(13) A North American Provider Survey of Cystic Fibrosis Related Diabetes Screening Practices

Background: Cystic Fibrosis Related Diabetes (CFRD) is highly prevalent in approximately 15% of teens and 50% of adults with cystic fibrosis (CF). CFRD is associated with declining pulmonary function, increased pulmonary exacerbations, worsened nutritional status, and increased risk of mortality; however its onset is often insidious. Guidelines recommend 2-hour oral glucose tolerance testing (OGTT) annually for people with CF ≥10 years of age, however Cystic Fibrosis Foundation (CFF) patient registry data have demonstrated consistently low OGTT screening rates (< 30% of adults and < 60% of youth nationally). Our aims were to conduct a survey of 1) CF center directors in the US and 2) Endocrinologists affiliated with the EnVision program in order to 1) characterize CFRD screening practices, 2) better understand provider perceived barriers to screening, and 3) identify potential strategies for improving CFRD screening.

Methods: Two REDCap surveys were developed consisting of 23 questions pertaining to CFRD screening practices. Questions were asked regarding CF center practice settings and population demographics, details surrounding how OGTTs were performed, the use of alternate diabetes screening strategies, and perceived barriers. The Endocrinologist survey included additional questions regarding interpretation and practice management based on results of OGTT and other measures of glycemia. The link to Survey #1 was sent out via listserv to CF Center Directors, who could designate an alternate individual at their discretion. The link to Survey #2 was sent out via group email distribution to mentors and mentees within EnVision I and II, a CFF program to foster Endocrinologists in the care of CF related endocrinopathies. Survey responses were summarized using means and standard deviations or medians and first and third quartiles for continuous variables and frequencies with percentages for categorical variables. Practices were compared using t-test or chi-squared tests depending on the distribution of variables. Data was summarized and analyzed in R.

Results: The survey response rate for CF Centers was 20.3% (59/290). Survey response rate for Endocrinologists was 62.5% (25/40). In regards to OGTT time points, 57% of CF centers surveyed obtain 0 and 120 min glucoses, 38% obtain 0, 60, and 120 min glucoses, and 4% obtain additional glucose values. Of the Endocrinologists surveyed, 20% obtain 0 and 120 min glucoses, 72% obtain 0, 60, and 120 min, and 8% obtain additional glucose values. Forty-nine percent of the CF centers reported >50% OGTT completion in the past year. Centers that always or almost always provide reminders to patients are about 5 times more likely to have OGTT completion rates >50% (p = 0.017). Both CF Centers and Endocrinologists reported utilizing alternative strategies to evaluate for diabetes such as HbA1c (23%, 28.6%), fasting plasma glucose (17.7%, 20.8%), CGM (10.8%, 18.2%), and fingerstick monitoring (20%, 15.6%), respectively.

Conclusions: Although OGTT is considered the gold standard screening method for CFRD, practice variation exists, completion rates remain suboptimal, and many providers are utilizing alternate glycemia screening methods. Having a reminder system for scheduling OGTTs may improve completion rates. Studies to improve our approach to CFRD screening are urgently needed.

Acknowledgements: This work was supported by the Cystic Fibrosis Foundation [grant numbers HICKS19GE0, MORAN19GE3] and STATNET [grant number ZEMANI20Y7].

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