Predictive factors of carcinoid syndrome among patients with gastrointestinal neuroendocrine tumors (GI NETs).

Abstract

e15690 Background: Carcinoid syndrome (CS) is associated with a significant symptom burden and deleterious impacts on quality of life. Patients may experience delays in CS diagnosis of 5 to 7 years from initial onset of symptoms, as symptoms may be mistaken for other diseases, such as irritable bowel syndrome or menopause. The current study attempts to detect factors predictive of CS prior to CS diagnosis among patients with GI NETs. Methods: Using a US administrative claims database (IMS PharMetrics) and a retrospective case-control study design, patients (≥18 years) who were newly diagnosed with GI NETs without CS (controls) were exactly matched to patients with CS (cases) based on NET diagnosis date (month and year) at a 3-to-1 ratio. For CS patients, the study index date was the first CS diagnosis date. Each control patient was assigned to have the same index month and year as the matched case patient. The most frequently observed conditions other than symptoms/diagnoses known to be associated with CS during the 1 year prior to the index date were assessed. These conditions were entered into a forward-stepwise logistic regression model to derive predictive factors. Similar methods were applied to another administrative claims database (Truven Health Analytics MarketScan) to validate these predictors. Results: In the development database 1,004 patients with GI NETs were identified, among whom 251 (25%) had CS and 753 (75%) were controls. In both databases, three factors prior to CS diagnosis were found consistently associated with higher risks for CS, including liver disorder [odds ratio (95% CI): 3.38 (2.07 - 5.51)], enlargement of lymph nodes [2.13 (1.10 - 4.11)], and abdominal mass [3.79 (1.87 - 7.69)]. Conclusions: By assessing patients with GI NET from two independent US claim databases, this study suggested that patients diagnosed with CS were 2-3 times more likely to be diagnosed with liver disorder, enlargement of lymph nodes, or abdominal mass, than those without CS during the one year prior to CS diagnosis. Future studies using patients’ medical charts are warranted to validate and interpret the findings. These findings, when validated, may aid physicians to diagnose CS patients earlier.