Background: Older adults with chronic obstructive pulmonary disease (COPD) and multiple cardiometabolic disorders may exhibit overlapping inflammatory and vascular abnormalities. Evidence regarding intravenous oxyhydrogen nanobubble (NB-HHO) formulations remains limited. Case presentation: A 78-year-old man with COPD, coronary artery disease, hypertension, type 2 diabetes mellitus, and ankylosing spondylitis received 15 adjunctive NB-HHO infusion sessions between 6 October and 19 November 2025, using the documented stepwise dose-titration protocol. Clinical observations: From baseline to the end of the treatment period, C-reactive protein changed from 5.2 to 2.2 mg/L, blood pressure from 172/97 to 146/71 mmHg, estimated glomerular filtration rate from 80 to 89 mL/min/1.73 m², total cholesterol from 333 to 297 mg/dL, LDL cholesterol from 201 to 170 mg/dL, and COPD Assessment Test score from 23 to 20. The patient also reported less productive cough and greater energy. Conclusion: These temporal changes are descriptive and hypothesis-generating. A single uncontrolled case with concurrent clinical management and incomplete formulation and safety information cannot establish efficacy, causality, or long-term safety.