Aims: The more stringent CF infection control (IP&C) guidelines introduced in 2013 required procedural adjustments at CF care centers. Similar to other CF care guidelines, such changes may represent a marker for leadership and teamwork. Here, we tested for associations between incidence rates (IR) of P. aeruginosa (PA) and adherence to CF care guidelines.
Methods: Using the CFF patient registry, pediatric and adult programs with >50 unique people with CF (pwCF) and at least 5 patient-years at risk in 2018 were analyzed. Incident PA was defined as a positive culture after at least 2-year PA negativity based on a minimum of 2 cultures/year. A center’s IR was calculated as the number of PA incident cases divided by pwCF years at risk. Variables included: 1) demographic and center related (center location, mean age, gender, race, and insurance) 2) CF-related factors (CFTR mutation, FEV1, BMI) 3) guideline adherence related to general CF care (e.g., seen by nutritionist) and/or more closely infection-related (e.g., culture frequency, inhaled antibiotics). Associations were modeled using weighted least-squares with stepwise selection and main effects without interactions of variables.
Results: The 214 programs (30,036 patients) included 80 adult, 107 pediatric, and 27 affiliate centers. The latter were classified as adults (n=2) and pediatric (n=25) based on average age of the population served. Southwest (SW) region was associated with an increase in PA IR of 0.05 compared to all other regions (p=0.007). A 10% increase in the proportion of pwCF without any F508 mutation was associated with a decrease in IR of 0.018 (p=0.011). A 10% increase in the proportion of pwCF with low BMI defined as below 10%ile was associated with a decrease in IR of 0.054 (p< 0.001). The number of guidelines met (defined as >80% of eligible pwCF being managed per guideline) was higher for Pediatric compared to Adult centers (7.4 (SD 2.0) vs. 4.9 (1.8), p< 0.001). Adherence to care guidelines were negatively associated with PA IR as per the following: A 10% increase in pwCF > 6 years prescribed mucolytics, pwCF and chronic PA being prescribed chronic macrolides, and pwCF having at least one annual nutrition visit were associated with decreases in IR of 0.019 (p=0.017), 0.008 (p=0.005), and 0.015 (p=0.035), respectively. A 10% increase in proportion of pwCF with oral glucose tolerance testing was associated with an increase in PA IR of 0.007 (p=0.018).
Conclusions: We found that CF center location (SW higher IR) was associated with PA IR, but found only weak associations between adherence to CF care guidelines and PA IR. Yet, the associations of both low BMI and annual nutritionist visits with PA incidence may indicate the importance of nutrition in CF.
Acknowledgements: We thank CFF for funding (MUHLEBAC19A0).
