INTRODUCTION
People with CF (pwCF) have frequent gastrointestinal (GI) symptoms, including abdominal pain and irregular bowel movements,1-3 which might contribute to significant morbidity and mortality.4 The majority of pwCF suffer from pancreatic insufficiency, leading to fat malabsorption, malnutrition and abdominal discomfort when not appropriately treated.5 Modulator therapy has been shown to improve lung function and body weight in pwCF, however, the impact of these modulators on GI symptoms is ambiguous and relatively unknown.6-8
Since GI symptoms are embarrassing, they are challenging to assess and often not reported to CF care team members. Therefore, there is little systematic data on the mechanisms underlying the development of GI symptoms in this population.1,9 Several pathophysiological mechanisms have been proposed, including malabsorption, altered GI-motility, psychological factors, diet and microbial dysbiosis.4,10 The presence of GI symptoms has been associated with neurophysiological and behavioral symptoms,11 such as anxiety/depression and health-related quality of life (HRQoL).12 It is well-established that pwCF are at increased risk for developing symptoms of anxiety/depression with negative consequences for CF disease management, health outcomes, adherence to treatment and HRQol.13-16 Biological factors, such as inflammation, pain, and sleep disturbance have an effect on pwCF. This can be explained by the gut-brain axis theory, describing the bidirectional linkage between the nervous system and the GI tract. The gut-brain axis links emotional and cognitive centers with the peripheral intestinal functions.17 More studies are needed to examine the potential links between GI symptoms, psychological symptoms, and HRQoL in pwCF.18
Given that GI symptoms may be embarrassing to report, difficult to assess, and often accompanied by substantial pain and disruptions of daily activities,19-24 a standardized instrument to measure these symptoms in pwCF, the GI Symptom Tracker, was developed by Dr. Quittner in collaboration with AbbVie Inc. (2017). This questionnaire consists of four subscales: Eating Challenges (4 items), Stools (8 items), Adherence Challenges (5 items), and Abdominal Symptoms (7 items). It has been developed to facilitate a standardized method of assessing the frequency and impact of GI symptoms, to improve communication between patient and provider, to open a dialogue about strategies to reduce GI symptoms, improve medication adherence, and maintain increased calorie intake, all with the goal of improving patients’ health outcomes. It was developed and validated in 11 CF centers in the US (n=179), demonstrating good reliability and validity.1 The Dutch translation was recently completed.20
The aim of this study was to investigate the relationship between GI symptoms, as measured by the Dutch GI Symptom Tracker, anxiety/depression and HRQoL in Dutch pwCF. We hypothesized that GI symptoms would be associated with elevated levels of anxiety and depression and worse HRQoL.