Social determinants of health,cystic fibrosis-related diabetes,and mental health in adult patients with cystic fibrosis: a critical synthesis of narrative review

Ethnicity and SES

SES incorporates an individual’s social or economic standing and represents a composite measure of income, education, and occupation. Therefore, low SES is associated with decreased academic attainment and lower household income. For PwCF, lower SES has been associated with increased disease severity, greater healthcare utilization, impaired QoL, and reduced survival.^21,23 To date, there are over 2000 identified disease-causing mutations in the CFTR gene, and PwCF who are ethnic minorities are more likely than their Caucasian counterparts to harbor genetic variances in the CFTR gene that are not identified using standard newborn screening panels, leading to disparities in care, including delayed diagnosis and treatment. ²⁴ In addition, PwCF who are ethnic minorities are more likely to have CFTR mutations that are not responsive to modern CFTR modulator therapies. Thus, despite therapeutic advances, PwCF who are racial and ethnic minorities, from low socioeconomic status, and/or female sex continue to experience worse clinical outcomes. ²⁵ Furthermore, controlling for SES and disease severity, African American and Hispanic PwCF reported worse emotional and social functioning compared to Caucasian PwCF. ²⁵ Also, using the CF Foundation Patient Registry, Hergenroeder and co-workers assessed PwCF aged 12 years and older (n = 17, 183) and sought to identify factors that are associated with the delay in initiation of ETI. Their findings indicate that having public health insurance and black and Hispanic ethnicity were associated with a longer wait time to first ETI prescription compared to Caucasians. ²⁶ A separate retrospective study in the US ²⁷ using data from the Cystic Fibrosis Patient Registry from 2010 to 2014 demonstrated 27% higher death rates for Hispanic PwCF compared with non-Hispanics after controlling for SES.

In the US, CF care centers are required to have a social worker as a member of their care team for accreditation and standards; however, formalized screening for social needs is not yet a formalized component of the CF care model. Jennings and co-authors ²⁸ screened adult PwCF for the prevalence of unmet health-related social needs using a survey that assessed social risk factors across eight domains (housing, food, transportation, utilities, healthcare access, medication access, income/employment, and education). One hundred thirty-two PwCF were recruited from outpatient clinics at a large academic center in the US, and 42% of individuals screened positive for unmet needs in one or more SDOH domains. Those who screened positive for SDOH and requested assistance were referred to external agencies (e.g., housing reported needs, food insecurity, transportation problems, income, and employment access) and received appropriate support. This quality improvement project showed that screening for SDOH and providing appropriate interventions to mitigate social difficulties in adult PwCF is a feasible component of the CF care model.

An observational study that examined the impact of SES on adherence to airway clearance therapy (using the high-frequency chest wall oscillation therapy for 4–6 weeks) in pediatric CF children was carried out with 12-months follow-up. Better adherence to airway clearance therapy was associated with higher household income (> $50,000) compared to lower income. ²⁹ In addition, households with a paternal college education, higher income (> $100,000), and unexposed to tobacco smoke were independently associated with higher lung function in children with cystic fibrosis. In contrast, CF children exposed to environmental tobacco smoke and household income < $40.000 had lower lung function, elevated respiratory symptoms or wheezes, and poorer nutritional status compared to children with higher income households. ³⁰ This underlies the importance of educating parents and children about smoking-free environment and encouraging parents to stop smoking at home.

Smoking exposure during Elexacaftor/Tezacaftor/Ivacaftor (ETI) treatment: ETI improves lung function and reduces acute exacerbation in PwCF. A retrospective ³¹ longitudinal analysis of data from the Cystic Fibrosis Foundation Patient Registry (2019–2021) on PwCF aged ⩾ 12 years (n = 15,000) examined the efficacy of ETI on clinically relevant outcomes over a 12-month follow-up. The findings indicate the benefit of ETI was not sustained beyond 6 months among those PwCF with tobacco smoking exposure (TSE). The TSE group did not gain as many significant benefits as the non-TSE group from ETI. This is due to the deleterious impact of cigarette smoking on CFTR function. ³² PwCF exposed to TSE had twice the odds of exhibiting pulmonary exacerbations compared to unexposed counterparts. Black PwCF were 53% percent increased risk for pulmonary exacerbations compared to White in the preceding 12-months. In addition, children with PwCF exposed to TSE and from low SES households are independently associated with progressive lung function decline. ³³ Therefore, smoking cessation and strategies to reduce passive smoking exposure should be highlighted and treated in routine pediatric and adult CF care, which may help to reduce pulmonary-related exacerbations and respiratory symptoms. ³⁴

Neighborhood and physical environment: Environmental factors such as traffic related air pollution exposure to elemental carbon attributable to traffic sources coupled with community level-material deprivation (poverty, education, housing, and healthcare access), were associated with a rapid decline in lung function in PwCF.^35,36 Similarly, higher environmental adversity (a composite score for geo-markers by ZIP code measuring air pollution and respiratory hazards, greenspace, crime, and socioeconomic deprivation) has been associated with increased risk of rapid decline in lung function and mortality.^34,35 Oates and colleagues ³⁷ observed that in pediatric patients with CF (n = 231) living in households of higher area-level deprivation (measured by area deprivation index, 1–100, a higher score implies greater deprivation), was associated with rural residence, lack of parental college education, and lower household income. Furthermore, the study underscored that high neighborhood deprivation was associated with a twofold increase in the odds of CF children having methicillin-resistant Staphylococcus aureus infection (MRSA). This highlights the importance of preventative strategies (e.g., education and hygiene) and treatment plans by healthcare providers to reduce the occurrence of MRSA infection, which is a worthy endeavor.

Geographical location: There is some evidence to suggest that healthcare disparities exist between rural and urban CF populations, and rural CF patients tend to have poorer outcomes (e.g., elevated risk of mortality). ³⁸ The exact causes are unclear. Living in rural areas might be a challenge for PwCF, and distance might play a role by limiting individuals to have access to specialized CF care centers. ³⁸ In a separate study, in Canada, British Columbia, adult CF patients who lived more than 2.5 h from a CF center were less likely to attend quarterly clinic visits, and at heightened risk of lung function decline compared to those within 45-minutes travel distance. ³⁹ In the US, transferring from CF pediatric care to adults’ CF care happens between the ages of 18 and 21 years old. However, care transition is not always smooth for PwCF. The risk factors that are associated with prolonged gaps in care were younger age at transfer, lack of health insurance, and relocation far away from the specialized CF center(s). ⁴⁰ Hence, care coordination is vital between individuals and healthcare providers during the transition period to optimize care for PwCF.

Healthcare access, affordability, and quality: In PwCF, the societal economic burden and impact on individuals’ health-related QoL is exorbitant. Quantifying the economic burden in the US population is difficult due to the variety of insurance options available, with many individuals receiving government-based health insurance while others are on private payer plans. In 2021, the total socioeconomic burden of CF in Canada accounted for $414 million (Canadian dollar). ⁴¹ Of these, direct costs (e.g., hospitalization) accounted for two-thirds of the total costs, with medications comprising all direct costs. Out-of-pocket costs to individuals and caregivers amount of 18.7% of all direct costs. Indirect costs representing absenteeism from work accounted for one-third of the total cost. Hassan and co-workers ⁴¹ examined the impact of exacerbation and healthcare cost from a retrospective data of the Medicaid Multi-State administrative claims database (2010–2014; n = 1196 CF patients) aged 6 years and older with 1 year follow-up. Forty-seven percent of the PwCF had inpatient admission, and 27% had subsequent hospitalizations during the follow-up, totaling 29.1 days per year in hospital. Moreover, healthcare expenditures for PwCF exponentially rose for acute exacerbation events with increasing age: (6–11 years, US $ 44,589 and 12–17 years, US $139, 024), to (18–26 years, US$116, 179 and 27–34 years US$ 387, 752). These data are likely reflective of the experience that individuals in other wealthy nations experience and provide evidence of the high-cost burden of CF disease. In addition, children with CF with acute exacerbations in the US were associated with increased emergency care utilization and hospitalization^42–44 and financial burden due to high-deductible insurance plans, on average, about $500.00 per month, ⁴⁵ including transportation expenses to and from the clinic, which are associated with unmet medical needs and heavily affect those with low income. ⁴⁶

A recent case-control study compared 1555 wait-listed to 1555 never wait-listed PwCF undergoing evaluation for lung transplant ⁴⁷ and assessed health status scores for PwCF. In this study, lower health status scores correlated with poorer health, and increased odds of being in wait list increased by 69%. In addition, individuals with higher socioeconomic barriers received a lung transplant about half as often as those with lower scores at the same level of medical severity. ⁴⁷ Similarly, other studies have previously associated ethnic minority status, low educational attainment, low household income, and residing in disadvantaged communities with higher odds of dying without lung transplantation in the US. ⁴⁸ Likewise, CF patients with Medicaid insurance are twice the odds of higher risk of death while in the waiting list for lung transplant compared to Medicare or private care insurance. ⁴⁹

Food insecurity: Thirty to sixty percent of PwCF experience debt, housing issues and food insecurity compared to the general population in the US.^50,51 The reasons for this disparity are multifactorial, including individuals with CF experiencing significantly increased caloric demands compared to individuals without CF, unstable employment, and nutritional status that is closely tied to impaired lung function. For these reasons, food insecurity is a particularly important domain of social need for PwCF. A recent self-reported survey showed that food insecurity was associated with adverse health outcomes, including lower lung function and increased hospitalizations ⁵² and underweight in both children and adults in PwCF. ⁵³ A qualitative interview that explored the impact of food insecurity in seventeen adults with CF and nine parents of children with CF patents identified five inter-related themes ⁵⁴ : (1) Food insecurity among CF patients and their families is onerous, (2) Financial constraints imposed by CF contribute to greater food insecurity, (3) Federal and state programs provide merely limited food assistance, (4) Shame and stigma engulf conversations around food insecurity discussions with CF care teams, and (5) emphasizing honest assessment of food insecurity screening in clinical settings becomes critical. ⁵⁴ These themes highlight the pervasiveness of food insecurity in the lives of PwCF and their families. Thus, it is important to provide adequate guidance and support, with an urgent need to normalize food insecurity screening and expand food assistance programs for PwCF, especially those from low SES groups.

In summary, we have identified health disparities in patients with cystic fibrosis, such as differences in SES, greater healthcare utilization, impaired QoL, food insecurity, poor social functioning, and higher barriers for lung transplant surgery, predominantly affecting more ethnic minorities compared to Whites in PwCF. These disparities were propelled by SDOH that included race/ethnicity, SES, geographical location exposed to atmospheric pollution, low SES, and poorer neighborhood status as shown in Figure 1.

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Figure 1.

The relationship between social determinants of health influence and outcomes for people with cystic fibrosis (PwCF). Factors within the domains of healthcare access, SES, neighborhood and environment, and ethnicity/genetic background play critical roles in shaping health trajectories in PwCF. This figure also demonstrates that these determinants are interconnected, as one disparity often contributes to another in a bidirectional way.