IPF-related mortality rates differ based on urban, rural areas

Key takeaways:

• An 18% higher adjusted mortality rate was found in medium/small metropolitan and rural areas vs. large metropolitan areas.
• Mortality rates and trends between the areas varied based on sex, age, race and region.

Individuals living in medium/small metropolitan and rural areas had increased idiopathic pulmonary fibrosis-related mortality rates vs. those living in large metropolitan areas, according to results published in CHEST.

“For everyday clinicians, the findings emphasize the importance of heightened awareness in diagnosing and treating IPF in rural patients, improving access to specialty care and addressing socioeconomic and environmental factors,” Niranjan Jeganathan, MD, MS, associate professor of medicine and associate clinical professor of cardiopulmonary sciences at Loma Linda University, told Healio. “Clinicians should also consider racial and regional disparities in IPF-related outcomes to tailor their care approaches effectively.”

Using the CDC Multiple Cause of Death Database, Jeganathan and Matheni Sathananthan, MD, associate professor of medicine at Loma Linda University, evaluated 344,483 IPF clinical syndrome deaths between 2006 and 2019, to find out how medium/small metropolitan and rural area IPF-related mortality rates and trends differ from those of large metropolitan areas.

Within the total cohort, 47.7% of deaths took place in large metropolitan areas, 33.8% took place in medium/small metropolitan areas and 18.5% took place in rural areas.

Adjusting for age revealed that medium/small metropolitan areas had the highest annual average IPF-clinical syndrome-related mortality rate at 75.6 per 1 million people. The next highest rate was found in rural areas at 74.5 per 1 million people and then in large metropolitan areas at 65.4 per 1 million people.

In medium/small vs. large metropolitan areas, researchers found that the sex and race-adjusted mortality rate ratio was 18% higher (1.18; 95% CI, 1.14-1.22), and this was also the case when placing rural areas against large metropolitan areas (1.18; 95% CI, 1.14-1.23).

Researchers further noted that mortality rates of all three areas did not increase or decrease over the course of 2006 to 2019.

Based on different subgroups (sex, age, race, region), mortality rates and trends between the areas varied.

Sex

In medium/small vs. large metropolitan areas, the mortality rate ratio was 1.13 (95% CI, 1.1-1.17) among women and 1.16 (95% CI, 1.14-1.19) among men. A similar set of increased rate ratios were observed in rural areas vs. large metropolitan areas for women (1.13; 95% CI, 1.09-1.16) and men (1.13; 95% CI, 1.1-1.16).

Mortality rates of men and women did not appear to change in large metropolitan and medium/small metropolitan areas from 2006 to 2019. In rural areas, men had higher rates as time progressed.

Age

Switching to age, researchers found that the youngest age group (45 to 54 years) in medium/small metropolitan areas had a 29% (95% CI, 1.22-1.38) higher rate than that of large metropolitan areas. In rural areas vs. large metropolitan areas, this age group had a 39% (95% CI, 1.31-1.48) greater mortality rate.

In both areas, these increased rates gradually declined as patients aged. The mortality rate ratio went up by 21% in the 55- to 64-year-old group in medium/small vs. large metropolitan areas and by 10% in the older than 65 years group. In rural areas vs. large metropolitan areas, the rate ratio went up by 26% in the 55- to 64-year-old group and by 16% in the older than 65 years group.

“One unexpected finding was that the urban-rural mortality difference was more pronounced in younger age groups, suggesting that IPF may develop at a younger age in those living in less urban areas,” Jeganathan told Healio.

Notable changes in mortality rates between 2006 and 2019 included a lower rate in the 45- to 54-year-old group living in large metropolitan areas, a lower rate in the 55- to 64-year-old group living in large metropolitan areas, a higher rate in the 55- to 64-year-old group living in rural areas and higher rates in the 75- to 85-year-old group and 85 years old or older group living in each of the three areas.

Race

Between medium/small metropolitan areas and large metropolitan areas, researchers observed increased mortality rates in medium/small metropolitan areas for Native American Individuals (1.71; 95% CI, 1.54-1.89), Asian individuals (1.29; 95% CI, 1.18-1.4), Hispanic individuals (1.14; 95% CI, 1.1-1.17), white individuals (1.12; 95% CI, 1.09-1.15) and Black individuals (1.08; 95% CI, 1.04-1.13).

Three of the five racial/ethnic groups also had increased mortality rates in rural areas vs. large metropolitan areas: Native American individuals (2.07; 95% CI, 1.87-2.29), Asian individuals (1.23; 95% CI, 1.13-1.34) and white individuals (1.1; 95% CI, 1.07-1.13).

Notable changes in mortality rates as time progressed included higher rates for white individuals in each of the three areas, higher rates for Asian individuals living in large metropolitan areas and lower rates for Asian individuals living in medium/small metropolitan areas.

Region

Mortality rates in medium/small vs. large metropolitan areas went up by 22% (95% CI, 1.18-1.25) in the Northeast, 11% (95% CI, 1.08-1.14) in the Midwest, 12% (95% CI, 1.09-1.16) in the South and 17% (95% CI, 1.14-1.2) in the West.

Similarly, rural area mortality rates were higher than large metropolitan area mortality rates in each of the four regions: Northeast (1.34; 95% CI, 1.3-1.38), Midwest (1.08; 95% CI, 1.05-1.11), South (1.08; 95% CI, 1.05-1.11) and West (1.13; 95% CI, 1.1-1.16).

Researchers noted that both the Northeast and South regions had higher mortality rates over the course of 2006 to 2019 in large metropolitan areas. Additionally, the Northeast had greater rates in medium/small metropolitan areas, whereas the South had greater rates in rural areas.

“The study’s findings underscore the need for policies aimed at improving access to ILD specialty care in rural areas, increasing funding for rural health care and implementing educational programs to raise awareness about the importance of early IPF diagnosis and treatment,” Jeganathan told Healio.

Moving forward, research on this topic may consider more factors, Jeganathan said.

“Future studies are likely to incorporate more comprehensive data collection, including environmental exposure histories and socioeconomic status, to better understand the factors contributing to urban-rural disparities in IPF outcomes,” Jeganathan told Healio. “Future studies will also focus on interventions such as telemedicine to mitigate these disparities in IPF mortality.”