Pioglitazone is a medicine approved for diabetes, and this study checks if it can help people with Pulmonary Hypertension (PH) caused by Chronic Lung Disease (CLD). PH means high blood pressure in the lungs and can make breathing hard. This study will help understand if pioglitazone can help improve energy use in cells. Participants will take either pioglitazone or a placebo (a pill with no medicine) each day for 28 days, have a 2-week break, then switch to the other pill for another 28 days. A placebo helps researchers understand the real effects of the medicine.

• Study Duration: Approximately 2 months, with visits to the clinic for tests.
• Requirements: Participants must fast (no eating) for 6 hours before visits.
• Risks: Possible side effects include allergic reactions or low blood sugar.

Eligibility: Must be over 18, diagnosed with PH due to CLD, and not have diabetes or other excluded conditions. Women must agree to use birth control during and after the study.