What is the most likely diagnosis for a patient with a decreased FEV1/FVC ratio showing obstructive lung disease?

In the scenario described, the patient presents with a decreased FEV1/FVC ratio, which is indicative of obstructive lung disease. Chronic obstructive pulmonary disease (COPD) is characterized by such a pattern. In obstructive lung diseases, airflow limitation is typically observed, leading to a reduced FEV1 (forced expiratory volume in one second) relative to the FVC (forced vital capacity), resulting in the decreased FEV1/FVC ratio.

COPD encompasses conditions such as emphysema and chronic bronchitis, which are caused by factors like chronic inhalation of noxious particles or gases, often from smoking. These conditions lead to inflammation, narrowing of the airways, and destruction of lung tissue, all contributing to obstructed airflow.

In summary, the diagnosis of chronic obstructive pulmonary disease aligns perfectly with the observed spirometric changes and the description of obstructive lung disease. The emphasis on decreased FEV1/FVC clearly points toward this condition.