Elevated rates and earlier onset of non-pulmonary comorbidities in adults with cystic fibrosis: a population-based study

Introduction — People with cystic fibrosis (pwCF) are living longer with increasing comorbidities. The objective of this study was to estimate the rate of emerging non-pulmonary comorbidities in adults with CF and to compare these rates with the non-CF population.

Methods — This is a population-based cohort study of adults using Canadian CF Registry data linked with health administrative databases in Ontario, Canada. Cardiovascular disease (CVD) and symptomatic kidney stone cases were identified using diagnostic and procedural codes. Chronic kidney disease (CKD) was defined as eGFR<60 mL/min/1.73m2. Cancer cases were obtained using the Ontario Cancer Registry. Poisson regression was used to estimate the rates per 1,000 person-years of follow-up.

Results — The age- and sex-adjusted rates of CVD, CKD, kidney stones, and cancer per 1,000 person years in the non-lung transplant cohort were 24.5 (95% CI 21.5-28.0), 3.7 (95% CI 2.7-5.2), 7.4 (95% CI 6.1-9.0), and 5.8 (95% CI 4.5-7.6) respectively. pwCF who received lung transplant had higher rates of all four conditions, and cancer and CKD occurred earlier compared to the non-transplant cohort. When comparing the CF to the non-CF population, pwCF without lung transplant had higher age- and sex-adjusted rates of CVD (RR 2.9, 95% CI 2.6-3.4), CKD (RR 2.1, 95% CI 1.5-2.9), kidney stones (RR 2.9, 95% CI 2.4-3.6) and cancer (RR 1.9, 95% CI 1.5-2.5). These events occurred at a median age of at least 20 years earlier in the CF cohort. In the post-transplant population, the rates of CVD, kidney stones, and cancers were similar between pwCF and the non-CF population, however events occurred earlier in pwCF.

Conclusion — Non-pulmonary complications occur at a high rate and at a younger age in pwCF compared to the non-CF population which highlights the importance of incorporating these issues in CF care models.