Cystic Fibrosis Care Gaps of 1 Year or More Linked to Decreased Lung Function

Discontinuous care in patients with cystic fibrosis (CF) is associated with reduced lung function, even after controlling for other factors associated with pulmonary compromise, according to a study in Annals of the American Thoracic Society.

Investigators sought to determine whether missed care resulted in reduced lung function among those with CR, using data from the US Cystic Fibrosis Foundation Patient Registry (CFFPR) from 2004 to 2016. Study participants were at least 6 years of age, had at least 3 years pulmonary function test data available, and had not undergone transplant.

The investigators categorized each patient encounter based on whether if followed a period of continuous vs discontinuous care. Discontinuous care was defined as the absence of data regarding patient encounters for a span at least 12 months in the primary analysis (with a variation in that gap used for the sensitivity analysis). Continuous care was defined as the absence of 12-month gaps in CFFPR data.

Lung function, the outcome of interest, was calculated based on measures of forced expiratory volume in 1 second percent predicted (FEV1PP) taken during each encounter. Categorical variables included sex, genotype, race, ethnicity, underweight status (based on body mass index), insurance type, CF-related diabetes, and chronic infection status.

A total of 24,328 patients with CF who had 1,082,899 separate encounters were included in the main longitudinal parametric model. Of this group, CF registry data indicated that 8413 individuals (43% female) had at least a single gap in care of at least 12 months and 15,915 individuals (51% female) had continuous care. The participants with continuous care were more likely to be female, White, and underweight, and to have CF-related diabetes or chronic methicillin-resistant Staphylococcus aureus infection.

Discontinuous care increased with age, occurring most frequently in adults. CR registry data showed that 6% to 9% of those aged 6 to 17 years had documented care discontinuity, which increased to 15% in those aged 18 to 21 years and to 30% in those aged older than 30 years of age. Notably, 75.8% of all encounters preceded by a 12-month gap occurred in patients at least 18 years of age.

Patients with CF who had a preceding period of discontinuous care generally had a decreased FEV1PP at their index visit vs those who had continuous care (model 1: absolute difference -0.81%; 95% CI, -1.00 to -0.61; P <.001). In model 2, the effect modification by age was minimal in preadolescents and adults older than 30 years of age but more pronounced in adolescence and early adulthood, where a clinically meaningful difference in FEV1PP was evident at the first appointment after a prolonged care gap. A peak difference of 1.5% (95% CI, -1.0 to -2.1) was found in FEV1PP between 18-year-olds with and without discontinuous care.

In analysis of the interactions of the CFTR genotype and age with the relationship between lung function and care continuity, the previously observed differences in lung function between continuous and discontinuous care in adolescence and early adulthood were greater in F508del homozygotes vs heterozygotes. At age 10, a significant decrease was observed in FEV1PP associated with discontinuous care of -1.7% (95% CI, -0.9 to -2.4). In young adulthood, the magnitude of this difference was much greater (-2.1%; 95% CI, -1.5 to -2.7).

In the sensitivity analysis, a 6-month gap in care was associated with -0.21 FEV1PP (95% CI, -0.31 to -0.11; P <.001), a 12-month gap was associated with -0.81 FEV1PP (95% CI, -0.61 to -1.00; P <.001), and an 18-month gap was associated with -1.17 FEV1PP (95% CI, -0.88 to -1.47; P <.001).

Study limitations include the use of data through 2016, which do not reflect use of treatments more recently approved by the FDA or the growing use of telehealth resulting from the COVID-19 pandemic; the assumption that a lack of CFFPR data was equivalent to a lack of care; and the lack of consideration of prescription refill data. 

“[E]mphasis on continued access of patients with CF to specialists with CF expertise is critically important, particularly as patients with CF enter late adolescence and early adulthood,” said study authors. “Our findings are provocative in the context of rising health care costs and increasing use of remote approaches to health maintenance,” the researchers added.