Please assess the completion status of the following clinical trial:

Trial Title: Environment Effect on Six-Minute Walk Test Performance

Study Design Characteristics:
- Allocation: RANDOMIZED
- Intervention Model: CROSSOVER
- Observational Model: None
- Primary Purpose: DIAGNOSTIC
- Time Perspective: None
- Masking: NONE
- Phase: None
- Number of Arms: 4.0

Eligibility Criteria:
Inclusion Criteria:~1. Age above 18 years.~2. Have a diagnosis of congenital Alpha-1 Antitrypsin Deficiency with an allelic combination of ZZ.~3. Have a Forced Expiratory Volume in 1 second (FEV1)\< 50% of predicted and FEV1/forced vital capacity (FVC) \< 70% (Global Initiative for Chronic Obstructive Lung Disease \[GOLD\] stage II, III, or IV).~4. Not currently prescribed Oxygen replacement at a rate of greater than 2 liters.~5. Willing and able to perform two six-minute walk tests.~6. Willing and able to provide written informed consent.~Exclusion Criteria:~1. Subject has had a moderate or severe pulmonary exacerbation during the 4 weeks before the study visit.~2. History of lung transplant.~3. Severe concomitant disease (e.g., congestive heart failure, clinically significant pulmonary fibrosis, malignant disease \[with the exception of skin cancers other than melanoma\], history of acute hypersensitivity pneumonitis reaction, or current chronic hypersensitivity pneumonitis).~4. Unwilling or unable to perform six-minute walk testing.~5. Mentally challenged adult subjects who cannot give independent informed consent.~6. In the opinion of the investigator the subject may have compliance problems with the protocol and the procedures of the protocol.~7. American Thoracic Society listed absolute contraindications to six-minute walk test: unstable angina or myocardial infarction during previous month.

- Gender: ALL
- Minimum Age: 18 Years
- Maximum Age: None
- Healthy Volunteers: f

Study Arms:
- six-minute walk study indoors first (Type: ACTIVE_COMPARATOR): Participants randomized to indoor six-minute walk test first
- six-minute walk study outdoors first (Type: EXPERIMENTAL): Participants randomized to outdoor six-minute walk test first
- six-minute walk study indoors second (Type: ACTIVE_COMPARATOR): Participants randomized to indoor six-minute walk test second
- six-minute walk study outdoors second (Type: EXPERIMENTAL): Participants randomized to outdoor six-minute walk test second

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