the University of California San Francisco, Fresno campus.



Amanda Balbi: Hello everyone, and welcome to another installment of Podcasts360—your go-to resource for medical news and clinical updates. I’m your moderator, Amanda Balbi with Consultant360.

Today we’re speaking with 2 amazing researchers who recently presented their latest study on pulmonary arterial hypertension at CHEST 2021.

Can you both introduce yourselves?

Bisharah Rizvi: Hi, my name is Bishara Rizvi. I'm an academic hospitalist at Saint Agnes Medical Center in Fresno, California.

Vijay Balasubramanian: Hi, my name is Dr Vijay Balasubramanian. I'm a professor of medicine at UCSF Fresno. I also direct the Palmer Hypertension Program. Pleasure to meet all of you.

Amanda Balbi: Thank you both for joining me today on our podcast. To start, Dr Rizvi, can you give us an overview of your study and its findings?

Bisharah Rizvi: Yes, so my research is on hospitalizations of idiopathic pulmonary arterial hypertension in the US. It's basically a comparison 10 years apart comparing 2007 vs 2017. Pulmonary arterial hypertension hospitalizations are associated with high morbidity and mortality and high health care costs. There aren't that many population-based studies done on this topic. There are some registries that we use to get demographic data on hospitalizations, but other than that we don't really have that many population-based studies, and that's what made us do this study.

For the data, we used the Health Care Utilization Project, the national in-patient sample database, which has administrative data of about 1000 hospitals in the US and has 8 million hospitalizations. That represents about 95% of the hospitalizations data in the US.

To identify the patients with pulmonary arterial hypertension, we had to use ICD codes. All patients over the age of 18 were included. And we looked at total box and physicians. What we saw was that there was a significant decrease in number of hospitalizations. The number of female admissions continued to stay high in both 2007 and 2017. They were like 65% and 68%. 

When we looked at the race, Whites continued to have the highest number of admissions compared to other races in both years, 67% (2007) and 64% (2017). There was a slight increase in African American and Hispanic admissions, but not very significant. It was from 17% (2007) to 19% (2017).

There were some regional variations when we looked at the trends. The hospitalizations in the Northeast region had decreased, but there was an increase in the hospitalizations in the Midwest, South, and West.

Looking at the all-cause mortality showed pretty good results. There was a significant decrease in all-cause mortality. In 2007, it was 6.4%, which decreased to 4.8% in 2017, and it was statistically significant.

There was no change in length of stay. The median was around 5 for both years. Then when we looked at other predictors of all-cause mortality in hospitalizations, patients in age group 45 to 64 and over 65 had higher mortality rates compared to the age group between 18 and 44.

Then, compared to females, males had significantly heart higher mortality, even though females had higher percentage of admissions, around 60%, but males had higher mortality. Compared to Whites, African Americans and Hispanics had lower rate of mortality, so Whites higher mortality.

When we looked at the bed size for mortality, even though there were higher percentage of admissions and larger bedside, small bedside hospitals were associated with higher mortality rates compared to all larger bedside hospitals.

Then we looked at the cardiac arrest outcomes. Compared to 2007, in 2017 there was higher percentage of patients who were hospitalized and had cardiac arrest, and an event of having a cardiac arrest was associated with significantly higher mortality. It had adjusted odds ratio of 27.2, which is significantly high.

In conclusion, this is basically a retrospective cohort study of patients with a diagnosis of idiopathic pulmonary hypertension, and it compares the outcomes of admissions 10 years apart. What we saw was that hospitalizations have decreased from 2007 to 2017. Mortality has also significantly decreased from 2007 to 2017, but there's a significant increase in health care costs for the hospitalizations.

And this is again retrospective study using a database, so we need more studies from hospitals that we can use to get more data on a similar topic.

There were some limitations that I do want to mention. We only used the ICD-10 code to get to the diagnosis. It won’t be very accurate, because some patients may not have the diagnosis of pulmonary arterial hypertension, but the ICD code was used. Or if there was a readmission of a patient with a pulmonary arterial hypertension, it counts as a new hospitalization, and then the admission might not be accurate.

Vijay Balasubramanian: Thank you, Bishara, for that very nice summary of the study. So, as Dr Rizvi indicated, the hospitalization data pertaining to pulmonary arterial hypertension is actually not very common at all. This particular data set derived from the national inpatient sample database really helps reflect the dynamics of PAH over a 10-year period.

The drop in hospitalizations may be attributed to more effective therapies, better diagnosis, and patients are being treated very well, and that is anticipated. Clearly, in 10 years, we're doing a better job of diagnosing and treating pulmonary hypertension, and it may be reflected by this reduced number in 2017.

And then the female/male distribution is also very congruent with our findings because this is a female-predominant disease. This database represents that split quite nicely. The predominant Caucasian population representation may just be because it's still a White-predominant disease. The numbers in the other ethnic minorities are substantially lower, and therefore, we may not be able to pick up a loud signal there.

Now, what was interesting was the regional differences, which Dr Rizvi alluded to, where the Northeast actually saw a substantial reduction in admissions. Maybe one can postulate that the concentration of PAH centers—if you look at the PAH centers map—around the Northeast area is extremely dense. The number of centers providing expert-level care, but as you start moving to the Midwest, to the South, and the West, the concentration of centers become more and more sparse. They are not as close to each other compared to the Northeast. 

Therefore, access to care might be an issue in these geographic areas, which might be the reason for that signal, which is actually a very interesting observation.

Amanda Balbi: Great, very well said. So, how can clinicians use your findings to improve patient care?

Vijay Balasubramanian: This data helps to get a more global understanding of the management, inpatient activity, and discharges. So, “How does this data reflect on an average practitioner?” is your question, and that might be related to, if you are a pulmonologist, it's good to understand your local expert center(s) and try to see whether the pulmonologist or the cardiologist or the primary care provider can build a bridge. 

It goes the other way around, too. The expert centers need to reach out to the local pulmonolgists and other practitioners to establish a relationship with them, getting to know them. That way it facilitates better patient referral and reduces difficulties with access to care. 

Obviously, better treatment modalities have substantially impacted inpatient activity, which is a good thing, but obviously the other thing that's also reflected in this study is the cost of PAH management is very high, because the management options that we have with all the territories are unfortunately very expensive. This may we do see a signal of that in the in the in this particular study.

More robust data would help in delineating some of these aspects further, but at least we can get very pertinent signals from this data that would impact care for PAH patients.

Amanda Balbi: Absolutely. Dr Rizvi, any thoughts?

Bisharah Rizvi: Exactly. For example, I work as a hospitalist. If any hospitalists see patients with pulmonary hypertension, we should make sure to refer them to pulmonary hypertension centers or pulmonary hypertension specialists for better care.

Amanda Balbi: What is your next step in this research? What’s next to study?

Vijay Balasubramanian: This study was done by using a database that was available to us, with many limitations. I think we need to do more wider hospital-based studies or a multicenter study to be able to get data regarding the demographics and the hospitalization outcomes.

Vijay Balasubramanian: Dr Rizvi is right. To get more specific information further, based on the limitations of the information that you can derive from this particular database, one can look to other major registry databases like the FAR registry by the Pulmonary Hypertension Association, which may be able to throw some light on some of the more-finer aspects of PAH inpatient hospitalization data, mortality outcomes, and all of that.

We were also planning to look into the hospitalization of using the more-current ICD-10 coding system and look for any new differences within the surpluses of PAH. But that is something that we are contemplating, depending on the limitations of the database itself.

Amanda Balbi: Great. Do you have any final thoughts to summarize?

Vijay Balasubramanian: I think the most important aspect of this particular study was it throws significant light into, in a positive way, that the hospitalizations for PAH have substantially reduced in a 10-year period. This might be because of improved awareness, detection, and better treatment opportunities and modalities.

And the other crucial aspect that we see is the regional variations may certainly reflect or represent access-to-care issues from expert centers. One needs to make sure that efforts are done to improve patients’ access to care, improve awareness, and that would lead to earlier diagnosis and better treatment and, therefore, better outcomes.

Amanda Balbi: Thank you both for speaking with me today and answering my questions about your research.

Bishara Rizvi: Thank you so much.

Vijay Balasubramanian: Thank you, Amanda. Thanks for the opportunity, and Dr Rizvi worked really hard on this project, and I congratulate her for coming up with such a lovely project with very important information and look forward to see whether we can get more data in the future.