Please assess the completion status of the following clinical trial:

Trial Title: Prevention of Cystic Fibrosis Diabetes

Study Design Characteristics:
- Allocation: RANDOMIZED
- Intervention Model: PARALLEL
- Observational Model: None
- Primary Purpose: PREVENTION
- Time Perspective: None
- Masking: TRIPLE
- Phase: PHASE3
- Number of Arms: 2.0

Eligibility Criteria:
Inclusion Criteria:~* Aged 13 years of age or older at the time of enrollment~* Diagnosis of cystic fibrosis (CF) confirmed by pilocarpine iontophoresis sweat chloride measurements and/or genotyping~* Clinically stable with no lower respiratory tract exacerbation requiring intravenous antibiotics in the three weeks prior to enrollment~* On a stable clinical treatment regimen for at least three weeks prior to enrollment~* Male or female. If female, is not lactating and has a negative pregnancy test at screening. If female of child bearing potential, willing to practice effective birth control (i.e. a method known to decrease the risk of pregnancy to less than 1%)~* Able to understand and provide informed consent~* Willing and able to comply with the study schedule and testing~* High risk prediabetes as defined by high-risk impaired fasting glucose levels of 110-125 mg/dl and/or a 2-hour plasma glucose level of 140 to 199 mg/dl found on an Oral Glucose Tolerance Test performed at screening 8 weeks or less before enrollment~* Available by telephone~* Has literacy and language skills required to fill out study material~Exclusion Criteria:~* Diagnosed with CF related diabetes~* Chronic heart failure with New York Heart Association (NYHA) class III/IV, ejection fraction less than 25%, or receiving digoxin~* Liver disease as defined by alanine aminotransferase (ALT) or aspartate aminotransferase (AST) three times above the upper limit of normal.~* Serum creatinine greater than 1.3 mg/dl for males and greater than 1.1 mg/dl for females or receiving chronic dialysis~* Taking chronic oral or intravenous glucocorticosteroids during the past month~* On insulin therapy during the past month~* CF lung disease severe enough to require daytime chronic oxygen therapy via nasal cannula during the past month~* Unable to perform pulmonary function testing~* History of any illness or condition that, in the opinion of the sponsor might confound the results of the study or pose an additional risk in administering study drug to the subject~* Post lung or liver transplant~* Listed and awaiting organ transplant~* Current drug or alcohol dependency~* Participating in another clinical drug trial or past participant within 30 days of enrollment~* Pancreatic sufficient~* History of acute pancreatitis as documented by characteristic clinical manifestations and elevation of serum amylase and lipase within the last 2 years.

- Gender: ALL
- Minimum Age: 13 Years
- Maximum Age: None
- Healthy Volunteers: f

Study Arms:
- Sitagliptin (Type: EXPERIMENTAL): CF patients receiving Sitagliptin.~Intervention: Dose is 100 mg taken orally once a day in the morning with breakfast. Duration is one year or until converted to CF diabetes, whichever comes sooner.
- Sugar pill (Type: PLACEBO_COMPARATOR): CF patients receiving placebo.~Intervention: Placebo is taken orally once a day in the morning with breakfast. Duration is one year or until converted to CF diabetes, whichever comes sooner.

Based on this trial design, predict the completion outcome and termination type (if applicable).